TW201524930A - Method for manufacturing optical glass, optical elements, and glass mold materials - Google Patents

Abstract

The present invention provides a method for manufacturing optical glass, optical elements, and glass mold materials having the expected high stability and high dispersion (low abbe number). The optical glass of the present invention, relative to the oxide conversion composition of the total glass mass, contains, in terms of mole%, more than 20% but less than 45% of P2O5, more than 15% but less than 60% of Nb2O5, and more than 3% but less than 50% of ZnO and MgO in total, the refractive index is above 1.75, and the abbe number is bigger than 10 but smaller than 35. Preferably, the optical glass contains, in terms of mole%, more than 0.1% but less than 20% in total of one or two ingredients selected from SiO2, Al2O3, and B2O3.

Description

Optical glass, optical element, and method of manufacturing glass molded body

The present invention relates to an optical glass, an optical element, and a method of producing a glass molded body.

In recent years, the digitization and high-definition of the optical system are rapidly advanced, and the optical components such as lenses used in various optical devices such as digital cameras and video cameras are highly accurate and lightweight. The requirements for miniaturization have become stronger.

Among the optical glasses for producing optical elements, in particular, there is a demand for a high refractive index glass having a high refractive index (n _d ) and a low Abbe number (ν _d ) which can reduce the weight and size of the optical element. high. For example, the optical glass described in Patent Document 1 has an Abbe number of 21 or more and less than 31, and the optical glass described in Patent Document 2 has an Abbe number of 22 or more and less than 25. Further, the optical glass described in Patent Document 11 has an Abbe number of 17 or more and less than 24, and the optical glass described in Patent Document 12 has an Abbe number of 17 or more and less than 27.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 8-157231

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-58845

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2003-238197

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2003-321245

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2003-335549

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2005-154248

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2009-143801

[Patent Document 8] Japanese Patent Laid-Open Publication No. 2010-83701

[Patent Document 9] Japanese Patent Laid-Open Publication No. 2011-57509

[Patent Document 10] Chinese Patent Publication No. 101134641

[Patent Document 11] Japanese Patent Laid-Open Publication No. 2004-83344

[Patent Document 12] Japanese Patent Laid-Open Publication No. 2009-209018

However, the optical glass described in Patent Document 1 to Patent Document 12 has a low Abbe number, but it is difficult to say that the optical glass has high stability and devitrification occurs.

Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide an optical glass, an optical element, and a method for producing a glass molded body having desired high stability and high dispersion (low Abbe number).

In order to solve the above problems, the inventors of the present invention have repeatedly tried hard to conduct experimental research, and as a result, it has been found that stability can be improved by keeping a specific amount of a P ₂ O ₅ component, a Nb ₂ O ₅ component, a ZnO component, and a MgO component in a specific balance. The dispersion is increased to complete the present invention. Specifically, as a first aspect of the present invention, the following (1) to (7) are provided.

(1) An optical glass containing 20% or more and 45% or less of P ₂ O ₅ component, 15% or more and 60% or less of Nb _{2 in} terms of mol% of the glass composition of the oxide conversion composition. The O ₅ component and the ZnO component and the MgO component in a total amount of 3% or more and 50% or less have a refractive index of 1.75 or more and an Abbe number of 10 or more and 35 or less.

(2) The optical glass of (1), which contains 0.1% or more and 20% or less of SiO ₂ component, Al ₂ O ₃ and B _{2 in} terms of mol% of the total glass mass of the composition of the oxide. One or two components of the O ₃ component.

(3) The optical glass according to (1) or (2), which contains 0% or more and 40% or less of TiO ₂ component based on the total mass of the glass of the oxide conversion composition.

(4) The optical glass according to any one of (1) to (3), which contains 0% or more and 25% or less of R ₂ O in terms of the total mass of the glass in terms of oxide conversion composition. In addition, R ₂ O/(ZnO+MgO) is 2.0 or less, and R is one or more selected from the group consisting of Li, Na, and K.

(5) The optical glass according to any one of (1) to (4), which contains 0% or more and 25% or less of MO component in terms of the total mass of the glass of the oxide conversion composition, and MO/(ZnO+MgO) is 0.5 or less. Here, M is one or more selected from the group consisting of Ca, Sr, and Ba.

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

(7) A method for producing a glass molded body, which uses the optical glass according to any one of (1) to (6), and press-forms the softened optical glass in a mold.

Moreover, the inventors have found that a specific amount of the P ₂ O ₅ component, the TiO ₂ component, the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component are contained in a specific balance, and can be contained. The present invention is completed by improving stability and increasing dispersion. Specifically, as a second aspect of the present invention, the following (8) to (18) are provided.

(8) An optical glass containing 20% or more and 45% or less of P ₂ O ₅ component, 30% or more and 65% or less of TiO _{2 in} terms of mol% of the glass composition of the oxide conversion composition. The component and the total of SiO ₂ component, GeO ₂ component, Al ₂ O ₃ component, Ga ₂ O ₃ and B ₂ O ₃ component of 0.5% or more and 30% or less, or a refractive index of 1.75. As described above, the Abbe number is 10 or more and 35 or less.

(9) The optical glass of (8), which contains a total of 0% or more and 40% or less of the R ₂ O component and the MO component in terms of the total mass of the glass in terms of the oxide conversion composition, here, R is one or more selected from the group consisting of Li, Na, and K, and M is one or more selected from the group consisting of Ca, Sr, and Ba.

(10) The optical glass of (8) or (9), which contains 3% or more and 35% or less of the ZnO component and the MgO component in terms of the total mass of the glass in terms of the oxide conversion composition.

(11) The optical glass according to any one of (8) to (10), which contains 0% or more and 50% or less of Nb ₂ O ₅ based on the total mass of the glass of the oxide conversion composition. ingredient.

(12) The optical glass according to any one of (8) to (11), which contains a total of 0% or more and 10% or less of SnO _{2 in terms of the} total mass of the glass in terms of oxide conversion composition. With Sb ₂ O ₃ ingredients.

(13) The optical glass according to any one of (8) to (12) which contains more than 0% of SiO ₂ component in mol% with respect to the total mass of the glass of the oxide conversion composition.

(14) The optical glass according to any one of (8) to (13), which contains more than 0% of the Al ₂ O ₃ component in mol% with respect to the total mass of the glass of the oxide-converted composition.

(15) The optical glass according to any one of (8) to (14) which contains a TiO ₂ component of less than 60% by mol% with respect to the total mass of the glass of the oxide conversion composition.

(16) The optical glass according to (8), which contains not less than 6% of the B ₂ O ₃ component in terms of mol% of the total glass mass of the oxide-converted composition.

(17) An optical element comprising the optical glass of any one of (8) to (16).

(18) A method for producing a glass molded body, which uses the optical glass according to any one of (8) to (17), and press-forms the softened optical glass in a mold.

According to a first aspect of the present invention, there is provided a method for producing an optical glass, an optical element, and a glass molded body, wherein the optical glass has a specific amount of a P ₂ O ₅ component, a Nb ₂ O ₅ component, a ZnO component, and a MgO. The ingredients are contained in a specific balance and have the desired high stability and high dispersion.

According to a second aspect of the present invention, there is provided a method of producing an optical glass, an optical element, and a glass molded body by using a specific amount of a P ₂ O ₅ component, a TiO ₂ component, a SiO ₂ component, and GeO ₂ The component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component are contained in a specific balance, and have desired high stability and high dispersion.

Fig. 1 is a graph showing the transmittance characteristics of the optical glass of Example 1.

Hereinafter, the embodiment of the optical glass of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and may be appropriately modified and implemented within the scope of the object of the present invention. In addition, in the case where the description is repeated, the description is omitted as appropriate, but the gist of the invention is not limited.

The first and second aspects of the present invention will be described.

First, the optical glass of the first aspect of the present invention contains 20% or more and 45% or less of P ₂ O ₅ component, 15% or more and 60% by mol% of the total glass mass of the oxide-converted composition. The Nb ₂ O ₅ component and the ZnO component and the MgO component of 5% or more and 50% or less in total have a refractive index of 1.75 or more and an Abbe number of 10 or more and 35 or less. By including a specific amount of the P ₂ O ₅ component, the Nb ₂ O ₅ component, and the TiO ₂ component in the optical glass, it is possible to suppress a decrease in the transmittance of visible light and to improve dispersion. Further, by reducing the Sb ₂ O ₃ component contained in the optical glass, it is possible to reduce the influence on the environment and reduce the unevenness and stain on the surface of the glass. Therefore, it is possible to provide an optical glass, an optical element, and a method for producing a glass molded body having a desired high transmittance and high dispersion and which can reduce irregularities and stains on the surface.

Next, the optical glass of the second aspect of the present invention contains 20% or more and 45% or less of P ₂ O ₅ component, 30% or more and 65% by mol% based on the total mass of the glass of the oxide conversion composition. The following TiO ₂ component and a total of 0.5% or more and 30% or less of the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component have a refractive index of 1.75. As described above, the Abbe number is 10 or more and 35 or less. By including a specific amount of the P ₂ O ₅ component, the TiO ₂ component, the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component in the optical glass, the devitrification resistance can be improved and the dispersion can be improved.

[Glass composition]

The composition range of each component constituting the optical glass of the first aspect and the second aspect of the present invention will be described below. In the present specification, the content of each component is expressed by the % of the total mass of the glass in terms of the composition of the oxide, unless otherwise specified. Here, the "oxide-converting composition" is determined by the fact that the oxide, the composite salt, and the metal fluoride which are used as the raw material of the glass constituent component of the first aspect of the present invention are all decomposed and changed into an oxide. In this case, the total mass of the produced oxide is set to 100 mol%, and the composition of each component contained in the glass is shown.

<About essential ingredients, optional ingredients>

Next, the essential components and optional components of the glass of the optical glass of the first aspect and the second aspect of the present invention will be preferably used.

In the following description, the effect of the upper limit or the lower limit of the content ratio of each component and the raw material of each component are as follows, and the content ratio and effect of the optical glass of the first aspect and the second aspect are not particularly described. The raw materials are the same. Further, the content ratio is a content ratio of the total mass of the glass with respect to the oxide-converted composition.

The P ₂ O ₅ component is a glass forming component and is an essential component for lowering the melting temperature of the glass. In particular, when the content of the P ₂ O ₅ component is 20% or more, the devitrification resistance is improved, and a glass having high stability can be easily obtained. On the other hand, by setting the content ratio of the P ₂ O ₅ component to 45% or less, a high refractive index can be obtained. Therefore, the content of the P ₂ O ₅ component is preferably 20%, more preferably 22%, still more preferably 24%, most preferably 25%, preferably 45%, more preferably It is 40%, more preferably 38%, further preferably 35%, and most preferably 32%.

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

The Nb ₂ O ₅ component is an essential component for increasing the refractive index and dispersion of the glass. In the first aspect, by setting the content ratio of the Nb ₂ O ₅ component to 15% or more, a high refractive index can be obtained, and a desired high dispersion can be obtained. On the other hand, by setting the content ratio of the Nb ₂ O ₅ component to 60% or less, the devitrification resistance can be improved by improving the stability of the glass. Therefore, the content of the Nb ₂ O ₅ component is preferably 15%, more preferably 20%, most preferably 23% as the lower limit, preferably 60%, more preferably 50%, most preferably Take 40% as the upper limit. The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ or the like as a raw material.

In the case of the optical glass of the second aspect, the content of the Nb ₂ O ₅ component is preferably 0%, more preferably 2%, most preferably 4%, and preferably 50%. More preferably, it is 40%, and the best is 30%.

Since the SiO ₂ component has an effect of improving the meltability, stability, and chemical durability of the glass, it is a component which can be arbitrarily added. Regarding the content thereof, in particular, by making the content of the SiO ₂ component more than 0%, the devitrification resistance of the glass can be improved. On the other hand, by containing the component ratio of SiO ₂ to 15% or less of SiO ₂ can be suppressed to reduce the stability of the resulting composition is easily obtained a high refractive index. Therefore, the content of the SiO ₂ component is preferably 15%, more preferably 12%, and most preferably 10%. The SiO ₂ component can be contained in the glass using, for example, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

Since the GeO ₂ component has the same function as the above SiO ₂ component, it is a component which can be arbitrarily added. By setting the content of the GeO ₂ component to 15% or less, the material cost can be reduced. Therefore, the content of the GeO ₂ component is preferably 15%, more preferably 10%, still more preferably 5%, most preferably 1%. The GeO ₂ component can be contained in the glass using, for example, GeO ₂ or the like as a raw material.

Since the Al ₂ O ₃ component has an effect of improving the meltability, stability, and chemical durability of the glass, it can be arbitrarily added. In particular, by setting the content of the Al ₂ O ₃ component to 15% or less, the meltability of the glass can be improved, and the devitrification tendency of the glass can be weakened. Therefore, the content of the Al ₂ O ₃ component is preferably more than 0%, and preferably 15%, more preferably 10%, most preferably 8%. The Al ₂ O ₃ component can be contained in the glass using, for example, Al ₂ O ₃ , Al(OH) ₃ , AlF ₃ or the like as a raw material.

Since the Ga ₂ O ₃ component has the same function as the above-mentioned Al ₂ O ₃ component, it is a component which can be arbitrarily added. By setting the content of the Ga ₂ O ₃ component to 10% or less, the devitrification resistance of the glass can be improved, and the material cost can be reduced. Therefore, the content of the Ga ₂ O ₃ component is preferably 10%, more preferably 8%, and most preferably 5%. The Ga ₂ O ₃ component can be contained in the glass using, for example, Ga ₂ O ₃ or GaF ₃ as a raw material.

The B ₂ O ₃ component is a component which improves the meltability and devitrification resistance of the glass, and is an optional component in the glass. In the first aspect, by setting the content of the B ₂ O ₃ component to less than 10%, it is possible to suppress a decrease in glass stability due to the B ₂ O ₃ component. Therefore, the content of the B ₂ O ₃ component is preferably set to less than 10%, more preferably 5%, and most preferably 1% as the upper limit. As the B ₂ O ₃ component, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ can be used. 10H ₂ O, BPO ₄ and the like are contained in the glass as a raw material.

In the case of the optical glass of the second aspect, the content of the B ₂ O ₃ component is preferably set to less than 6%, more preferably 3%, most preferably 1%.

The ZnO component is an optional component which lowers the liquidus temperature of the glass and increases the resistance to devitrification of the glass, and is a component which is difficult to reduce the transmittance to visible light and is an optional component in the glass. In the first aspect, by setting the content of the ZnO component to 50% or less, high refractive index and high dispersion can be easily obtained. Therefore, the content of the ZnO component is preferably 50%, more preferably 45%, and most preferably 40%. The ZnO component can be contained in the glass using, for example, ZnO, ZnF ₂ or the like as a raw material.

In the case of the optical glass of the second aspect, the content of the ZnO component is preferably 35%, more preferably 25%, and most preferably 15%.

The MgO component is an optional component which lowers the liquidus temperature of the glass and increases the resistance to devitrification of the glass, and is a component which is difficult to reduce the transmittance to visible light and is an optional component in the glass. In the first aspect, by setting the content of the MgO component to 50% or less, high refractive index and high dispersion can be easily obtained. Therefore, the content of the MgO component is preferably 50%, more preferably 45%, and most preferably 40%. The MgO component can be contained in the glass using, for example, MgCO ₃ or MgF ₂ as a raw material.

In the case of the optical glass of the second aspect, the content of the MgO component is preferably 35%, more preferably 25%, and most preferably 15%.

The CaO component is an optional component which lowers the liquidus temperature of the glass and increases the resistance to devitrification of the glass, and is a component which is difficult to reduce the transmittance to visible light and is an optional component in the glass. In the first aspect, when the content ratio of the CaO component is 25% or less, high refractive index and high dispersion can be easily obtained, and deterioration of devitrification resistance and chemical durability of the glass can be suppressed. Therefore, the content of the CaO component is preferably 25%, more preferably 20%, and most preferably 15%. The CaO component can be contained in the glass using, for example, CaCO ₃ or CaF ₂ as a raw material.

In the case of the optical glass of the second aspect, the content of the CaO component is preferably 15%, more preferably 10%, and most preferably 5.0%. The CaO component can be contained in the glass using, for example, CaCO ₃ or CaF ₂ as a raw material.

The SrO component is an optional component which lowers the liquidus temperature of the glass and increases the resistance to devitrification of the glass, and is an arbitrary component in the glass. In the first aspect, when the content ratio of the SrO component is 25% or less, high refractive index and high dispersion can be easily obtained, and deterioration of devitrification resistance and chemical durability of the glass can be suppressed. Therefore, the content of the SrO component is preferably 25%, more preferably 20%, and most preferably 15%. The SrO component can be contained in the glass using, for example, Sr(NO ₃ ) ₂ or SrF ₂ as a raw material.

In the case of the optical glass of the second aspect, the content of the SrO component is preferably 10%, more preferably 8%, and most preferably 5%.

The BaO component is an optional component which increases the refractive index of the glass and improves the resistance to devitrification of the glass, and is a component which is difficult to reduce the transmittance to visible light and is an optional component in the glass. In particular, by setting the content of the BaO component to 25% or less, high refractive index and high dispersion can be easily obtained, and deterioration in devitrification resistance and chemical durability can be suppressed. Therefore, the content of the BaO component is preferably 25%, more preferably 20%, more preferably 16%, and most preferably 15%. Here, in particular, in terms of obtaining a glass having a large dispersion (the Abbe number is small), the content of the BaO component is preferably 12% or less. The BaO component can be contained in the glass using, for example, BaCO ₃ , Ba(NO ₃ ) ₂ , BaF ₂ or the like as a raw material.

The Li ₂ O component is an optional component which improves the stability and transparency of the glass and lowers the transition temperature (Tg) of the glass, and is an optional component in the glass. In the first aspect, by setting the content ratio of the Li ₂ O component to 25% or less, a high refractive index can be easily obtained, and stability of the glass can be improved, and occurrence of devitrification or the like can be reduced. Therefore, the content of the Li ₂ O component is preferably 25%, more preferably 20%, and most preferably 15%. The Li ₂ O component can be contained in the glass using, for example, Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

In the case of the optical glass of the second aspect, the content of the Li ₂ O component is preferably 10%, more preferably 8%, and most preferably 5%.

The Na ₂ O component is an optional component which improves the stability and transparency of the glass and lowers the transition temperature (Tg) of the glass. In the first aspect, by setting the content of the Na ₂ O component to less than 25%, a high refractive index can be easily obtained, and stability of the glass can be improved, and occurrence of devitrification or the like can be reduced. Therefore, the content of the Na ₂ O component is preferably set to be less than 25%, more preferably 20%, and most preferably 15%. The Na ₂ O component can be contained in the glass using, for example, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like as a raw material.

The content of the Na ₂ O component is preferably set to less than 10%, more preferably 8%, and most preferably 5%.

In the case of the optical glass of the second aspect, the content of the Na ₂ O component is preferably set to less than 10%, more preferably 8%, and most preferably 5%.

The K ₂ O component is an optional component which improves the stability and transparency of the glass and lowers the transition temperature (Tg) of the glass, and is an optional component in the glass. In the first aspect, by setting the content of the K ₂ O component to 25% or less, a high refractive index can be easily obtained, and stability of the glass can be improved, and occurrence of devitrification or the like can be reduced. Therefore, the content of the K ₂ O component is preferably 25%, more preferably 20%, and most preferably 15%. The K ₂ O component can be contained in the glass using, for example, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material.

The content of the K ₂ O component is preferably 10%, more preferably 8%, and most preferably 5%.

In the case of the optical glass of the second aspect, the content of the K ₂ O component is preferably 10%, more preferably 8%, and most preferably 5%.

The TiO ₂ component is an optional component that increases the refractive index and dispersion of the glass and improves the chemical durability of the glass. In the first aspect, by setting the content of the TiO ₂ component to 0% or more, a high refractive index can be obtained, and a desired high dispersion can be obtained. On the other hand, by setting the content of the TiO ₂ component to 40% or less, the stability and transparency of the glass can be improved. Therefore, the content of the TiO ₂ component is preferably 0%, more preferably 1%, still more preferably 3%. On the other hand, the content of the TiO ₂ component is preferably 40%, more preferably 35%, and most preferably 30%. The TiO ₂ component can be contained in the glass using, for example, TiO ₂ or the like as a raw material.

In particular, in the case of the optical glass of the second aspect, by setting the content of the TiO ₂ component to 65% or less, the devitrification resistance can be improved by improving the stability of the glass. The content of the TiO ₂ component is preferably 30.0%, more preferably 30.5%, still more preferably 31.0%. On the other hand, the content of the TiO ₂ component is preferably 65%, more preferably 60%, and most preferably 58%.

The ZrO ₂ component is an optional component which reduces the color of the glass, increases the transmittance to visible light of a short wavelength, and promotes stable glass formation, and improves the devitrification resistance of the glass. In particular, by setting the content of the ZrO ₂ component to 10% or less, the decrease in the refractive index due to the ZrO ₂ component can be suppressed, so that a desired high refractive index can be easily obtained. Therefore, the content of the ZrO ₂ component is preferably 10%, more preferably 8%, and most preferably 5%. The ZrO ₂ component can be contained in the glass using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

The Ta ₂ O ₅ component is a component that increases the refractive index of the glass and is an optional component in the glass. In particular, by setting the content of the Ta ₂ O ₅ component to 10% or less, it is difficult to devitrify the glass. Therefore, the content of the Ta ₂ O ₅ component is preferably 10%, more preferably 8%, and most preferably 5%. The Ta ₂ O ₅ component can be contained in the glass using, for example, Ta ₂ O ₅ or the like as a raw material.

The content of the Ta ₂ O ₅ component is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%.

The WO ₃ component is an optional component which increases the refractive index of the glass and increases the dispersion of the glass, and is an arbitrary component in the glass. In the first aspect, by setting the content of the WO ₃ component to 10% or less, the devitrification resistance of the glass can be improved, and the decrease in the transmittance of the visible light of the short-wavelength of the glass can be suppressed. Therefore, the content of the WO ₃ component is preferably 10%, more preferably 5%, and most preferably 1%. The WO ₃ component can be contained in the glass using, for example, WO ₃ or the like as a raw material.

In the case of the optical glass of the second aspect, the content of the WO ₃ component is preferably 20.0%, more preferably 10%, and most preferably 5%. Further, even if the WO ₃ component is not contained, an optical glass having a desired high dispersion and high transmittance can be obtained. However, by containing more than 0% of the WO ₃ component, the dispersion of the glass can be improved, so that it can be easily combined. High dispersion of glass and transparency to visible light. Therefore, the content of the WO ₃ component in this case is preferably set to be more than 0%, more preferably 1.0%, still more preferably 3.0%, and most preferably 4.0% as a lower limit.

The Y ₂ O ₃ component is a component which increases the refractive index of the glass and has a large effect on the dispersion adjustment, and is an optional component in the optical glass of the first aspect of the invention. In particular, by setting the content of the Y ₂ O ₃ component to 10% or less, it is possible to suppress a decrease in the devitrification resistance of the glass and to suppress an increase in the glass transition point (Tg). Therefore, the content of the Y ₂ O ₃ component is preferably 10%, more preferably 8%, and most preferably 5%. The Y ₂ O ₃ component can be contained in the glass using, for example, Y ₂ O ₃ or YF ₃ as a raw material.

The La ₂ O ₃ component is a component which increases the refractive index of the glass and has a large effect on the dispersion adjustment, and is an arbitrary component in the glass. In particular, by setting the content of the La ₂ O ₃ component to 10% or less, the dispersion of the glass can be increased, and the devitrification resistance of the glass can be improved. Therefore, the content of the La ₂ O ₃ component is preferably 10%, more preferably 8%, and most preferably 5%. As the La ₂ O ₃ component, for example, La ₂ O ₃ or La(NO ₃ ) ₃ can be used. XH ₂ O (X is an arbitrary integer) or the like is contained in the glass as a raw material.

The Gd ₂ O ₃ component is a component which increases the refractive index of the glass and has a large effect on the dispersion adjustment, and is an arbitrary component in the glass. In particular, by setting the content of the Gd ₂ O ₃ component to 10% or less, the dispersion of the glass can be increased, and the devitrification resistance of the glass can be improved. Therefore, the content of the Gd ₂ O ₃ component is preferably 10%, more preferably 8%, and most preferably 5%. The Gd ₂ O ₃ component can be contained in the glass using, for example, Gd ₂ O ₃ , GdF ₃ or the like as a raw material.

The Bi ₂ O ₃ component is a component which increases the refractive index and dispersion of the glass and is an optional component in the optical glass of the first aspect of the present invention. In the first aspect, when the content of the Bi ₂ O ₃ component is 10% or less, the stability of the glass can be improved, so that the deterioration of the devitrification resistance can be suppressed, and the decrease in the transmittance of the glass can be suppressed. Therefore, the content of the Bi ₂ O ₃ component is preferably 10%, more preferably 5%, and most preferably less than 1%.

In the case of the optical glass of the second aspect, the content of the Bi ₂ O ₃ component is preferably 15.0%, more preferably 13.0%, and most preferably less than 10.0%.

The TeO ₂ component is a glass forming component and is an optional component that increases the refractive index and dispersion of the glass and increases the transmittance. In particular, by setting the content of the TeO ₂ component to more than 0%, the dispersion and refractive index of the glass can be increased, so that the desired Abbe number (ν _d ) and the refractive index can be obtained. On the other hand, by setting the content of the TeO ₂ component to 30.0% or less, the liquidus temperature of the glass can be lowered, and the devitrification resistance at the time of glass formation can be improved. Moreover, if it is contained in a large amount, abrasion resistance is deteriorated. Therefore, the content of the TeO ₂ component is preferably 0%, more preferably 0.5%, and most preferably 1% as a lower limit. Further, the content of the TeO ₂ component is preferably 30%, more preferably 20%, still more preferably 10%, and most preferably less than 5%. The TeO ₂ component can be contained in the glass using, for example, TeO ₂ or the like as a raw material.

The SnO ₂ component is a component which is an element of the optical glass of the first aspect of the present invention, which is a component which reduces the oxidation of the molten glass, clarifies the molten glass, and hardly deteriorates the transmittance of the glass to light. In particular, by setting the content of the SnO ₂ component to 6% or less, it is difficult to cause coloring of the glass or devitrification of the glass due to reduction of the molten glass. Further, since the alloying of the SnO ₂ component and the melting device (especially a noble metal such as Pt) is reduced, the life of the melting device can be extended. Therefore, the content of the SnO ₂ component is preferably 6%, more preferably 5%, and most preferably 4%. The SnO ₂ component can be contained in the glass using, for example, SnO, SnO ₂ , SnF ₂ , SnF ₄ or the like as a raw material.

The Sb ₂ O ₃ component is a component that increases the transmittance of the glass to visible light having a short wavelength, and is a component having a defoaming effect when the glass is melted, and is an optional component in the optical glass. In the first aspect, when the content of the Sb ₂ O ₃ component is 1.0% or less, excessive foaming during glass melting is less likely to occur, so that it is difficult to make the Sb ₂ O ₃ component and the melting device (especially Pt). Alloying occurs in precious metals. Therefore, the content of the Sb ₂ O ₃ component is preferably 1.0%, more preferably 0.9%, still more preferably 0.8%. In particular, even when a small amount of the Sb ₂ O ₃ component is contained, the Sb ₂ O ₃ component volatilizes from the molten glass and adheres to the mold as an impurity, which causes unevenness and stain on the surface of the glass molded body. On the other hand, by setting the content of the Sb ₂ O ₃ component to 0.7% or less, the Sb component which is the main component of the impurities is removed from the glass, whereby the impurities adhering to the mold are reduced, so that the formation of the glass molded body can be reduced. Concavities and blemishes on the surface. Therefore, the content of the Sb ₂ O ₃ component is preferably 0.7%, more preferably 0.6%, still more preferably 0.5%. In particular, in the first aspect of the invention, it is preferred to use a glass which does not substantially contain the Sb component. When the press molding temperature is raised, the formation of impurities in the mold becomes remarkable, and the effect obtained by substantially not containing the Sb component becomes remarkable.

In the case of the optical glass of the second aspect, the content of the Sb ₂ O ₃ component is preferably 0.01%, more preferably 0.005%, still more preferably 0.001%.

In the optical glass according to the first aspect of the present invention, it is preferable to contain a total of 3% or more and 50% or less of the ZnO component and the MgO component.

Thereby, the meltability, stability, and transparency of the glass are remarkably improved, and there is an effect that the desired optical constant can be easily obtained. Therefore, the total amount of the ZnO component and the MgO component is preferably 3%, more preferably 5%, still more preferably 7%, most preferably 9%, more preferably 50%, still more preferably 45%, the best is 40% as the upper limit.

In the optical glass according to the second aspect of the present invention, it is preferable to contain a total of 3% or more and 35% or less of a ZnO component and a MgO component. Therefore, the total amount of the ZnO component and the MgO component is preferably 3%, more preferably 4%, most preferably 4.5% as the lower limit, more preferably 35%, still more preferably 33%, most preferably 30%. % is the upper limit.

In the optical glass according to the first aspect of the present invention, it is preferable to contain one or two of the SiO ₂ component, the Al ₂ O ₃ and the B ₂ O ₃ component in a total amount of 0.1% or more and 20% or less.

Thereby, there is an effect that the meltability, stability, and chemical durability of the glass are greatly improved. Therefore, the total of one or two components of the SiO ₂ component, the Al ₂ O ₃ and the B ₂ O ₃ component is preferably 0.5%, more preferably 1%, and most preferably 3% is the lower limit. The upper limit is 20%, more preferably 15%, and most preferably 10%.

In the optical glass according to the first aspect of the present invention, it is preferable to contain one or two of the SiO ₂ component and the Al ₂ O ₃ component in a total amount of 0.1% or more and 20% or less.

Thereby, there is an effect that the meltability, stability, and chemical durability of the glass are greatly improved. Therefore, the total of one or two of the SiO ₂ component and the Al ₂ O ₃ component is preferably 0.5%, more preferably 1%, most preferably 3%, and preferably 20%. More preferably, it is 15%, and the best is 10%.

In the optical glass according to the first aspect of the present invention, it is preferable to contain 0% or more and 30% or less of R ₂ O components. Here, R is at least one selected from the group consisting of Li, Na, and K.

Thereby, the meltability, stability, and transparency of the glass can be improved, and the effect of obtaining a glass having a lower Tg can be easily obtained. Therefore, the total amount of the R ₂ O components is preferably 30%, more preferably 25%, and most preferably 20%.

In the optical glass according to the first aspect of the present invention, R ₂ O/(ZnO+MgO) is preferably 2.0 or less. Here, R is at least one selected from the group consisting of Li, Na, and K.

Thereby, an optical glass having higher stability can be manufactured. Therefore, R ₂ O/(ZnO+MgO) is preferably 2.0%, more preferably 1.5%, and most preferably 0.8%.

In the optical glass according to the first aspect of the present invention, it is preferable to contain 0% or more and 30% or less of the MO component. Here, M is one or more selected from the group consisting of Ca, Sr, and Ba.

Thereby, an optical glass having higher stability can be manufactured. Therefore, the MO component is preferably at 30%, more preferably at 20%, and most preferably at 15%.

In the optical glass according to the first aspect of the invention, it is preferable that MO/(ZnO+MgO) is 0.5 or less. Here, M is one or more selected from the group consisting of Ca, Sr, and Ba.

Thereby, an optical glass having higher stability can be manufactured. Therefore, MO / (ZnO + MgO) is preferably 0.5%, more preferably 0.45%, and most preferably 0.4%.

In the optical glass according to the second aspect of the present invention, it is preferable that the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, the Ga ₂ O ₃ and the B ₂ O ₃ component are contained in a total amount of 0.5% or more and 30% or less. One or two or more components.

Thereby, there is an effect that the meltability, stability, and chemical durability of the glass are greatly improved. Therefore, the total of one or more of the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component is preferably 0.5%, more preferably 2.5%, and most preferably 4.5. % is the lower limit, preferably 30%, more preferably 20%, and most preferably 10%.

In the optical glass according to the second aspect of the present invention, it is preferable to contain one or two of an SiO ₂ component, a GeO ₂ component, an Al ₂ O ₃ component, and a Ga ₂ O ₃ component in a total amount of 0.5% or more and 30% or less. The above ingredients.

Thereby, there is an effect that the meltability, stability, and chemical durability of the glass are greatly improved. Therefore, the total of one or more of the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component is preferably 0.5%, more preferably 2.5%, and most preferably 4.5. % is the lower limit, preferably 30%, more preferably 20%, and most preferably 10%.

In the optical glass according to the second aspect of the present invention, it is preferable to contain a total of 0% or more and 30% or less of the R ₂ O component and the MO component. Here, R is one or more selected from the group consisting of Li, Na, and K, and M is one or more selected from the group consisting of Ca, Sr, and Ba.

Thereby, the meltability and stability of the glass are improved, and the effect of obtaining a desired optical constant is easy. Therefore, the total of the R ₂ O component and the MO component is preferably 30%, more preferably 15%, and most preferably 5%.

In the optical glass according to the second aspect of the present invention, it is preferable to contain a total of 3% or more and 35% or less of a ZnO component and a MgO component. Therefore, the total amount of the ZnO component and the MgO component is preferably 3%, more preferably 4%, most preferably 4.5% as the lower limit, more preferably 35%, still more preferably 33%, most preferably 30%. % is the upper limit.

Thereby, the meltability, stability, and transparency of the glass are remarkably improved, and there is an effect that the desired optical constant can be easily obtained.

In the optical glass according to the second aspect of the present invention, it is preferable to contain a total of 0% or more and 10% or less of the SnO ₂ component and the Sb ₂ O ₃ component. Therefore, the total of the SnO ₂ component and the Sb ₂ O ₃ component is preferably 0%, more preferably 0.10%, most preferably 0.18% as the lower limit, more preferably 10%, still more preferably 5%, most Jia is based on 4%.

Thereby, a sufficient defoaming effect can be exhibited, and the effect which contributes to the transparency improvement of glass is provided.

In the optical glass according to the first aspect of the present invention, it is preferable that (1) contains 20% or more and 45% or less of P ₂ O ₅ component, 15% or more and 60% or less of Nb ₂ O ₅ component, and 5 in total. The ZnO component and the MgO component of % or more and 50% or less have a refractive index of 1.75 or more, an Abbe number of 10 or more and 35 or less, and (2) the total mass of the glass relative to the oxide-converted composition, in terms of mol%, One or two of the SiO ₂ component and the Al ₂ O ₃ component are 0.1% or more and 20% or less in total.

Thereby, an optical glass having high stability and transparency can be produced.

Further, in the optical glass according to the second aspect of the present invention, it is preferable to contain 20 to 45% of P ₂ O ₅ component, 0 to 50% by mol% based on the total mass of the glass in terms of oxide conversion composition. Nb ₂ O ₅ component, 0 to 12% BaO component, 0 to 6% B ₂ O ₃ component, 30 to 65% TiO ₂ component, total 0 to 40% R ₂ O component and MO component, total 3 to 30% of the ZnO component and the MgO component, a total of 0 to 10% of the SnO ₂ component and the Sb ₂ O ₃ component, more than 0% of the SiO ₂ component, more than 0% of the Al ₂ O ₃ component, and a total of 0.5 One or two or more components of the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, and the Ga ₂ O ₃ component of 30%.

Thereby, an optical glass excellent in stability can be produced.

<About ingredients that should not be included>

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

In the optical glass according to the first aspect of the present invention and the optical glass of the second aspect, other components may be added as needed within a range that does not impair the characteristics of the glass of the present invention.

Among them, the transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo have a glass transition even when they are contained in a small amount alone or in a small amount. The coloring of the glass imparts an absorption property to a specific wavelength in the visible light range, and therefore it is preferable that the optical glass having a wavelength in the visible light range is substantially not contained.

Further, lead compounds such as PbO and arsenic compounds such as As ₂ O ₃ and various components of Th, Cd, Tl, Os, Be, and Se have been used as harmful chemical materials in recent years, and are intended to be used in control, not only in the manufacturing steps of glass, but even The processing steps and disposal after productization also require measures for environmental countermeasures. Therefore, when it is important to take into consideration the influence of the environment, it is preferable to remove the unavoidable incorporation, and it is preferable that it does not substantially contain such. Thereby, the optical glass does not substantially contain a substance that pollutes the environment. Therefore, the optical glass can be manufactured, processed, and disposed of without seeking special environmental measures.

[Physical properties of optical glass]

The optical glass of the first aspect of the invention has a higher refractive index (n _d ) and has a specific dispersion. In particular, the refractive index (n _d ) of the optical glass of the first aspect of the invention is preferably 1.75, more preferably 1.80, most preferably 1.84 as the lower limit, more preferably 2.20, more preferably 2.10, the best is to use 2.02 as the upper limit. Further, the Abbe number (ν _d ) of the optical glass of the first aspect of the invention is preferably 10, more preferably 13, most preferably 17 or less, more preferably 35, more preferably 30, the best is to use 24 as the upper limit. By this, the degree of freedom in optical design is widened, and even if the thickness of the element is reduced, a large amount of refraction of light can be obtained.

Further, in the case of optical glass, it is required to be colored less, but the glass of the first aspect of the present invention is colored depending on the composition at the time of molding. However, heat treatment is then carried out for 4 hours or more at a temperature near the glass transition point, whereby the coloration disappears, and a transparent glass which satisfies the application is obtained. In particular, when the optical glass of the first aspect of the present invention is expressed by the transmittance of glass, the sample having a thickness of 10 mm exhibits a wavelength (λ ₇₀ ) of 70% of the light transmittance of 500 nm or less, more preferably 480 nm or less. The best is below 450nm. Thereby, the transparency of the glass in the visible light range is improved, so that the optical glass can be used as a material of an optical element such as a lens. Further, in the first aspect of the present invention, the glass obtained by melting and slowly cooling the glass material may have the above-described transmittance, and it is more preferable that the heat treatment is not required to suppress the coloration of the glass. The transmittance of the glass before the heat treatment has the above transmittance.

[Method of Manufacturing Glass Formed Body]

The optical glass according to the first aspect of the present invention is produced, for example, in the following manner. In other words, the raw materials are uniformly mixed in such a manner that the respective components are within a specific content ratio, and the produced mixture is introduced into a quartz crucible or an alumina crucible, and coarsely melted, followed by introduction of gold crucible, platinum rhodium, and platinum alloy. Or 铱坩埚, melting and stirring homogenization in a temperature range of 1250 to 1500 ° C, defoaming, etc., and then descending to a suitable temperature, and then casting to a mold for slow cooling, thereby producing the optical aspect of the first aspect of the present invention. glass.

As a method of forming an optical element from optical glass produced in this manner, a method for grinding and polishing after re-heat press or a method of pressing a preform into a preform can be used.

In particular, in the case of pressurizing the mold, the preform comprising the optical glass according to the first aspect of the present invention is constituted by a mold part including, for example, an upper mold, a lower mold, and a sleeve mold. Heating is performed in the mold to soften and press-form. Here, the material of the base material of the mold and the material of the protective film formed on the molding surface of the mold are not particularly limited as long as they are not melted into the softened preform, and a known material can be used. The material of the base material of the mold is preferably a known mold material such as tungsten carbide (WC), tantalum carbide (SiC) or stainless steel alloy, and the material of the protective film is preferably the outermost layer comprising Pt, Au, Ir, At least one or more of element groups consisting of Ni, Cr, Mo, Rh, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Re, and C Material. By making the base material of the mold from such a material, the base material of the mold is not easily deformed, so that the life of the mold can be extended. Among them, in terms of easiness of processing, a metal such as a stainless steel alloy may be used as the base material of the mold. Further, by being selected from the group consisting of Pt, Au, Ir, Ni, Cr, Mo, Rh, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one of the elements of the group consisting of Tm, Yb, Lu, Re, and C forms the outermost layer of the protective film, and can suppress the reaction between the softened glass and the protective film, thereby further reducing impurities on the protective film. Attached. Further, the softening of the preform is not limited to being performed by heating in the mold.

The press forming is performed, for example, in the following order. After the preform is placed in the center of the molding surface of the lower mold inserted into the through hole of the sleeve mold, the upper mold is inserted into the through hole of the sleeve mold. At this time, the molding surface of the lower mold is opposed to the molding surface of the upper mold. Next, the preform is heated together with the mold, and when the glass constituting the preform is softened, the preform is pressed by the upper mold and the lower mold to pressurize the preform. Thereby, the preform is spread inside the cavity surrounded by the closed mold upper mold, the lower mold and the sleeve mold, so that the glass can be filled inside the mold cavity. That is, the shape of the inner surface of the cavity can be transferred to the glass.

Here, regarding the mold, the relative positions of the molding surfaces of the upper mold, the lower mold, and the sleeve mold in the mold closing state and the angle formed by the normal to the molding surface are precisely formed so that the cavity has a specific shape. Further, before the end of the pressurization by the mold, the orientations of the upper mold and the lower mold are opposed to each other, and the central axes of the upper mold and the lower mold are uniformly maintained. By these, it is possible to produce a glass molded body in which the optical function surface and the position determining reference plane are formed with a high-precision positional relationship and an angle.

[Production of optical components]

The optical glass according to the first aspect of the present invention is useful for various optical elements and optical designs. Among them, it is preferable to press-form the optical glass according to the first aspect of the present invention to produce a lens, a mirror, a mirror, and the like. Optical element. Thereby, when the obtained optical element is used for an optical device that transmits visible light such as a camera or a projector, high-precision imaging characteristics can be realized with high definition, and the optical system of the optical device can be miniaturized. .

[Examples]

The composition (mol%), the refractive index (n _d ), the Abbe number (ν _d ), the glass transition temperature (° C.) of the examples (No. 1 to No. 32) of the first aspect of the present invention, The measurement results of the yield point (At, ° C) and the coefficient of linear expansion (10 ^-7 /K) are shown in Tables 1 to 3. Further, the following examples are for illustrative purposes only and are not limited to the embodiments.

The optical glass of the first embodiment (No. 1 to No. 32) of the first aspect of the present invention is selected from oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and partial phosphors. A high-purity raw material used for a usual optical glass such as a phosphoric acid compound is weighed and uniformly mixed as a raw material of each component as a ratio of the composition of each of the examples shown in Tables 1 to 3, and then introduced into a quartz crucible or In the platinum crucible, according to the melting difficulty of the glass composition, it is melted in an electric furnace at a temperature range of 1300 to 1450 ° C, stirred and homogenized, and then cast into a mold to prepare a test piece.

In the optical glass system of the comparative example, the composition of the ZnO component and the MgO component was set to 0% with respect to the examples (No. 1 to No. 32) of the first aspect of the present invention, but the vitrification was not carried out.

Here, the refractive index (n _d ) and the Abbe number (ν _d ) of the glass of the examples (No. 1 to No. 32) were measured based on the Japan Optical Glass Industry Association standard JOGIS01-2003. In addition, as the glass used for the measurement, the annealing conditions were such that the slow cooling rate was -25 ° C / hr, and the treatment was carried out in a slow cooling furnace.

In addition, the glass transition temperature (Tg, °C) and the drop point (At, °C) are obtained by measuring the above temperature and the elongation of the sample according to the Japanese Optical Glass Industry Association standard JOGIS08-2003 "Method for Measuring Thermal Expansion of Optical Glass". The thermal expansion curve is obtained.

Regarding the linear expansion coefficient (10 ^-7 /K), the average linear expansion coefficient at 100 to 300 ° C was obtained according to the Japanese Optical Glass Industry Association standard JOGIS 08-2003 "Method for Measuring Thermal Expansion of Optical Glass".

As shown in Tables 1 to 3, the optical glass of the first aspect of the present invention has an Abbe number (ν _d ) of 10 or more, and more specifically, 17 or more, and the Abbe number ( ν _d ) is 35 or less, and more specifically, 24 or less. On the other hand, the glass of the comparative example was not vitrified.

Further, in the optical glass of the first aspect of the present invention, the refractive index (n _d ) is 1.75 or more, more specifically 1.84 or more, and the refractive index (n _d ) is 2.20 or less, more detailed. In terms of 2.02 or less, it is within the desired range. On the other hand, the glass of the comparative example was not vitrified.

Further, in the optical glass of the first embodiment of the present invention, devitrification or the like did not occur. On the other hand, the optical glass of the comparative example was not vitrified. Therefore, it is understood that the optical glass of the first aspect of the present invention has high resistance to devitrification.

Further, the optical elements produced using the glass of the compositions described in Examples 1 to 32 did not have irregularities and stains on the surface. Therefore, it is understood that the optical glass according to the first aspect of the present invention can reduce irregularities and stains on the surface of the glass molded body, and can be stably press-formed into various optical elements, that is, the shape of a lens and a crucible.

Fig. 1 is a graph showing the transmittance characteristics of the optical glass of Example 1. The thickness of the optical glass used for the measurement was 10 mm. As shown in FIG. 1, the transmittance is more than 70% from about 430 nm, and a high transmittance of 80% or more is achieved.

Here, the transmittance of the glass is measured in accordance with the Japanese Optical Glass Industry Association standard JOGIS02.

Therefore, it is understood that the optical glass of the embodiment of the first aspect of the present invention has desired high stability and high dispersion, and can reduce irregularities and stains on the surface.

[Physical properties of optical glass]

The optical glass of the second aspect of the present invention has a high refractive index (n _d ) and has a specific dispersion. In particular, the refractive index (n _d ) of the optical glass of the second aspect of the invention is preferably 1.75, more preferably 1.76, most preferably 1.78 as the lower limit, more preferably 2.20, more preferably 2.10, the best is to use 2.00 as the upper limit. Further, the Abbe number (ν _d ) of the optical glass of the second aspect of the invention is preferably 10, more preferably 13, most preferably 17 or less, more preferably 35, more preferably 30, the best is to use 22 as the upper limit. By this, the degree of freedom in optical design is widened, and even if the thickness of the element is reduced, a large amount of refraction of light can be obtained.

Further, in the case of optical glass, it is required to be colored less, but the glass of the second aspect of the present invention is colored depending on the composition at the time of molding. However, it was later turned into glass The temperature in the vicinity of the shift point is heat-treated for 4 hours or more, whereby the coloring disappears, and a transparent glass which satisfies the application is obtained. Thereby, the transparency of the glass in the visible light range is improved, so that the optical glass can be used as a material of an optical element such as a lens.

[Method of Manufacturing Glass Formed Body]

The optical glass of the second aspect of the present invention can be produced in the same manner as the optical glass of the first aspect.

[Production of optical components]

The optical glass of the second aspect of the present invention can be produced in the same manner as the optical glass of the first aspect.

[Examples]

The composition (mol%) of the second aspect of the present invention (No. 33 to No. 58), the refractive index (n _d ), the Abbe number (ν _d ), and the glass transition temperature (° C.) The measurement results of the drop point (At, °C) and the coefficient of linear expansion (10 ^-7 /K) are shown in Tables 4 to 6. Further, the following examples are for illustrative purposes only and are not limited to the embodiments.

In the optical glass of the second aspect of the present invention (No. 33 to No. 58), oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and partial oxides each having a corresponding ratio are selected. A high-purity raw material used for a usual optical glass such as a phosphoric acid compound is weighed and uniformly mixed as a raw material of each component in the ratio of the composition of each of the examples shown in Tables 4 to 6, and then introduced into a quartz crucible or In the platinum crucible, according to the melting difficulty of the glass composition, it is melted in an electric furnace at a temperature range of 1400 to 1450 ° C, stirred and homogenized, and then cast into a mold to prepare a test piece.

The optical glass system of the comparative example was set to the composition of the second aspect of the present invention (No. 33 to No. 58), and the composition of the ZnO component and the MgO component was 0%, but was not vitrified.

Here, the measurement of the refractive index (n _d ) and the Abbe number (ν _d ) of the glass of the examples (No. 33 to No. 58), the glass transition temperature (° C.), and the measurement of the drop point (At, ° C) were measured. The measurement of the coefficient of linear expansion (10 ^-7 /K) was carried out in the same manner as in the case of the optical glass of the example of the first aspect.

As shown in Tables 4 to 6, the optical glass of the second aspect of the present invention has an Abbe number (ν _d ) of 10 or more, more specifically, 17 or more, and the Abbe number (ν). _d ) is 35 or less, and more specifically, is less than 22, which is within the lower range desired. On the other hand, the optical glass of the comparative example was not vitrified.

Further, in the optical glass of the second aspect of the present invention, the refractive index (n _d ) is 1.75 or more, more specifically 1.78 or more, and the refractive index (n _d ) is 2.20 or less, more detailed. In terms of 2.00 or less, it is within the desired range. On the other hand, the optical glass of the comparative example was not vitrified.

Further, in the optical glass of the second aspect of the present invention, devitrification or the like did not occur. On the other hand, the optical glass of the comparative example was not vitrified. Therefore, it is understood that the optical glass of the second aspect of the present invention has high resistance to devitrification.

Further, the optical elements produced using the glass of the compositions described in Examples 33 to 58 did not have irregularities and stains on the surface. Therefore, it is understood that the optical glass according to the second aspect of the present invention can reduce the irregularities and stains on the surface of the glass molded body, and can be stably press-formed into various optical elements, that is, the shape of the lens and the crucible.

Therefore, it is understood that the optical glass of the embodiment of the second aspect of the present invention has a desired high transmittance and high dispersion, and can reduce irregularities and stains on the surface.

The present invention has been described in detail with reference to the preferred embodiments of the invention.

Claims (16)

An optical glass containing 20% or more and 45% or less of P ₂ O ₅ component, 15% or more and 60% or less of Nb ₂ O ₅ component based on the total mass of the glass in terms of oxide conversion composition. The ZnO component and the MgO component in a total amount of 3% or more and 50% or less have a refractive index of 1.75 or more and an Abbe number of 10 or more and 35 or less. The optical glass of claim 1, which contains, in mol%, a total of 0.1% or more and 20% or less of SiO ₂ component, Al ₂ O ₃ and B ₂ O ₃ components, based on the total mass of the glass of the oxide conversion composition. One or two of the ingredients. The optical glass of claim 1 which contains 0% or more and 40% or less of TiO ₂ component based on the total mass of the glass in terms of oxide conversion composition. The optical glass of claim 1, which contains 0% or more and 25% or less of R ₂ O components in terms of mol% of the glass, and R ₂ O/(ZnO+MgO) It is 2.0 or less, and R is one or more types selected from the group consisting of Li, Na, and K. The optical glass of claim 1, which contains 0% or more and 25% or less of MO component in terms of mol% of the glass, and MO/(ZnO+MgO) is 0.5 or less, Here, M is one or more selected from the group consisting of Ca, Sr, and Ba. An optical glass containing 20% or more and 45% or less of P ₂ O ₅ component, 30% or more and 65% or less of TiO ₂ component in terms of mol% of the glass composition of the oxide conversion composition, and A total of 0.5% or more and 30% or less of the SiO ₂ component, the GeO ₂ component, the Al ₂ O ₃ component, the Ga ₂ O ₃ and the B ₂ O ₃ component, or a refractive index of 1.75 or more. The number of shells is 10 or more and 35 or less. The optical glass of claim 6, which contains a total of 0% or more and 40% or less of the R ₂ O component and the MO component in terms of the total mass of the glass in terms of the oxide conversion composition, where R is selected. One or more of the group consisting of Li, Na, and K, and M is one or more selected from the group consisting of Ca, Sr, and Ba. The optical glass of the claim 6 contains a total of 3% or more and 35% or less of the ZnO component and the MgO component in terms of the total mass of the glass in terms of the oxide conversion composition. The optical glass of claim 6 which contains 0% or more and 50% or less of Nb ₂ O ₅ component in terms of mol% of the total glass mass of the oxide conversion composition. The optical glass of the claim 6 contains a total of 0% or more and 10% or less of the SnO ₂ component and the Sb ₂ O ₃ component in terms of the total mass of the glass in terms of the oxide conversion composition. The optical glass of claim 6, which contains more than 0% of the SiO ₂ component in mole % with respect to the total mass of the glass of the oxide-converted composition. The optical glass of claim 6, which contains more than 0% of the Al ₂ O ₃ component in mole % with respect to the total glass mass of the oxide-converted composition. The optical glass of claim 6 which contains less than 60% of the TiO ₂ component in mole % with respect to the total mass of the glass of the oxide conversion composition. The optical glass of claim 6 which contains less than 6% of the B ₂ O ₃ component in mole % with respect to the total mass of the glass of the oxide conversion composition. An optical element comprising the optical glass of any one of claims 1 to 14. A method of producing a glass formed body, which uses the optical glass according to any one of claims 1 to 14, to press-form the softened optical glass in a mold.