JP2015063460A - Optical glass and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical glass and an optical element capable of reducing surface roughness and clouding while having a desired high transmittance and high dispersion.SOLUTION: The optical glass comprises, with respect to the total mass of the glass in terms of an oxide composition represented by mass%, 5.0% or more and 40.0% or less of a POcomponent, 10.0% or more and 60.0% or less of a NbOcomponent, and 5.0% or more and 45.0% or less of a TiOcomponent, and contains a SbOcomponent by 1.0 mass% or less of an external percentage with respect to an oxide-basis mass of the glass. The optical element is obtained from the above optical glass as a base material.

Description

  The present invention relates to an optical glass and an optical element.

  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, it has a high refractive index (n _d ) of 1.70 or more and 2.20 or less, which can reduce the weight and size of the optical element, and is 10 or more and 40 or less. There is a great demand for high refractive index glass having an Abbe number (ν _d ) of. As such a high refractive index glass, for example, a glass represented by Patent Document 1 is known as an optical glass having an Abbe number of 21 or less.

JP 2005-206433 A

However, the glass disclosed in Patent Document 1 has a lower transparency to visible light as the Abbe number (ν _d ) is lower (for example, the value of λ ₇₀ is larger), and a glass with a lower Abbe number (ν _d ) is yellow. Or it is colored orange. For this reason, the glass disclosed in Patent Document 1 is not suitable for use in transmitting light having a wavelength in the visible region even if it has a desired high dispersion.

In addition, the glass disclosed in Patent Document 1 essentially contains Sb ₂ O ₃ , which has stricter environmental regulations. Further, when a glass molded body is manufactured by means of press molding using glass containing Sb ₂ O ₃ as described above, unevenness and fogging are likely to occur on the surface of the glass molded body to which the shape of the mold is transferred. A glass molded body having irregularities or fogging on the surface is insufficient to meet the optical design requirements that have been increasing in recent years.

The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to achieve a desired high transmittance and high dispersion (low) even if it contains little or no Sb ₂ O _3. It is an object to provide an optical glass and an optical element having an Abbe number).

In order to solve the above-mentioned problems, the present inventors have conducted intensive test studies, and as a result, contain a predetermined amount of P ₂ O ₅ component, Nb ₂ O ₅ component and TiO ₂ component while maintaining a predetermined balance. Thus, even if the Sb ₂ O ₃ component is hardly contained, the decrease in the transmittance for visible light can be suppressed, the dispersion can be increased, and the unevenness and fogging on the surface of the glass molded body can be reduced. It came to be completed. Specifically, the present invention provides the following.

(1) the entire mass of the glass in terms of oxide composition, _P 2 _{O 5} ingredient 40.0% 5.0% or more of the following in mass%, _Nb 2 _{O 5} ingredient 10.0% or more 60.0% An optical glass containing 5.0% or more and 45.0% or less of a TiO ₂ component, and an Sb ₂ O ₃ component of 1.0% by mass or less based on an externally divided mass% with respect to the oxide-based mass.

(2) The optical glass according to (1), which contains more than 15.0% of a TiO ₂ component by mass% with respect to the total mass of the glass having an oxide equivalent composition.

(3) the entire mass of the glass in terms of oxide composition, _B less than 2 _{O 3} component from 0 to 10.0% by mass% and / or BaO component from 0 to 20.0%
The optical glass according to (1) or (2), further containing each component of

(4) The optical glass according to (3), which contains less than 2.0% of a B ₂ O ₃ component by mass% with respect to the total glass mass of the oxide equivalent composition.

(5) as oxide entire mass of the glass composition,% by mass Li ₂ O component from 0 to 10.0% and / or Na ₂ O component less than 0 to 15.0% and / or _{K 2} O ingredient 0 ~ 10.0%
The optical glass according to any one of (1) to (4), further comprising:

(6) The optical glass according to (5), wherein the Na ₂ O component is contained in an amount of% by mass with respect to the total mass of the oxide-converted composition in an amount of 4.0%.

(7) The optical glass according to (5) or (6), wherein the mass sum Li ₂ O + Na ₂ O + K ₂ O with respect to the total glass mass of the oxide equivalent composition is less than 15.0%.

(8) mass ratio _Na 2 _O in the oxide composition in terms of _{/ (Li 2 O + Na 2} O + K 2 O) is 0.40 to (5) from any one of (7) an optical glass.

(9) The optical glass according to any one of (5) to (8), which includes two or more components among a Li ₂ O component, a Na ₂ O component, and a K ₂ O component.

(10) 0 to 5.0% of MgO component and / or 0 to 10.0% of CaO component and / or 0 to 10.0% of SrO component with respect to the total glass mass of the oxide equivalent composition.
The optical glass according to any one of (1) to (9), further containing each component of

  (11) The optical glass according to (10), wherein the mass sum MgO + CaO + SrO + BaO is 20.0% or less with respect to the total glass mass of the oxide equivalent composition.

  (12) The optical glass according to (11), wherein the mass sum MgO + CaO + SrO + BaO is 12.0% or less with respect to the total glass mass of the oxide equivalent composition.

(13) the entire mass of the glass in terms of oxide composition, _Y 2 _{O 3} component from 0 to 10.0% and / or _La 2 _{O 3} component from 0 to 10.0% and / or _Gd 2 _{O 3} in mass% Ingredient 0-10.0%
The optical glass according to any one of (1) to (12), further comprising:

(14) The optical glass according to (13), wherein the mass sum Y ₂ O ₃ + La ₂ O ₃ + Gd ₂ O ₃ with respect to the total glass mass of the oxide equivalent composition is 20.0% or less.

(15) SiO ₂ component 0 to 10.0% and / or GeO ₂ component 0 to 10.0% and / or Bi ₂ O ₃ component 0 to 15% by mass with respect to the total glass mass of the oxide-converted composition 0.0% and / or ZrO ₂ component 0 to 10.0% and / or ZnO component 0 to 10.0% and / or Al ₂ O ₃ component 0 to 10.0% and / or Ta ₂ O ₅ component 0 10.0% and / or WO ₃ component 0-20.0%
The optical glass according to any one of (1) to (14), further comprising:

(16) A wavelength (λ ₇₀ ) having a refractive index (nd) of 1.70 or more and 2.20 or less, an Abbe number (νd) of 10 or more and 40 or less, and a spectral transmittance of 70% is 500 nm. The optical glass according to any one of (1) to (15) below.

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

  (18) A method for producing a glass molded body, wherein the optical glass according to any one of (1) to (16) is used and press molding is performed in a mold on the softened optical glass.

According to the present invention, a predetermined amount of P ₂ O ₅ component, Nb ₂ O ₅ component, and TiO ₂ component are contained, so that a desired high transmittance can be obtained even if only a small amount or no Sb ₂ O ₃ is contained. It is possible to provide an optical glass and an optical element that can reduce surface irregularities and haze while having a high rate and high dispersion.

In the optical glass of the present invention, the P ₂ O ₅ component is 5.0% to 40.0% and the Nb ₂ O ₅ component is 10.0 to 60.0% by mass with respect to the total mass of the oxide-converted glass. %, And TiO ₂ component is contained in an amount of 5.0 to 45.0%, and the Sb ₂ O ₃ component is 1.0% by mass or less in an externally divided mass% with respect to the oxide-based mass. 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 and an optical element that can reduce surface irregularities and fogging while having a 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 expressed in mass% with respect to the total mass of the glass in terms of oxide. 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 mass of the said production | generation oxide into 100 mass%.

<Ingredients whose content should be suppressed>
First, the component which should suppress content in the optical glass of this invention is demonstrated.

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 in the outer ratio with respect to the mass of the oxide equivalent composition is preferably 1.0%, more preferably 0.5%, and still more preferably 0.3%. 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 0.01% or less at an outer mass% based on the oxide-based mass, the Sb component that has been the main component of impurities is removed from the glass. Thereby, since the impurities adhering to the mold are reduced, 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 on an external basis with respect to the oxide-based mass is preferably 0.01%, more preferably 0.005%, and still more preferably 0.001%. 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.

In addition, the content of the Sb ₂ O ₃ component in this specification is such that the optical glass of the present invention is composed of an oxide in which all of the cation components contained in the glass and oxygen sufficient to balance the charges of these cation components are combined. Assuming that it is formed, the total mass of the glass made of these oxides is taken as 100%, and the content of the Sb ₂ O ₃ component is expressed by mass% (extraordinary division with respect to the mass based on oxide). Mass%).

<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 a component that lowers the melting temperature of the glass. In particular, the transmittance of the glass in the visible region can be increased by setting the content of the P ₂ O ₅ component to 5.0% or more. On the other hand, a high refractive index can be obtained by setting the content of the P ₂ O ₅ component to 40.0% or less. Therefore, the content of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 5.0%, more preferably 8.0%, and most preferably 10.0%, and preferably 40%. The upper limit is 0.0%, more preferably 35.0%, and most preferably 30.0%. 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.

Nb ₂ O ₅ component is a component for increasing the refractive index and dispersion of the glass. In particular, when the content of the Nb ₂ O ₅ component is 10.0% 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 60.0% or less. Therefore, the content of the Nb ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 20.0%, and most preferably 30.0%, and preferably 60%. The upper limit is 0.0%, more preferably 58.0%, and most preferably 55.0%. The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ as a raw material.

The TiO ₂ component is a 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 5.0% 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 45.0% or less, the devitrification resistance can be increased by increasing the stability of the glass. Therefore, the content of the TiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 5.0%, more preferably 8.0%, and even more preferably 11.0%. From the viewpoint of particularly enhancing the dispersion of the glass, the content of the TiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably more than 15.0%, and most preferably 16.0%. . On the other hand, the content of the TiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 45.0%, more preferably 40.0%, and most preferably 35.0%. The TiO ₂ component can be contained in the glass using, for example, TiO ₂ as a raw material.

The B ₂ O ₃ component is a component that increases devitrification resistance by promoting the formation of a stable glass, and is an optional component in the glass. In particular, by setting the content ratio of the B ₂ O ₃ component to less than 10.0%, a decrease in the refractive index due to the B ₂ O ₃ component can be suppressed, so that a high refractive index can be easily obtained. Therefore, the content of the B ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably less than 10.0%, more preferably 8.0%, and most preferably 5.0%. Here, it is preferable that the content ratio of the B ₂ O ₃ component is 2.0% or less in that the transmittance for visible light with a short wavelength is particularly increased. In particular, when paying attention to the transmittance for visible light having a short wavelength, the content of the B ₂ O ₃ component is preferably set to the upper limit of 2.0%, more preferably less than 2.0%, and still more preferably 1. The upper limit is 5%, and most preferably less than 1.0%. 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 BaO component is a component that increases the refractive index of the glass and increases the devitrification resistance of the glass, and 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 BaO component to 20.0% 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. Therefore, the content of the BaO component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 13.0% as an upper limit, still more preferably less than 5.0%, most preferably 4. The upper limit is 5%. Here, it is preferable that the content rate of the BaO component with respect to the total glass mass of the oxide conversion composition is 12.0% or less in terms of obtaining a glass having a particularly large dispersion (small Abbe number). 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, with a component that lowers the melting temperature of the glass, or to enhance the devitrification resistance when forming glass, which is an optional component in the glass. In particular, by setting the content of the Li ₂ O component to 10.0% 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 glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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 a component that lowers the melting temperature of the glass, and is a component that increases devitrification resistance during glass formation, and is an optional component in the glass. In particular, by setting the content of the Na ₂ O component to less than 15.0%, 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 content of the Na ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably less than 15.0%, more preferably 12.0%, and most preferably 10.0%. Although Na 2 _O component it is possible to obtain an optical glass having desired properties without containing, by containing a Na 2 _O component, since the liquidus temperature of the glass is increased, the glass denitrification The permeability can be further increased. Therefore, in this case, the content of the Na ₂ O component with respect to the total amount of glass in the oxide-converted composition is preferably 0.1%, more preferably 2.0% as the lower limit, and even more preferably from 4.0%. It is contained in a large amount, most preferably 4.2%. 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 a component that lowers the melting temperature of the glass, and is a component that increases devitrification resistance during glass formation, and is an optional component in the glass. In particular, by setting the content of the K ₂ O component to 10.0% 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 content of the K ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 6.0%. 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.

In the optical glass of the present invention, the mass sum of the content of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na and K) is less than 15.0%. preferable. Accordingly, since the decrease in the refractive index and dispersion by Rn 2 _O component is suppressed, it is possible to easily obtain a high refractive index and high dispersion. Moreover, since the stability of the glass is enhanced, the occurrence of devitrification and the like can be reduced. Therefore, the mass sum of the content ratio of the Rn ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably less than 15.0%, more preferably 12.0%, and most preferably 10.0%. To do. Although it is possible to obtain an optical glass having a desired high transmittance and high dispersion without containing any Rn ₂ O component, the mass sum of at least one component selected from these components can be obtained. Since the liquidus temperature of glass is raised by setting it as 0.1% or more, devitrification resistance at the time of glass formation can be improved. Therefore, the mass sum of the content ratio of the Rn ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 0.1%, more preferably 0.5%, and most preferably 1.0%.

In the optical glass of the present invention, the mass ratio of the content of the Na ₂ O component to the content of the Rn ₂ O component is preferably 0.40 or more. Thereby, since the devitrification resistance of the optical glass is enhanced, an optical glass having desired optical characteristics can be more stably produced. Even if the total amount of the Rn ₂ O component is the Na ₂ O component (that is, even if the mass ratio Na ₂ O / (Li ₂ O + Na ₂ O + K ₂ O) is 1), a desired optical glass is produced. However, when the upper limit of the mass ratio is set to 0.65 or less, the dispersion of the glass is hardly lowered, so that a desired high dispersion can be easily obtained. Therefore, the mass ratio Na ₂ O / (Li ₂ O + Na ₂ O + K ₂ O) in the oxide equivalent composition is preferably 0.40, more preferably 0.45, and most preferably 0.50. The mass ratio Na ₂ O / (Li ₂ O + Na ₂ O + K ₂ O) is preferably 0.65, more preferably 0.62, and most preferably 0.60.

Further, the optical glass of the present invention, Li ₂ O component, it is preferable to contain two or more components of the Na ₂ O component and _{K 2} O component. Thereby, since the glass transition point (Tg) of optical glass becomes low, the shaping | molding temperature in press molding can be lowered | hung, and the unevenness | corrugation and fogging of the glass surface after performing press molding can be reduced further. Here, in particular, by containing two or more components of Li ₂ O component, Na ₂ O component and K ₂ O component and keeping the BaO component within a predetermined range, the Abbe number of the glass is further reduced. Therefore, further high dispersion can be achieved.

The MgO component is a 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 MgO component is 5.0% or less, a high refractive index and high dispersion can be easily obtained. Therefore, the content of the MgO component with respect to the total glass mass of the oxide-converted composition is preferably 5.0%, more preferably 4.0%, and most preferably 3.0%. 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 a 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, by making the content of the CaO component 10.0% or less, it is possible to easily obtain a high refractive index and a high dispersion, and to suppress a decrease in the devitrification resistance and chemical durability of the glass. it can. Therefore, the content of the CaO component with respect to the total glass mass of the oxide-converted composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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 a 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, by making the content of the SrO component 10.0% or less, it is possible to easily obtain a high refractive index and a high dispersion, and to suppress a decrease in devitrification resistance and chemical durability of the glass. it can. Therefore, the content of the SrO component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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.

  In the optical glass of the present invention, the mass sum of the content ratio of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is 20.0% or less. preferable. Thereby, since the fall of the refractive index and dispersion | distribution by RO component is suppressed, it can make it easy to obtain a high refractive index and high dispersion | distribution. Therefore, the mass sum of the content ratio of the RO component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 17.0%, and most preferably 15.0%.

The Y ₂ O ₃ component is a component that increases the refractive index of the glass and improves the chemical durability of the glass, and is an optional component in the glass. In particular, when the content of the Y ₂ O ₃ component is 10.0% or less, the dispersion of the glass can be increased, and the devitrification resistance of the glass can be increased. Therefore, the content of the Y ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. Y ₂ O ₃ component, as a raw material for example using _{Y 2 O 3, YF 3,} Gd 2 O 3, GdF 3, Yb 2 O 3 or the like can be contained in the glass.

The La ₂ O ₃ component is a component that increases the refractive index of the glass and improves the chemical durability of the glass, and is an optional component in the glass. In particular, when the content of the La ₂ O ₃ component is 10.0% or less, the dispersion of the glass can be increased and the devitrification resistance of the glass can be increased. Therefore, the content of the La ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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 improves the chemical durability of the glass, and is an optional component in the glass. In particular, when the content of the Gd ₂ O ₃ component is 10.0% or less, the dispersion of the glass can be increased and the devitrification resistance of the glass can be increased. Therefore, the content of the Gd ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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.

In the optical glass of the present invention, the mass sum of the contents of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of Y, La, and Gd) is 20.0% or less. Is preferred. By making this mass sum 20.0% or less, an increase in the Abbe number due to the Ln ₂ O ₃ component can be suppressed, so that the dispersion of the glass can be increased. Therefore, the mass sum of the content of the Ln ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 10.0%, and most preferably 5.0%. .

The SiO ₂ component is a component that increases the transmittance for visible light of a short wavelength by reducing the coloring of the glass and increases the devitrification resistance of the glass by promoting stable glass formation. It is. In particular, by setting the content of the SiO ₂ component to 10.0% or less, a decrease in the refractive index due to the SiO ₂ component can be suppressed, so that a high refractive index can be easily obtained. Therefore, the content of the SiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. In particular, when paying attention to the transmittance for visible light having a short wavelength, the content of the SiO ₂ component is preferably less than 2.0%, more preferably 1.0%, and most preferably 0.8%. To do. 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 increases the refractive index of the glass and enhances the devitrification resistance of the glass by promoting stable glass formation, and is an optional component in the glass. In particular, by setting the content of the GeO ₂ component is 10.0% or less, can reduce material costs of the glass. Therefore, the content of the GeO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. The GeO ₂ component can be contained in the glass using, for example, GeO ₂ 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 15.0% or less, the stability of the glass can be improved, so that a decrease in devitrification resistance can be suppressed, and a decrease in the transmittance of the glass can be reduced. Can be suppressed. Therefore, the content ratio of the Bi ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 15.0%, more preferably 13.0%, and most preferably less than 10.0%.

The ZrO ₂ component is a component that reduces the coloration of the glass and increases the transmittance for short-wavelength visible light, promotes stable glass formation, and increases the devitrification resistance of the glass, and is an optional component in the glass. . In particular, by making the content of the ZrO ₂ component 10.0% 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 content of the ZrO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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 ZnO component is a 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 ZnO component is 10.0% or less, a high refractive index and high dispersion can be easily obtained. Therefore, the content of the ZnO component with respect to the total glass mass of the oxide-converted composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. The ZnO component can be contained in the glass using, for example, ZnO, ZnF ₂ or the like as a raw material.

The Al ₂ O ₃ component is a component that increases the viscosity at the time of glass melting while improving the chemical durability of the glass, and is an optional component in the glass. In particular, by making the content of the Al ₂ O ₃ component 10.0% 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 glass mass of the oxide-converted composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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.

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 10.0% or less, the glass can be made hard to devitrify. Therefore, the content of the Ta ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. 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 a 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 setting the content of the WO ₃ component to 20.0% 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 content of the WO ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. Although WO ₃ ingredient is possible to obtain an optical glass having a desired high dispersion and high transmittance even without containing a WO ₃ components that contain more than 0%, the dispersion of the glass is enhanced Therefore, it is possible to easily achieve both high dispersion of glass and transparency to visible light. Accordingly, the content of the WO ₃ component with respect to the total glass mass of the oxide-converted composition in this case is preferably more than 0%, more preferably 1.0%, even more preferably 3.0%, and most preferably 4. 0.0% is the lower limit. The WO ₃ component can be contained in the glass using, for example, WO ₃ as a raw material.

<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, except for Ti, Zr, Nb, W, La, Gd, Y, Yb and Lu, each transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Mo is independent of each other. Or, even when it is contained in a small amount in combination, the glass is colored and has the property of causing absorption at a specific wavelength in the visible range. .

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.

The glass composition of the present invention cannot be expressed directly in the description of mol% because the composition is expressed by mass% with respect to the total mass of the glass of oxide conversion composition, but various properties required in the present invention. The composition expressed by mol% of each component present in the glass composition satisfying the above conditions generally takes the following values in terms of oxide conversion.
P ₂ O ₅ component 5.0~40.0mol%,
Nb ₂ O ₅ component 5.0～30.0Mol% and TiO ₂ component 8.0～60.0Mol%
And _B 2 _{O 3} component 0～20.0Mol% and / or BaO component 0～20.0Mol% and / or Li ₂ O component 0～30.0Mol% and / or Na ₂ O component 0～30.0Mol% and / Or K ₂ O component 0 to 15.0 mol% and / or MgO component 0 to 20.0 mol% and / or CaO component 0 to 25.0 mol% and / or SrO component 0 to 15.0 mol% and / or Y ₂ O ₃ component 0-8.0 mol% and / or La ₂ O ₃ component 0-6.0 mol% and / or Gd ₂ O ₃ component 0-6.0 mol% and / or SiO ₂ component 0-20.0 mol% and / Or GeO ₂ component 0 to 15.0 mol% and / or Bi ₂ O ₃ component 0 to 3.0 mol% and / or ZrO ₂ component 0 to 13.0 mol% and / or ZnO component 0 to 2 0.0Mol% and / or _Al 2 _{O 3} component 0～15.0Mol% and / or _Ta 2 _{O 5} component 0～3.0Mol% and / or WO ₃ components 0～15.0Mol%

[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 1.70, more preferably 1.80, and most preferably with a lower limit on 1.91, preferably 2.20, more preferably 2. 10, most preferably 2.00 is the upper limit. Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 10, more preferably 12, most preferably 15 as a lower limit, preferably 40, more preferably 30, and most preferably 20 as an upper limit. . 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.

Further, the optical glass of the present invention needs to be less colored. 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, and most preferably. Is 470 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 putting in a crucible or iridium crucible, melting in a temperature range of 1000 to 1250 ° C, homogenizing with stirring and blowing out bubbles, then 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 by 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. Thus, 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 can be manufactured.

[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.

The composition of the embodiment of the present invention (Nanba1～nanba31) and Comparative Example (Nanba1～nanba2) (wt%), and the concentration of _Sb 2 _{O 3} component of these glasses (oxide basis Table 1 to Table 1 show the results of the wavelengths (λ ₇₀ , λ ₅ ) at which the refractive index (n _d ), the Abbe number (ν _d ), and the spectral transmittance show 70% and 5%. Table 5 shows. The following examples are merely for illustrative purposes, and are not limited to these examples.

  As for the optical glass of the Example (No.1-No.31) of this invention, and the glass of a comparative example (No.1-No.2), all are an oxide, a hydroxide, respectively corresponding as a raw material of each component, High purity raw materials used in ordinary optical glass such as carbonates, nitrates, fluorides, hydroxides, metaphosphoric acid compounds, etc. are selected so that the composition ratios of the respective examples shown in Tables 1 to 5 are obtained. And then uniformly mixed, put into a quartz crucible or platinum crucible, melted in a temperature range of 1000 to 1250 ° C. in an electric furnace depending on the melting difficulty of the glass composition, homogenized with stirring and then into the mold Casting and a test piece were produced.

Here, the refractive index (n _d ) and the Abbe number (ν _d ) of the glasses of Examples (No. 1 to No. 31) and Comparative Examples (No. 1 to No. 2) are the standards of the Japan Optical Glass Industry Association. Measurement was performed based on JOGIS01-2003. The glass used in this measurement was annealed under a slow cooling furnace with a slow cooling rate of −25 ° C./hr.

Moreover, the transmittance | permeability of the glass of an Example (No.1-No.31) and a comparative example (No.1-No.2) was measured according to Japan Optical Glass Industry Association standard JOGIS02. In the present invention, the presence / absence and degree of coloration of the glass were determined by measuring the transmittance of the glass. Specifically, the glass bulk material, a sample having a thickness of 10 ± 0.1 mm with parallel polished face, the light transmittance by the method specified in quickly JOGIS02- ¹⁹⁷⁵ after annealing (spectral transmittance) lambda ₇₀ (Wavelength at 70% transmittance) was determined.

As shown in Tables 1 to 5, all of the optical glasses of the examples of the present invention had λ ₇₀ (wavelength at 70% transmittance) of 500 nm or less, more specifically 470 nm or less. On the other hand, in the glass of the comparative example, λ ₇₀ was larger than 500 nm. For this reason, it became clear that the optical glass of the Example of this invention was hard to color compared with the glass of a comparative example.

The optical glasses of the examples of the present invention all have an Abbe number (ν _d ) of 10 or more, more specifically 15 or more, and this Abbe number (ν _d ) is 40 or less, and a desired range. It was in. More specifically, the optical glasses of Examples 1 to 20 and Examples 24 to 31 all had an Abbe number (ν _d ) of 20 or less. On the other hand, the glass of the comparative example had an Abbe number (ν _d ) greater than 20. For this reason, it became clear that the optical glass of the Example of this invention has a low Abbe number ((nu) _d ) compared with the glass of a comparative example.

The optical glasses of the examples of the present invention all have a refractive index (n _d ) of 1.70 or more, more specifically 1.91 or more, and this refractive index (n _d ) is 2.20 or less. More specifically, it was 2.00 or less, and was within the desired range. Among these, the glass described in Examples 3 to 13, Examples 15 to 17 and Examples 24 to 31 had a refractive index of 1.92 or more, and the refractive index was higher than that of the glass of the comparative example. For this reason, it became clear that the optical glass of the Example of this invention exists in the range of predetermined refractive index ( _nd ).

  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. On the other hand, the optical element produced using the glass having the composition described in Comparative Example 1 was uneven or cloudy 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.

  Therefore, it became clear that the optical glass of the example of the present invention can reduce surface irregularities and haze while having the desired high transmittance 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 (18)

The P ₂ O ₅ component is 5.0% or more and 40.0% or less, the Nb ₂ O ₅ component is 10.0% or more and 60.0% or less, and by mass% with respect to the total glass mass of the oxide conversion composition, and An optical glass containing 5.0% or more and 45.0% or less of a TiO ₂ component, and having an Sb ₂ O ₃ component of 1.0% by mass or less based on an externally divided mass% with respect to the oxide-based mass. The entire mass of the glass in terms of oxide composition, mass% of an optical glass according to claim 1, further comprising more than 15.0% of TiO ₂ component. The entire mass of the glass in terms of oxide composition, _B less than 2 _{O 3} component from 0 to 10.0% by mass% and / or BaO component from 0 to 20.0%
The optical glass of Claim 1 or 2 which further contains each component of these. Terms of oxides entire mass of the glass composition,% by mass B ₂ O ₃ component containing less than 2.0% claim 3, wherein the optical glass. Li ₂ O component 0 to 10.0% and / or Na ₂ O component 0 to less than 15.0% and / or K ₂ O component 0 to 10% by mass with respect to the total glass mass of the oxide equivalent composition. 0%
The optical glass according to claim 1, further comprising: Terms of oxides entire mass of the glass composition, according to claim 5, wherein the optical glass containing more than 4.0% of Na 2 _O component in mass%. The optical glass according to claim 5 or 6, wherein the mass sum Li ₂ O + Na ₂ O + K ₂ O is less than 15.0% relative to the total glass mass of the oxide equivalent composition. 8. The optical glass according to claim 5, wherein a mass ratio Na ₂ O / (Li ₂ O + Na ₂ O + K ₂ O) in an oxide-converted composition is 0.40 or more. The optical glass according to any one of claims 5 to 8, comprising two or more components of Li ₂ O component, Na ₂ O component, and K ₂ O component. MgO component 0 to 5.0% and / or CaO component 0 to 10.0% and / or SrO component 0 to 10.0% by mass% with respect to the total glass mass of the oxide conversion composition
The optical glass according to claim 1, further comprising:   11. The optical glass according to claim 10, wherein the mass sum MgO + CaO + SrO + BaO is 20.0% or less with respect to the total glass mass of the oxide equivalent composition.   The optical glass according to claim 11, wherein a mass sum MgO + CaO + SrO + BaO is 12.0% or less with respect to a total glass mass of an oxide conversion composition. The entire mass of the glass in terms of oxide composition, from 0 to 10.0% _Y 2 _{O 3} component in% by weight and / or _La 2 _{O 3} component from 0 to 10.0% and / or _Gd 2 _{O 3} component 0 10.0%
The optical glass according to claim 1, further comprising: The optical glass according to claim 13, wherein the sum of masses Y ₂ O ₃ + La ₂ O ₃ + Gd ₂ O ₃ with respect to the total glass mass of the oxide equivalent composition is 20.0% or less. SiO ₂ component 0 to 10.0% and / or GeO ₂ component 0 to 10.0% and / or Bi ₂ O ₃ component 0 to 15.0% by mass% with respect to the total glass mass of oxide conversion composition And / or ZrO ₂ component 0 to 10.0% and / or ZnO component 0 to 10.0% and / or Al ₂ O ₃ component 0 to 10.0% and / or Ta ₂ O ₅ component 0 to 10.0 % And / or WO ₃ component 0 to 20.0%
The optical glass according to claim 1, further comprising: The wavelength (λ ₇₀ ) having a refractive index (nd) of 1.70 or more and 2.20 or less, an Abbe number (νd) of 10 or more and 40 or less, and a spectral transmittance of 70% is 500 nm or less. The optical glass according to claim 1.   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 softened optical glass using the optical glass in any one of Claims 1-16.