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WO2012133422A1 - Optical glass, preform, and optical element - Google Patents

Optical glass, preform, and optical element Download PDF

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Publication number
WO2012133422A1
WO2012133422A1 PCT/JP2012/057957 JP2012057957W WO2012133422A1 WO 2012133422 A1 WO2012133422 A1 WO 2012133422A1 JP 2012057957 W JP2012057957 W JP 2012057957W WO 2012133422 A1 WO2012133422 A1 WO 2012133422A1
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WO
WIPO (PCT)
Prior art keywords
component
glass
optical glass
less
optical
Prior art date
Application number
PCT/JP2012/057957
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French (fr)
Japanese (ja)
Inventor
哲也 津田
Original Assignee
株式会社オハラ
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Publication date
Priority claimed from JP2011186050A external-priority patent/JP5748613B2/en
Priority claimed from JP2011186053A external-priority patent/JP5748614B2/en
Application filed by 株式会社オハラ filed Critical 株式会社オハラ
Priority to CN2012800158423A priority Critical patent/CN103459339A/en
Publication of WO2012133422A1 publication Critical patent/WO2012133422A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/12—Silica-free oxide glass compositions
    • C03C3/14—Silica-free oxide glass compositions containing boron
    • C03C3/15—Silica-free oxide glass compositions containing boron containing rare earths
    • C03C3/155—Silica-free oxide glass compositions containing boron containing rare earths containing zirconium, titanium, tantalum or niobium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C03C4/0092—Compositions for glass with special properties for glass with improved high visible transmittance, e.g. extra-clear glass

Definitions

  • the present invention relates to an optical glass, a preform, and an optical element.
  • Optical systems such as digital cameras and video cameras, although large and small, contain blurs called aberrations. This aberration is classified into monochromatic aberration and chromatic aberration. In particular, the chromatic aberration is strongly dependent on the material characteristics of the lens used in the optical system.
  • chromatic aberration is corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but this combination can only correct aberrations in the red region and the green region, and remains in the blue region.
  • This blue region aberration that cannot be removed is called a secondary spectrum.
  • the partial dispersion ratio ( ⁇ g, F) is used as an index of the optical characteristics to be noticed in the optical design.
  • an optical material having a large partial dispersion ratio ( ⁇ g, F) is used for the low dispersion side lens, and the partial dispersion ratio ( By using an optical material having a small ⁇ g, F), the secondary spectrum is corrected well.
  • the partial dispersion ratio ( ⁇ g, F) is expressed by the following equation (1).
  • ⁇ g, F (n g ⁇ n F ) / (n F ⁇ n C ) (1)
  • optical glass there is an approximately linear relationship between a partial dispersion ratio ( ⁇ g, F) representing partial dispersion in a short wavelength region and an Abbe number ( ⁇ d ).
  • the straight line representing this relationship plots the partial dispersion ratio and Abbe number of NSL7 and PBM2 on the Cartesian coordinates employing the partial dispersion ratio ( ⁇ g, F) on the vertical axis and the Abbe number ( ⁇ d ) on the horizontal axis. It is represented by a straight line connecting two points and is called a normal line (see FIG. 1).
  • Normal glass which is the standard for normal lines, differs depending on the optical glass manufacturer, but each company defines it with almost the same slope and intercept.
  • NSL7 and PBM2 are optical glasses manufactured by OHARA, Inc., and the Abbe number ( ⁇ d ) of PBM2 is 36.3, the partial dispersion ratio ( ⁇ g, F) is 0.5828, and the Abbe number ( ⁇ d ) of NSL7. Is 60.5, and the partial dispersion ratio ( ⁇ g, F) is 0.5436.
  • optical glasses as shown in Patent Documents 1 to 3 are known.
  • the glasses disclosed in Patent Documents 1 to 3 have a small partial dispersion ratio and are not sufficient for use as a lens for correcting the secondary spectrum. Further, the glasses disclosed in Patent Documents 1 to 3 are not highly transparent with respect to visible light, and are not sufficient for use in transmitting visible light. That is, there is a demand for an optical glass having a small Abbe number ( ⁇ d ), high dispersion, a small partial dispersion ratio ( ⁇ g, F), and high transparency to visible light.
  • ⁇ d Abbe number
  • ⁇ g, F small partial dispersion ratio
  • the present invention has been made in view of the above problems, and the object of the present invention is to have a small Abbe number ( ⁇ d ) and a partial dispersion while the refractive index (n d ) is within a desired range.
  • the object is to obtain an optical glass having a small ratio ( ⁇ g, F) and enhanced transparency to visible light, and a preform and an optical element using the optical glass.
  • the present inventors have conducted intensive test studies.
  • the ZrO 2 component is used in combination as necessary.
  • the glass has a high refractive index, but the glass has a desired partial dispersion ratio ( ⁇ g, F) between the Abbe number ( ⁇ d ).
  • the glass coloring is reduced while the stability of the glass is enhanced. As a result, the present invention has been completed.
  • a ZrO 2 component is used in combination, and by making these contents within a predetermined range, coloring and devitrification hardly occur when the glass is reheated. I also found out. Specifically, the present invention provides the following.
  • the glass the total amount of substance of the oxide composition in terms of, B 2 O 3 component 55.0% 25.0% or more of the following in mol%, Ln 2 O 3 ingredient 6.0% or more 30.0 % or less (wherein, Ln is La, Gd, Y, 1 or more selected from the group consisting of Yb), and Nb 2 O 5 component contains less more 25.0% than 0%, the ZrO 2 component
  • the partial dispersion ratio ( ⁇ g, F) is in the range of ⁇ d ⁇ 31 with respect to the Abbe number ( ⁇ d), ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) ⁇ ( ⁇ g, F) ⁇ ( ⁇ 0.00275 ⁇ ⁇ d + 0.68125), and in the range of ⁇ d> 31, ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) ⁇ ( ⁇ g, F) ⁇ ( ⁇ 0.00162 ⁇ ⁇ d + 0.64622 ) Optical glass that satisfies the relationship.
  • any description of the optical glass of the molar sum to the glass the total amount of substance of the oxide composition in terms of (Nb 2 O 5 + ZrO 2 + La 2 O 3) is 15.0% or more (1) to (5).
  • the molar sum of the Rn 2 O component (wherein Rn is at least one selected from the group consisting of Li, Na, K, and Cs) with respect to the total amount of glass in an oxide equivalent composition is 30.0% or less.
  • the molar sum of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Zn) with respect to the total amount of glass in an oxide equivalent composition is 35.0% or less
  • the B 2 O 3 component, the rare earth component, and the Nb 2 O 5 component are used in combination, and the content of these components and the content of the ZrO 2 component are within a predetermined range, whereby the high refractive index of the glass is obtained.
  • the partial dispersion ratio ( ⁇ g, F) of the glass has a desired relationship with the Abbe number ( ⁇ d ), and the coloring of the glass is reduced. Therefore, an optical glass having a low Abbe number ( ⁇ d ), a small partial dispersion ratio ( ⁇ g, F) and high transparency to visible light while having a refractive index (n d ) within a desired range, and A preform and an optical element using can be obtained.
  • the B 2 O 3 component is 25.0% or more and 55.0% or less, and the Ln 2 O 3 component is 6.0% in mol% with respect to the total amount of the glass having an oxide conversion composition. More than 30.0% (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, Yb), and Nb 2 O 5 component more than 0% and 25.0% or less,
  • the content of the ZrO 2 component is 10.0% or less
  • the partial dispersion ratio ( ⁇ g, F) is within the range of ⁇ d ⁇ 31 with respect to the Abbe number ( ⁇ d) ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) ⁇ ( ⁇ g, F) ⁇ ( ⁇ 0.00275 ⁇ ⁇ d + 0.68125) is satisfied, and in the range of ⁇ d> 31, ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) ⁇ ( ⁇ g, F) ⁇ ( ⁇ 0.00162 X ⁇ d + 0.64622)
  • the glass has a high refractive index. It is done.
  • the Nb 2 O 5 component is used and its content is within a predetermined range, whereby the glass is highly dispersed (lower Abbe number).
  • a rare-earth component such as La 2 O 3 component and Nb 2 O 5 component are used together with a ZrO 2 component as necessary, and the content thereof is within a predetermined range, whereby the partial dispersion ratio of the glass ( ⁇ g, F) has a desired relationship with the Abbe number ( ⁇ d ).
  • the B 2 O 3 component and the La 2 O 3 component are used in combination, and the content of these components is within a predetermined range, so that the color of the glass is reduced while the stability of the glass is enhanced. Therefore, an optical glass having a low Abbe number ( ⁇ d ), a small partial dispersion ratio ( ⁇ g, F), and a high transparency to visible light, while the refractive index (n d ) is within a desired range; A preform and an optical element using the same can be obtained.
  • each component constituting the optical glass of the present invention 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 mol% with respect to the total amount of glass in the oxide equivalent composition.
  • the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as the raw material of the glass component of the present invention are all decomposed and changed into oxides when melted. It is the composition which described each component contained in glass by making the total substance amount of the said production
  • the B 2 O 3 component is an essential component that is indispensable as a glass-forming oxide in the optical glass of the present invention containing a large amount of rare earth oxides.
  • the content of the B 2 O 3 component is preferably 25.0%, more preferably 28.0%, still more preferably 32.0%, and most preferably 36.0%.
  • the content of the B 2 O 3 component is preferably 55.0%, more preferably 50.0%, and most preferably 48.0%.
  • the B 2 O 3 component H 3 BO 3 , Na 2 B 4 O 7 , Na 2 B 4 O 7 .10H 2 O, BPO 4 or the like can be used as a raw material.
  • the molar sum of the Ln 2 O 3 component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is 6.0% or more and 30.0% or less. It is preferable that in particular, by setting the molar sum of the Ln 2 O 3 component to 6.0% or more, the glass has a low partial dispersion ratio while increasing the refractive index and Abbe number of the glass. It is possible to easily obtain a glass having a desired ratio between the partial dispersion ratio and the Abbe number. Accordingly, the lower limit of the molar sum of the Ln 2 O 3 component is preferably 6.0%, more preferably 10.0%, and most preferably 13.0%.
  • the molar sum of Ln 2 O 3 component is preferably 30.0%, more preferably 25.0%, and most preferably 22.0%.
  • the Nb 2 O 5 component is a component that increases the refractive index of the glass, decreases the Abbe number, and decreases the partial dispersion ratio.
  • the specific gravity of the glass can be reduced and the partial dispersion ratio of the glass can be reduced while increasing the refractive index of the glass and reducing the Abbe number.
  • the content of the Nb 2 O 5 component 25.0% or less, the deterioration of the devitrification resistance of the glass due to the excessive content of the Nb 2 O 5 component is suppressed, and the glass transmits visible light. Reduction in rate can be suppressed.
  • the content of the Nb 2 O 5 component is preferably more than 0%, more preferably 1.0%, still more preferably 2.0%, still more preferably 4.5%, and even more preferably 5.0. %, More preferably 5.5%, and most preferably 8.0%. Further, the content of this Nb 2 O 5 component is preferably 25.0%, more preferably 20.0%, and most preferably 17.0%.
  • Nb 2 O 5 or the like can be used as a raw material.
  • the ZrO 2 component is a component that lowers the partial dispersion ratio of the glass while increasing the refractive index of the glass to increase the devitrification resistance, and is an optional component in the optical glass of the present invention.
  • the content of the ZrO 2 component is preferably 15.0%, more preferably 12.0%, and still more preferably 10.0%.
  • the content of this ZrO 2 component is more preferably 9.0%, and even more preferably 8.0%.
  • ZrO 2 component is may not contain, by containing a ZrO 2 component, can easily lower the partial dispersion ratio while increasing the refractive index of the glass.
  • the content of the ZrO 2 component is preferably more than 0%, more preferably 0.5%, and most preferably 2.0%.
  • ZrO 2 component ZrO 2 , ZrF 4 or the like can be used as a raw material.
  • the La 2 O 3 component is a component that increases the refractive index of the glass and decreases the partial dispersion ratio, and is an optional component in the optical glass of the present invention.
  • the content of the La 2 O 3 component is preferably 30.0%, more preferably 25.0%, still more preferably 22.0%, and most preferably 20.0%.
  • the La 2 O 3 component may not be contained, but by containing the La 2 O 3 component, a glass having a small specific gravity and a high refractive index and a small partial dispersion ratio can be obtained more easily. Therefore, the content of the La 2 O 3 component is preferably more than 0%, more preferably 7.0%, still more preferably 11.0%, and most preferably 14.0%.
  • the La 2 O 3 component La 2 O 3 , La (NO 3 ) 3 .XH 2 O (X is an arbitrary integer) or the like can be used as a raw material.
  • the Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component are components that increase the refractive index of the glass, and are optional components in the optical glass of the present invention.
  • the devitrification resistance of the glass can be increased by setting the content of each of the Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component to 15.0% or less.
  • the number can be made difficult to increase.
  • the upper limit of each content of the Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%.
  • Gd 2 O 3 component, Gd 2 O 3 component, and Yb 2 O 3 component Gd 2 O 3 , GdF 3 , Y 2 O 3 , YF 3 , Yb 2 O 3 and the like can be used as raw materials.
  • the ratio of the content of the La 2 O 3 component to the content of the Ln 2 O 3 component is preferably 0.5 or more.
  • the content of the La 2 O 3 component which has a strong effect of reducing the partial dispersion ratio among rare earth elements, is relatively increased, so that the partial dispersion ratio is reduced while obtaining the desired devitrification resistance of the glass. can do. Therefore, the molar ratio La 2 O 3 / Ln 2 O 3 in the oxide equivalent composition is preferably 0.5, more preferably 0.7, and most preferably 0.8.
  • the upper limit of this ratio is not particularly limited, and may be 1.0.
  • the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component is preferably more than 4.6% and not more than 30.0%.
  • the sum is more than 4.6%, the components that lower the partial dispersion ratio increase, so that an optical glass having a lower partial dispersion ratio can be obtained.
  • the solubility and devitrification resistance of the glass can be improved.
  • the molar sum (Nb 2 O 5 + ZrO 2 ) is preferably more than 4.6%, more preferably more than 5.0%, still more preferably more than 5.8%, most preferably 9 More than 0%.
  • the molar sum (Nb 2 O 5 + ZrO 2 ) is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%.
  • the sum of the contents of the Nb 2 O 5 component, the ZrO 2 component, and the La 2 O 3 component is preferably 15.0% or more.
  • the molar sum (Nb 2 O 5 + ZrO 2 + La 2 O 3 ) is preferably 15.0%, more preferably 20.0%, still more preferably 23.0%, and most preferably 26.4%.
  • the sum of the total amount of these components is not limited as long as stable glass is obtained, the solubility and devitrification resistance of glass can be improved by making it 50.0% or less, for example.
  • this molar sum (Nb 2 O 5 + ZrO 2 + La 2 O 3 ) is preferably 50.0%, more preferably 45.0%, and most preferably 40.0%.
  • the TiO 2 component is a component that lowers the Abbe number and improves devitrification resistance while increasing the refractive index of the glass, and is an optional component in the optical glass of the present invention.
  • the content of the TiO 2 component is 20.0% or less, the coloring of the glass can be reduced, and the internal transmittance of the glass at a visible short wavelength (500 nm or less) can be increased.
  • the content of the TiO 2 component below 20.0%, because the partial dispersion ratio is hard to rise, it is possible to easily obtain a glass having a low partial dispersion ratio.
  • the upper limit of the content of the TiO 2 component is preferably 20.0%, more preferably 15.0%, still more preferably 9.0%, still more preferably 8.1%, and even more preferably 7.0%. And more preferably less than 5.0%, and most preferably 2.8%.
  • TiO 2 component TiO 2 or the like can be used as a raw material.
  • the sum of the contents of the Nb 2 O 5 component and the TiO 2 component is preferably more than 6.5% and 35.0% or less.
  • the lower limit of the molar sum (Nb 2 O 5 + TiO 2 ) is preferably more than 6.5%, more preferably 8.0%, and most preferably 9.0%.
  • the molar sum (Nb 2 O 5 + TiO 2 ) is preferably 35.0%, more preferably less than 30.0%, even more preferably 25.0%, and most preferably 20.0%. % Is the upper limit.
  • the ratio of the content of the TiO 2 component to the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component is preferably 1.00 or less.
  • the content of the TiO 2 component that increases the partial dispersion ratio is relative to the content of the Nb 2 O 5 component and the ZrO 2 component that decrease the partial dispersion ratio. Therefore, an optical glass having a lower partial dispersion ratio can be obtained. This also to reduce the content of TiO 2 component to color the glass, it is possible to obtain an optical glass that is preferably used in applications which transmits visible light.
  • the molar ratio TiO 2 / (Nb 2 O 5 + ZrO 2 ) of the oxide conversion composition is preferably 1.00, more preferably 0.80, and most preferably 0.70.
  • the lower limit of this molar ratio is not particularly limited, and may be 0.
  • the WO 3 component is a component that increases the refractive index of the glass to lower the Abbe number and increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention.
  • the content of the WO 3 component 30.0% or less, an increase in the partial dispersion ratio of the glass can be suppressed, and the transmittance of the glass with respect to visible light can be made difficult to decrease.
  • devitrification and coloring by reheating can be reduced by reducing the WO 3 component.
  • the upper limit of the content of the WO 3 component is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%.
  • the WO 3 component may not be contained, but by containing the WO 3 component, a glass having a desired high refractive index and a low Abbe number and having high devitrification resistance can be obtained. Therefore, the content of the WO 3 component is preferably more than 0%, more preferably 1.0%, still more preferably 1.7%, and most preferably 2.5%. As the WO 3 component, WO 3 or the like can be used as a raw material.
  • the molar sum of the TiO 2 component and the WO 3 component is preferably 35.0% or less.
  • the molar sum (TiO 2 + WO 3 ) is preferably 35.0%, more preferably less than 33.0%, still more preferably 25.0%, and most preferably 20.0%.
  • the molar sum may be 0% from the viewpoint of further increasing the visible light transmittance, but by increasing the molar sum, the refractive index can be further increased and the Abbe number can be further decreased.
  • the molar sum (TiO 2 + WO 3 ) is preferably more than 0%, more preferably 1.0%, still more preferably 3.0%, and most preferably 5.0%.
  • the ratio of the sum of the contents of the TiO 2 component and the WO 3 component to the sum of the contents of the ZrO 2 component and the B 2 O 3 component is preferably 0.700 or less.
  • the molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in the oxide equivalent composition is preferably 0.700, more preferably 0.600, and most preferably 0.500.
  • this ratio may be 0, it is possible to easily obtain a desired refractive index and dispersion by making this molar ratio larger than 0.
  • the molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in the oxide equivalent composition is preferably greater than 0, more preferably 0.050, and most preferably 0.100. .
  • the MgO component, CaO component, SrO component, and BaO component are components that adjust the refractive index, meltability, and devitrification of the glass, and are optional components in the optical glass of the present invention.
  • the content of MgO component 15.0% or less, or by making the content of CaO component, SrO component and / or BaO component 20.0% or less, the refractive index of these components can be reduced. Reduction and devitrification can be reduced. Further, this can suppress an increase in the partial dispersion ratio. Therefore, the content of the MgO component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%.
  • the content of the CaO component is preferably 20.0%, more preferably 15.0%, still more preferably 13.0%, still more preferably 10.0%, and most preferably 7.5%. To do.
  • the contents of the SrO component and the BaO component are each preferably 20.0%, more preferably 15.0%, still more preferably 9.0%, still more preferably 7.5%, and most preferably 4.8. % Is the upper limit.
  • MgCO 3 , MgF 2 , CaCO 3 , CaF 2 , Sr (NO 3 ) 2 , SrF 2 , BaCO 3 , Ba (NO 3 ) 2 , BaF 2 and the like can be used as raw materials.
  • the ZnO component is a component that lowers the glass transition point (Tg) and lowers the melting temperature of the glass raw material, and is an optional component in the optical glass of the present invention.
  • devitrification of the glass can be reduced by setting the content of the ZnO component to 35.0% or less. This can also reduce the specific gravity of the glass and suppress the increase in the partial dispersion ratio.
  • the upper limit of the content of the ZnO component is preferably 35.0%, more preferably 30.0%, further preferably 25.0%, further preferably 20.0%, and most preferably 15.0%. To do.
  • the content of the ZnO component is preferably more than 0%, more preferably 1.0%, still more preferably 5.0%, and most preferably 8.0%.
  • ZnO component ZnO, ZnF 2 or the like can be used as a raw material.
  • the RO component (wherein R is one or more selected from the group consisting of Zn, Mg, Ca, Sr, and Ba) is a useful component for increasing the devitrification resistance of the glass.
  • R is one or more selected from the group consisting of Zn, Mg, Ca, Sr, and Ba
  • the total content of RO components is preferably 35.0%, more preferably 25.0%, and most preferably 20.0%.
  • the Li 2 O component is a component that lowers the glass transition point and lowers the partial dispersion ratio of the glass, and is an optional component in the optical glass of the present invention.
  • the upper limit of the content of the Li 2 O component is preferably 25.0%, more preferably 12.0%, and most preferably 7.0%.
  • Li 2 CO 3 , LiNO 3 , LiF, or the like can be used as a raw material.
  • the Na 2 O component and the K 2 O component are components that improve the meltability of the glass, lower the glass transition point, and increase the devitrification resistance of the glass, and are optional components in the optical glass of the present invention. .
  • the content of the Na 2 O component and / or the K 2 O component 25.0% or less, the refractive index of the glass is hardly lowered and the devitrification of the glass can be reduced. Therefore, the content of the Na 2 O component and the K 2 O component is preferably 25.0%, more preferably 12.0%, and most preferably 7.0%, respectively.
  • the Na 2 O component and the K 2 O component may use Na 2 CO 3 , NaNO 3 , NaF, Na 2 SiF 6 , K 2 CO 3 , KNO 3 , KF, KHF 2 , K 2 SiF 6, etc. as raw materials. it can.
  • Cs 2 O component is a component to lower the glass transition point, which is an optional component of the optical glass of the present invention.
  • devitrification of the glass can be reduced by setting the content of the Cs 2 O component to 10.0% or less.
  • the content of the Cs 2 O component is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
  • Cs 2 O component Cs 2 CO 3 , CsNO 3 or the like can be used as a raw material.
  • the sum of the contents of the Rn 2 O component (wherein Rn is one or more selected from the group consisting of Li, Na, K and Cs) is 30.0% or less. Is preferred.
  • the molar sum is 30.0% or less, the refractive index of the glass is hardly lowered, and devitrification at the time of glass formation can be reduced.
  • devitrification and coloring by reheating can be reduced by reducing the Rn 2 O component. Therefore, the upper limit of the molar sum of the content of the Rn 2 O component is preferably 30.0%, more preferably 20.0%, still more preferably 15.0%, and most preferably 10.0%.
  • the optical glass of the present invention it is preferable that (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) is 0.70 or more.
  • B 2 O 3 component and the ZrO 2 component, Ln 2 O 3 component and WO 3 to increase devitrification or coloring at this time to reduce the devitrification or coloring when performing reheating the glass Since it increases relative to the component and the Rn 2 O component, devitrification and coloring during reheating hardly occur, and an optical glass having high press moldability can be easily obtained.
  • the molar ratio (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) of the oxide equivalent composition is preferably 0.70, more preferably 0.90, and most preferably 1.00. Is the lower limit.
  • the upper limit of the molar ratio is not particularly limited, but the molar ratio of the optical glass of the present invention is generally 5.00 or less, more specifically 4.00 or less, and more specifically 3.00 or less. There are many cases.
  • the SiO 2 component is a component that increases the viscosity of the molten glass, promotes stable glass formation, and reduces devitrification (generation of crystal) that is not desirable as an optical glass, and is an optional component in the optical glass of the present invention. .
  • the content of SiO 2 component is preferably 20.0%, more preferably 13.0%, still more preferably 8.0%, still more preferably 6.0%, still more preferably 3.5%,
  • the upper limit is 3.3%.
  • the content of this SiO 2 component is 1.7% or less. Further, from the viewpoint of easily obtaining a lower partial dispersion ratio and a high refractive index, it is also preferable that no SiO 2 component is contained.
  • SiO 2 component SiO 2 , K 2 SiF 6 , Na 2 SiF 6 or the like can be used as a raw material.
  • the ratio of the content of the SiO 2 component to the content of the B 2 O 3 component is preferably 0.50 or less.
  • the upper limit of the molar ratio (SiO 2 / B 2 O 3 ) in the oxide equivalent composition is preferably 0.50, more preferably 0.30, and most preferably 0.10.
  • P 2 O 5 component is a component which enhances the devitrification resistance, which is an optional component of the optical glass of the present invention.
  • the content of the P 2 O 5 component is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%.
  • Al (PO 3 ) 3 , Ca (PO 3 ) 2 , Ba (PO 3 ) 2 , BPO 4 , H 3 PO 4 or the like can be used as a raw material.
  • GeO 2 component increases the refractive index of the glass, or to enhance resistance to devitrification, which is an optional component of the optical glass of the present invention.
  • the content of the GeO 2 component is 20.0% or less, the amount of expensive GeO 2 component used is reduced, so that the material cost of the glass can be reduced.
  • the content of the GeO 2 component is preferably 20.0%, more preferably 10.0%, further preferably 4.0%, and most preferably 1.4%.
  • the GeO 2 component GeO 2 or the like can be used as a raw material.
  • the Ta 2 O 5 component is a component that increases the refractive index of the glass, decreases the partial dispersion ratio of the glass, and increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention.
  • the content of Ta 2 O 5 component is 7.5% or less, the amount of Ta 2 O 5 component, which is a rare mineral resource, is reduced, and the glass is easily melted at a lower temperature. The production cost can be reduced. Further, it is possible to easily obtain an optical glass having a lower partial dispersion ratio and a lower specific gravity. Therefore, the content of the Ta 2 O 5 component is preferably 7.5%, more preferably 5.0%, still more preferably 3.0%, still more preferably 2.0%, still more preferably 1.0%. Is the upper limit. In particular, from the viewpoint of further reducing the glass production cost, it is most preferable not to contain a Ta 2 O 5 component. As the Ta 2 O 5 component, Ta 2 O 5 or the like can be used as a raw material.
  • the Bi 2 O 3 component is a component that raises the refractive index of the glass to lower the Abbe number and lowers the glass transition point (Tg), and is an optional component in the optical glass of the present invention.
  • an increase in the partial dispersion ratio of the glass can be suppressed by setting the content of the Bi 2 O 3 component to 15.0% or less.
  • the content of the Bi 2 O 3 component is preferably 15.0%, more preferably 10.0%, still more preferably 5.0%, still more preferably 3.0%, and most preferably 1.0%. Is the upper limit.
  • Bi 2 O 3 component Bi 2 O 3 or the like can be used as a raw material.
  • the TeO 2 component is a component that increases the refractive index of the glass, lowers the partial dispersion ratio of the glass, and lowers the glass transition point (Tg), and is an optional component in the optical glass of the present invention.
  • the content of the TeO 2 component is preferably 30.0%, more preferably 15.0%, and still more preferably 7.0%.
  • TeO 2 has a problem that it can be alloyed with platinum when melting a glass raw material in a crucible made of platinum or a melting tank in which a portion in contact with molten glass is formed of platinum. Therefore, particularly from the viewpoint of reducing alloying with platinum, the content of the TeO 2 component is most preferably less than 0.2%.
  • TeO 2 component can use TeO 2 or the like as a raw material.
  • the Al 2 O 3 component is a component that improves the chemical durability of the glass and improves the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention.
  • the upper limit of the content of the Al 2 O 3 component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%.
  • Al 2 O 3 component Al 2 O 3 , Al (OH) 3 , AlF 3 or the like can be used as a raw material.
  • the Sb 2 O 3 component is a component that defoams the molten glass and is an optional component in the optical glass of the present invention. If sb 2 O 3 content is too high, the transmittance in the short wavelength region of the visible light region is deteriorated. Accordingly, the content of the Sb 2 O 3 component is preferably 1.0%, more preferably 0.5%, and most preferably 0.3%.
  • Sb 2 O 3 component Sb 2 O 3 , Sb 2 O 5 , Na 2 H 2 Sb 2 O 7 .5H 2 O, or the like can be used as a raw material.
  • components of the fining defoaming of glass is not limited to the above Sb 2 O 3 ingredients may be used known refining agents and defoamers in the field of glass production, or a combination thereof .
  • optical glass of the present invention other components can be added as needed within a range not impairing the properties of the glass.
  • the transition metal components such as V, Cr, Mn, Co, Ni, Cu, Ag, and Mo, excluding Ti, Zr, and Nb, are colored by the glass even when each of them is contained alone or in combination. Since it has a property of causing absorption at a specific wavelength in the visible range, it is preferable that the optical glass using the wavelength in the visible range does not substantially contain.
  • lead compounds such as PbO, 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.
  • the optical glass is substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking any special environmental measures.
  • the glass that is preferably used as the optical glass of the present invention cannot be expressed directly in the description of mass% because the composition is expressed in mol% with respect to the total amount of glass of oxide conversion composition.
  • the composition expressed by mass% of each component present in the glass composition satisfying various required properties generally takes the following values in terms of oxide composition.
  • composition expressed by mass% of the ZrO 2 component contained in the optical glass of the present invention may be generally 0 to 7.0 mass% in terms of oxide.
  • 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 platinum crucible, a quartz crucible or an alumina crucible and roughly melted, then a gold crucible, a platinum crucible In a platinum alloy crucible or iridium crucible, melt in a temperature range of 1100 to 1400 ° C. for 3 to 5 hours, stir and homogenize to blow out bubbles, etc., then lower the temperature to 1000 to 1300 ° C. and then finish stirring This is done by removing the striae, casting into a mold and slow cooling.
  • the optical glass of the present invention preferably has a predetermined refractive index and dispersion (Abbe number). More specifically, the refractive index (n d ) of the optical glass of the present invention is preferably 1.80, more preferably 1.83, and most preferably 1.85. On the other hand, the upper limit of the refractive index (n d ) of the optical glass of the present invention is generally 2.00 or less, more specifically 1.97 or less, and more specifically 1.95 or less in many cases. Moreover, the Abbe number ( ⁇ d ) of the optical glass of the present invention is preferably 40, more preferably 38, more preferably 35, and most preferably less than 33.
  • the lower limit of the Abbe number ( ⁇ d ) of the optical glass of the present invention is generally 20 or more, more specifically 23 or more, and more specifically 25 or more in many cases.
  • 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.
  • the optical glass of the present invention has a low partial dispersion ratio ( ⁇ g, F). More specifically, the partial dispersion ratio ( ⁇ g, F) of the optical glass of the present invention is within the range of ⁇ d ⁇ 31 with respect to the Abbe number ( ⁇ d ) ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822). ⁇ ( ⁇ g, F) ⁇ ( ⁇ 0.00275 ⁇ ⁇ d + 0.68125) is satisfied, and ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) ⁇ ( ⁇ g, F) ⁇ ( ⁇ in the range of ⁇ d > 31 0.00162 ⁇ ⁇ d + 0.64622).
  • the lower limit of the partial dispersion ratio ( ⁇ g, F) of the optical glass at ⁇ d ⁇ 31 is preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822), more preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.63922), Most preferred is ( ⁇ 0.00162 ⁇ ⁇ d + 0.64022).
  • the upper limit of the partial dispersion ratio ( ⁇ g, F) of the optical glass at ⁇ d ⁇ 31 is preferably ( ⁇ 0.00275 ⁇ ⁇ d + 0.68125), more preferably ( ⁇ 0.00275 ⁇ ⁇ d + 0.68025), Most preferred is ( ⁇ 0.00275 ⁇ ⁇ d + 0.67925).
  • the lower limit of the partial dispersion ratio ( ⁇ g, F) of the optical glass at ⁇ d > 31 is preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822), more preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.63922), most preferably Preferably, it is ( ⁇ 0.00162 ⁇ ⁇ d + 0.64022).
  • the upper limit of the partial dispersion ratio ( ⁇ g, F) of the optical glass at ⁇ d > 31 is preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.64622), more preferably ( ⁇ 0.00162 ⁇ ⁇ d + 0.64522). Most preferred is ( ⁇ 0.00162 ⁇ ⁇ d + 0.64422).
  • the partial dispersion ratio ( ⁇ g, F) of general glass is higher than that of the normal line, and the partial dispersion ratio ( ⁇ g, F) of general glass is high.
  • the Abbe number ( ⁇ d ) are represented by curves.
  • the optical glass of this invention has little coloring.
  • the wavelength ( ⁇ 70 ) indicating a spectral transmittance of 70% in a sample having a thickness of 10 mm is 500 nm or less, more preferably 470 nm or less, and still more preferably. Is 450 nm or less, and most preferably 430 nm or less.
  • the optical glass of the present invention has a wavelength ( ⁇ 80 ) of 560 nm or less, more preferably 540 nm or less, and most preferably, when the sample has a thickness of 10 mm and exhibits a spectral transmittance of 80%.
  • a wavelength ( ⁇ 5 ) showing a spectral transmittance of 5% in a sample having a thickness of 10 mm is 420 nm or less, more preferably 400 nm or less, and most preferably 380 nm or less.
  • this optical glass can be preferably used as a material for an optical element such as a lens.
  • the optical glass of the present invention preferably has a small specific gravity. More specifically, the specific gravity of the optical glass of the present invention is preferably 5.00 [g / cm 3 ] or less. Thereby, since the mass of an optical element and an optical apparatus using the same is reduced, it can contribute to the weight reduction of an optical apparatus. Therefore, the specific gravity of the optical glass of the present invention is preferably 5.00, more preferably 4.90, and preferably 4.80.
  • the specific gravity of the optical glass of the present invention is generally about 3.00 or more, more specifically 3.50 or more, and more specifically 4.00 or more in many cases.
  • the specific gravity of the optical glass of the present invention is measured based on Japan Optical Glass Industry Association Standard JOGIS05-1975 “Method for Measuring Specific Gravity of Optical Glass”.
  • the optical glass of the present invention preferably has good press formability. That is, the optical glass of the present invention divides the transmittance of light (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (ii) by the transmittance of d-line of the test piece before the reheating test.
  • the measured value is preferably 0.95 or more.
  • a lambda 70 is a wavelength at which the transmittance of the reheating test (a) before the specimen is 70% and the difference between the lambda 70 of the test piece after the reheating test is 20nm or less.
  • the value obtained by dividing the transmittance of the light beam (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (ii) by the transmittance of the d-line of the test piece before the reheating test (ii) is The lower limit is preferably 0.95, more preferably 0.96, and most preferably 0.97.
  • the difference between the lambda 70 of the test piece after the reheating test and lambda 70 of reheating test (a) prior to the test piece (b) is preferably 20 nm, more preferably 18 nm, and most preferably a maximum of 16nm To do.
  • reheating test (A) a test piece 15 mm ⁇ 15 mm ⁇ 30 mm is reheated, and the temperature is raised from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes. This is carried out by keeping the temperature at 80 ° C. higher than the transition temperature (Tg) for 30 minutes, then naturally cooling to room temperature, and polishing the two opposing surfaces of the test piece to a thickness of 10 mm and visually observing them.
  • Tg transition temperature
  • a glass molded body can be produced from the produced optical glass by means of mold press molding such as reheat press molding or precision press molding. That is, a preform for mold press molding is prepared from optical glass, and after performing reheat press molding on the preform, polishing is performed to prepare a glass molded body, or for example, polishing is performed.
  • the preform can be precision press-molded to produce a glass molded body.
  • the means for producing the glass molded body is not limited to these means.
  • the glass molded body produced in this manner is useful for various optical elements, and among them, it is particularly preferable to use for optical elements such as lenses and prisms.
  • optical elements such as lenses and prisms.
  • color bleeding due to chromatic aberration in the transmitted light of the optical system provided with the optical element is reduced. Therefore, when this optical element is used in a camera, a photographing object can be expressed more accurately, and when this optical element is used in a projector, a desired image can be projected with higher definition.
  • the glasses of the examples and comparative examples of the present invention are ordinary optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and metaphosphate compounds corresponding to the raw materials of the respective components.
  • the high-purity raw materials used in the above are selected, weighed so as to have the composition ratios of the examples and comparative examples shown in Tables 1 to 11, and mixed uniformly, and then put into a platinum crucible, and glass
  • permeability of the glass of an Example and a comparative example was measured according to Japan Optical Glass Industry Association standard JOGIS02.
  • the presence / absence and degree of coloration of the glass were determined by measuring the transmittance of the glass.
  • a face parallel polished product having a thickness of 10 ⁇ 0.1 mm was measured for a spectral transmittance of 200 to 800 nm in accordance with JISZ8722, and ⁇ 5 (wavelength at a transmittance of 5%), ⁇ 70 (transmittance).
  • the wavelength at 70%) and ⁇ 80 (wavelength at 80% transmittance) were determined.
  • permeability before and after the reheating test (ii) of the glass of an Example and a comparative example was measured as follows.
  • the value obtained by dividing the transmittance of the light beam (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (b) by the d-line transmittance of the test piece before the reheating test is the reheating test (b).
  • the front and rear glasses were subjected to the Japan Optical Glass Industry Association Standard JOGIS02-2003.
  • the d-line spectral transmittance of a face-parallel polished product having a thickness of 10 ⁇ 0.1 mm was measured in accordance with JISZ8722, and (d-line transmittance after reheating test (ii)) / (reheated)
  • the d-line transmittance before the test (A) was determined, and the change in the maximum transmittance before and after the reheating test (A) was evaluated.
  • the difference between ⁇ 70 which is the wavelength at which the transmittance of the test piece before the reheating test (A) becomes 70%, and ⁇ 70 of the test piece after the reheating test is the same as before and after the reheating test (A).
  • the glass calculated lambda 70 (the wavelength when the transmittance of 70%) in the above test method, the test piece after the reheating test and lambda 70 of reheating test (a) prior to the test piece (a) lambda
  • Tg transition temperature
  • the optical glasses of the examples of the present invention have a partial dispersion ratio ( ⁇ g, F) of ( ⁇ 0.00275 ⁇ ⁇ d + 0.68125) or less when ⁇ d ⁇ 31. More specifically, it was ( ⁇ 0.00275 ⁇ ⁇ d + 0.68020) or less. In the case of ⁇ d > 31, the partial dispersion ratio ( ⁇ g, F) was ( ⁇ 0.00162 ⁇ ⁇ d + 0.64622) or less, more specifically, ( ⁇ 0.00162 ⁇ ⁇ d + 0.64538) or less.
  • the partial dispersion ratio ( ⁇ g, F) is ( ⁇ 0.00162 ⁇ ⁇ d + 0.63822) or more, more specifically ( ⁇ 0.00162 ⁇ ⁇ d + 0.64050) or more.
  • Met the relationship between the partial dispersion ratio ( ⁇ g, F) and the Abbe number ( ⁇ d ) for the glass of the example of the present application is as shown in FIG. Therefore, it was found that these partial dispersion ratios ( ⁇ g, F) are within a desired range.
  • the glasses of the comparative examples No. A, No. C to No.
  • the optical glass of the example of the present invention has a smaller partial dispersion ratio ( ⁇ g, F) in the relational expression with the Abbe number ( ⁇ d ) than the glass of the 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 1.89 or more, and this refractive index (n d ) is 2.20 or less. More specifically, it was 1.94 or less, and was within a desired range.
  • the optical glasses of the examples of the present invention each have an Abbe number ( ⁇ d ) of 20 or more, more specifically 29 or more, and this Abbe number ( ⁇ d ) of 40 or less, more specifically 33. And within the desired range.
  • the glass of the comparative example of the present invention (No. D) is, [nu d was more than 34. Therefore, it has been clarified that the optical glass of the example of the present invention has a smaller Abbe number ( ⁇ d ) than the glass of the comparative example (No. D).
  • optical glasses of the examples of the present invention all had a specific gravity of 5.00 or less, more specifically 4.78 or less, and were within a desired range.
  • each of ⁇ 70 (wavelength at a transmittance of 70%) was 500 nm or less, more specifically, 434 nm or less.
  • the optical glasses of the examples of the present invention all had ⁇ 5 (wavelength at 5% transmittance) of 420 nm or less, more specifically 371 nm or less.
  • the optical glasses of the examples of the present invention each had a ⁇ 80 (wavelength at 80% transmittance) of 560 nm or less, more specifically 531 nm or less. For this reason, it became clear that the optical glass of the Example of this invention has the high transmittance
  • the optical glass of the example of the present invention has a high transmittance for visible light and a small chromatic aberration, while the refractive index (n d ) and the Abbe number ( ⁇ d ) are within the desired ranges. became.
  • the optical glass of the Example of this invention is the value which divided
  • D) of the present invention has the d-line transmittance of the test piece after the reheating test (ii) and the d-line transmittance of the test piece before the reheating test.
  • the transmittance was less than 70% for all wavelengths of visible light. Therefore, it became clear that the optical glass of the example of the present invention is less likely to be colored or devitrified by reheating than the glass of the comparative examples (No. C, No. D).

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Abstract

Provided is an optical glass exhibiting enhanced transparency with regard to visible light and having a small Abbe number (νd) and partial dispersion ratio (θg,F) while the refraction index (nd) is within a desired range. The optical glass contains, in mol% relative to the entire amount of the glass in terms of oxides, 25.0% to 55.0% of a B2O3 component and 6.0% to 30.0% of an Ln2O3 component (in the formula, Ln represents one or more element selected from among La, Gd, Y, and Yb), and more than 0% to 25.0% or less of an Nb2O5 component, and has a ZrO2 component content of 15.0% or less, wherein the partial dispersion ratio (θg,F) and the Abbe number (νd) satisfy the relationship of (-0.00162×νd+0.63822)≤(θg,F)≤(-0.00275×νd+0.68125) when νd≤31 and satisfy the relationship of (-0.00162×νd+0.63822)≤(θg,F)≤(-0.00162×νd+0.64622) when νd>31.

Description

光学ガラス、プリフォーム及び光学素子Optical glass, preform and optical element
　本発明は、光学ガラス、プリフォーム及び光学素子に関する。 The present invention relates to an optical glass, a preform, and an optical element.
　デジタルカメラやビデオカメラ等の光学系は、その大小はあるが、収差と呼ばれるにじみを含んでいる。この収差は単色収差と色収差に分類されるが、特に色収差は、光学系に使用されるレンズの材料特性に強く依存している。 Optical systems such as digital cameras and video cameras, although large and small, contain blurs called aberrations. This aberration is classified into monochromatic aberration and chromatic aberration. In particular, the chromatic aberration is strongly dependent on the material characteristics of the lens used in the optical system.
　一般に色収差は、低分散の凸レンズと高分散の凹レンズとを組み合わせて補正されるが、この組み合わせでは赤色領域と緑色領域の収差の補正しかできず、青色領域の収差が残る。この除去しきれない青色領域の収差を二次スペクトルと呼ぶ。二次スペクトルを補正するには、青色領域のｇ線（４３５．８３５ｎｍ）の動向を加味した光学設計を行う必要がある。このとき、光学設計で着目される光学特性の指標として、部分分散比（θｇ，Ｆ）が用いられている。上述の低分散のレンズと高分散のレンズとを組み合わせた光学系では、低分散側のレンズに部分分散比（θｇ，Ｆ）の大きい光学材料を用い、高分散側のレンズに部分分散比（θｇ，Ｆ）の小さい光学材料を用いることで、二次スペクトルが良好に補正される。 Generally, chromatic aberration is corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but this combination can only correct aberrations in the red region and the green region, and remains in the blue region. This blue region aberration that cannot be removed is called a secondary spectrum. In order to correct the secondary spectrum, it is necessary to perform an optical design in consideration of the trend of the g-line (435.835 nm) in the blue region. At this time, the partial dispersion ratio (θg, F) is used as an index of the optical characteristics to be noticed in the optical design. In the optical system combining the low dispersion lens and the high dispersion lens, an optical material having a large partial dispersion ratio (θg, F) is used for the low dispersion side lens, and the partial dispersion ratio ( By using an optical material having a small θg, F), the secondary spectrum is corrected well.
　部分分散比（θｇ，Ｆ）は、下式（１）により示される。
θｇ，Ｆ＝（ｎｇ－ｎＦ）／（ｎＦ－ｎＣ）・・・・・・（１） The partial dispersion ratio (θg, F) is expressed by the following equation (1).
θg, F = (n g −n F ) / (n F −n C ) (1)
　光学ガラスには、短波長域の部分分散性を表す部分分散比（θｇ，Ｆ）とアッベ数（νｄ）との間に、およそ直線的な関係がある。この関係を表す直線は、部分分散比（θｇ，Ｆ）を縦軸に、アッベ数（νｄ）を横軸に採用した直交座標上で、ＮＳＬ７とＰＢＭ２の部分分散比及びアッベ数をプロットした２点を結ぶ直線で表され、ノーマルラインと呼ばれている（図１参照）。ノーマルラインの基準となるノーマルガラスは光学ガラスメーカー毎によっても異なるが、各社ともほぼ同等の傾きと切片で定義している。（ＮＳＬ７とＰＢＭ２は株式会社オハラ社製の光学ガラスであり、ＰＢＭ２のアッベ数（νｄ）は３６．３，部分分散比（θｇ，Ｆ）は０．５８２８、ＮＳＬ７のアッベ数（νｄ）は６０．５、部分分散比（θｇ，Ｆ）は０．５４３６である。） In optical glass, there is an approximately linear relationship between a partial dispersion ratio (θg, F) representing partial dispersion in a short wavelength region and an Abbe number (ν d ). The straight line representing this relationship plots the partial dispersion ratio and Abbe number of NSL7 and PBM2 on the Cartesian coordinates employing the partial dispersion ratio (θg, F) on the vertical axis and the Abbe number (ν d ) on the horizontal axis. It is represented by a straight line connecting two points and is called a normal line (see FIG. 1). Normal glass, which is the standard for normal lines, differs depending on the optical glass manufacturer, but each company defines it with almost the same slope and intercept. (NSL7 and PBM2 are optical glasses manufactured by OHARA, Inc., and the Abbe number (ν d ) of PBM2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν d ) of NSL7. Is 60.5, and the partial dispersion ratio (θg, F) is 0.5436.)
　ここで、高分散を有するガラスとしては、例えば特許文献１～３に示されるような光学ガラスが知られている。 Here, as glass having high dispersion, for example, optical glasses as shown in Patent Documents 1 to 3 are known.
特開２００５－１７９１４２号公報JP 2005-179142 A 特開２００５－２４７６１３号公報JP 2005-247613 A 特開２００７－２５４１９７号公報JP 2007-254197 A
　しかし、特許文献１～３で開示されたガラスは、部分分散比が小さくなく、前記二次スペクトルを補正するレンズとして使用するには十分でなかった。また、特許文献１～３で開示されたガラスは、可視光に対する透明性が高くなく、特に可視光を透過する用途に用いるには十分でなかった。すなわち、アッベ数（νｄ）が小さく高分散であり、部分分散比（θｇ，Ｆ）が小さく、且つ可視光に対する透明性が高い光学ガラスが求められている。 However, the glasses disclosed in Patent Documents 1 to 3 have a small partial dispersion ratio and are not sufficient for use as a lens for correcting the secondary spectrum. Further, the glasses disclosed in Patent Documents 1 to 3 are not highly transparent with respect to visible light, and are not sufficient for use in transmitting visible light. That is, there is a demand for an optical glass having a small Abbe number (ν d ), high dispersion, a small partial dispersion ratio (θg, F), and high transparency to visible light.
　本発明は、上記問題点に鑑みてなされたものであって、その目的とするところは、屈折率（ｎｄ）が所望の範囲内にありながら、アッベ数（νｄ）が小さく、部分分散比（θｇ，Ｆ）が小さく、且つ可視光に対する透明性が高められた光学ガラスと、これを用いたプリフォーム及び光学素子を得ることにある。 The present invention has been made in view of the above problems, and the object of the present invention is to have a small Abbe number (ν d ) and a partial dispersion while the refractive index (n d ) is within a desired range. The object is to obtain an optical glass having a small ratio (θg, F) and enhanced transparency to visible light, and a preform and an optical element using the optical glass.
　本発明者らは、上記課題を解決するために、鋭意試験研究を重ねた結果、希土類成分（Ｌｎ２Ｏ３成分）及びＮｂ２Ｏ５成分に加え、必要に応じてＺｒＯ２成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスの高屈折率化が図られながらも、ガラスの部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で所望の関係を有することを見出した。また、Ｂ２Ｏ３成分、希土類成分（Ｌｎ２Ｏ３成分）及びＺｒＯ２成分の含有量を所定の範囲内にすることによって、ガラスの安定性が高められながらも、ガラスの着色が低減されることを見出し、本発明を完成するに至った。 In order to solve the above-mentioned problems, the present inventors have conducted intensive test studies. As a result, in addition to the rare earth component (Ln 2 O 3 component) and the Nb 2 O 5 component, the ZrO 2 component is used in combination as necessary. By setting these contents within a predetermined range, the glass has a high refractive index, but the glass has a desired partial dispersion ratio (θg, F) between the Abbe number (ν d ). Found to have a relationship. Further, by setting the contents of the B 2 O 3 component, the rare earth component (Ln 2 O 3 component) and the ZrO 2 component within the predetermined ranges, the glass coloring is reduced while the stability of the glass is enhanced. As a result, the present invention has been completed.
　それとともに、Ｂ２Ｏ３成分に加え、必要に応じてＺｒＯ２成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスを再加熱した際に着色や失透が起こり難くなることをも見出した。
　具体的には、本発明は以下のようなものを提供する。 At the same time, in addition to the B 2 O 3 component, if necessary, a ZrO 2 component is used in combination, and by making these contents within a predetermined range, coloring and devitrification hardly occur when the glass is reheated. I also found out.
Specifically, the present invention provides the following.
　（１）　酸化物換算組成のガラス全物質量に対して、モル％でＢ２Ｏ３成分を２５．０％以上５５．０％以下、Ｌｎ２Ｏ３成分を６．０％以上３０．０％以下（式中、ＬｎはＬａ、Ｇｄ、Ｙ、Ｙｂからなる群より選択される１種以上）、及びＮｂ２Ｏ５成分を０％より多く２５．０％以下含有し、ＺｒＯ２成分の含有量が１５．０％以下であり、部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で、νｄ≦３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００２７５×νｄ＋０．６８１２５）の関係を満たし、νｄ＞３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００１６２×νｄ＋０．６４６２２）の関係を満たす光学ガラス。 (1) the glass the total amount of substance of the oxide composition in terms of, B 2 O 3 component 55.0% 25.0% or more of the following in mol%, Ln 2 O 3 ingredient 6.0% or more 30.0 % or less (wherein, Ln is La, Gd, Y, 1 or more selected from the group consisting of Yb), and Nb 2 O 5 component contains less more 25.0% than 0%, the ZrO 2 component When the content is 15.0% or less and the partial dispersion ratio (θg, F) is in the range of νd ≦ 31 with respect to the Abbe number (νd), (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (−0.00275 × νd + 0.68125), and in the range of νd> 31, (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (−0.00162 × νd + 0.64622 ) Optical glass that satisfies the relationship.
　（２）　酸化物換算組成のガラス全物質量に対して、モル％でＺｒＯ２成分の含有量が１０．０％以下である（１）記載の光学ガラス。 (2) The optical glass according to (1), wherein the content of the ZrO 2 component is 10.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.
　（３）　酸化物換算組成のガラス全物質量に対して、モル％で
Ｌａ２Ｏ３成分　０～３０．０％及び／又は
Ｇｄ２Ｏ３成分　０～１５．０％及び／又は
Ｙ２Ｏ３成分　０～１５．０％及び／又は
Ｙｂ２Ｏ３成分　０～１５．０％
を含有する（１）又は（２）記載の光学ガラス。 (3) La 2 O 3 component 0 to 30.0% and / or Gd 2 O 3 component 0 to 15.0% and / or Y 2 O in mol% with respect to the total amount of glass in the oxide conversion composition 3 components 0 to 15.0% and / or Yb 2 O 3 components 0 to 15.0%
(1) or (2) optical glass containing.
　（４）　酸化物換算組成におけるモル比Ｌａ２Ｏ３／Ｌｎ２Ｏ３が０．５以上である（１）から（３）のいずれか記載の光学ガラス。 (4) as oxide molar ratio La 2 O 3 / Ln 2 O 3 is one wherein the optical glass is 0.5 or more (1) to (3) in the composition.
　（５）　酸化物換算組成のガラス全物質量に対するＮｂ２Ｏ５成分及びＺｒＯ２成分の含有量の和が４．６％より多く３０．０％以下である（１）から（４）のいずれか記載の光学ガラス。 (5) Any of (1) to (4), wherein the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component with respect to the total glass material amount of the oxide conversion composition is more than 4.6% and not more than 30.0% Or an optical glass.
　（６）　酸化物換算組成のガラス全物質量に対するモル和（Ｎｂ２Ｏ５＋ＺｒＯ２＋Ｌａ２Ｏ３）が１５．０％以上である（１）から（５）のいずれか記載の光学ガラス。 (6) any description of the optical glass of the molar sum to the glass the total amount of substance of the oxide composition in terms of (Nb 2 O 5 + ZrO 2 + La 2 O 3) is 15.0% or more (1) to (5).
　（７）　酸化物換算組成のガラス全物質量に対して、モル％でＴｉＯ２成分の含有量が２０．０％以下である（１）から（６）のいずれか記載の光学ガラス。 (7) as oxide with respect to the glass the total amount of substance of the composition, mole% in either described optical glass of the content of TiO 2 component is less than 20.0% (1) to (6).
　（８）　酸化物換算組成のモル比ＴｉＯ２／（Ｎｂ２Ｏ５＋ＺｒＯ２）が１．００以下である（１）から（７）のいずれか記載の光学ガラス。 (8) The optical glass according to any one of (1) to (7), wherein the molar ratio TiO 2 / (Nb 2 O 5 + ZrO 2 ) of the oxide conversion composition is 1.00 or less.
　（９）　酸化物換算組成のガラス全物質量に対するＮｂ２Ｏ５成分及びＴｉＯ２成分の含有量の和が６．５％より多く３５．０％以下である（１）から（８）のいずれか記載の光学ガラス。 (9) Any of (1) to (8), wherein the sum of the contents of Nb 2 O 5 component and TiO 2 component is more than 6.5% and 35.0% or less with respect to the total amount of glass in the oxide equivalent composition Or an optical glass.
　（１０）　酸化物換算組成のガラス全物質量に対して、モル％でＷＯ３成分の含有量が３０．０％以下である（１）から（９）のいずれか記載の光学ガラス。 (10) The optical glass according to any one of (1) to (9), wherein the content of the WO 3 component is 30.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.
　（１１）　酸化物換算組成のガラス全物質量に対するＴｉＯ２成分及びＷＯ３成分のモル和が３５．０％以下である（１）から（１０）のいずれか記載の光学ガラス。 (11) The optical glass according to any one of (1) to (10), wherein the molar sum of the TiO 2 component and the WO 3 component is 35.0% or less with respect to the total amount of the glass having an oxide equivalent composition.
　（１２）　酸化物換算組成におけるモル比（ＴｉＯ２＋ＷＯ３）／（ＺｒＯ２＋Ｂ２Ｏ３）が０．７００以下である（１）から（１１）のいずれか記載の光学ガラス。 (12) The optical glass according to any one of (1) to (11), wherein the molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in the oxide equivalent composition is 0.700 or less.
　（１３）　酸化物換算組成のガラス全物質量に対して、モル％で
Ｌｉ２Ｏ成分　０～２５．０％及び／又は
Ｎａ２Ｏ成分　０～２５．０％及び／又は
Ｋ２Ｏ成分　０～２５．０％及び／又は
Ｃｓ２Ｏ成分　０～１０．０％
である（１）から（１２）のいずれか記載の光学ガラス。 (13) 0 to 25.0% of Li 2 O component and / or 0 to 25.0% of Na 2 O component and / or K 2 O component in mol% with respect to the total amount of the glass having an oxide conversion composition 0 ~ 25.0% and / or Cs 2 O component 0 ~ 10.0%
The optical glass according to any one of (1) to (12).
　（１４）　酸化物換算組成のガラス全物質量に対するＲｎ２Ｏ成分（式中、ＲｎはＬｉ、Ｎａ、Ｋ、Ｃｓからなる群より選択される１種以上）のモル和が３０．０％以下である（１）から（１３）のいずれか記載の光学ガラス。 (14) The molar sum of the Rn 2 O component (wherein Rn is at least one selected from the group consisting of Li, Na, K, and Cs) with respect to the total amount of glass in an oxide equivalent composition is 30.0% or less. The optical glass according to any one of (1) to (13).
　（１５）　酸化物換算組成のモル比（Ｂ２Ｏ３＋ＺｒＯ２）／（Ｌｎ２Ｏ３＋ＷＯ３＋Ｒｎ２Ｏ）が０．７０以上である（１）から（１４）のいずれか記載の光学ガラス。 (15) The optical component according to any one of (1) to (14), wherein a molar ratio (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) of the oxide equivalent composition is 0.70 or more. Glass.
　（１６）　酸化物換算組成のガラス全物質量に対して、モル％で
ＭｇＯ成分　０～１５．０％及び／又は
ＣａＯ成分　０～２０．０％及び／又は
ＳｒＯ成分　０～２０．０％及び／又は
ＢａＯ成分　０～２０．０％及び／又は
ＺｎＯ成分　０～３５．０％
である（１）から（１５）のいずれか記載の光学ガラス。 (16) 0 to 15.0% of MgO component and / or 0 to 20.0% of CaO component and / or 0 to 20.0% of SrO component and in terms of mol% with respect to the total amount of glass in the oxide conversion composition / Or BaO component 0-20.0% and / or ZnO component 0-35.0%
The optical glass according to any one of (1) to (15).
　（１７）　酸化物換算組成のガラス全物質量に対するＲＯ成分（式中、ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎからなる群より選択される１種以上）のモル和が３５．０％以下である（１）から（１６）のいずれか記載の光学ガラス。 (17) The molar sum of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Zn) with respect to the total amount of glass in an oxide equivalent composition is 35.0% or less The optical glass according to any one of (1) to (16).
　（１８）　酸化物換算組成のガラス全物質量に対して、モル％で
ＳｉＯ２成分　０～２０．０％及び／又は
Ｐ２Ｏ５成分　０～３０．０％及び／又は
ＧｅＯ２成分　０～２０．０％及び／又は
Ｔａ２Ｏ５成分　０～７．５％及び／又は
Ｂｉ２Ｏ３成分　０～１５．０％及び／又は
ＴｅＯ２成分　０～３０．０％及び／又は
Ａｌ２Ｏ３成分　０～１５．０％及び／又は
Ｓｂ２Ｏ３成分　０～１．０％
である（１）から（１７）のいずれか記載の光学ガラス。 (18) 0 to 20.0% of SiO 2 component and / or 0 to 30.0% of P 2 O 5 component and / or GeO 2 component 0 to 0% in terms of mol% with respect to the total amount of glass of oxide conversion composition 20.0% and / or Ta 2 O 5 component 0 to 7.5% and / or Bi 2 O 3 component 0 to 15.0% and / or TeO 2 component 0 to 30.0% and / or Al 2 O 3 components 0 to 15.0% and / or Sb 2 O 3 components 0 to 1.0%
The optical glass according to any one of (1) to (17).
　（１９）　１．８０以上２．００以下の屈折率（ｎｄ）を有し、２０以上４０以下のアッベ数（νｄ）を有する（１）から（１８）のいずれか記載の光学ガラス。 (19) The optical glass according to any one of (1) to (18), having a refractive index (nd) of 1.80 to 2.00 and an Abbe number (νd) of 20 to 40.
　（２０）　分光透過率が７０％を示す波長（λ７０）が５００ｎｍ以下である（１）から（１９）のいずれか記載の光学ガラス。 (20) The optical glass according to any one of (1) to (19), wherein a wavelength (λ 70 ) having a spectral transmittance of 70% is 500 nm or less.
　（２１）　前記再加熱試験（イ）前の試験片の透過率が７０％となる波長であるλ７０と前記再加熱試験後の試験片のλ７０との差が２０ｎｍ以下である（１）から（２０）のいずれか記載の光学ガラス。
　〔再加熱試験（イ）：試験片１５ｍｍ×１５ｍｍ×３０ｍｍを再加熱し、室温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度まで昇温し、前記光学ガラスのガラス転移温度（Ｔｇ）よりも８０℃高い温度で３０分間保温し、その後常温まで自然冷却し、試験片の対向する２面を厚み１０ｍｍに研磨した後に目視観察する。〕 (21) the difference between the lambda 70 of reheating test (a) before the transmittance of the test piece is wavelength at which 70% lambda 70 and the reheating test after the test piece is 20nm or less (1) To (20).
[Reheating test (A): Re-testing a specimen 15 mm × 15 mm × 30 mm, raising the temperature from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes, and the glass transition temperature of the optical glass The sample is kept at a temperature 80 ° C. higher than (Tg) for 30 minutes, then naturally cooled to room temperature, and two opposing surfaces of the test piece are polished to a thickness of 10 mm and visually observed. ]
　（２２）　再加熱試験（イ）後の試験片の波長５８７．５６ｎｍの光線（ｄ線）の透過率を前記再加熱試験前の試験片のｄ線の透過率で除した値が、０．９５以上となる（１）から（２１）のいずれか記載の光学ガラス。
　〔再加熱試験（イ）：試験片１５ｍｍ×１５ｍｍ×３０ｍｍを再加熱し、室温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度まで昇温し、前記光学ガラスのガラス転移温度（Ｔｇ）よりも８０℃高い温度で３０分間保温し、その後常温まで自然冷却し、試験片の対向する２面を厚み１０ｍｍに研磨した後に目視観察する。〕 (22) The value obtained by dividing the transmittance of light (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (A) by the transmittance of d-line of the test piece before the reheating test is 0. The optical glass according to any one of (1) to (21), which is 95 or more.
[Reheating test (A): Re-testing a specimen 15 mm × 15 mm × 30 mm, raising the temperature from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes, and the glass transition temperature of the optical glass The sample is kept at a temperature 80 ° C. higher than (Tg) for 30 minutes, then naturally cooled to room temperature, and two opposing surfaces of the test piece are polished to a thickness of 10 mm and visually observed. ]
　（２３）　（１）から（２２）のいずれか記載の光学ガラスからなる研磨加工用及び／又は精密プレス成形用のプリフォーム。 (23) A preform for polishing and / or precision press molding made of the optical glass according to any one of (1) to (22).
　（２４）　（１）から（２２）のいずれか記載の光学ガラスを研削及び／又は研磨してなる光学素子。 (24) An optical element obtained by grinding and / or polishing the optical glass according to any one of (1) to (22).
　（２５）　（１）から（２２）のいずれか記載の光学ガラスを精密プレス成形してなる光学素子。 (25) An optical element formed by precision press-molding the optical glass according to any one of (1) to (22).
　本発明によれば、Ｂ２Ｏ３成分、希土類成分及びＮｂ２Ｏ５成分を併用し、これらの含有量とＺｒＯ２成分の含有量を所定の範囲内にすることによって、ガラスの高屈折率及び高分散化が図られながらも、ガラスの部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で所望の関係を有し、且つガラスの着色が低減される。従って、屈折率（ｎｄ）が所望の範囲内にありながら、アッベ数（νｄ）が小さく、部分分散比（θｇ，Ｆ）が小さく、且つ可視光に対する透明性が高い光学ガラスと、これを用いたプリフォーム及び光学素子を得ることができる。 According to the present invention, the B 2 O 3 component, the rare earth component, and the Nb 2 O 5 component are used in combination, and the content of these components and the content of the ZrO 2 component are within a predetermined range, whereby the high refractive index of the glass is obtained. In addition, while achieving high dispersion, the partial dispersion ratio (θg, F) of the glass has a desired relationship with the Abbe number (ν d ), and the coloring of the glass is reduced. Therefore, an optical glass having a low Abbe number (ν d ), a small partial dispersion ratio (θg, F) and high transparency to visible light while having a refractive index (n d ) within a desired range, and A preform and an optical element using can be obtained.
部分分散比（θｇ，Ｆ）が縦軸でアッベ数（νｄ）が横軸の直交座標に表されるノーマルラインを示す図である。It is a figure which shows the normal line by which partial dispersion ratio ((theta) g, F) is represented on the orthogonal coordinate of a vertical axis | shaft and Abbe number ((nu) d ) on a horizontal axis. 本願の実施例のガラスについての部分分散比（θｇ，Ｆ）とアッベ数（νｄ）の関係を示す図である。It is a figure which shows the relationship between the partial dispersion ratio ((theta) g, F) and the Abbe number ((nu) d ) about the glass of the Example of this application.
　本発明の光学ガラスは、酸化物換算組成のガラス全物質量に対して、モル％でＢ２Ｏ３成分を２５．０％以上５５．０％以下、Ｌｎ２Ｏ３成分を６．０％以上３０．０％以下（式中、ＬｎはＬａ、Ｇｄ、Ｙ、Ｙｂからなる群より選択される１種以上）、及びＮｂ２Ｏ５成分を０％より多く２５．０％以下含有し、ＺｒＯ２成分の含有量が１０．０％以下であり、部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で、νｄ≦３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００２７５×νｄ＋０．６８１２５）の関係を満たし、νｄ＞３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００１６２×νｄ＋０．６４６２２）の関係を満たす。Ｌａ２Ｏ３成分等の希土類成分及びＮｂ２Ｏ５成分に、必要に応じてＺｒＯ２成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスの高屈折率化が図られる。それとともに、Ｎｂ２Ｏ５成分を用い、その含有量を所定の範囲内にすることによって、ガラスの高分散化（低アッベ数化）が図られる。それとともに、Ｌａ２Ｏ３成分等の希土類成分及びＮｂ２Ｏ５成分に、必要に応じてＺｒＯ２成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスの部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で所望の関係を有する。それとともに、Ｂ２Ｏ３成分及びＬａ２Ｏ３成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスの安定性が高められながらも、ガラスの着色が低減される。このため、屈折率（ｎｄ）が所望の範囲内にありながら、アッベ数（νｄ）が小さく、部分分散比（θｇ，Ｆ）が小さく、且つ可視光に対する透明性が高い光学ガラスと、これを用いたプリフォーム及び光学素子を得ることができる。 In the optical glass of the present invention, the B 2 O 3 component is 25.0% or more and 55.0% or less, and the Ln 2 O 3 component is 6.0% in mol% with respect to the total amount of the glass having an oxide conversion composition. More than 30.0% (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, Yb), and Nb 2 O 5 component more than 0% and 25.0% or less, The content of the ZrO 2 component is 10.0% or less, and the partial dispersion ratio (θg, F) is within the range of νd ≦ 31 with respect to the Abbe number (νd) (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (−0.00275 × νd + 0.68125) is satisfied, and in the range of νd> 31, (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (−0.00162 Xνd + 0.64622) is satisfied. If the ZrO 2 component is used in combination with rare earth components such as La 2 O 3 component and Nb 2 O 5 component as necessary, and the content thereof is within a predetermined range, the glass has a high refractive index. It is done. At the same time, the Nb 2 O 5 component is used and its content is within a predetermined range, whereby the glass is highly dispersed (lower Abbe number). At the same time, a rare-earth component such as La 2 O 3 component and Nb 2 O 5 component are used together with a ZrO 2 component as necessary, and the content thereof is within a predetermined range, whereby the partial dispersion ratio of the glass (Θg, F) has a desired relationship with the Abbe number (ν d ). At the same time, the B 2 O 3 component and the La 2 O 3 component are used in combination, and the content of these components is within a predetermined range, so that the color of the glass is reduced while the stability of the glass is enhanced. Therefore, an optical glass having a low Abbe number (ν d ), a small partial dispersion ratio (θg, F), and a high transparency to visible light, while the refractive index (n d ) is within a desired range; A preform and an optical element using the same can be obtained.
　それとともに、Ｂ２Ｏ３成分に加え、必要に応じてＺｒＯ２成分を併用し、これらの含有量を所定の範囲内にすることによって、ガラスを再加熱した際に着色や失透が起こり難くなる。このため、上述の優れた特性を有しながらも、高いプレス成形性を有する光学ガラスと、これを用いたプリフォーム及び光学素子を得ることができる。 At the same time, in addition to the B 2 O 3 component, if necessary, a ZrO 2 component is used in combination, and by making these contents within a predetermined range, coloring and devitrification hardly occur when the glass is reheated. Become. For this reason, it is possible to obtain an optical glass having a high press formability and a preform and an optical element using the same while having the above-described excellent characteristics.
　以下、本発明の光学ガラスの実施形態について詳細に説明するが、本発明は、以下の実施形態に何ら限定されるものではなく、本発明の目的の範囲内において、適宜変更を加えて実施することができる。なお、説明が重複する箇所については、適宜説明を省略する場合があるが、発明の趣旨を限定するものではない。 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 may be implemented with appropriate modifications within the scope of the object of the present invention. be able to. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the meaning of invention is not limited.
［ガラス成分］
　本発明の光学ガラスを構成する各成分の組成範囲を以下に述べる。本明細書中において、各成分の含有量は特に断りがない場合は、全て酸化物換算組成のガラス全物質量に対するモル％で表示されるものとする。ここで、「酸化物換算組成」とは、本発明のガラス構成成分の原料として使用される酸化物、複合塩、金属弗化物等が溶融時に全て分解され酸化物へ変化すると仮定した場合に、当該生成酸化物の総物質量を１００モル％として、ガラス中に含有される各成分を表記した組成である。 [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 mol% with respect to the total amount of glass in the oxide equivalent composition. Here, the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as the raw material of the glass component of the present invention are all decomposed and changed into oxides 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%.
＜必須成分、任意成分について＞
　Ｂ２Ｏ３成分は、希土類酸化物を多く含む本発明の光学ガラスにおいて、ガラス形成酸化物として欠かすことの出来ない必須成分である。特に、Ｂ２Ｏ３成分の含有量を２５．０％以上にすることで、ガラスの耐失透性を高め、且つガラスの分散を小さくすることができる。また、Ｂ２Ｏ３成分を含有することで、ガラスの比重を小さくでき、且つ再加熱による失透及び着色を低減できる。従って、Ｂ２Ｏ３成分の含有量は、好ましくは２５．０％、より好ましくは２８．０％、さらに好ましくは３２．０％、最も好ましくは３６．０％を下限とする。一方、Ｂ２Ｏ３成分の含有量を５５．０％以下にすることで、より大きな屈折率を得易くし、部分分散比の上昇を抑えることができる。従って、Ｂ２Ｏ３成分の含有量は、好ましくは５５．０％、より好ましくは５０．０％、最も好ましくは４８．０％を上限とする。Ｂ２Ｏ３成分は、原料としてＨ３ＢＯ３、Ｎａ２Ｂ４Ｏ７、Ｎａ２Ｂ４Ｏ７・１０Ｈ２Ｏ、ＢＰＯ４等を用いることができる。 <About essential and optional components>
The B 2 O 3 component is an essential component that is indispensable as a glass-forming oxide in the optical glass of the present invention containing a large amount of rare earth oxides. In particular, by setting the content of the B 2 O 3 component to 25.0% or more, the devitrification resistance of the glass can be improved and the dispersion of the glass can be reduced. Further, by containing B 2 O 3 component, the specific gravity of the glass can be reduced, thereby reducing the devitrification and coloring due and reheating. Therefore, the content of the B 2 O 3 component is preferably 25.0%, more preferably 28.0%, still more preferably 32.0%, and most preferably 36.0%. On the other hand, by making the content of the B 2 O 3 component 55.0% or less, it is possible to easily obtain a larger refractive index and to suppress an increase in the partial dispersion ratio. Therefore, the content of the B 2 O 3 component is preferably 55.0%, more preferably 50.0%, and most preferably 48.0%. As the B 2 O 3 component, H 3 BO 3 , Na 2 B 4 O 7 , Na 2 B 4 O 7 .10H 2 O, BPO 4 or the like can be used as a raw material.
　本発明の光学ガラスは、Ｌｎ２Ｏ３成分（式中、ＬｎはＬａ、Ｇｄ、Ｙ、Ｙｂからなる群より選択される１種以上）のモル和が６．０％以上３０．０％以下であることが好ましい。特に、Ｌｎ２Ｏ３成分のモル和を６．０％以上にすることで、ガラスの屈折率及びアッベ数がいずれも高められながらも、ガラスの部分分散比が低くなるため、所望の高い屈折率を有し、且つ、部分分散比とアッベ数との間で所望の関係を有するガラスを得易くすることができる。従って、Ｌｎ２Ｏ３成分のモル和は、好ましくは６．０％、より好ましくは１０．０％、最も好ましくは１３．０％を下限とする。一方、Ｌｎ２Ｏ３成分のモル和を３０．０％以下にすることで、ガラスの液相温度が低くなるため、ガラスの失透を低減できる。従って、Ｌｎ２Ｏ３成分の含有量のモル和は、好ましくは３０．０％、より好ましくは２５．０％、最も好ましくは２２．０％を上限とする。 In the optical glass of the present invention, the molar sum of the Ln 2 O 3 component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is 6.0% or more and 30.0% or less. It is preferable that In particular, by setting the molar sum of the Ln 2 O 3 component to 6.0% or more, the glass has a low partial dispersion ratio while increasing the refractive index and Abbe number of the glass. It is possible to easily obtain a glass having a desired ratio between the partial dispersion ratio and the Abbe number. Accordingly, the lower limit of the molar sum of the Ln 2 O 3 component is preferably 6.0%, more preferably 10.0%, and most preferably 13.0%. On the other hand, by making the molar sum of Ln 2 O 3 component below 30.0%, because the liquidus temperature of the glass is lowered, thereby reducing the devitrification of the glass. Therefore, the molar sum of the contents of the Ln 2 O 3 component is preferably 30.0%, more preferably 25.0%, and most preferably 22.0%.
　Ｎｂ２Ｏ５成分は、ガラスの屈折率を高め、アッベ数を低くし、且つ部分分散比を低くする成分である。特に、Ｎｂ２Ｏ５成分を必須成分として含有することで、ガラスの屈折率を高め、アッベ数を低くしながらも、ガラスの比重を小さくし、ガラスの部分分散比を小さくすることができる。また、Ｎｂ２Ｏ５成分の含有量を２５．０％以下にすることで、Ｎｂ２Ｏ５成分の過剰な含有によるガラスの耐失透性の悪化を抑え、且つ、ガラスの可視光に対する透過率の低下を抑えることができる。従って、Ｎｂ２Ｏ５成分の含有量は、好ましくは０％より多くし、より好ましくは１．０％、さらに好ましくは２．０％、さらに好ましくは４．５％、さらに好ましくは５．０％、さらに好ましくは５．５％、最も好ましくは８．０％を下限とする。また、このＮｂ２Ｏ５成分の含有量は、好ましくは２５．０％、より好ましくは２０．０％、最も好ましくは１７．０％を上限とする。Ｎｂ２Ｏ５成分は、原料としてＮｂ２Ｏ５等を用いることができる。 The Nb 2 O 5 component is a component that increases the refractive index of the glass, decreases the Abbe number, and decreases the partial dispersion ratio. In particular, by containing the Nb 2 O 5 component as an essential component, the specific gravity of the glass can be reduced and the partial dispersion ratio of the glass can be reduced while increasing the refractive index of the glass and reducing the Abbe number. Further, by making the content of the Nb 2 O 5 component 25.0% or less, the deterioration of the devitrification resistance of the glass due to the excessive content of the Nb 2 O 5 component is suppressed, and the glass transmits visible light. Reduction in rate can be suppressed. Accordingly, the content of the Nb 2 O 5 component is preferably more than 0%, more preferably 1.0%, still more preferably 2.0%, still more preferably 4.5%, and even more preferably 5.0. %, More preferably 5.5%, and most preferably 8.0%. Further, the content of this Nb 2 O 5 component is preferably 25.0%, more preferably 20.0%, and most preferably 17.0%. As the Nb 2 O 5 component, Nb 2 O 5 or the like can be used as a raw material.
　ＺｒＯ２成分は、ガラスの屈折率を高めて耐失透性を高めつつ、ガラスの部分分散比を低くする成分であり、本発明の光学ガラス中の任意成分である。しかしながら、ＺｒＯ２量が多すぎると、逆に耐失透性が悪化する。従って、ＺｒＯ２成分の含有量は、好ましくは１５．０％、より好ましくは１２．０％、さらに好ましくは１０．０％を上限とする。このＺｒＯ２成分の含有量は、さらに好ましくは９．０％、さらに好ましくは８．０％を上限としてもよい。なお、ＺｒＯ２成分は含有しなくてもよいが、ＺｒＯ２成分を含有することで、ガラスの屈折率を高めつつ部分分散比をより低くし易くできる。また、ＺｒＯ２成分を含有することで、再加熱による失透及び着色を低減できる。従って、ＺｒＯ２成分の含有量は、好ましくは０％より多くし、より好ましくは０．５％、最も好ましくは２．０％を下限とする。ＺｒＯ２成分は、原料としてＺｒＯ２、ＺｒＦ４等を用いることができる。 The ZrO 2 component is a component that lowers the partial dispersion ratio of the glass while increasing the refractive index of the glass to increase the devitrification resistance, and is an optional component in the optical glass of the present invention. However, if the amount of ZrO 2 is too large, the devitrification resistance is deteriorated. Therefore, the content of the ZrO 2 component is preferably 15.0%, more preferably 12.0%, and still more preferably 10.0%. The content of this ZrO 2 component is more preferably 9.0%, and even more preferably 8.0%. Incidentally, ZrO 2 component is may not contain, by containing a ZrO 2 component, can easily lower the partial dispersion ratio while increasing the refractive index of the glass. Further, by containing a ZrO 2 component, it can be reduced devitrification and coloring due to reheating. Therefore, the content of the ZrO 2 component is preferably more than 0%, more preferably 0.5%, and most preferably 2.0%. As the ZrO 2 component, ZrO 2 , ZrF 4 or the like can be used as a raw material.
　Ｌａ２Ｏ３成分は、ガラスの屈折率を高めるとともに、部分分散比を小さくする成分であり、本発明の光学ガラス中の任意成分である。特に、Ｌａ２Ｏ３成分の含有量を３０．０％以下にすることで、ガラスの安定性を高めてガラスの失透を低減し、且つガラスのアッベ数の上昇を抑えることができる。また、Ｌａ２Ｏ３成分を低減することで、再加熱による失透及び着色を低減できる。従って、Ｌａ２Ｏ３成分の含有量は、好ましくは３０．０％、より好ましくは２５．０％、さらに好ましくは２２．０％、最も好ましくは２０．０％を上限とする。なお、Ｌａ２Ｏ３成分は含有しなくてもよいが、Ｌａ２Ｏ３成分を含有することで、比重が小さく、且つ、屈折率が高く部分分散比の小さいガラスをより得易くできる。従って、Ｌａ２Ｏ３成分の含有量は、好ましくは０％より多くし、より好ましくは７．０％、さらに好ましくは１１．０％、最も好ましくは１４．０％を下限とする。Ｌａ２Ｏ３成分は、原料としてＬａ２Ｏ３、Ｌａ（ＮＯ３）３・ＸＨ２Ｏ（Ｘは任意の整数）等を用いることができる。 The La 2 O 3 component is a component that increases the refractive index of the glass and decreases the partial dispersion ratio, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the La 2 O 3 component to 30.0% or less, it is possible to increase the stability of the glass, reduce the devitrification of the glass, and suppress the increase in the Abbe number of the glass. Moreover, devitrification and coloring by reheating can be reduced by reducing the La 2 O 3 component. Therefore, the content of the La 2 O 3 component is preferably 30.0%, more preferably 25.0%, still more preferably 22.0%, and most preferably 20.0%. The La 2 O 3 component may not be contained, but by containing the La 2 O 3 component, a glass having a small specific gravity and a high refractive index and a small partial dispersion ratio can be obtained more easily. Therefore, the content of the La 2 O 3 component is preferably more than 0%, more preferably 7.0%, still more preferably 11.0%, and most preferably 14.0%. As the La 2 O 3 component, La 2 O 3 , La (NO 3 ) 3 .XH 2 O (X is an arbitrary integer) or the like can be used as a raw material.
　Ｙ２Ｏ３成分、Ｇｄ２Ｏ３成分及びＹｂ２Ｏ３成分は、ガラスの屈折率を高める成分であり、本発明の光学ガラス中の任意成分である。特に、Ｙ２Ｏ３成分、Ｇｄ２Ｏ３成分及びＹｂ２Ｏ３成分の含有量をそれぞれ１５．０％以下にすることで、ガラスの耐失透性を高めることができ、且つガラスのアッベ数を高まり難くすることができる。従って、Ｙ２Ｏ３成分、Ｇｄ２Ｏ３成分及びＹｂ２Ｏ３成分のそれぞれの含有量は、好ましくは１５．０％、より好ましくは１０．０％、最も好ましくは５．０％を上限とする。Ｙ２Ｏ３成分、Ｇｄ２Ｏ３成分及びＹｂ２Ｏ３成分は、原料としてＧｄ２Ｏ３、ＧｄＦ３、Ｙ２Ｏ３、ＹＦ３、Ｙｂ２Ｏ３等を用いることができる。 The Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component are components that increase the refractive index of the glass, and are optional components in the optical glass of the present invention. In particular, the devitrification resistance of the glass can be increased by setting the content of each of the Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component to 15.0% or less. The number can be made difficult to increase. Accordingly, the upper limit of each content of the Y 2 O 3 component, the Gd 2 O 3 component, and the Yb 2 O 3 component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%. And As the Y 2 O 3 component, Gd 2 O 3 component, and Yb 2 O 3 component, Gd 2 O 3 , GdF 3 , Y 2 O 3 , YF 3 , Yb 2 O 3 and the like can be used as raw materials.
　本発明の光学ガラスは、Ｌｎ２Ｏ３成分の含有量に対するＬａ２Ｏ３成分の含有量の比率が０．５以上であることが好ましい。これにより、希土類元素の中でも部分分散比を小さくする作用の強いＬａ２Ｏ３成分の含有量が相対的に増加するため、ガラスの所望の耐失透性を得ながらも、部分分散比を小さくすることができる。従って、酸化物換算組成におけるモル比Ｌａ２Ｏ３／Ｌｎ２Ｏ３は、好ましくは０．５、より好ましくは０．７、最も好ましくは０．８を下限とする。なお、この比率の上限は特に限定されず、１．０であってもよい。 In the optical glass of the present invention, the ratio of the content of the La 2 O 3 component to the content of the Ln 2 O 3 component is preferably 0.5 or more. As a result, the content of the La 2 O 3 component, which has a strong effect of reducing the partial dispersion ratio among rare earth elements, is relatively increased, so that the partial dispersion ratio is reduced while obtaining the desired devitrification resistance of the glass. can do. Therefore, the molar ratio La 2 O 3 / Ln 2 O 3 in the oxide equivalent composition is preferably 0.5, more preferably 0.7, and most preferably 0.8. The upper limit of this ratio is not particularly limited, and may be 1.0.
　また、本発明の光学ガラスは、Ｎｂ２Ｏ５成分及びＺｒＯ２成分の含有量の和が４．６％より多く３０．０％以下であることが好ましい。特に、この和を４．６％より多くすることで、これら部分分散比を下げる成分が増加するため、より部分分散比の低い光学ガラスを得ることができる。一方で、この和を３０．０％以下にすることで、ガラスの溶解性や耐失透性を高めることができる。従って、モル和（Ｎｂ２Ｏ５＋ＺｒＯ２）は、好ましくは４．６％より多くし、より好ましくは５．０％より多くし、さらに好ましくは５．８％より多くし、最も好ましくは９．０％より多くする。一方で、このモル和（Ｎｂ２Ｏ５＋ＺｒＯ２）は、好ましくは３０．０％、より好ましくは２５．０％、最も好ましくは２０．０％を上限とする。 In the optical glass of the present invention, the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component is preferably more than 4.6% and not more than 30.0%. In particular, when the sum is more than 4.6%, the components that lower the partial dispersion ratio increase, so that an optical glass having a lower partial dispersion ratio can be obtained. On the other hand, by making this sum 30.0% or less, the solubility and devitrification resistance of the glass can be improved. Accordingly, the molar sum (Nb 2 O 5 + ZrO 2 ) is preferably more than 4.6%, more preferably more than 5.0%, still more preferably more than 5.8%, most preferably 9 More than 0%. On the other hand, the molar sum (Nb 2 O 5 + ZrO 2 ) is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%.
　また、本発明の光学ガラスは、Ｎｂ２Ｏ５成分、ＺｒＯ２成分及びＬａ２Ｏ３成分の含有量の和が１５．０％以上であることが好ましい。特に、この和を１５．０％以上にすることで、ガラスの部分分散比を下げるこれらの成分が増加するため、より部分分散比の低い光学ガラスを得ることができる。従って、モル和（Ｎｂ２Ｏ５＋ＺｒＯ２＋Ｌａ２Ｏ３）は、好ましくは１５．０％、より好ましくは２０．０％、さらに好ましくは２３．０％、最も好ましくは２６．４％を下限とする。なお、これら成分の合計量の和は、安定なガラスが得られる限り限定されないが、例えば５０．０％以下にすることで、ガラスの溶解性や耐失透性を高めることができる。一方で、このモル和（Ｎｂ２Ｏ５＋ＺｒＯ２＋Ｌａ２Ｏ３）は、好ましくは５０．０％、より好ましくは４５．０％、最も好ましくは４０．０％を上限とする。 In the optical glass of the present invention, the sum of the contents of the Nb 2 O 5 component, the ZrO 2 component, and the La 2 O 3 component is preferably 15.0% or more. In particular, by setting this sum to 15.0% or more, these components that lower the partial dispersion ratio of the glass increase, so that an optical glass having a lower partial dispersion ratio can be obtained. Accordingly, the molar sum (Nb 2 O 5 + ZrO 2 + La 2 O 3 ) is preferably 15.0%, more preferably 20.0%, still more preferably 23.0%, and most preferably 26.4%. And In addition, although the sum of the total amount of these components is not limited as long as stable glass is obtained, the solubility and devitrification resistance of glass can be improved by making it 50.0% or less, for example. On the other hand, this molar sum (Nb 2 O 5 + ZrO 2 + La 2 O 3 ) is preferably 50.0%, more preferably 45.0%, and most preferably 40.0%.
　ＴｉＯ２成分は、ガラスの屈折率を高めつつ、アッベ数を低くし、耐失透性を改善する成分であり、本発明の光学ガラス中の任意成分である。特に、ＴｉＯ２成分の含有量を２０．０％以下にすることで、ガラスの着色を低減し、可視短波長（５００ｎｍ以下）におけるガラスの内部透過率を高めることができる。また、ＴｉＯ２成分の含有量を２０．０％以下にすることで、部分分散比が上昇し難くなるため、低い部分分散比を有するガラスを得易くすることができる。従って、ＴｉＯ２成分の含有量は、好ましくは２０．０％、より好ましくは１５．０％、さらに好ましくは９．０％、さらに好ましくは８．１％、さらに好ましくは７．０％を上限とし、さらに好ましくは５．０％未満とし、最も好ましくは２．８％を上限とする。ＴｉＯ２成分は、原料としてＴｉＯ２等を用いることができる。 The TiO 2 component is a component that lowers the Abbe number and improves devitrification resistance while increasing the refractive index of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the TiO 2 component is 20.0% or less, the coloring of the glass can be reduced, and the internal transmittance of the glass at a visible short wavelength (500 nm or less) can be increased. Further, by setting the content of the TiO 2 component below 20.0%, because the partial dispersion ratio is hard to rise, it is possible to easily obtain a glass having a low partial dispersion ratio. Accordingly, the upper limit of the content of the TiO 2 component is preferably 20.0%, more preferably 15.0%, still more preferably 9.0%, still more preferably 8.1%, and even more preferably 7.0%. And more preferably less than 5.0%, and most preferably 2.8%. As the TiO 2 component, TiO 2 or the like can be used as a raw material.
　本発明の光学ガラスは、Ｎｂ２Ｏ５成分及びＴｉＯ２成分の含有量の和が６．５％より多く３５．０％以下であることが好ましい。特に、この和を６．５％より多くすることで、ガラスのアッベ数が低くなるため、より低いアッベ数を有するガラスを得易くすることができる。一方で、この和を３５．０％以下にすることで、これら成分の過剰な含有による失透を低減できる。従って、モル和（Ｎｂ２Ｏ５＋ＴｉＯ２）は、好ましくは６．５％超、より好ましくは８．０％、最も好ましくは９．０％を下限とする。一方で、このモル和（Ｎｂ２Ｏ５＋ＴｉＯ２）は、好ましくは３５．０％を上限とし、より好ましくは３０．０％未満とし、さらに好ましくは２５．０％、最も好ましくは２０．０％を上限とする。 In the optical glass of the present invention, the sum of the contents of the Nb 2 O 5 component and the TiO 2 component is preferably more than 6.5% and 35.0% or less. In particular, when the sum is more than 6.5%, the Abbe number of the glass is lowered, so that a glass having a lower Abbe number can be easily obtained. On the other hand, devitrification due to excessive inclusion of these components can be reduced by making this sum 35.0% or less. Therefore, the lower limit of the molar sum (Nb 2 O 5 + TiO 2 ) is preferably more than 6.5%, more preferably 8.0%, and most preferably 9.0%. On the other hand, the molar sum (Nb 2 O 5 + TiO 2 ) is preferably 35.0%, more preferably less than 30.0%, even more preferably 25.0%, and most preferably 20.0%. % Is the upper limit.
　本発明の光学ガラスは、Ｎｂ２Ｏ５成分及びＺｒＯ２成分の含有量の和に対する、ＴｉＯ２成分の含有量の割合が１．００以下であることが好ましい。これにより、屈折率を高めてアッベ数を低下させる成分の中でも、部分分散比を高めるＴｉＯ２成分の含有量が、部分分散比を下げるＮｂ２Ｏ５成分及びＺｒＯ２成分の含有量に相対して減少するため、より低い部分分散比を有する光学ガラスを得ることができる。また、これによりガラスを着色するＴｉＯ２成分の含有量が減少するため、可視光を透過させる用途に好ましく用いられる光学ガラスを得ることができる。従って、酸化物換算組成のモル比ＴｉＯ２／（Ｎｂ２Ｏ５＋ＺｒＯ２）は、好ましくは１．００、より好ましくは０．８０、最も好ましくは０．７０を上限とする。一方で、このモル比の下限は特に限定されず、０であってもよい。 In the optical glass of the present invention, the ratio of the content of the TiO 2 component to the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component is preferably 1.00 or less. As a result, among the components that increase the refractive index and decrease the Abbe number, the content of the TiO 2 component that increases the partial dispersion ratio is relative to the content of the Nb 2 O 5 component and the ZrO 2 component that decrease the partial dispersion ratio. Therefore, an optical glass having a lower partial dispersion ratio can be obtained. This also to reduce the content of TiO 2 component to color the glass, it is possible to obtain an optical glass that is preferably used in applications which transmits visible light. Therefore, the molar ratio TiO 2 / (Nb 2 O 5 + ZrO 2 ) of the oxide conversion composition is preferably 1.00, more preferably 0.80, and most preferably 0.70. On the other hand, the lower limit of this molar ratio is not particularly limited, and may be 0.
　ＷＯ３成分は、ガラスの屈折率を高めてアッベ数を低くし、且つガラスの耐失透性を高める成分であり、本発明の光学ガラス中の任意成分である。特に、ＷＯ３成分の含有量を３０．０％以下にすることで、ガラスの部分分散比の上昇を抑え、且つガラスの可視光に対する透過率を低下し難くすることができる。また、ＷＯ３成分を低減することで、再加熱による失透及び着色を低減できる。従って、ＷＯ３成分の含有量は、好ましくは３０．０％、より好ましくは２５．０％、最も好ましくは２０．０％を上限とする。なお、ＷＯ３成分は含有しなくてもよいが、ＷＯ３成分を含有することで、所望の高い屈折率及び低いアッベ数を有し、耐失透性の高いガラスを得ることができる。従って、ＷＯ３成分の含有量は、好ましくは０％より多くし、より好ましくは１．０％、さらに好ましくは１．７％、最も好ましくは２．５％を下限とする。ＷＯ３成分は、原料としてＷＯ３等を用いることができる。 The WO 3 component is a component that increases the refractive index of the glass to lower the Abbe number and increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention. In particular, by making the content of the WO 3 component 30.0% or less, an increase in the partial dispersion ratio of the glass can be suppressed, and the transmittance of the glass with respect to visible light can be made difficult to decrease. Moreover, devitrification and coloring by reheating can be reduced by reducing the WO 3 component. Accordingly, the upper limit of the content of the WO 3 component is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%. The WO 3 component may not be contained, but by containing the WO 3 component, a glass having a desired high refractive index and a low Abbe number and having high devitrification resistance can be obtained. Therefore, the content of the WO 3 component is preferably more than 0%, more preferably 1.0%, still more preferably 1.7%, and most preferably 2.5%. As the WO 3 component, WO 3 or the like can be used as a raw material.
　本発明の光学ガラスは、ＴｉＯ２成分及びＷＯ３成分のモル和が３５．０％以下であることが好ましい。これにより、ガラスの着色が低減するため、特に可視光に対する透過率の高いガラスを得ることができる。従って、モル和（ＴｉＯ２＋ＷＯ３）は、好ましくは３５．０％、より好ましくは３３．０％未満とし、さらに好ましくは２５．０％、最も好ましくは２０．０％を上限とする。なお、このモル和は、より可視光の透過率を高める観点では０％であってもよいが、０％より多くすることで、屈折率をより高くでき、且つアッベ数をより低くできる。従って、モル和（ＴｉＯ２＋ＷＯ３）は、好ましくは０％より多くし、より好ましくは１．０％、さらに好ましくは３．０％、最も好ましくは５．０％を下限とする。 In the optical glass of the present invention, the molar sum of the TiO 2 component and the WO 3 component is preferably 35.0% or less. Thereby, since coloring of glass reduces, glass with especially high transmittance | permeability with respect to visible light can be obtained. Therefore, the molar sum (TiO 2 + WO 3 ) is preferably 35.0%, more preferably less than 33.0%, still more preferably 25.0%, and most preferably 20.0%. The molar sum may be 0% from the viewpoint of further increasing the visible light transmittance, but by increasing the molar sum, the refractive index can be further increased and the Abbe number can be further decreased. Accordingly, the molar sum (TiO 2 + WO 3 ) is preferably more than 0%, more preferably 1.0%, still more preferably 3.0%, and most preferably 5.0%.
　また、本発明の光学ガラスは、ＺｒＯ２成分及びＢ２Ｏ３成分の含有量の和に対する、ＴｉＯ２成分及びＷＯ３成分の含有量の和の比率が０．７００以下であることが好ましい。これにより、より可視光に対する透過率の高い光学ガラスを得易くできる。従って、酸化物換算組成におけるモル比（ＴｉＯ２＋ＷＯ３）／（ＺｒＯ２＋Ｂ２Ｏ３）は、好ましくは０．７００、より好ましくは０．６００、最も好ましくは０．５００を上限とする。なお、この比率は０であってもよいが、このモル比を０より大きくすることで、所望の屈折率及び分散を得易くできる。従って、酸化物換算組成におけるモル比（ＴｉＯ２＋ＷＯ３）／（ＺｒＯ２＋Ｂ２Ｏ３）は、好ましくは０より大きくし、より好ましくは０．０５０、最も好ましくは０．１００を下限とする。 In the optical glass of the present invention, the ratio of the sum of the contents of the TiO 2 component and the WO 3 component to the sum of the contents of the ZrO 2 component and the B 2 O 3 component is preferably 0.700 or less. Thereby, it is possible to easily obtain an optical glass having a higher transmittance for visible light. Therefore, the molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in the oxide equivalent composition is preferably 0.700, more preferably 0.600, and most preferably 0.500. Although this ratio may be 0, it is possible to easily obtain a desired refractive index and dispersion by making this molar ratio larger than 0. Accordingly, the molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in the oxide equivalent composition is preferably greater than 0, more preferably 0.050, and most preferably 0.100. .
　ＭｇＯ成分、ＣａＯ成分、ＳｒＯ成分及びＢａＯ成分は、ガラスの屈折率や熔融性、失透性を調整する成分であり、本発明の光学ガラス中の任意成分である。特に、ＭｇＯ成分の含有量を１５．０％以下にすること、若しくは、ＣａＯ成分、ＳｒＯ成分及び／又はＢａＯ成分の含有量を２０．０％以下にすることで、これらの成分による屈折率の低下や失透を低減することができる。また、これにより部分分散比の上昇を抑えることができる。従って、ＭｇＯ成分の含有量は、好ましくは１５．０％、より好ましくは１０．０％、最も好ましくは５．０％を上限とする。また、ＣａＯ成分の含有量は、好ましくは２０．０％、より好ましくは１５．０％、さらに好ましくは１３．０％、さらに好ましくは１０．０％、最も好ましくは７．５％を上限とする。また、ＳｒＯ成分及びＢａＯ成分の含有量は、それぞれ好ましくは２０．０％、より好ましくは１５．０％、さらに好ましくは９．０％、さらに好ましくは７．５％、最も好ましくは４．８％を上限とする。これらの成分は、原料としてＭｇＣＯ３、ＭｇＦ２、ＣａＣＯ３、ＣａＦ２、Ｓｒ（ＮＯ３）２、ＳｒＦ２、ＢａＣＯ３、Ｂａ（ＮＯ３）２、ＢａＦ２等を用いることができる。 The MgO component, CaO component, SrO component, and BaO component are components that adjust the refractive index, meltability, and devitrification of the glass, and are optional components in the optical glass of the present invention. In particular, by making the content of MgO component 15.0% or less, or by making the content of CaO component, SrO component and / or BaO component 20.0% or less, the refractive index of these components can be reduced. Reduction and devitrification can be reduced. Further, this can suppress an increase in the partial dispersion ratio. Therefore, the content of the MgO component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%. The content of the CaO component is preferably 20.0%, more preferably 15.0%, still more preferably 13.0%, still more preferably 10.0%, and most preferably 7.5%. To do. The contents of the SrO component and the BaO component are each preferably 20.0%, more preferably 15.0%, still more preferably 9.0%, still more preferably 7.5%, and most preferably 4.8. % Is the upper limit. As these components, MgCO 3 , MgF 2 , CaCO 3 , CaF 2 , Sr (NO 3 ) 2 , SrF 2 , BaCO 3 , Ba (NO 3 ) 2 , BaF 2 and the like can be used as raw materials.
　ＺｎＯ成分は、ガラス転移点（Ｔｇ）を下げ、ガラス原料の熔解温度を下げる成分であり、本発明の光学ガラス中の任意成分である。特に、ＺｎＯ成分の含有量を３５．０％以下にすることで、ガラスの失透を低減することができる。また、これによりガラスの比重を小さくし、部分分散比の上昇を抑えることができる。従って、ＺｎＯ成分の含有量は、好ましくは３５．０％、より好ましくは３０．０％、さらに好ましくは２５．０％、さらに好ましくは２０．０％、最も好ましくは１５．０％を上限とする。なお、ＺｎＯ成分は含有しなくてもよいが、ＺｎＯ成分を含有することにより、ガラス転移点が低くなるため、プレス成形を行い易い光学ガラスを得易くできる。従って、ＺｎＯ成分の含有量は、好ましくは０％より多く、より好ましくは１．０％、さらに好ましくは５．０％、最も好ましくは８．０％を下限とする。ＺｎＯ成分は、原料としてＺｎＯ、ＺｎＦ２等を用いることができる。 The ZnO component is a component that lowers the glass transition point (Tg) and lowers the melting temperature of the glass raw material, and is an optional component in the optical glass of the present invention. In particular, devitrification of the glass can be reduced by setting the content of the ZnO component to 35.0% or less. This can also reduce the specific gravity of the glass and suppress the increase in the partial dispersion ratio. Accordingly, the upper limit of the content of the ZnO component is preferably 35.0%, more preferably 30.0%, further preferably 25.0%, further preferably 20.0%, and most preferably 15.0%. To do. In addition, although it does not need to contain a ZnO component, since a glass transition point becomes low by containing a ZnO component, it can obtain easily the optical glass which is easy to perform press molding. Therefore, the content of the ZnO component is preferably more than 0%, more preferably 1.0%, still more preferably 5.0%, and most preferably 8.0%. As the ZnO component, ZnO, ZnF 2 or the like can be used as a raw material.
　本発明の光学ガラスでは、ＲＯ成分（式中、ＲはＺｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｂａからなる群より選択される１種以上）は、ガラスの耐失透性を高めるために有用な成分であるが、これらＲＯ成分の合計含有量が多すぎると、かえってガラスの耐失透性が悪化し易くなり、ガラスの屈折率も低くなり易くなる。また、部分分散比も高くなる。従って、ＲＯ成分の合計含有量は、好ましくは３５．０％、より好ましくは２５．０％、最も好ましくは２０．０％を上限とする。 In the optical glass of the present invention, the RO component (wherein R is one or more selected from the group consisting of Zn, Mg, Ca, Sr, and Ba) is a useful component for increasing the devitrification resistance of the glass. However, if the total content of these RO components is too large, the devitrification resistance of the glass tends to deteriorate, and the refractive index of the glass tends to decrease. Also, the partial dispersion ratio is increased. Therefore, the total content of RO components is preferably 35.0%, more preferably 25.0%, and most preferably 20.0%.
　Ｌｉ２Ｏ成分は、ガラス転移点を下げ、且つガラスの部分分散比を低くする成分であり、本発明の光学ガラス中の任意成分である。特に、Ｌｉ２Ｏ成分の含有量を２５．０％以下にすることで、ガラスの屈折率の低下や失透を低減できる。従って、Ｌｉ２Ｏ成分の含有量は、好ましくは２５．０％、より好ましくは１２．０％、最も好ましくは７．０％を上限とする。Ｌｉ２Ｏ成分は、原料としてＬｉ２ＣＯ３、ＬｉＮＯ３、ＬｉＦ等を用いることができる。 The Li 2 O component is a component that lowers the glass transition point and lowers the partial dispersion ratio of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the Li 2 O component is 25.0% or less, it is possible to reduce the decrease in the refractive index and devitrification of the glass. Therefore, the upper limit of the content of the Li 2 O component is preferably 25.0%, more preferably 12.0%, and most preferably 7.0%. For the Li 2 O component, Li 2 CO 3 , LiNO 3 , LiF, or the like can be used as a raw material.
　Ｎａ２Ｏ成分及びＫ２Ｏ成分は、ガラスの熔融性を改善し、ガラス転移点を低くするとともに、ガラスの耐失透性を高める成分であり、本発明の光学ガラス中の任意成分である。特に、Ｎａ２Ｏ成分及び／又はＫ２Ｏ成分の含有量を２５．０％以下にすることで、ガラスの屈折率を低下し難くし、ガラスの失透を低減することができる。従って、Ｎａ２Ｏ成分及びＫ２Ｏ成分の含有量は、それぞれ好ましくは２５．０％、より好ましくは１２．０％、最も好ましくは７．０％を上限とする。Ｎａ２Ｏ成分及びＫ２Ｏ成分は、原料としてＮａ２ＣＯ３、ＮａＮＯ３、ＮａＦ、Ｎａ２ＳｉＦ６、Ｋ２ＣＯ３、ＫＮＯ３、ＫＦ、ＫＨＦ２、Ｋ２ＳｉＦ６等を用いることができる。 The Na 2 O component and the K 2 O component are components that improve the meltability of the glass, lower the glass transition point, and increase the devitrification resistance of the glass, and are optional components in the optical glass of the present invention. . In particular, by making the content of the Na 2 O component and / or the K 2 O component 25.0% or less, the refractive index of the glass is hardly lowered and the devitrification of the glass can be reduced. Therefore, the content of the Na 2 O component and the K 2 O component is preferably 25.0%, more preferably 12.0%, and most preferably 7.0%, respectively. The Na 2 O component and the K 2 O component may use Na 2 CO 3 , NaNO 3 , NaF, Na 2 SiF 6 , K 2 CO 3 , KNO 3 , KF, KHF 2 , K 2 SiF 6, etc. as raw materials. it can.
　Ｃｓ２Ｏ成分は、ガラス転移点を低くする成分であり、本発明の光学ガラス中の任意成分である。特に、Ｃｓ２Ｏ成分の含有量を１０．０％以下にすることでガラスの失透を低減できる。従って、Ｃｓ２Ｏ成分の含有量は、好ましくは１０．０％、より好ましくは５．０％、さらに好ましくは３．０％を上限とする。Ｃｓ２Ｏ成分は、原料としてＣｓ２ＣＯ３、ＣｓＮＯ３等を用いることができる。 Cs 2 O component is a component to lower the glass transition point, which is an optional component of the optical glass of the present invention. In particular, devitrification of the glass can be reduced by setting the content of the Cs 2 O component to 10.0% or less. Accordingly, the content of the Cs 2 O component is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%. As the Cs 2 O component, Cs 2 CO 3 , CsNO 3 or the like can be used as a raw material.
　本発明の光学ガラスでは、Ｒｎ２Ｏ成分（式中、ＲｎはＬｉ、Ｎａ、Ｋ及びＣｓからなる群より選択される１種以上）の含有量の和が、３０．０％以下であることが好ましい。特に、このモル和を３０．０％以下にすることで、ガラスの屈折率を低下し難くし、ガラス形成時の失透を低減することができる。また、Ｒｎ２Ｏ成分を低減することで、再加熱による失透及び着色を低減できる。従って、Ｒｎ２Ｏ成分の含有量のモル和は、好ましくは３０．０％、より好ましくは２０．０％、さらに好ましくは１５．０％、最も好ましくは１０．０％を上限とする。 In the optical glass of the present invention, the sum of the contents of the Rn 2 O component (wherein Rn is one or more selected from the group consisting of Li, Na, K and Cs) is 30.0% or less. Is preferred. In particular, when the molar sum is 30.0% or less, the refractive index of the glass is hardly lowered, and devitrification at the time of glass formation can be reduced. Moreover, devitrification and coloring by reheating can be reduced by reducing the Rn 2 O component. Therefore, the upper limit of the molar sum of the content of the Rn 2 O component is preferably 30.0%, more preferably 20.0%, still more preferably 15.0%, and most preferably 10.0%.
　また、本発明の光学ガラスでは、（Ｂ２Ｏ３＋ＺｒＯ２）／（Ｌｎ２Ｏ３＋ＷＯ３＋Ｒｎ２Ｏ）が０．７０以上であることが好ましい。これにより、ガラスに対して再加熱を行ったときの失透や着色を低減するＢ２Ｏ３成分やＺｒＯ２成分が、このときの失透や着色を増加させるＬｎ２Ｏ３成分やＷＯ３成分、Ｒｎ２Ｏ成分に相対して増加するため、再加熱時の失透や着色が起こり難くプレス成形性の高い光学ガラスを得易くできる。従って、酸化物換算組成のモル比（Ｂ２Ｏ３＋ＺｒＯ２）／（Ｌｎ２Ｏ３＋ＷＯ３＋Ｒｎ２Ｏ）は、好ましくは０．７０、より好ましくは０．９０、最も好ましくは１．００を下限とする。一方で、このモル比の上限は特に限定されないが、本発明の光学ガラスのこのモル比は、概ね５．００以下、より詳細には４．００以下、さらに詳細には３．００以下であることが多い。 Further, the optical glass of the present invention, it is preferable that (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) is 0.70 or more. Thus, B 2 O 3 component and the ZrO 2 component, Ln 2 O 3 component and WO 3 to increase devitrification or coloring at this time to reduce the devitrification or coloring when performing reheating the glass Since it increases relative to the component and the Rn 2 O component, devitrification and coloring during reheating hardly occur, and an optical glass having high press moldability can be easily obtained. Therefore, the molar ratio (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) of the oxide equivalent composition is preferably 0.70, more preferably 0.90, and most preferably 1.00. Is the lower limit. On the other hand, the upper limit of the molar ratio is not particularly limited, but the molar ratio of the optical glass of the present invention is generally 5.00 or less, more specifically 4.00 or less, and more specifically 3.00 or less. There are many cases.
　ＳｉＯ２成分は、熔融ガラスの粘度を高め、安定なガラス形成を促し、光学ガラスとして好ましくない失透（結晶物の発生）を低減する成分であり、本発明の光学ガラス中の任意成分である。特に、ＳｉＯ２成分の含有量を２０．０％以下にすることで、ガラスの部分分散比を低くし、ガラス転移点の上昇を抑え、ガラスの比重を小さくし、且つ本発明が目的とする高屈折率を得易くすることができる。従って、ＳｉＯ２成分の含有量は、好ましくは２０．０％、より好ましくは１３．０％、さらに好ましくは８．０％、さらに好ましくは６．０％、さらに好ましくは３．５％、さらに好ましくは３．３％を上限とする。特にガラスの熔解性を高める観点では、このＳｉＯ２成分の含有量を１．７％以下にすることも好ましい。また、より低い部分分散比と高い屈折率を得易くする観点では、ＳｉＯ２成分を含有しないことも好ましい。ＳｉＯ２成分は、原料としてＳｉＯ２、Ｋ２ＳｉＦ６、Ｎａ２ＳｉＦ６等を用いることができる。 The SiO 2 component is a component that increases the viscosity of the molten glass, promotes stable glass formation, and reduces devitrification (generation of crystal) that is not desirable as an optical glass, and is an optional component in the optical glass of the present invention. . In particular, by setting the content of SiO 2 component to 20.0% or less, the partial dispersion ratio of the glass is lowered, the rise of the glass transition point is suppressed, the specific gravity of the glass is reduced, and the present invention is intended. A high refractive index can be easily obtained. Therefore, the content of the SiO 2 component is preferably 20.0%, more preferably 13.0%, still more preferably 8.0%, still more preferably 6.0%, still more preferably 3.5%, Preferably, the upper limit is 3.3%. In particular, from the viewpoint of improving the meltability of the glass, it is also preferable that the content of this SiO 2 component is 1.7% or less. Further, from the viewpoint of easily obtaining a lower partial dispersion ratio and a high refractive index, it is also preferable that no SiO 2 component is contained. As the SiO 2 component, SiO 2 , K 2 SiF 6 , Na 2 SiF 6 or the like can be used as a raw material.
　本発明の光学ガラスは、Ｂ２Ｏ３成分の含有量に対するＳｉＯ２成分の含有量の比率が０．５０以下であることが好ましい。これにより、ガラスの比重を大きくするＳｉＯ２成分の含有量に相対して、ガラスの比重を小さくするＢ２Ｏ３成分の含有量が増加するため、高い耐失透性を有しながらも、より比重の小さい光学ガラスを得ることができる。従って、酸化物換算組成におけるモル比（ＳｉＯ２／Ｂ２Ｏ３）は、好ましくは０．５０、より好ましくは０．３０、最も好ましくは０．１０を上限とする。 In the optical glass of the present invention, the ratio of the content of the SiO 2 component to the content of the B 2 O 3 component is preferably 0.50 or less. Thereby, relative to the content of SiO 2 component that increases the specific gravity of the glass, the content of B 2 O 3 component that decreases the specific gravity of the glass increases, so while having high devitrification resistance, An optical glass having a smaller specific gravity can be obtained. Therefore, the upper limit of the molar ratio (SiO 2 / B 2 O 3 ) in the oxide equivalent composition is preferably 0.50, more preferably 0.30, and most preferably 0.10.
　Ｐ２Ｏ５成分は、耐失透性を高める成分であり、本発明の光学ガラス中の任意成分である。特に、Ｐ２Ｏ５成分の含有量を３０．０％以下にすることで、ガラスの化学的耐久性、特に耐水性の低下を抑えることができる。従って、Ｐ２Ｏ５成分の含有量は、好ましくは３０．０％、より好ましくは２０．０％、最も好ましくは１０．０％を上限とする。Ｐ２Ｏ５成分は、原料としてＡｌ（ＰＯ３）３、Ｃａ（ＰＯ３）２、Ｂａ（ＰＯ３）２、ＢＰＯ４、Ｈ３ＰＯ４等を用いることができる。 P 2 O 5 component is a component which enhances the devitrification resistance, which is an optional component of the optical glass of the present invention. In particular, by setting the content of the P 2 O 5 component to 30.0% or less, it is possible to suppress a decrease in chemical durability, particularly water resistance, of the glass. Accordingly, the content of the P 2 O 5 component is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. As the P 2 O 5 component, Al (PO 3 ) 3 , Ca (PO 3 ) 2 , Ba (PO 3 ) 2 , BPO 4 , H 3 PO 4 or the like can be used as a raw material.
　ＧｅＯ２成分は、ガラスの屈折率を高め、耐失透性を高める成分であり、本発明の光学ガラス中の任意成分である。特に、ＧｅＯ２成分の含有量を２０．０％以下にすることで、高価なＧｅＯ２成分の使用量が低減されるため、ガラスの材料コストを低減することができる。従って、ＧｅＯ２成分の含有量は、好ましくは２０．０％、より好ましくは１０．０％、さらに好ましくは４．０％、最も好ましくは１．４％を上限とする。ＧｅＯ２成分は、原料としてＧｅＯ２等を用いることができる。 GeO 2 component increases the refractive index of the glass, or to enhance resistance to devitrification, which is an optional component of the optical glass of the present invention. In particular, when the content of the GeO 2 component is 20.0% or less, the amount of expensive GeO 2 component used is reduced, so that the material cost of the glass can be reduced. Accordingly, the content of the GeO 2 component is preferably 20.0%, more preferably 10.0%, further preferably 4.0%, and most preferably 1.4%. As the GeO 2 component, GeO 2 or the like can be used as a raw material.
　Ｔａ２Ｏ５成分は、ガラスの屈折率を高め、ガラスの部分分散比を下げ、且つガラスの耐失透性を高める成分であり、本発明の光学ガラス中の任意成分である。特に、Ｔａ２Ｏ５成分の含有量を７．５％以下にすることで、希少鉱物資源であるＴａ２Ｏ５成分の使用量が減るとともに、ガラスがより低温で溶解し易くなるため、ガラスの生産コストを低減することができる。また、部分分散比がより低く、比重が小さい光学ガラスを得易くすることができる。従って、Ｔａ２Ｏ５成分の含有量は、好ましくは７．５％、より好ましくは５．０％、さらに好ましくは３．０％、さらに好ましくは２．０％、さらに好ましくは１．０％を上限とする。特に、ガラスの製造コストをより低減できる観点では、Ｔａ２Ｏ５成分を含有しないことが最も好ましい。Ｔａ２Ｏ５成分は、原料としてＴａ２Ｏ５等を用いることができる。 The Ta 2 O 5 component is a component that increases the refractive index of the glass, decreases the partial dispersion ratio of the glass, and increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of Ta 2 O 5 component is 7.5% or less, the amount of Ta 2 O 5 component, which is a rare mineral resource, is reduced, and the glass is easily melted at a lower temperature. The production cost can be reduced. Further, it is possible to easily obtain an optical glass having a lower partial dispersion ratio and a lower specific gravity. Therefore, the content of the Ta 2 O 5 component is preferably 7.5%, more preferably 5.0%, still more preferably 3.0%, still more preferably 2.0%, still more preferably 1.0%. Is the upper limit. In particular, from the viewpoint of further reducing the glass production cost, it is most preferable not to contain a Ta 2 O 5 component. As the Ta 2 O 5 component, Ta 2 O 5 or the like can be used as a raw material.
　Ｂｉ２Ｏ３成分は、ガラスの屈折率を高めてアッベ数を低くし、且つガラス転移点（Ｔｇ）を低くする成分であり、本発明の光学ガラス中の任意成分である。特に、Ｂｉ２Ｏ３成分の含有量を１５．０％以下にすることで、ガラスの部分分散比の上昇を抑えることができる。また、Ｂｉ２Ｏ３成分の含有量を１５．０％以下にすることで、ガラスの耐失透性の低下を抑えることができる。従って、Ｂｉ２Ｏ３成分の含有量は、好ましくは１５．０％、より好ましくは１０．０％、さらに好ましくは５．０％、さらに好ましくは３．０％、最も好ましくは１．０％を上限とする。Ｂｉ２Ｏ３成分は、原料としてＢｉ２Ｏ３等を用いることができる。 The Bi 2 O 3 component is a component that raises the refractive index of the glass to lower the Abbe number and lowers the glass transition point (Tg), and is an optional component in the optical glass of the present invention. In particular, an increase in the partial dispersion ratio of the glass can be suppressed by setting the content of the Bi 2 O 3 component to 15.0% or less. Further, by setting the content of Bi 2 O 3 component below 15.0%, it is possible to suppress a decrease in resistance to devitrification of the glass. Accordingly, the content of the Bi 2 O 3 component is preferably 15.0%, more preferably 10.0%, still more preferably 5.0%, still more preferably 3.0%, and most preferably 1.0%. Is the upper limit. As the Bi 2 O 3 component, Bi 2 O 3 or the like can be used as a raw material.
　ＴｅＯ２成分は、ガラスの屈折率を上げ、ガラスの部分分散比を低くし、ガラス転移点（Ｔｇ）を低くする成分であり、本発明の光学ガラス中の任意成分である。特に、ＴｅＯ２成分の含有量を３０．０％以下にすることで、ガラスの着色を低減し、ガラスの可視光に対する透過率を高めることができる。従って、ＴｅＯ２成分の含有量は、好ましくは３０．０％、より好ましくは１５．０％、さらに好ましくは７．０％を上限とする。ここで、ＴｅＯ２は白金製の坩堝や、熔融ガラスと接する部分が白金で形成されている熔融槽でガラス原料を熔融する際、白金と合金化しうる問題がある。そのため、特に白金との合金化を低減する観点では、ＴｅＯ２成分の含有量を０．２％未満にすることが最も好ましい。ＴｅＯ２成分は、原料としてＴｅＯ２等を用いることができる。 The TeO 2 component is a component that increases the refractive index of the glass, lowers the partial dispersion ratio of the glass, and lowers the glass transition point (Tg), and is an optional component in the optical glass of the present invention. In particular, by setting the content of the TeO 2 component to 30.0% or less, it is possible to reduce the coloration of the glass and increase the transmittance of the glass with respect to visible light. Therefore, the content of the TeO 2 component is preferably 30.0%, more preferably 15.0%, and still more preferably 7.0%. Here, TeO 2 has a problem that it can be alloyed with platinum when melting a glass raw material in a crucible made of platinum or a melting tank in which a portion in contact with molten glass is formed of platinum. Therefore, particularly from the viewpoint of reducing alloying with platinum, the content of the TeO 2 component is most preferably less than 0.2%. TeO 2 component can use TeO 2 or the like as a raw material.
　Ａｌ２Ｏ３成分は、ガラスの化学的耐久性を高め、ガラスの耐失透性を向上する成分であり、本発明の光学ガラス中の任意成分である。特に、Ａｌ２Ｏ３成分の含有量を１５．０％以下にすることで、Ａｌ２Ｏ３成分の過剰な含有による失透を低減できる。従って、Ａｌ２Ｏ３成分の含有量は、好ましくは１５．０％、より好ましくは１０．０％、最も好ましくは５．０％を上限とする。Ａｌ２Ｏ３成分は、原料としてＡｌ２Ｏ３、Ａｌ（ＯＨ）３、ＡｌＦ３等を用いることができる。 The Al 2 O 3 component is a component that improves the chemical durability of the glass and improves the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Al 2 O 3 component to 15.0% or less, devitrification due to excessive inclusion of the Al 2 O 3 component can be reduced. Therefore, the upper limit of the content of the Al 2 O 3 component is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%. As the Al 2 O 3 component, Al 2 O 3 , Al (OH) 3 , AlF 3 or the like can be used as a raw material.
　Ｓｂ２Ｏ３成分は、熔融ガラスを脱泡する成分であり、本発明の光学ガラス中の任意成分である。Ｓｂ２Ｏ３量が多すぎると、可視光領域の短波長領域における透過率が悪くなる。従って、Ｓｂ２Ｏ３成分の含有量は、好ましくは１．０％、より好ましくは０．５％、最も好ましくは０．３％を上限とする。Ｓｂ２Ｏ３成分は、原料としてＳｂ２Ｏ３、Ｓｂ２Ｏ５、Ｎａ２Ｈ２Ｓｂ２Ｏ７・５Ｈ２Ｏ等を用いることができる。 The Sb 2 O 3 component is a component that defoams the molten glass and is an optional component in the optical glass of the present invention. If sb 2 O 3 content is too high, the transmittance in the short wavelength region of the visible light region is deteriorated. Accordingly, the content of the Sb 2 O 3 component is preferably 1.0%, more preferably 0.5%, and most preferably 0.3%. As the Sb 2 O 3 component, Sb 2 O 3 , Sb 2 O 5 , Na 2 H 2 Sb 2 O 7 .5H 2 O, or the like can be used as a raw material.
　なお、ガラスを清澄し脱泡する成分は、上記のＳｂ２Ｏ３成分に限定されるものではなく、ガラス製造の分野における公知の清澄剤や脱泡剤、或いはそれらの組み合わせを用いることができる。 Incidentally, components of the fining defoaming of glass is not limited to the above Sb 2 O 3 ingredients may be used known refining agents and defoamers in the field of glass production, or a combination thereof .
＜含有すべきでない成分について＞
　次に、本発明の光学ガラスに含有すべきでない成分、及び含有することが好ましくない成分について説明する。 <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.
　本発明の光学ガラスには、他の成分をガラスの特性を損なわない範囲で必要に応じて添加することができる。 In the optical glass of the present invention, other components can be added as needed within a range not impairing the properties of the glass.
　ただし、Ｔｉ、Ｚｒ、Ｎｂを除く、Ｖ、Ｃｒ、Ｍｎ、Ｃｏ、Ｎｉ、Ｃｕ、Ａｇ及びＭｏ等の各遷移金属成分は、それぞれを単独又は複合して少量含有した場合でもガラスが着色し、可視域の特定の波長に吸収を生じる性質があるため、特に可視領域の波長を使用する光学ガラスにおいては、実質的に含まないことが好ましい。 However, the transition metal components such as V, Cr, Mn, Co, Ni, Cu, Ag, and Mo, excluding Ti, Zr, and Nb, are colored by the glass even when each of them is contained alone or in combination. Since it has a property of causing absorption at a specific wavelength in the visible range, it is preferable that the optical glass using the wavelength in the visible range does not substantially contain.
　さらに、ＰｂＯ等の鉛化合物及びＡｓ２Ｏ３等のヒ素化合物、並びに、Ｔｈ、Ｃｄ、Ｔｌ、Ｏｓ、Ｂｅ、Ｓｅの各成分は、近年有害な化学物資として使用を控える傾向にあり、ガラスの製造工程のみならず、加工工程、及び製品化後の処分に至るまで環境対策上の措置が必要とされる。従って、環境上の影響を重視する場合には、不可避な混入を除き、これらを実質的に含有しないことが好ましい。これにより、光学ガラスに環境を汚染する物質が実質的に含まれなくなる。そのため、特別な環境対策上の措置を講じなくとも、この光学ガラスを製造し、加工し、及び廃棄することができる。 Furthermore, lead compounds such as PbO, 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 any special environmental measures.
　本発明の光学ガラスとして好ましく用いられるガラスは、その組成が酸化物換算組成のガラス全物質量に対するモル％で表されているため直接的に質量％の記載に表せるものではないが、本発明において要求される諸特性を満たすガラス組成物中に存在する各成分の質量％表示による組成は、酸化物換算組成で概ね以下の値をとる。
Ｂ２Ｏ３成分　１２．０～２５．０質量％及び
Ｎｂ２Ｏ５成分　０質量％超～４０．０質量％
並びに
ＺｒＯ２成分　０～１０．０質量％及び／又は
Ｌａ２Ｏ３成分　０～６０．０質量％及び／又は
Ｇｄ２Ｏ３成分　０～３０．０質量％及び／又は
Ｙ２Ｏ３成分　０～２５．０質量％及び／又は
Ｙｂ２Ｏ３成分　０～３０．０質量％及び／又は
ＴｉＯ２成分　０～１０．０質量％及び／又は
ＷＯ３成分　０～４５．０質量％及び／又は
Ｌｉ２Ｏ成分　０～５．０質量％及び／又は
Ｎａ２Ｏ成分　０～１２．０質量％及び／又は
Ｋ２Ｏ成分　０～２０．０質量％及び／又は
Ｃｓ２Ｏ成分　０～２５．０質量％及び／又は
ＭｇＯ成分　０～３．０質量％及び／又は
ＣａＯ成分　０～７．０質量％及び／又は
ＳｒＯ成分　０～１２．０質量％及び／又は
ＢａＯ成分　０～２０．０質量％及び／又は
ＺｎＯ成分　０～３０．０質量％及び／又は
ＳｉＯ２成分　０～１０．０質量％及び／又は
Ｐ２Ｏ５成分　０～３０．０質量％及び／又は
ＧｅＯ２成分　０～２０．０質量％及び／又は
Ｔａ２Ｏ５成分　０～２０．０質量％及び／又は
Ｂｉ２Ｏ３成分　０～４０．０質量％及び／又は
ＴｅＯ２成分　０～３０．０質量％及び／又は
Ａｌ２Ｏ３成分　０～１０．０質量％及び／又は
Ｓｂ２Ｏ３成分　０～２．０質量％ The glass that is preferably used as the optical glass of the present invention cannot be expressed directly in the description of mass% because the composition is expressed in mol% with respect to the total amount of glass of oxide conversion composition. The composition expressed by mass% of each component present in the glass composition satisfying various required properties generally takes the following values in terms of oxide composition.
B 2 O 3 component 12.0-25.0% by mass and Nb 2 O 5 component 0% by mass to 40.0% by mass
And ZrO 2 component 0 to 10.0% by mass and / or La 2 O 3 component 0 to 60.0% by mass and / or Gd 2 O 3 component 0 to 30.0% by mass and / or Y 2 O 3 component 0 ˜25.0 mass% and / or Yb 2 O 3 component 0-30.0 mass% and / or TiO 2 component 0-10.0 mass% and / or WO 3 component 0-45.0 mass% and / or Li 2 O component 0-5.0% by mass and / or Na 2 O component 0-12.0% by mass and / or K 2 O component 0-20.0% by mass and / or Cs 2 O component 0-25. 0% by mass and / or MgO component 0-3.0% by mass and / or CaO component 0-7.0% by mass and / or SrO component 0-12.0% by mass and / or BaO component 0-20.0% by mass % And / or ZnO component 0 to 30.0% by mass and / or SiO 2 Component 0 to 10.0% by mass and / or P 2 O 5 component 0 to 30.0% by mass and / or GeO 2 component 0 to 20.0% by mass and / or Ta 2 O 5 component 0 to 20.0 mass % And / or Bi 2 O 3 component 0-40.0% by mass and / or TeO 2 component 0-30.0% by mass and / or Al 2 O 3 component 0-10.0% by mass and / or Sb 2 O 3 components 0-2.0 mass%
　なお、本発明の光学ガラスに含まれるＺｒＯ２成分の質量％表示による組成は、酸化物換算組成で概ね０～７．０質量％であってもよい。 The composition expressed by mass% of the ZrO 2 component contained in the optical glass of the present invention may be generally 0 to 7.0 mass% in terms of oxide.
［製造方法］
　本発明の光学ガラスは、例えば以下のように作製される。すなわち、上記原料を各成分が所定の含有量の範囲内になるように均一に混合し、作製した混合物を白金坩堝、石英坩堝又はアルミナ坩堝に投入して粗溶融した後、金坩堝、白金坩堝、白金合金坩堝又はイリジウム坩堝に入れて１１００～１４００℃の温度範囲で３～５時間溶融し、攪拌均質化して泡切れ等を行った後、１０００～１３００℃の温度に下げてから仕上げ攪拌を行って脈理を除去し、金型に鋳込んで徐冷することにより作製される。 [Production method]
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 platinum crucible, a quartz crucible or an alumina crucible and roughly melted, then a gold crucible, a platinum crucible In a platinum alloy crucible or iridium crucible, melt in a temperature range of 1100 to 1400 ° C. for 3 to 5 hours, stir and homogenize to blow out bubbles, etc., then lower the temperature to 1000 to 1300 ° C. and then finish stirring This is done by removing the striae, casting into a mold and slow cooling.
＜物性＞
　本発明の光学ガラスは、所定の屈折率及び分散（アッベ数）を有することが好ましい。より具体的には、本発明の光学ガラスの屈折率（ｎｄ）は、好ましくは１．８０、より好ましくは１．８３、最も好ましくは１．８５を下限とする。一方、本発明の光学ガラスの屈折率（ｎｄ）の上限は、概ね２．００以下、より具体的には１．９７以下、さらに具体的には１．９５以下であることが多い。また、本発明の光学ガラスのアッベ数（νｄ）は、好ましくは４０、より好ましくは３８、より好ましくは３５を上限とし、最も好ましくは３３未満とする。一方、本発明の光学ガラスのアッベ数（νｄ）の下限は、概ね２０以上、より具体的には２３以上、さらに具体的には２５以上であることが多い。これらにより、光学設計の自由度が広がり、さらに素子の薄型化を図っても大きな光の屈折量を得ることができる。 <Physical properties>
The optical glass of the present invention preferably has a predetermined refractive index and dispersion (Abbe number). More specifically, the refractive index (n d ) of the optical glass of the present invention is preferably 1.80, more preferably 1.83, and most preferably 1.85. On the other hand, the upper limit of the refractive index (n d ) of the optical glass of the present invention is generally 2.00 or less, more specifically 1.97 or less, and more specifically 1.95 or less in many cases. Moreover, the Abbe number (ν d ) of the optical glass of the present invention is preferably 40, more preferably 38, more preferably 35, and most preferably less than 33. On the other hand, the lower limit of the Abbe number (ν d ) of the optical glass of the present invention is generally 20 or more, more specifically 23 or more, and more specifically 25 or more in many cases. 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.
　また、本発明の光学ガラスは、低い部分分散比（θｇ，Ｆ）を有する。より具体的には、本発明の光学ガラスの部分分散比（θｇ，Ｆ）は、アッベ数（νｄ）との間で、νｄ≦３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００２７５×νｄ＋０．６８１２５）の関係を満たし、且つ、νｄ＞３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００１６２×νｄ＋０．６４６２２）の関係を満たす。これにより、ノーマルラインに近付けられた部分分散比（θｇ，Ｆ）を有する光学ガラスが得られるため、この光学ガラスから形成される光学素子の色収差を低減できる。ここで、νｄ≦３１における光学ガラスの部分分散比（θｇ，Ｆ）の下限は、好ましくは（－０．００１６２×νｄ＋０．６３８２２）、より好ましくは（－０．００１６２×νｄ＋０．６３９２２）、最も好ましくは（－０．００１６２×νｄ＋０．６４０２２）である。一方で、νｄ≦３１における光学ガラスの部分分散比（θｇ，Ｆ）の上限は、好ましくは（－０．００２７５×νｄ＋０．６８１２５）、より好ましくは（－０．００２７５×νｄ＋０．６８０２５）、最も好ましくは（－０．００２７５×νｄ＋０．６７９２５）である。また、νｄ＞３１における光学ガラスの部分分散比（θｇ，Ｆ）の下限は、好ましくは（－０．００１６２×νｄ＋０．６３８２２）、より好ましくは（－０．００１６２×νｄ＋０．６３９２２）、最も好ましくは（－０．００１６２×νｄ＋０．６４０２２）である。一方で、νｄ＞３１における光学ガラスの部分分散比（θｇ，Ｆ）の上限は、好ましくは（－０．００１６２×νｄ＋０．６４６２２）、より好ましくは（－０．００１６２×νｄ＋０．６４５２２）、最も好ましくは（－０．００１６２×νｄ＋０．６４４２２）である。なお、特にアッベ数（νｄ）が小さい領域では、一般的なガラスの部分分散比（θｇ，Ｆ）はノーマルラインよりも高い値にあり、一般的なガラスの部分分散比（θｇ，Ｆ）とアッベ数（νｄ）の関係は曲線で表される。しかしながら、この曲線の近似が困難であるため、本発明では、一般的なガラスよりも部分分散比（θｇ，Ｆ）が低いことを、νｄ＝３１を境に異なった傾きを有する直線を用いて表した。 Moreover, the optical glass of the present invention has a low partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is within the range of ν d ≦ 31 with respect to the Abbe number (ν d ) (−0.00162 × νd + 0.63822). ≦ (θg, F) ≦ (−0.00275 × νd + 0.68125) is satisfied, and (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (− in the range of ν d > 31 0.00162 × νd + 0.64622). As a result, an optical glass having a partial dispersion ratio (θg, F) close to the normal line can be obtained, so that chromatic aberration of an optical element formed from the optical glass can be reduced. Here, the lower limit of the partial dispersion ratio (θg, F) of the optical glass at ν d ≦ 31 is preferably (−0.00162 × νd + 0.63822), more preferably (−0.00162 × νd + 0.63922), Most preferred is (−0.00162 × νd + 0.64022). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the optical glass at ν d ≦ 31 is preferably (−0.00275 × νd + 0.68125), more preferably (−0.00275 × νd + 0.68025), Most preferred is (−0.00275 × νd + 0.67925). The lower limit of the partial dispersion ratio (θg, F) of the optical glass at ν d > 31 is preferably (−0.00162 × νd + 0.63822), more preferably (−0.00162 × νd + 0.63922), most preferably Preferably, it is (−0.00162 × νd + 0.64022). On the other hand, the upper limit of the partial dispersion ratio (θg, F) of the optical glass at ν d > 31 is preferably (−0.00162 × νd + 0.64622), more preferably (−0.00162 × νd + 0.64522). Most preferred is (−0.00162 × νd + 0.64422). In particular, in a region where the Abbe number (ν d ) is small, the partial dispersion ratio (θg, F) of general glass is higher than that of the normal line, and the partial dispersion ratio (θg, F) of general glass is high. And the Abbe number (ν d ) are represented by curves. However, since it is difficult to approximate this curve, the present invention uses a straight line having a different slope from ν d = 31 as a partial dispersion ratio (θg, F) lower than that of general glass. Expressed.
　また、本発明の光学ガラスは、着色が少ないことが好ましい。特に、本発明の光学ガラスは、ガラスの透過率で表すと、厚み１０ｍｍのサンプルで分光透過率７０％を示す波長（λ７０）が５００ｎｍ以下であり、より好ましくは４７０ｎｍ以下であり、さらに好ましくは４５０ｎｍ以下であり、最も好ましくは４３０ｎｍ以下である。また、本発明の光学ガラスは、ガラスの透過率で表すと、厚み１０ｍｍのサンプルで分光透過率８０％を示す波長（λ８０）が５６０ｎｍ以下であり、より好ましくは５４０ｎｍ以下であり、最も好ましくは５２０ｎｍ以下である。また、本発明の光学ガラスは、厚み１０ｍｍのサンプルで分光透過率５％を示す波長（λ５）が４２０ｎｍ以下であり、より好ましくは４００ｎｍ以下であり、最も好ましくは３８０ｎｍ以下である。これにより、ガラスの吸収端が紫外領域の近傍に位置するようになり、可視域におけるガラスの透明性が高められるため、この光学ガラスをレンズ等の光学素子の材料として好ましく用いることができる。 Moreover, it is preferable that the optical glass of this invention has little coloring. In particular, when the optical glass of the present invention is represented by the transmittance of the glass, the wavelength (λ 70 ) indicating a spectral transmittance of 70% in a sample having a thickness of 10 mm is 500 nm or less, more preferably 470 nm or less, and still more preferably. Is 450 nm or less, and most preferably 430 nm or less. In addition, the optical glass of the present invention has a wavelength (λ 80 ) of 560 nm or less, more preferably 540 nm or less, and most preferably, when the sample has a thickness of 10 mm and exhibits a spectral transmittance of 80%. Is 520 nm or less. In the optical glass of the present invention, a wavelength (λ 5 ) showing a spectral transmittance of 5% in a sample having a thickness of 10 mm is 420 nm or less, more preferably 400 nm or less, and most preferably 380 nm or less. Thereby, the absorption edge of the glass is positioned in the vicinity of the ultraviolet region, and the transparency of the glass in the visible region is enhanced. Therefore, this optical glass can be preferably used as a material for an optical element such as a lens.
　また、本発明の光学ガラスは、比重が小さいことが好ましい。より具体的には、本発明の光学ガラスの比重は５．００［ｇ／ｃｍ３］以下であることが好ましい。これにより、光学素子やそれを用いた光学機器の質量が低減されるため、光学機器の軽量化に寄与することができる。従って、本発明の光学ガラスの比重は、好ましくは５．００、より好ましくは４．９０、好ましくは４．８０を上限とする。なお、本発明の光学ガラスの比重は、概ね３．００以上、より詳細には３．５０以上、さらに詳細には４．００以上であることが多い。なお、本発明の光学ガラスの比重は、日本光学硝子工業会規格ＪＯＧＩＳ０５－１９７５「光学ガラスの比重の測定方法」に基づいて測定する。 The optical glass of the present invention preferably has a small specific gravity. More specifically, the specific gravity of the optical glass of the present invention is preferably 5.00 [g / cm 3 ] or less. Thereby, since the mass of an optical element and an optical apparatus using the same is reduced, it can contribute to the weight reduction of an optical apparatus. Therefore, the specific gravity of the optical glass of the present invention is preferably 5.00, more preferably 4.90, and preferably 4.80. The specific gravity of the optical glass of the present invention is generally about 3.00 or more, more specifically 3.50 or more, and more specifically 4.00 or more in many cases. The specific gravity of the optical glass of the present invention is measured based on Japan Optical Glass Industry Association Standard JOGIS05-1975 “Method for Measuring Specific Gravity of Optical Glass”.
　また、本発明の光学ガラスは、プレス成形性が良好であることが好ましい。すなわち、本発明の光学ガラスは、再加熱試験（イ）後の試験片の波長５８７．５６ｎｍの光線（ｄ線）の透過率を、再加熱試験前の試験片のｄ線の透過率で除した値が、０．９５以上であることが好ましい。また、再加熱試験（イ）前の試験片の透過率が７０％となる波長であるλ７０と、再加熱試験後の試験片のλ７０との差が２０ｎｍ以下であることが好ましい。これにより、リヒートプレス加工を想定した再加熱試験によっても失透及び着色が起こり難くなることで、ガラスの光線透過率が失われ難くなるため、ガラスに対してリヒートプレス加工に代表される再加熱処理を行い易くできる。すなわち、複雑な形状の光学素子をプレス成形で作製できるため、製造コストが安く、且つ生産性の良い光学素子製造を実現することができる。 The optical glass of the present invention preferably has good press formability. That is, the optical glass of the present invention divides the transmittance of light (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (ii) by the transmittance of d-line of the test piece before the reheating test. The measured value is preferably 0.95 or more. Also, a lambda 70 is a wavelength at which the transmittance of the reheating test (a) before the specimen is 70% and the difference between the lambda 70 of the test piece after the reheating test is 20nm or less. This makes it difficult for devitrification and coloring to occur even in a reheating test assuming reheat press processing, so that the light transmittance of the glass is less likely to be lost. Processing can be facilitated. That is, since an optical element having a complicated shape can be produced by press molding, it is possible to realize optical element production with low production cost and high productivity.
　ここで、再加熱試験（イ）後の試験片の波長５８７．５６ｎｍの光線（ｄ線）の透過率を、再加熱試験（イ）前の試験片のｄ線の透過率で除した値は、好ましくは０．９５、より好ましくは０．９６、最も好ましくは０．９７を下限とする。また、再加熱試験（イ）前の試験片のλ７０と再加熱試験（イ）後の試験片のλ７０との差は、好ましくは２０ｎｍ、より好ましくは１８ｎｍ、最も好ましくは１６ｎｍを上限とする。 Here, the value obtained by dividing the transmittance of the light beam (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (ii) by the transmittance of the d-line of the test piece before the reheating test (ii) is The lower limit is preferably 0.95, more preferably 0.96, and most preferably 0.97. Further, the difference between the lambda 70 of the test piece after the reheating test and lambda 70 of reheating test (a) prior to the test piece (b) is preferably 20 nm, more preferably 18 nm, and most preferably a maximum of 16nm To do.
　なお、再加熱試験（イ）は、試験片１５ｍｍ×１５ｍｍ×３０ｍｍを再加熱し、室温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度まで昇温し、前記光学ガラスのガラス転移温度（Ｔｇ）よりも８０℃高い温度で３０分間保温し、その後常温まで自然冷却し、試験片の対向する２面を厚み１０ｍｍに研磨した後に目視観察することにより行われる。 In the reheating test (A), a test piece 15 mm × 15 mm × 30 mm is reheated, and the temperature is raised from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes. This is carried out by keeping the temperature at 80 ° C. higher than the transition temperature (Tg) for 30 minutes, then naturally cooling to room temperature, and polishing the two opposing surfaces of the test piece to a thickness of 10 mm and visually observing them.
［プリフォーム及び光学素子］
　作製された光学ガラスから、例えばリヒートプレス成形や精密プレス成形等のモールドプレス成形の手段を用いて、ガラス成形体を作製することができる。すなわち、光学ガラスからモールドプレス成形用のプリフォームを作製し、このプリフォームに対してリヒートプレス成形を行った後で研磨加工を行ってガラス成形体を作製したり、例えば研磨加工を行って作製したプリフォームに対して精密プレス成形を行ってガラス成形体を作製したりすることができる。なお、ガラス成形体を作製する手段は、これらの手段に限定されない。 [Preforms and optical elements]
A glass molded body can be produced from the produced optical glass by means of mold press molding such as reheat press molding or precision press molding. That is, a preform for mold press molding is prepared from optical glass, and after performing reheat press molding on the preform, polishing is performed to prepare a glass molded body, or for example, polishing is performed. The preform can be precision press-molded to produce a glass molded body. In addition, the means for producing the glass molded body is not limited to these means.
　このようにして作製されるガラス成形体は、様々な光学素子に有用であるが、その中でも特に、レンズやプリズム等の光学素子の用途に用いることが好ましい。これにより、光学素子が設けられる光学系の透過光における、色収差による色のにじみが低減される。そのため、この光学素子をカメラに用いた場合は撮影対象物をより正確に表現でき、この光学素子をプロジェクタに用いた場合は所望の映像をより高精彩に投影できる。 The glass molded body produced in this manner is useful for various optical elements, and among them, it is particularly preferable to use for optical elements such as lenses and prisms. As a result, color bleeding due to chromatic aberration in the transmitted light of the optical system provided with the optical element is reduced. Therefore, when this optical element is used in a camera, a photographing object can be expressed more accurately, and when this optical element is used in a projector, a desired image can be projected with higher definition.
　本発明の実施例（Ｎｏ．１～Ｎｏ．６３）及び比較例（Ｎｏ．Ａ～Ｎｏ．Ｆ）の組成、並びに、屈折率（ｎｄ）、アッベ数（νｄ）、部分分散比（θｇ，Ｆ）、分光透過率が５％、７０％及び８０％を示す波長（λ５、λ７０、λ８０）、比重、並びに再加熱試験（イ）前後の透過率の変動を表１～表１１に示す。なお、以下の実施例はあくまで例示の目的であり、これらの実施例のみ限定されるものではない。 Composition of Examples (No. 1 to No. 63) and Comparative Examples (No. A to No. F) of the present invention, refractive index (n d ), Abbe number (ν d ), partial dispersion ratio (θg F), wavelengths (λ 5 , λ 70 , λ 80 ) exhibiting spectral transmittances of 5%, 70%, and 80%, specific gravity, and transmittance fluctuations before and after the reheating test (a) are shown in Tables 1 to 11 shows. The following examples are merely for illustrative purposes, and are not limited to these examples.
　本発明の実施例及び比較例のガラスは、いずれも各成分の原料として各々相当する酸化物、水酸化物、炭酸塩、硝酸塩、弗化物、水酸化物、メタ燐酸化合物等の通常の光学ガラスに使用される高純度の原料を選定し、表１～表１１に示した各実施例及び比較例の組成の割合になるように秤量して均一に混合した後、白金坩堝に投入し、ガラス組成の熔融難易度に応じて電気炉で１１００～１４００℃の温度範囲で３～５時間溶解し、攪拌均質化して泡切れ等を行った後、１０００～１３００℃に温度を下げて攪拌均質化してから金型に鋳込み、徐冷してガラスを作製した。 The glasses of the examples and comparative examples of the present invention are ordinary optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and metaphosphate compounds corresponding to the raw materials of the respective components. The high-purity raw materials used in the above are selected, weighed so as to have the composition ratios of the examples and comparative examples shown in Tables 1 to 11, and mixed uniformly, and then put into a platinum crucible, and glass Depending on the melting difficulty of the composition, dissolve in an electric furnace at a temperature range of 1100-1400 ° C for 3-5 hours, stir homogenize, blow out bubbles, etc., then lower the temperature to 1000-1300 ° C and homogenize with stirring Then, it was cast into a mold and slowly cooled to produce glass.
　ここで、実施例及び比較例のガラスの屈折率（ｎｄ）、アッベ数（νｄ）及び部分分散比（θｇ，Ｆ）は、日本光学硝子工業会規格ＪＯＧＩＳ０１―２００３に基づいて測定した。そして、求められたアッベ数（νｄ）及び部分分散比（θｇ，Ｆ）の値について、関係式（θｇ，Ｆ）＝－ａ×νｄ＋ｂにおける、傾きａが０．００１６２及び０．００２７５のときの切片ｂを求めた。なお、本測定に用いたガラスは、徐冷降温速度を－２５℃／ｈｒとして、徐冷炉にて処理を行ったものを用いた。 Here, the refractive index (n d ), Abbe number (ν d ), and partial dispersion ratio (θg, F) of the glasses of Examples and Comparative Examples were measured based on Japan Optical Glass Industry Association Standard JOGIS01-2003. Then, with respect to the obtained Abbe number (ν d ) and partial dispersion ratio (θg, F), the slope a in the relational expression (θg, F) = − a × ν d + b is 0.00162 and 0.00275. The intercept b at that time was determined. The glass used in this measurement was a glass that had been treated in a slow cooling furnace at a slow cooling rate of −25 ° C./hr.
　また、実施例及び比較例のガラスの透過率は、日本光学硝子工業会規格ＪＯＧＩＳ０２に準じて測定した。なお、本発明においては、ガラスの透過率を測定することで、ガラスの着色の有無と程度を求めた。具体的には、厚さ１０±０．１ｍｍの対面平行研磨品をＪＩＳＺ８７２２に準じ、２００～８００ｎｍの分光透過率を測定し、λ５（透過率５％時の波長）、λ７０（透過率７０％時の波長）及びλ８０（透過率８０％時の波長）を求めた。 Moreover, the transmittance | permeability of the glass of an Example and a comparative example 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, a face parallel polished product having a thickness of 10 ± 0.1 mm was measured for a spectral transmittance of 200 to 800 nm in accordance with JISZ8722, and λ 5 (wavelength at a transmittance of 5%), λ 70 (transmittance). The wavelength at 70%) and λ 80 (wavelength at 80% transmittance) were determined.
　また、実施例及び比較例のガラスの比重は、日本光学硝子工業会規格ＪＯＧＩＳ０５－１９７５「光学ガラスの比重の測定方法」に基づいて測定した。 In addition, the specific gravity of the glass of Examples and Comparative Examples was measured based on Japan Optical Glass Industry Association Standard JOGIS05-1975 “Measurement Method of Specific Gravity of Optical Glass”.
　また、実施例及び比較例のガラスの再加熱試験（イ）前後の透過率の変動は、以下のようにして測定した。
　再加熱試験（イ）後の試験片の波長５８７．５６ｎｍの光線（ｄ線）の透過率を再加熱試験前の試験片のｄ線の透過率で除した値は、再加熱試験（イ）前後のガラスに対して、日本光学硝子工業会規格ＪＯＧＩＳ０２－２００３に準じて行った。具体的には、厚さ１０±０．１ｍｍの対面平行研磨品をＪＩＳＺ８７２２に準じ、ｄ線の分光透過率を測定し、（再加熱試験（イ）後のｄ線透過率）／（再加熱試験（イ）前のｄ線透過率）を求め、再加熱試験（イ）前後の最大透過率の変化を評価した。
　一方で、再加熱試験（イ）前の試験片の透過率が７０％となる波長であるλ７０と再加熱試験後の試験片のλ７０との差は、再加熱試験（イ）前後のガラスに対して、上述の試験方法でλ７０（透過率７０％時の波長）を求め、再加熱試験（イ）前の試験片のλ７０と再加熱試験（イ）後の試験片のλ７０との差を評価した。
　ここで、再加熱試験（イ）は、１５ｍｍ×１５ｍｍ×３０ｍｍの試験片を、凹型耐火物上に載せて電気炉に入れて再加熱し、常温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度（耐火物に落ち込む温度）まで昇温し、その温度で３０分保温した後、常温まで冷却して炉外に取り出し、内部で観察できるように対向する２面を厚さ１０ｍｍに研磨した後、研磨したガラス試料を目視観察する方法で行った。
Moreover, the fluctuation | variation of the transmittance | permeability before and after the reheating test (ii) of the glass of an Example and a comparative example was measured as follows.
The value obtained by dividing the transmittance of the light beam (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (b) by the d-line transmittance of the test piece before the reheating test is the reheating test (b). The front and rear glasses were subjected to the Japan Optical Glass Industry Association Standard JOGIS02-2003. Specifically, the d-line spectral transmittance of a face-parallel polished product having a thickness of 10 ± 0.1 mm was measured in accordance with JISZ8722, and (d-line transmittance after reheating test (ii)) / (reheated) The d-line transmittance before the test (A) was determined, and the change in the maximum transmittance before and after the reheating test (A) was evaluated.
On the other hand, the difference between λ 70 , which is the wavelength at which the transmittance of the test piece before the reheating test (A) becomes 70%, and λ 70 of the test piece after the reheating test is the same as before and after the reheating test (A). the glass, calculated lambda 70 (the wavelength when the transmittance of 70%) in the above test method, the test piece after the reheating test and lambda 70 of reheating test (a) prior to the test piece (a) lambda The difference from 70 was evaluated.
Here, in the reheating test (A), a test piece of 15 mm × 15 mm × 30 mm is placed on an indented refractory and placed in an electric furnace and reheated, and the transition temperature (Tg) of each sample is 150 minutes from room temperature. The temperature is raised to a temperature higher than 80 ° C. (the temperature falling into the refractory), kept at that temperature for 30 minutes, cooled to room temperature, taken out of the furnace, and the two opposing faces are 10 mm thick so that they can be observed inside Then, the polished glass sample was visually observed.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000002
  
Figure JPOXMLDOC01-appb-T000002
  
Figure JPOXMLDOC01-appb-T000003
  
Figure JPOXMLDOC01-appb-T000003
  
Figure JPOXMLDOC01-appb-T000004
  
Figure JPOXMLDOC01-appb-T000004
  
Figure JPOXMLDOC01-appb-T000005
  
Figure JPOXMLDOC01-appb-T000005
  
Figure JPOXMLDOC01-appb-T000006
  
Figure JPOXMLDOC01-appb-T000006
  
Figure JPOXMLDOC01-appb-T000007
  
Figure JPOXMLDOC01-appb-T000007
  
Figure JPOXMLDOC01-appb-T000008
  
Figure JPOXMLDOC01-appb-T000008
  
Figure JPOXMLDOC01-appb-T000009
  
Figure JPOXMLDOC01-appb-T000009
  
Figure JPOXMLDOC01-appb-T000010
  
Figure JPOXMLDOC01-appb-T000010
  
Figure JPOXMLDOC01-appb-T000011
  
Figure JPOXMLDOC01-appb-T000011
  
　表１～表１１に表されるように、本発明の実施例の光学ガラスは、νｄ≦３１のものは部分分散比（θｇ，Ｆ）が（－０．００２７５×νｄ＋０．６８１２５）以下、より詳細には（－０．００２７５×νｄ＋０．６８０２０）以下であった。また、νｄ＞３１のものは、部分分散比（θｇ，Ｆ）が（－０．００１６２×νｄ＋０．６４６２２）以下、より詳細には（－０．００１６２×νｄ＋０．６４５３８）以下であった。その反面で、本発明の実施例の光学ガラスは、部分分散比（θｇ，Ｆ）が（－０．００１６２×νｄ＋０．６３８２２）以上、より詳細には（－０．００１６２×νｄ＋０．６４０５０）以上であった。すなわち、本願の実施例のガラスについての部分分散比（θｇ，Ｆ）とアッベ数（νｄ）の関係は、図２に示されるようになった。そのため、これらの部分分散比（θｇ，Ｆ）が所望の範囲内にあることがわかった。一方、本発明の比較例（Ｎｏ．Ａ、Ｎｏ．Ｃ～Ｎｏ．Ｆ）のガラスは、νｄ＞３１であり、且つ部分分散比（θｇ，Ｆ）が（－０．００１６２×νｄ＋０．６４６２２）を超えていた。また、本発明の比較例（Ｎｏ．Ｂ）のガラスは、νｄ≦３１であり、且つ部分分散比（θｇ，Ｆ）が（－０．００２７５×νｄ＋０．６８１２５）を超えていた。従って、本発明の実施例の光学ガラスは、比較例のガラスに比べ、アッベ数（νｄ）との関係式において部分分散比（θｇ，Ｆ）が小さいことが明らかになった。 As shown in Tables 1 to 11, the optical glasses of the examples of the present invention have a partial dispersion ratio (θg, F) of (−0.00275 × νd + 0.68125) or less when ν d ≦ 31. More specifically, it was (−0.00275 × νd + 0.68020) or less. In the case of ν d > 31, the partial dispersion ratio (θg, F) was (−0.00162 × νd + 0.64622) or less, more specifically, (−0.00162 × νd + 0.64538) or less. On the other hand, in the optical glass of the example of the present invention, the partial dispersion ratio (θg, F) is (−0.00162 × νd + 0.63822) or more, more specifically (−0.00162 × νd + 0.64050) or more. Met. That is, the relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν d ) for the glass of the example of the present application is as shown in FIG. Therefore, it was found that these partial dispersion ratios (θg, F) are within a desired range. On the other hand, the glasses of the comparative examples (No. A, No. C to No. F) of the present invention have ν d > 31 and the partial dispersion ratio (θg, F) is (−0.00162 × νd + 0.64622). ). The glass of Comparative Example (No. B) of the present invention had ν d ≦ 31 and the partial dispersion ratio (θg, F) exceeded (−0.00275 × νd + 0.68125). Therefore, it was clarified that the optical glass of the example of the present invention has a smaller partial dispersion ratio (θg, F) in the relational expression with the Abbe number (ν d ) than the glass of the comparative example.
　また、本発明の実施例の光学ガラスは、いずれも屈折率（ｎｄ）が１．７０以上、より詳細には１．８９以上であるとともに、この屈折率（ｎｄ）は２．２０以下、より詳細には１．９４以下であり、所望の範囲内であった。 The optical glasses of the examples of the present invention all have a refractive index (n d ) of 1.70 or more, more specifically 1.89 or more, and this refractive index (n d ) is 2.20 or less. More specifically, it was 1.94 or less, and was within a desired range.
　また、本発明の実施例の光学ガラスは、いずれもアッベ数（νｄ）が２０以上、より詳細には２９以上であるとともに、このアッベ数（νｄ）は４０以下、より詳細には３３以下であり、所望の範囲内であった。一方、本発明の比較例（Ｎｏ．Ｄ）のガラスは、νｄが３４を超えていた。従って、本発明の実施例の光学ガラスは、比較例（Ｎｏ．Ｄ）のガラスに比べてアッベ数（νｄ）が小さいことが明らかになった。 The optical glasses of the examples of the present invention each have an Abbe number (ν d ) of 20 or more, more specifically 29 or more, and this Abbe number (ν d ) of 40 or less, more specifically 33. And within the desired range. On the other hand, the glass of the comparative example of the present invention (No. D) is, [nu d was more than 34. Therefore, it has been clarified that the optical glass of the example of the present invention has a smaller Abbe number (ν d ) than the glass of the comparative example (No. D).
　また、本発明の実施例の光学ガラスは、いずれも比重が５．００以下、より詳細には４．７８以下であり、所望の範囲内であった。 Also, the optical glasses of the examples of the present invention all had a specific gravity of 5.00 or less, more specifically 4.78 or less, and were within a desired range.
　また、本発明の実施例の光学ガラスは、λ７０（透過率７０％時の波長）がいずれも５００ｎｍ以下、より詳細には４３４ｎｍ以下であった。また、本発明の実施例の光学ガラスは、λ５（透過率５％時の波長）がいずれも４２０ｎｍ以下、より詳細には３７１ｎｍ以下であった。また、本発明の実施例の光学ガラスは、λ８０（透過率８０％時の波長）がいずれも５６０ｎｍ以下、より詳細には５３１ｎｍ以下であった。このため、本発明の実施例の光学ガラスは、可視光に対する透過率が高く着色し難いことが明らかになった。 In addition, in the optical glasses of the examples of the present invention, each of λ 70 (wavelength at a transmittance of 70%) was 500 nm or less, more specifically, 434 nm or less. The optical glasses of the examples of the present invention all had λ 5 (wavelength at 5% transmittance) of 420 nm or less, more specifically 371 nm or less. In addition, the optical glasses of the examples of the present invention each had a λ 80 (wavelength at 80% transmittance) of 560 nm or less, more specifically 531 nm or less. For this reason, it became clear that the optical glass of the Example of this invention has the high transmittance | permeability with respect to visible light, and is hard to be colored.
　従って、本発明の実施例の光学ガラスは、屈折率（ｎｄ）及びアッベ数（νｄ）が所望の範囲内にありながら、可視光に対する透過率が高く、且つ色収差が小さいことが明らかになった。 Therefore, it is clear that the optical glass of the example of the present invention has a high transmittance for visible light and a small chromatic aberration, while the refractive index (n d ) and the Abbe number (ν d ) are within the desired ranges. became.
　また、本発明の実施例の光学ガラスは、再加熱試験（イ）後の試験片のｄ線の透過率を再加熱試験前の試験片のｄ線の透過率で除した値が、いずれも０．９５以上、より詳細には０．９７以上であり、所望の範囲内であった。また、本発明の実施例の光学ガラスは、再加熱試験（イ）前後の試験片の透過率λ７０の差が２０ｎｍ以下、より詳細には１５ｎｍ以下であり、所望の範囲内であった。一方、本発明の比較例（Ｎｏ．Ｃ、Ｎｏ．Ｄ）のガラスは、再加熱試験（イ）後の試験片のｄ線の透過率を再加熱試験前の試験片のｄ線の透過率で除した値が０．９５未満であり、再加熱試験（イ）後は可視光の全ての波長に対して透過率が７０％未満であった。従って、本発明の実施例の光学ガラスは、比較例（Ｎｏ．Ｃ、Ｎｏ．Ｄ）のガラスに比べ、再加熱による着色や失透が起こり難いことも明らかになった。 Moreover, the optical glass of the Example of this invention is the value which divided | segmented the transmittance | permeability of d line | wire of the test piece after a reheating test (ii) by the d line | wire transmittance | permeability of the test piece before a reheating test. It was 0.95 or more, more specifically 0.97 or more, and was within the desired range. Further, in the optical glass of the example of the present invention, the difference in the transmittance λ 70 between the test pieces before and after the reheating test (ii) was 20 nm or less, more specifically 15 nm or less, and was within a desired range. On the other hand, the glass of the comparative example (No. C, No. D) of the present invention has the d-line transmittance of the test piece after the reheating test (ii) and the d-line transmittance of the test piece before the reheating test. Was less than 0.95, and after the reheating test (A), the transmittance was less than 70% for all wavelengths of visible light. Therefore, it became clear that the optical glass of the example of the present invention is less likely to be colored or devitrified by reheating than the glass of the comparative examples (No. C, No. D).
　以上、本発明を例示の目的で詳細に説明したが、本実施例はあくまで例示の目的のみであって、本発明の思想及び範囲を逸脱することなく多くの改変を当業者により成し得ることが理解されよう。 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 (25)

  1. 　酸化物換算組成のガラス全物質量に対して、モル％でＢ２Ｏ３成分を２５．０％以上５５．０％以下、Ｌｎ２Ｏ３成分を６．０％以上３０．０％以下（式中、ＬｎはＬａ、Ｇｄ、Ｙ、Ｙｂからなる群より選択される１種以上）、及びＮｂ２Ｏ５成分を０％より多く２５．０％以下含有し、ＺｒＯ２成分の含有量が１５．０％以下であり、部分分散比（θｇ，Ｆ）がアッベ数（νｄ）との間で、νｄ≦３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００２７５×νｄ＋０．６８１２５）の関係を満たし、νｄ＞３１の範囲において（－０．００１６２×νｄ＋０．６３８２２）≦（θｇ，Ｆ）≦（－０．００１６２×νｄ＋０．６４６２２）の関係を満たす光学ガラス。 The B 2 O 3 component is 25.0% or more and 55.0% or less, and the Ln 2 O 3 component is 6.0% or more and 30.0% or less (% by mol%) with respect to the total amount of glass in the oxide conversion composition ( In the formula, Ln contains at least one selected from the group consisting of La, Gd, Y, and Yb), and Nb 2 O 5 component more than 0% and 25.0% or less, and the content of ZrO 2 component is It is 15.0% or less, and the partial dispersion ratio (θg, F) is within the range of νd ≦ 31 (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ with the Abbe number (νd). The relationship of (−0.00275 × νd + 0.68125) is satisfied, and in the range of νd> 31, the relationship of (−0.00162 × νd + 0.63822) ≦ (θg, F) ≦ (−0.00162 × νd + 0.64622) Optical glass that meets.
  2. 　酸化物換算組成のガラス全物質量に対して、モル％でＺｒＯ２成分の含有量が１０．０％以下である請求項１記載の光学ガラス。 2. The optical glass according to claim 1, wherein the content of the ZrO 2 component is 10.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.
  3. 　酸化物換算組成のガラス全物質量に対して、モル％で
    Ｌａ２Ｏ３成分　０～３０．０％及び／又は
    Ｇｄ２Ｏ３成分　０～１５．０％及び／又は
    Ｙ２Ｏ３成分　０～１５．０％及び／又は
    Ｙｂ２Ｏ３成分　０～１５．０％
    を含有する請求項１又は２記載の光学ガラス。     La 2 O 3 component 0 to 30.0% and / or Gd 2 O 3 component 0 to 15.0% and / or Y 2 O 3 component 0 in mol% with respect to the total amount of glass in the oxide conversion composition ~ 15.0% and / or Yb 2 O 3 component 0 ~ 15.0%
    The optical glass according to claim 1 or 2, comprising:
  4. 　酸化物換算組成におけるモル比Ｌａ２Ｏ３／Ｌｎ２Ｏ３が０．５以上である請求項１から３のいずれか記載の光学ガラス。 4. The optical glass according to claim 1, wherein the molar ratio La 2 O 3 / Ln 2 O 3 in the oxide equivalent composition is 0.5 or more.
  5. 　酸化物換算組成のガラス全物質量に対するＮｂ２Ｏ５成分及びＺｒＯ２成分の含有量の和が４．６％より多く３０．０％以下である請求項１から４のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 4, wherein the sum of the contents of the Nb 2 O 5 component and the ZrO 2 component with respect to the total amount of the glass having an oxide equivalent composition is more than 4.6% and not more than 30.0%. .
  6. 　酸化物換算組成のガラス全物質量に対するモル和（Ｎｂ２Ｏ５＋ＺｒＯ２＋Ｌａ２Ｏ３）が１５．０％以上である請求項１から５のいずれか記載の光学ガラス。 6. The optical glass according to claim 1, wherein a molar sum (Nb 2 O 5 + ZrO 2 + La 2 O 3 ) with respect to the total amount of the glass having an oxide conversion composition is 15.0% or more.
  7. 　酸化物換算組成のガラス全物質量に対して、モル％でＴｉＯ２成分の含有量が２０．０％以下である請求項１から６のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 6, wherein the content of the TiO 2 component is 20.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.
  8. 　酸化物換算組成のモル比ＴｉＯ２／（Ｎｂ２Ｏ５＋ＺｒＯ２）が１．００以下である請求項１から７のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 7, wherein a molar ratio TiO 2 / (Nb 2 O 5 + ZrO 2 ) of an oxide conversion composition is 1.00 or less.
  9. 　酸化物換算組成のガラス全物質量に対するＮｂ２Ｏ５成分及びＴｉＯ２成分の含有量の和が６．５％より多く３５．０％以下である請求項１から８のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 8, wherein the sum of the contents of the Nb 2 O 5 component and the TiO 2 component with respect to the total amount of the glass having an oxide conversion composition is more than 6.5% and not more than 35.0%. .
  10. 　酸化物換算組成のガラス全物質量に対して、モル％でＷＯ３成分の含有量が３０．０％以下である請求項１から９のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 9, wherein the content of the WO 3 component is 30.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.
  11. 　酸化物換算組成のガラス全物質量に対するＴｉＯ２成分及びＷＯ３成分のモル和が３５．０％以下である請求項１から１０のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 10, wherein a molar sum of the TiO 2 component and the WO 3 component with respect to the total amount of the glass having an oxide conversion composition is 35.0% or less.
  12. 　酸化物換算組成におけるモル比（ＴｉＯ２＋ＷＯ３）／（ＺｒＯ２＋Ｂ２Ｏ３）が０．７００以下である請求項１から１１のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 11, wherein a molar ratio (TiO 2 + WO 3 ) / (ZrO 2 + B 2 O 3 ) in an oxide equivalent composition is 0.700 or less.
  13. 　酸化物換算組成のガラス全物質量に対して、モル％で
    Ｌｉ２Ｏ成分　０～２５．０％及び／又は
    Ｎａ２Ｏ成分　０～２５．０％及び／又は
    Ｋ２Ｏ成分　０～２５．０％及び／又は
    Ｃｓ２Ｏ成分　０～１０．０％
    である請求項１から１２のいずれか記載の光学ガラス。     Li 2 O component 0-25.0% and / or Na 2 O component 0-25.0% and / or K 2 O component 0-25. 0% and / or Cs 2 O component 0-10.0%
    The optical glass according to any one of claims 1 to 12.
  14. 　酸化物換算組成のガラス全物質量に対するＲｎ２Ｏ成分（式中、ＲｎはＬｉ、Ｎａ、Ｋ、Ｃｓからなる群より選択される１種以上）のモル和が３０．０％以下である請求項１から１３のいずれか記載の光学ガラス。 The molar sum of the Rn 2 O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) with respect to the total amount of glass in the oxide equivalent composition is 30.0% or less Item 14. The optical glass according to any one of Items 1 to 13.
  15. 　酸化物換算組成のモル比（Ｂ２Ｏ３＋ＺｒＯ２）／（Ｌｎ２Ｏ３＋ＷＯ３＋Ｒｎ２Ｏ）が０．７０以上である請求項１から１４のいずれか記載の光学ガラス。 Molar ratios of oxides composition in terms of (B 2 O 3 + ZrO 2 ) / (Ln 2 O 3 + WO 3 + Rn 2 O) is 0.70 or more in the optical glass according to any one of claims 1 to 14 is.
  16. 　酸化物換算組成のガラス全物質量に対して、モル％で
    ＭｇＯ成分　０～１５．０％及び／又は
    ＣａＯ成分　０～２０．０％及び／又は
    ＳｒＯ成分　０～２０．０％及び／又は
    ＢａＯ成分　０～２０．０％及び／又は
    ＺｎＯ成分　０～３５．０％
    である請求項１から１５のいずれか記載の光学ガラス。     MgO component 0 to 15.0% and / or CaO component 0 to 20.0% and / or SrO component 0 to 20.0% and / or BaO in mol% with respect to the total amount of glass of oxide conversion composition Component 0-20.0% and / or ZnO component 0-35.0%
    The optical glass according to any one of claims 1 to 15.
  17. 　酸化物換算組成のガラス全物質量に対するＲＯ成分（式中、ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ、Ｚｎからなる群より選択される１種以上）のモル和が３５．０％以下である請求項１から１６のいずれか記載の光学ガラス。 The molar sum of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Zn) with respect to the total amount of glass in the oxide equivalent composition is 35.0% or less. Item 17. The optical glass according to any one of Items 1 to 16.
  18. 　酸化物換算組成のガラス全物質量に対して、モル％で
    ＳｉＯ２成分　０～２０．０％及び／又は
    Ｐ２Ｏ５成分　０～３０．０％及び／又は
    ＧｅＯ２成分　０～２０．０％及び／又は
    Ｔａ２Ｏ５成分　０～７．５％及び／又は
    Ｂｉ２Ｏ３成分　０～１５．０％及び／又は
    ＴｅＯ２成分　０～３０．０％及び／又は
    Ａｌ２Ｏ３成分　０～１５．０％及び／又は
    Ｓｂ２Ｏ３成分　０～１．０％
    である請求項１から１７のいずれか記載の光学ガラス。     SiO 2 component 0 to 20.0% and / or P 2 O 5 component 0 to 30.0% and / or GeO 2 component 0 to 20.0 in mol% with respect to the total amount of glass in oxide-converted composition % And / or Ta 2 O 5 component 0 to 7.5% and / or Bi 2 O 3 component 0 to 15.0% and / or TeO 2 component 0 to 30.0% and / or Al 2 O 3 component 0 ~ 15.0% and / or Sb 2 O 3 component 0 ~ 1.0%
    The optical glass according to any one of claims 1 to 17.
  19. 　１．８０以上２．００以下の屈折率（ｎｄ）を有し、２０以上４０以下のアッベ数（νｄ）を有する請求項１から１８のいずれか記載の光学ガラス。 The optical glass according to claim 1, having a refractive index (nd) of 1.80 or more and 2.00 or less and an Abbe number (νd) of 20 or more and 40 or less.
  20. 　分光透過率が７０％を示す波長（λ７０）が５００ｎｍ以下である請求項１から１９のいずれか記載の光学ガラス。 The optical glass according to any one of claims 1 to 19, wherein the wavelength (λ 70 ) at which the spectral transmittance is 70% is 500 nm or less.
  21. 　前記再加熱試験（イ）前の試験片の透過率が７０％となる波長であるλ７０と前記再加熱試験後の試験片のλ７０との差が２０ｎｍ以下である請求項１から２０のいずれか記載の光学ガラス。
    　〔再加熱試験（イ）：試験片１５ｍｍ×１５ｍｍ×３０ｍｍを再加熱し、室温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度まで昇温し、前記光学ガラスのガラス転移温度（Ｔｇ）よりも８０℃高い温度で３０分間保温し、その後常温まで自然冷却し、試験片の対向する２面を厚み１０ｍｍに研磨した後に目視観察する。〕     21. The difference between λ 70 , which is a wavelength at which the transmittance of the test piece before the reheating test (ii) is 70%, and λ 70 of the test piece after the reheating test is 20 nm or less. Any one of the optical glasses.
    [Reheating test (A): Re-testing a specimen 15 mm × 15 mm × 30 mm, raising the temperature from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes, and the glass transition temperature of the optical glass The sample is kept at a temperature 80 ° C. higher than (Tg) for 30 minutes, then naturally cooled to room temperature, and two opposing surfaces of the test piece are polished to a thickness of 10 mm and visually observed. ]
  22. 　再加熱試験（イ）後の試験片の波長５８７．５６ｎｍの光線（ｄ線）の透過率を前記再加熱試験前の試験片のｄ線の透過率で除した値が、０．９５以上となる請求項１から２１のいずれか記載の光学ガラス。
    　〔再加熱試験（イ）：試験片１５ｍｍ×１５ｍｍ×３０ｍｍを再加熱し、室温から１５０分で各試料の転移温度（Ｔｇ）より８０℃高い温度まで昇温し、前記光学ガラスのガラス転移温度（Ｔｇ）よりも８０℃高い温度で３０分間保温し、その後常温まで自然冷却し、試験片の対向する２面を厚み１０ｍｍに研磨した後に目視観察する。〕     The value obtained by dividing the transmittance of light (d-line) having a wavelength of 587.56 nm of the test piece after the reheating test (A) by the transmittance of the d-line of the test piece before the reheating test is 0.95 or more. The optical glass according to any one of claims 1 to 21.
    [Reheating test (A): Re-testing a specimen 15 mm × 15 mm × 30 mm, raising the temperature from room temperature to a temperature 80 ° C. higher than the transition temperature (Tg) of each sample in 150 minutes, and the glass transition temperature of the optical glass The sample is kept at a temperature 80 ° C. higher than (Tg) for 30 minutes, then naturally cooled to room temperature, and two opposing surfaces of the test piece are polished to a thickness of 10 mm and visually observed. ]
  23. 　請求項１から２２のいずれか記載の光学ガラスからなる研磨加工用及び／又は精密プレス成形用のプリフォーム。 A preform for polishing and / or precision press molding comprising the optical glass according to any one of claims 1 to 22.
  24. 　請求項１から２２のいずれか記載の光学ガラスを研削及び／又は研磨してなる光学素子。 An optical element obtained by grinding and / or polishing the optical glass according to any one of claims 1 to 22.
  25. 　請求項１から２２のいずれか記載の光学ガラスを精密プレス成形してなる光学素子。 An optical element formed by precision press-molding the optical glass according to any one of claims 1 to 22.
PCT/JP2012/057957 2011-03-29 2012-03-27 Optical glass, preform, and optical element WO2012133422A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3950620A4 (en) * 2019-04-05 2022-12-28 Nippon Electric Glass Co., Ltd. Decorative glass article

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008254953A (en) * 2007-04-03 2008-10-23 Ohara Inc Optical glass
WO2009096437A1 (en) * 2008-01-31 2009-08-06 Hoya Corporation Optical glass
JP2011026185A (en) * 2009-06-30 2011-02-10 Ohara Inc Optical glass, preform material, and optical element

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008254953A (en) * 2007-04-03 2008-10-23 Ohara Inc Optical glass
WO2009096437A1 (en) * 2008-01-31 2009-08-06 Hoya Corporation Optical glass
JP2011026185A (en) * 2009-06-30 2011-02-10 Ohara Inc Optical glass, preform material, and optical element

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3950620A4 (en) * 2019-04-05 2022-12-28 Nippon Electric Glass Co., Ltd. Decorative glass article

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