JP6347816B2 - Optical glass, optical element, and method for producing glass molded body - Google Patents

Description

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

  In recent years, digitalization and high definition of devices using optical systems have been rapidly progressing, and higher precision for optical elements such as lenses used in various optical devices, including photographing devices such as digital cameras and video cameras, The demand for light weight and downsizing is increasing.

Among optical glasses for producing optical elements, in particular, there is a demand for 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. It is very high. As such a high refractive index glass, 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. doing.

JP-A-8-157231 JP 2001-58845 A JP 2003-238197 A JP 2003-321245 A JP 2003-335549 A JP 2005-154248 A JP 2009-143801 A JP 2010-83701 A JP 2011-57509 A Published Chinese Patent No. 101134641

  However, although the optical glass described in Patent Documents 1 to 10 has a low Abbe number, it is difficult to say that the stability is high, and devitrification or the like may occur.

  Then, this invention is made | formed in view of the said problem, Comprising: Optical glass which has desired high stability and high dispersion | distribution (low Abbe number), an optical element, and the manufacturing method of a glass molded object are provided. With the goal.

In order to solve the above-mentioned problems, the present inventor has conducted intensive studies, and as a result, contains a predetermined amount of P ₂ O ₅ component, Nb ₂ O ₅ component, ZnO component, and MgO component while maintaining a predetermined balance. As a result, it was found that stability can be enhanced and dispersion can be enhanced, and the present invention has been completed. Specifically, the present invention provides the following.

(1) the glass the total amount of substance of the oxide composition in terms of a _molar%, P 2 _{O 5} ingredient 45% 20% or more of the following, _Nb 2 _{O 5} ingredient 15% or more 60% or less, ZnO component and MgO An optical glass containing the components in a total amount of 5% to 50%, having a refractive index of 1.75 or more and an Abbe number of 10 to 35.

(2) 0.1% or more and 20% or less of the total amount of one or two of the SiO ₂ component and the Al ₂ O ₃ component in mol% with respect to the total amount of glass in the oxide conversion composition The optical glass according to (1).

(3) The optical glass according to (1) or (2), which contains 0% or more and 40% or less of a TiO ₂ component in mol% with respect to the total amount of the glass having an oxide conversion composition.

(4) The content of the R ₂ O component is 0% or more and 25% or less, and the R ₂ O / (ZnO + MgO) is 2.0 or less with respect to the total amount of glass in the oxide conversion composition (1). The optical glass according to any one of (3) to (3).
Here, R is at least one selected from the group consisting of Li, Na and K.

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

(6) An optical element made of the optical glass according to 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-molds the softened optical glass in a mold.

According to the present invention, a desired amount of P ₂ O ₅ component, Nb ₂ O ₅ component, ZnO component, and MgO component are contained while maintaining a predetermined balance, so that an optical device having desired high stability and high dispersion is obtained. A method for producing glass, an optical element, and a glass molded body can be provided.

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

The optical glass of the present invention is 20% or more and 45% or less of the P ₂ O ₅ component, and 15% or more and 60% or less of the Nb ₂ O ₅ component in mol% with respect to the total amount of glass in the oxide conversion composition The ZnO component and the MgO component are contained in a total amount of 5% to 50%, the refractive index is 1.75 or more, and the Abbe number is 10 to 35. When the optical glass contains a predetermined amount of P ₂ O ₅ component, Nb ₂ O ₅ component, and TiO ₂ component, a decrease in transmittance with respect to visible light is suppressed, and dispersion is increased. Moreover, by reducing the Sb ₂ O ₃ component contained in the optical glass, the influence on the environment is reduced, and unevenness and fogging on the surface of the glass are reduced. Therefore, it is possible to provide an optical glass, an optical element, and a method for producing a glass molded body that can reduce surface irregularities and fogging while having desired high transmittance and high dispersion.

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

[Glass component]
The composition range of each component constituting the optical glass of the present invention is described below. In the present specification, unless otherwise specified, the content of each component is all expressed in mol% with respect to the total amount of glass having an oxide equivalent composition. Here, the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as a raw material of the glass constituent of the present invention are all decomposed and changed into an oxide when melted. It is the composition which described each component contained in glass by making the total substance amount of the said production | generation oxide into 100 mol%.

<About essential and optional components>
Next, the essential components and optional components of the glass that are preferably used as the optical glass of the present invention will be described.

The P ₂ O ₅ component is a glass forming component and an essential component that lowers the melting temperature of the glass. In particular, by setting the content ratio of the P ₂ O ₅ component to 20% or more, the devitrification resistance is improved, and a highly stable glass can be easily obtained. On the other hand, a high refractive index can be obtained by setting the content of the P ₂ O ₅ component to 45% or less. Therefore, the content of the P ₂ O ₅ component with respect to the total amount of glass in the oxide conversion composition is preferably 20%, more preferably 22%, and most preferably 24%, preferably 45%, more preferably The upper limit is 35%, 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 that increases the refractive index and dispersion of the glass. In particular, by setting the content 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, devitrification resistance can be increased by increasing the stability of the glass by setting the content of the Nb ₂ O ₅ component to 60% or less. Therefore, the content of the Nb ₂ O ₅ component with respect to the total amount of glass in the oxide conversion composition is preferably 15%, more preferably 20%, most preferably 23%, and preferably 60%, more preferably The upper limit is 50%, most preferably 40%. The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ as a raw material.

Since the SiO ₂ component is effective in improving the meltability, stability and chemical durability of the glass, it can be optionally added. In particular, the devitrification resistance of the glass can be increased by making the content of the SiO ₂ component greater than 0%. On the other hand, by setting the content of the SiO ₂ component to 15% or less, a decrease in stability due to the SiO ₂ component can be suppressed, and a high refractive index can be easily obtained. Accordingly, the content of the SiO ₂ component with respect to the total amount of the glass having an oxide conversion composition is preferably 15%, more preferably 12%, and most preferably 10%. SiO ₂ component as a raw material such as _{SiO 2, K 2 SiF 6,} Na 2 SiF 6 and the like can contain in the glass by using.

The GeO ₂ component is a component that can be arbitrarily added because it has the same function as the above-described SiO ₂ component. By making the content of the GeO ₂ component 10% or less, the material cost can be reduced. Accordingly, the content of the GeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 10%, more preferably 5%, and most preferably 1%. The GeO ₂ component can be contained in the glass using, for example, GeO ₂ as a raw material.

Since the Al ₂ O ₃ component is effective in improving the meltability, stability and chemical durability of the glass, it can be added arbitrarily. In particular, by making the content of the Al ₂ O ₃ component 15% or less, it is possible to weaken the devitrification tendency of the glass while improving the meltability of the glass. Therefore, the content of the Al ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably more than 0%, preferably 15%, more preferably 10%, and 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.

The Ga ₂ O ₃ component is a component that can be arbitrarily added because it has the same effect as the Al ₂ O ₃ component described above. By setting the content of the Ga ₂ O ₃ component to 10% or less, the material cost can be reduced while improving the devitrification resistance of the glass. Therefore, the upper limit of the content ratio of the Ga ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition 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 , GaF ₃ or the like as a raw material.

B ₂ O ₃ component is a component for enhancing the meltability and devitrification resistance of the glass, which is an optional component in the glass. In particular, by making the content rate of the B ₂ O ₃ component 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 with respect to the total amount of glass in the oxide conversion composition is preferably less than 10%, more preferably 5%, and most preferably 1%. The B ₂ O ₃ component can be contained in the glass using, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ · 10H ₂ O, BPO ₄ or the like as a raw material.

The ZnO component is an optional component that lowers the liquidus temperature of the glass and increases the devitrification resistance of the glass, and is a component that makes it difficult to reduce the transmittance for visible light, and is an optional component in the glass. In particular, when the content of the ZnO component is 50% or less, a high refractive index and high dispersion can be easily obtained. Therefore, the upper limit of the content of the ZnO component with respect to the total amount of glass in the oxide conversion composition 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.

The MgO component is an optional component that lowers the liquidus temperature of the glass and increases the devitrification resistance of the glass, and is a component that makes it difficult to reduce the transmittance for visible light, and is an optional component in the glass. In particular, when the content of the MgO component is 45% or less, a high refractive index and high dispersion can be easily obtained. Therefore, the upper limit of the content of the MgO component with respect to the total amount of glass in the oxide conversion composition 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.

The CaO component is an optional component that lowers the liquidus temperature of the glass and increases the devitrification resistance of the glass, and is a component that makes it difficult to reduce the transmittance for visible light, and is an optional component in the glass. In particular, by setting the content of the CaO component to 25% or less, it is possible to easily obtain a high refractive index and high dispersion, and it is possible to suppress a decrease in the devitrification resistance and chemical durability of the glass. Therefore, the upper limit of the content of the CaO component with respect to the total amount of glass having an oxide conversion composition is preferably 25%, more preferably 20%, and most preferably 15%. The CaO component can be contained in the glass using, for example, CaCO ₃ , CaF ₂ or the like as a raw material.

The SrO component is an optional component that lowers the liquidus temperature of the glass and increases the devitrification resistance of the glass, and is an optional component in the glass. In particular, when the content of the SrO component is 25% or less, it is possible to easily obtain a high refractive index and high dispersion, and it is possible to suppress a decrease in the devitrification resistance and chemical durability of the glass. Therefore, the upper limit of the content of the SrO component with respect to the total amount of glass in the oxide conversion composition 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 , SrF ₂ or the like as a raw material.

The BaO component is an optional component that increases the refractive index of the glass and increases the devitrification resistance of the glass, and is a component that makes it difficult to reduce the transmittance for visible light, and is an optional component in the glass. In particular, when the content of the BaO component is 25% or less, it is possible to easily obtain a high refractive index and high dispersion, and it is possible to suppress a decrease in devitrification resistance and chemical durability. Accordingly, the content of the BaO component with respect to the total amount of glass in the oxide conversion composition is preferably 25%, more preferably 20%, and most preferably 15%. Here, it is preferable that the content rate of the BaO component with respect to the total amount of glass in the oxide conversion composition is 12.0% or less in that a glass having a large dispersion (small Abbe number) can be obtained. 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.

Li 2 _O component is an optional component to lower the glass transition temperature (Tg) of to increase the stability and transparency of the glass, which is an optional component in the glass. In particular, by setting the content of the Li ₂ O component to 25% or less, it is possible to easily obtain a high refractive index, and it is possible to increase the stability of the glass and reduce the occurrence of devitrification and the like. Therefore, the upper limit of the content ratio of the Li ₂ O component with respect to the total amount of glass in the oxide conversion composition 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.

The Na ₂ O component is an optional component that increases the stability and transparency of the glass and lowers the glass transition temperature (Tg), and is an optional component in the glass. In particular, by setting the content of the Na ₂ O component to less than 25%, it is possible to easily obtain a high refractive index, and it is possible to increase the stability of the glass and reduce the occurrence of devitrification and the like. Accordingly, the content of the Na ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably 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 K ₂ O component is an optional component that increases the stability and transparency of the glass and lowers the glass transition temperature (Tg), and is an optional component in the glass. In particular, by setting the content of the K ₂ O component to 25% or less, it is possible to easily obtain a high refractive index, and it is possible to increase the stability of the glass and reduce the occurrence of devitrification and the like. Therefore, the upper limit of the content ratio of the K ₂ O component with respect to the total amount of glass in the oxide conversion composition 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 TiO ₂ component is an optional component that increases the refractive index and dispersion of the glass and increases the chemical durability of the glass. In particular, when the content of the TiO ₂ component is 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 in 40% or less, it is possible to increase the stability and transparency of the glass. Therefore, the content of the TiO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 0%, more preferably 1%, and even more preferably 3%. On the other hand, the content of the TiO ₂ component with respect to the total amount of glass in the oxide conversion composition 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 as a raw material.

The ZrO ₂ component is an optional component that reduces the coloration of the glass to increase the transmittance for visible light of short wavelengths and promotes stable glass formation to increase the devitrification resistance of the glass. is there. In particular, by setting the content of the ZrO ₂ component to 10% or less, a 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 upper limit of the content of the ZrO ₂ component with respect to the total amount of glass in the oxide conversion composition 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.

Ta ₂ O ₅ component is a component that raises the refractive index of the glass, which is an optional component in the glass. In particular, by making the content of the Ta ₂ O ₅ component 10% or less, it is possible to make the glass difficult to devitrify. Therefore, the content of the Ta ₂ O ₅ component with respect to the total amount of glass in the oxide conversion composition 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 as a raw material.

The WO ₃ component is an optional component that increases the refractive index of the glass and increases the dispersion of the glass, and is an optional component in the glass. In particular, by making the content of the WO ₃ component 10% or less, it is possible to increase the devitrification resistance of the glass and to suppress a decrease in the transmittance of the glass with respect to visible light having a short wavelength. Accordingly, the upper limit of the content of the WO ₃ component with respect to the total amount of glass in the oxide conversion composition 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 as a raw material.

Y ₂ O ₃ component increases the refractive index of the glass is a component that has a large effect on adjustment of the dispersion, an optional component of the optical glass of the present invention. In particular, by setting the content of the Y ₂ O ₃ component to 10% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the devitrification resistance of the glass. Therefore, the upper limit of the content of the Y ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition 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 , YF ₃ or the like as a raw material.

The La ₂ O ₃ component is a component that increases the refractive index of the glass and has a great effect on adjusting the dispersion, and is an optional component in the glass. In particular, when the content of the La ₂ O ₃ component is 10% or less, the dispersion of the glass can be increased and the devitrification resistance of the glass can be increased. Therefore, the upper limit of the content of the La ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 10%, more preferably 8%, and most preferably 5%. The La ₂ O ₃ component can be contained in the glass using, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer) or the like as a raw material.

The Gd ₂ O ₃ component is a component that increases the refractive index of the glass and has a great effect on adjusting the dispersion, and is an optional component in the glass. In particular, when the content of the Gd ₂ O ₃ component is 10% or less, the dispersion of the glass can be increased and the devitrification resistance of the glass can be increased. Therefore, the upper limit of the content of the Gd ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition 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.

Bi ₂ O ₃ component is a component that raises the refractive index and dispersion of the glass, an optional component of the optical glass of the present invention. In particular, by making the content of the Bi ₂ O ₃ component 10% or less, the stability of the glass can be enhanced, so that a decrease in devitrification resistance can be suppressed and a decrease in the transmittance of the glass can be suppressed. Can do. Therefore, the content of the Bi ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 10%, more preferably 5%, and most preferably less than 1%.

The TeO ₂ component is a glass forming component and is an optional component that increases the transmittance while increasing the refractive index and dispersion of the glass. In particular, by making the content of the TeO ₂ component exceed 0%, the dispersion and refractive index of the glass can be increased, so that the desired Abbe number (ν _d ) and 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 increased. Moreover, when it contains abundantly, abrasion resistance will be deteriorated. Therefore, the content of the TeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 0%, more preferably 0.5%, and most preferably 1%. Further, the content of the TeO ₂ component is preferably 30%, more preferably 20%, and most preferably less than 5%. The TeO ₂ component can be contained in the glass using, for example, TeO ₂ as a raw material.

The SnO ₂ component is a component that reduces the oxidation of the molten glass to clarify the molten glass and makes it difficult to deteriorate the transmittance of the glass against light irradiation, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the SnO ₂ component to 6% or less, it is possible to make it difficult to cause coloration of the glass due to the reduction of the molten glass and devitrification of the glass. Further, since the alloying of the SnO ₂ component and the melting equipment (especially a noble metal such as Pt) is reduced, the life of the melting equipment can be extended. Therefore, the upper limit of the content of the SnO ₂ component with respect to the total amount of glass in the oxide conversion composition 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 with respect to visible light having a short wavelength and has a defoaming effect when the glass is melted, and is an optional component in the optical glass of the present invention. . Here, by setting the content of the Sb ₂ O ₃ component to 1.0% or less, excessive foaming hardly occurs at the time of melting the glass. Therefore, the Sb ₂ O ₃ component is dissolved in a melting facility (especially a noble metal such as Pt). And can be made difficult to alloy. Therefore, the content of the Sb ₂ O ₃ component is preferably 1.0%, more preferably 0.9%, and 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 fogging on the surface of the glass molded body. . Therefore, by setting the content of the Sb ₂ O ₃ component to 0.7% or less, the Sb component, which has been the main component of the impurities, is removed from the glass, thereby reducing impurities attached to the mold. Therefore, unevenness and fogging formed on the surface of the glass molded body can be reduced. Therefore, the content of the Sb ₂ O ₃ component is preferably 0.7%, more preferably 0.6%, and still more preferably 0.5%. In particular, in the present invention, it is most preferable to use a glass that does not substantially contain an Sb component. In the case where the press molding temperature is increased, the formation of impurities in the mold becomes significant, so that the effect of substantially not including the Sb component becomes significant.

The optical glass of the present invention preferably contains a ZnO component and a MgO component in a total amount of 5% to 50%.
Thereby, the meltability, stability, and transparency of the glass are remarkably improved, and the desired optical constant can be easily obtained. Therefore, the total amount of the ZnO component and the MgO component is preferably 5%, more preferably 7%, most preferably 9%, and preferably 50%, more preferably 45%, most preferably 40%. The upper limit.

In the optical glass 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% to 20%.
Thereby, there exists an effect which the meltability, stability, and chemical durability of glass improve significantly. Accordingly, one or two of the SiO ₂ component and the Al ₂ O ₃ component is a total amount, preferably 0.5%, more preferably 1%, most preferably 3%, preferably The upper limit is 20%, more preferably 15%, and most preferably 10%.

In the optical glass of the present invention, the R ₂ O component is preferably contained in an amount of 0% to 30%. 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 are improved, and there is an effect that it is easy to obtain a glass having a lower Tg. Therefore, the total amount of the R ₂ O component is preferably 30%, more preferably 25%, and most preferably 20%.

In the optical glass 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, it becomes possible to manufacture optical glass with higher stability. Therefore, the upper limit of R ₂ O / (ZnO + MgO) is preferably 2.0%, more preferably 1.5%, and most preferably 0.8%.

In the optical glass of the present invention, the MO component is preferably contained in an amount of 0% to 30%. Here, M is at least one selected from the group consisting of Ca, Sr, and Ba.
Thereby, it becomes possible to manufacture optical glass with higher stability. Accordingly, the upper limit of the MO component is preferably 30%, more preferably 20%, and most preferably 15%.

In the optical glass of the present invention, MO / (ZnO + MgO) is preferably 0.5 or less. Here, M is at least one selected from the group consisting of Ca, Sr, and Ba.
Thereby, it becomes possible to manufacture optical glass with higher stability. Therefore, the upper limit of MO / (ZnO + MgO) is preferably 0.5%, more preferably 0.45%, and most preferably 0.4%.

In the optical glass of the present invention, (1) P ₂ O ₅ component is 20% or more and 45% or less, Nb ₂ O ₅ component is 15% or more and 60% or less, and the total amount of ZnO component and MgO component is 5% or more and 50%. And the refractive index is 1.75 or more, the Abbe number is 10 or more and 35 or less, and (2) the SiO ₂ component and the Al ₂ O _{3 in} mol% with respect to the total amount of glass in the oxide conversion composition. It is preferable that the total amount of one or two of the components is 0.1% or more and 20% or less.
Thereby, it becomes possible to manufacture optical glass with high stability and transparency.

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

  Other components can be added to the optical glass of the present invention as needed within a range not impairing the properties of the glass of the present invention.

  However, even if each transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Mo is contained alone or in combination with a small amount, the glass is colored and has a specific wavelength in the visible range. In particular, optical glass using a wavelength in the visible region is preferably substantially free from absorption.

Furthermore, lead compounds such as PbO and arsenic compounds such as As ₂ O ₃ and components of Th, Cd, Tl, Os, Be and Se have been refraining from being used as harmful chemical substances in recent years. Environmental measures are required not only in the manufacturing process but also in the processing process and disposal after commercialization. Therefore, when importance is placed on the environmental impact, it is preferable not to substantially contain them except for inevitable mixing. As a result, the optical glass is substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking special environmental measures.

[Physical properties of optical glass]
The optical glass of the present invention has a high refractive index (n _d ) and a predetermined dispersion. In particular, the refractive index of the optical glass of the present invention _{(n d)} is preferably 1.75, more preferably 1.80, and most preferably with a lower limit on 1.84, preferably 2.20, more preferably 2. 10, most preferably 2.02. Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 10, more preferably 13, most preferably 17, the lower limit, preferably 35, more preferably 30, most preferably 24. . As a result, the degree of freedom in optical design is increased, and a large amount of light refraction can be obtained even if the device is made thinner.

Moreover, in the case of optical glass, it is necessary that there is little coloring, but the glass of this invention may be colored at the time of shape | molding by a composition. However, after that, by performing a heat treatment at a temperature in the vicinity of the glass transition point for 4 hours or more, the color disappears and a transparent glass that can satisfy the application can be obtained. In particular, when the optical glass of the present invention is represented by the transmittance of the glass, the wavelength (λ ₇₀ ) showing a spectral transmittance of 70% in a sample having a thickness of 10 mm is 500 nm or less, more preferably 480 nm or less, most preferably. Is 450 nm or less. Thereby, since the transparency of the glass in the visible region is enhanced, this optical glass can be used as a material for an optical element such as a lens. In the present invention, the glass subjected to the heat treatment after melting and slow cooling the glass material may have the above-mentioned transmittance, but from the viewpoint of eliminating the need to suppress the coloring of the glass by performing the heat treatment. More preferably, the transmittance of the glass before the heat treatment has the above-described transmittance.

[Method for producing glass molded body]
The optical glass of the present invention is produced, for example, as follows. That is, the above raw materials are uniformly mixed so that each component is within a predetermined content range, and the prepared mixture is put into a quartz crucible or an alumina crucible and roughly melted, and then a gold crucible, a platinum crucible, a platinum alloy It is prepared by melting in a crucible or iridium crucible in a temperature range of 1250-1500 ° C., stirring and homogenizing, blowing out bubbles, etc., lowering to an appropriate temperature, casting into a mold, and slow cooling. .

  As a means for producing an optical element from the thus produced optical glass, a method of grinding and polishing after reheat pressing or a method of producing a preform and performing mold pressing can be used.

  In particular, when performing mold pressing, the preform made of the optical glass of the present invention is softened by heating with a mold composed of, for example, an upper mold, a lower mold, and a sleeve mold, and press molding is performed. Do. 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 the material does not dissolve in the softened preform, and a known material is used. Can do. Among them, the material of the mold base material is preferably a known mold material such as tungsten carbide (WC), silicon carbide (SiC), or stainless steel alloy, and the protective film material is the outermost layer. Selected from the element group consisting of Pt, Au, Ir, Ni, Cr, Mo, Rh, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Re, and C A material containing at least one kind of element is preferable. By producing the mold base material from such a material, it becomes difficult for the mold base material to be deformed, so that the life of the mold can be extended. However, for ease of processing, a metal such as a stainless alloy may be used for the base material of the mold. Further, the outermost surface layer of the protective film is Pt, Au, Ir, Ni, Cr, Mo, Rh, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Re In addition, since the reaction between the softened glass and the protective film is suppressed by manufacturing the element from at least one element selected from the element group consisting of C and C, the adhesion of impurities to the protective film can be further reduced. The softening of the preform is not limited to heating by heating in the mold.

  The press molding is performed by the following procedure, for example. After the preform is placed at 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 and the mold are heated together, and when the glass constituting the preform is softened, pressing is performed by pressing the preform with the upper mold and the lower mold. As a result, the preform is pushed out into the cavity surrounded by the closed upper mold, lower mold, and sleeve mold, so that the glass can be filled into the cavity. That is, the shape of the inner surface of the cavity can be transferred to the glass.

  Here, in the mold, the cavity has a predetermined shape with respect to the relative positions of the molding surfaces of the upper mold, the lower mold, and the sleeve mold in the closed state, and the angle formed by the normal line of the molding surface. To form precisely. Further, until the press with the mold is completed, the upper mold and the lower mold are accurately maintained so that the directions of the upper mold and the lower mold face each other and the central axes of the upper mold and the lower mold coincide with each other. As a result, it is possible to produce a glass molded body in which the optical function surface and the positioning reference surface are formed with a highly accurate positional relationship and angle.

[Production of optical elements]
The optical glass of the present invention is useful for various optical elements and optical designs. In particular, the optical glass of the present invention is press-molded to produce optical elements such as lenses, prisms, and mirrors. It is preferable. As a result, when the obtained optical element is used in an optical device that transmits visible light, such as a camera and a projector, an optical system in these optical devices while realizing high-definition and high-precision imaging characteristics. Can be miniaturized.

Composition (mol%), refractive index (n _d ), Abbe number (ν _d ), glass transition temperature (° C.), yield point (At, ° C) of Examples (No. 1 to No. 32) of the present invention. ) And the measurement results of the linear expansion coefficient (10 ⁻⁷ / K) are shown in Tables 1 to 3. The following examples are merely for illustrative purposes, and are not limited to these examples.

  The optical glasses of the examples (No. 1 to No. 32) of the present invention are all oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric acids corresponding to the raw materials of the respective components. A high-purity raw material used for ordinary optical glass such as a compound is selected, weighed so as to have a composition ratio of each example shown in Tables 1 to 3, and mixed uniformly, and then a quartz crucible or platinum It put into the crucible, melt | dissolved in the temperature range of 1300-1450 degreeC with the electric furnace according to the difficulty of melting of a glass composition, and after stirring and homogenizing, it casted in the metal mold | die and produced the test piece.

  The optical glass of the comparative example had a composition in which the ZnO component and the MgO component were 0% with respect to the examples (No. 1 to No. 32) of the present invention, but did not vitrify.

Here, the refractive index (n _d ) and Abbe number (ν _d ) of the glasses of Examples (No. 1 to No. 32) were measured based on Japan Optical Glass Industry Association Standard JOGIS01-2003. The glass used in this measurement was annealed under a slow cooling furnace with a slow cooling rate of −25 ° C./hr.

Further, the glass transition temperature (° C), the yield point (At, ° C), the glass transition temperature (Tg), and the yield point (At) are measured by the Japan Optical Glass Industry Association Standard JOGIS08-2003 “Thermal expansion of optical glass. According to the “measurement method”, the temperature and the elongation of the sample were measured and obtained from the thermal expansion curve obtained.
The linear expansion coefficient (10 ⁻⁷ / K) was determined as an average linear expansion coefficient at 100 to 300 ° C. in accordance with Japan Optical Glass Industry Association Standard JOGIS08-2003 “Measurement Method of Thermal Expansion of Optical Glass”.

As shown in Tables 1 to 3, all of the optical glasses according to the examples of the present invention have an Abbe number (ν _d ) of 10 or more, more specifically 17 or more, and the Abbe number (ν _d). ) Was 35 or less, more specifically 24 or less. On the other hand, the glass of the comparative example was not vitrified.

The optical glasses of the examples of the present invention all have a refractive index (n _d ) of 1.75 or more, more specifically 1.84 or more, and this refractive index (n _d ) is 2.20 or less. More specifically, it was 2.02 or less, and was within the desired range. On the other hand, the glass of the comparative example was not vitrified.

  Furthermore, no devitrification or the like occurred in any of the optical glasses of the examples of the present invention. On the other hand, the optical glass of the comparative example was not vitrified. For this reason, it became clear that the optical glass of this invention has high devitrification resistance.

  Moreover, the optical element produced using the glass of the composition described in Examples 1-31 did not produce unevenness and fogging on the surface. For this reason, it has been clarified that the optical glass of the present invention can be stably press-molded into various optical elements, that is, lenses and prisms, while reducing unevenness and fogging on the surface of the glass molded body.

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 is 10 mm. As shown in FIG. 1, the transmittance exceeds 70% from about 430 nm, and a high transmittance of 80% or more is realized.
Here, the transmittance | permeability of glass was measured according to Japan Optical Glass Industry Association standard JOGIS02.

  Therefore, it became clear that the optical glass of the example of the present invention can reduce surface irregularities and fogging while having the desired high stability and high dispersion.

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

Claims (6)

With respect to the total amount of glass in oxide equivalent composition,
P ₂ O ₅ component is 24 % or more and 34 % or less,
15% or more and 40 % or less of Nb ₂ O ₅ component,
Bi ₂ O ₃ component 0-5% (excluding 5%),
TiO ₂ component is 0% or more and 10% or less,
WO ₃ component 1% or less,
Li ₂ O component is 10% or less,
BaO component is 15% or less,
Containing a ZnO component and a MgO component in a total amount of 9 % to 40%,
R ₂ O / (ZnO + MgO) (R is one or more selected from the group consisting of Li, Na and K) is 1.5 or less,
An optical glass having a refractive index of 1.75 or more and an Abbe number of 10 to 35. Claim containing 0.1% or more and 20% or less of the total amount of one or two of the SiO ₂ component and the Al ₂ O ₃ component in mol% with respect to the total amount of glass in oxide equivalent composition. Item 5. The optical glass according to Item 1.   The optical glass of Claim 1 or Claim 2 which contains a ZnO component 0% or more and 40% or less by mol% with respect to the glass total substance amount of an oxide conversion composition. The glass the total amount of substance of the oxide composition in terms of, in mol%, the _{R 2} O component containing 25% or less than _0%, according claim 1 R 2 O / (ZnO + MgO) is 1.5 or less Item 4. The optical glass according to any one of Items 3 to 3.
Here, R is at least one selected from the group consisting of Li, Na and K. An optical element made of the optical glass according to claim 1 . The manufacturing method of the glass forming body which press-molds in the metal mold | die with respect to the said optical glass softened using the optical glass of any one of Claims 1-4 .

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