WO2021060362A1 - Verre optique et élément optique - Google Patents

Verre optique et élément optique Download PDF

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Publication number
WO2021060362A1
WO2021060362A1 PCT/JP2020/035992 JP2020035992W WO2021060362A1 WO 2021060362 A1 WO2021060362 A1 WO 2021060362A1 JP 2020035992 W JP2020035992 W JP 2020035992W WO 2021060362 A1 WO2021060362 A1 WO 2021060362A1
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Prior art keywords
content
glass
tio
optical
mass
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PCT/JP2020/035992
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English (en)
Japanese (ja)
Inventor
俊伍 桑谷
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Hoya株式会社
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Priority claimed from JP2019175787A external-priority patent/JP2021050126A/ja
Priority claimed from JP2020002064A external-priority patent/JP7481847B2/ja
Priority claimed from JP2020125251A external-priority patent/JP2022021586A/ja
Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to CN202080002703.1A priority Critical patent/CN112867699A/zh
Publication of WO2021060362A1 publication Critical patent/WO2021060362A1/fr

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Classifications

    • 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
    • C03C3/16—Silica-free oxide glass compositions containing phosphorus
    • C03C3/21—Silica-free oxide glass compositions containing phosphorus containing titanium, zirconium, vanadium, tungsten or molybdenum
    • 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
    • C03C3/04—Glass compositions containing silica
    • C03C3/062—Glass compositions containing silica with less than 40% silica by weight
    • 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
    • C03C3/04—Glass compositions containing silica
    • C03C3/062—Glass compositions containing silica with less than 40% silica by weight
    • C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
    • 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
    • C03C3/16—Silica-free oxide glass compositions containing phosphorus
    • C03C3/19—Silica-free oxide glass compositions containing phosphorus containing boron
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements

Definitions

  • the present invention relates to optical glass and optical elements.
  • Optical elements incorporated in in-vehicle optical equipment and optical elements incorporated in heat-generating optical equipment are used in environments with large temperature changes. Fluctuations in optical characteristics such as the refractive index due to temperature changes affect the imaging characteristics of the optical system.
  • the temperature coefficient of the relative refractive index (dn / dT) represents the change in the refractive index with respect to the temperature change. In an optical element whose refractive index decreases as the temperature rises, the temperature coefficient of relative refractive index becomes negative. On the contrary, in an optical element in which the refractive index increases as the temperature rises, the temperature coefficient of the relative refractive index becomes positive.
  • the productivity is inferior, and the glass melting equipment (for example, a crucible, a stirring equipment for molten glass, etc.) in the melting process is eroded, and the economic efficiency is also inferior. Therefore, a glass having a low liquidus temperature LT, that is, a glass having a low melting temperature and molding temperature of the glass is required.
  • Patent Document 1 discloses an optical glass in which the temperature coefficient (dn / dT) of the relative refractive index is negative. However, it has been found that the glass of Patent Document 1 has a high liquidus temperature LT and is inferior in productivity and economy.
  • the average coefficient of linear thermal expansion of the optical element is important when performing optical design.
  • a low refractive index low dispersion glass material and a high refractive index high dispersion glass material are combined, the smaller the difference in the average linear thermal expansion coefficient of the glass material, the better the bonding.
  • a low refractive index low dispersion glass material containing fluorine usually has a large average linear thermal expansion coefficient. Therefore, the high refractive index and high dispersion glass material to be combined with it is also required to have a high average linear thermal expansion coefficient.
  • the optical glass disclosed in Patent Document 2 has a high refractive index but a low dispersion and a small average linear thermal expansion coefficient. Therefore, there is a demand for optical glass having a high refractive index and a high dispersion and a large average linear thermal expansion coefficient.
  • an object of the present invention is to provide an optical glass having a low temperature coefficient (dn / dT) of a relative refractive index due to a temperature change and a large average linear thermal expansion coefficient, and an optical element made of the optical glass.
  • the gist of the present invention is as follows. (1)
  • the refractive index nd is 1.63 to 1.80, and the refractive index nd is 1.63 to 1.80.
  • the Abbe number ⁇ d is 22 to 34
  • the content of Nb 2 O 5 is 25 to 55% by mass
  • the content of WO 3 is less than 30% by mass
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 36 to 60% by mass.
  • Mass ratio of total contents of 2 O 3 and Ta 2 O 5 [(TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ) / (P 2 O 5 + B 2 O 3 + SiO 2 + Al 2 O 3) + Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.10 or less,
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B 2 O 3 )] is 0.50 or less.
  • (A) The content of P 2 O 5 is 20 to 36% by mass, and the content is 20 to 36% by mass.
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.50 or less.
  • P 2 O 5 mass ratio of the content of B 2 O 3 to the content of [B 2 O 3 / P 2 O 5] is 0.05 to 0.39
  • the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO and BaO is 8.0% by mass or less.
  • the content of P 2 O 5 is 25 to 38% by mass, and the content is 25 to 38% by mass.
  • the content of Al 2 O 3 is less than 5% by mass
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the total content of MgO, CaO, SrO and BaO [MgO + CaO + SrO + BaO] is 7.0% by mass or less.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 0.25 or more.
  • the content of P 2 O 5 is 25 to 50% by mass, and the content is 25 to 50% by mass.
  • the content of TiO 2 is 10 to 50% by mass,
  • the Nb 2 O 5 content is 5 to 30% by mass,
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 35 to 60% by mass.
  • Mass ratio of TiO 2 content to total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 / (TIO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3) + Ta 2 O 5 )] is 0.25 or more, Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • A) The content of WO 3 is 7% by mass or less.
  • the content of P 2 O 5 is 25 to 50% by mass, and the content is 25 to 50% by mass.
  • the Nb 2 O 5 content is 14-40% by mass.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 35 to 60% by mass.
  • Mass ratio of TiO 2 content to total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 / (TIO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3) + Ta 2 O 5 )] is 0.25 or more, P 2 O 5 mass ratio of the content of B 2 O 3 to the content of [B 2 O 3 / P 2 O 5] is 0.05 to 0.39
  • the total content of Li 2 O, Na 2 O, K 2 O and Cs 2 O [Li 2 O + Na 2 O + K 2 O + Cs 2 O] is 10% by mass or more.
  • K 2 O weight ratio of Na 2 O content to the content of [Na 2 O / K 2 O ] is 1.50 or more, an optical glass.
  • the temperature coefficient dn / dT of the relative refractive index at the wavelength of the He-Ne laser (633 nm) is ⁇ 0.1 ⁇ 10 -6 to -13.0 ⁇ 10 -6 ° C -1 in the range of 20 to 40 ° C.
  • the optical glass according to any one of (1), (2), (4) to (6).
  • an optical glass having a low temperature coefficient (dn / dT) of a relative refractive index due to a temperature change and a large average linear thermal expansion coefficient, and an optical element made of the optical glass.
  • the glass composition of optical glass in the present invention and the present specification is expressed on an oxide basis.
  • the "oxide-based glass composition” refers to a glass composition obtained by converting all glass raw materials into those that are decomposed at the time of melting and exist as oxides in optical glass, and the notation of each glass component is Following the convention, it is described as SiO 2 , TiO 2 , and so on.
  • the content and total content of the glass component are based on mass, and "%" means “mass%”.
  • the content of the glass component can be quantified by a known method, for example, an inductively coupled plasma emission spectroscopic analysis method (ICP-AES), an inductively coupled plasma mass analysis method (ICP-MS), or the like.
  • ICP-AES inductively coupled plasma emission spectroscopic analysis method
  • ICP-MS inductively coupled plasma mass analysis method
  • the content of the constituent component is 0%, which means that the constituent component is substantially not contained, and the component is allowed to be contained at an unavoidable impurity level.
  • thermal stability refers to the difficulty of crystal precipitation in glass.
  • thermal stability refers to the difficulty of crystal precipitation when the molten glass solidifies
  • devitrification resistance refers to the difficulty of crystal precipitation when the solidified glass is reheated, as in the case of reheat pressing. It shall refer to the difficulty.
  • the refractive index refers to the refractive index nd at the d-line (wavelength 587.56 nm) of helium unless otherwise specified.
  • ⁇ d is used as a value representing a property related to dispersion, and is expressed by the following equation.
  • nF is the refractive index of blue hydrogen at the F line (wavelength 486.13 nm)
  • nC is the refractive index of red hydrogen at the C line (656.27 nm).
  • ⁇ d (nd-1) / nF-nC ... (1)
  • optical glass of the present invention will be described separately for the first embodiment, the second embodiment, and the third embodiment.
  • the optical glass is The refractive index nd is 1.63 to 1.80, and the refractive index nd is 1.63 to 1.80.
  • the Abbe number ⁇ d is 22 to 34,
  • the content of Nb 2 O 5 is 25 to 55% by mass,
  • the content of WO 3 is less than 30% by mass,
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 36 to 60% by mass.
  • Mass ratio of total contents of 2 O 3 and Ta 2 O 5 [(TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ) / (P 2 O 5 + B 2 O 3 + SiO 2 + Al 2 O 3) + Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.10 or less,
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B 2 O 3 )] is 0.50 or less.
  • the following (A) or (B) is satisfied.
  • (A) The content of P 2 O 5 is 20 to 36% by mass, and the content is 20 to 36% by mass.
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.50 or less.
  • P 2 O 5 mass ratio of the content of B 2 O 3 to the content of [B 2 O 3 / P 2 O 5] is 0.05 to 0.39
  • the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO and BaO is 8.0% by mass or less.
  • the content of P 2 O 5 is 25 to 38% by mass, and the content is 25 to 38% by mass.
  • the content of Al 2 O 3 is less than 5% by mass
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the total content of MgO, CaO, SrO and BaO [MgO + CaO + SrO + BaO] is 7.0% by mass or less.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 0.25 or more.
  • the optical glass according to the first embodiment means the optical glass according to the first embodiment satisfying the above (A) and the optical glass according to the first embodiment satisfying the above (B). And.
  • the refractive index nd is 1.63 to 1.80.
  • the lower limit of the refractive index nd may be 1.65, 1.67, or 1.69, and the upper limit of the refractive index nd may be 1.79, 1.78, or 1.77.
  • the refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components having the function of relatively increasing the refractive index nd are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2 , La 2 O 3, etc. Is.
  • the components having a function of relatively lowering the refractive index nd are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O and the like. is there.
  • TIO 2 , Nb 2 O 5 with respect to the total content of P 2 O 5 , B 2 O 3 , SiO 2 , Al 2 O 3 , Li 2 O, Na 2 O, K 2 O and Cs 2 O, Mass ratio of total contents of WO 3 , Bi 2 O 3 and Ta 2 O 5 [(TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ) / (P 2 O 5 + B 2 O 3 + SiO 2) + Al 2 O 3 + Li 2 O + Na 2 O + K 2 O + Cs 2 O)] can be increased to increase the refractive index nd, and decreasing the mass ratio can decrease the refractive index nd.
  • the Abbe number ⁇ d is 22 to 34.
  • the lower limit of the Abbe number ⁇ d may be 22.5, 23, or 23.5, and the upper limit of the Abbe number ⁇ d may be 32, 30, or 28.
  • the Abbe number ⁇ d can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components that relatively lower the Abbe number ⁇ d, that is, the highly dispersed components, are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2, and the like.
  • the components that relatively increase the Abbe number ⁇ d, that is, the low dispersion components are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O, La 2 O 3 , BaO, CaO, SrO and the like.
  • the content of Nb 2 O 5 is 25 to 55%.
  • the lower limit of the content of Nb 2 O 5 is preferably 27%, more preferably 29%, 31%, and 33% in that order.
  • the upper limit of the content of Nb 2 O 5 is preferably 53%, more preferably 51%, 49%, and 47% in that order.
  • Nb 2 O 5 is a component that contributes to high refractive index and high dispersion. Therefore, by setting the content of Nb 2 O 5 in the above range, an optical glass having a desired optical constant can be obtained. On the other hand, if the content of Nb 2 O 5 is too large, the coloring of the glass may be strengthened.
  • the content of WO 3 is less than 30%.
  • the upper limit of the content of WO 3 is preferably 20%, more preferably 15%, 10%, and 5%.
  • the content of WO 3 is preferably low, and the lower limit thereof is preferably 0%.
  • the content of WO 3 may be 0%.
  • the transmittance can be increased and the increase in the specific gravity of the glass can be suppressed. Further, the temperature coefficient (dn / dT) of the relative refractive index can be lowered.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 36 to 60%.
  • the lower limit of the total content is preferably 38%, more preferably 40%, 41%, and 42%.
  • the upper limit of the total content is preferably 58%, more preferably 56%, 54%, and 52%.
  • TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 are components that contribute to high dispersion of glass. Therefore, by setting the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] in the above range, an optical glass having a desired optical constant can be obtained. In addition, the thermal stability of the glass can be improved. On the other hand, if the total content is too large, an optical glass having a desired optical constant may not be obtained, the thermal stability of the glass may be lowered, and the coloring of the glass may be strengthened.
  • the upper limit of the mass ratio is preferably 1.07, and more preferably 1.04, 1.02, and 1.00 in that order.
  • the lower limit of the mass ratio is more preferably 0.50, and more preferably 0.55, 0.60, and 0.65.
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B 2 O 3 )] is 0. It is 50 or less.
  • optical glass according to the first embodiment satisfies (A) or (B) as described above.
  • (A) will be described in detail.
  • the optical glass according to the first embodiment is (A)
  • the content of P 2 O 5 is 20 to 36% by mass, and the content is 20 to 36% by mass.
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.50 or less.
  • P 2 O 5 mass ratio of the content of B 2 O 3 to the content of [B 2 O 3 / P 2 O 5] is 0.05 to 0.39
  • the total content of MgO, CaO, SrO and BaO [MgO + CaO + SrO + BaO] is 8.0% by mass or less. Can meet the requirements of.
  • the content of P 2 O 5 is 20 to 36 percent.
  • the lower limit of the content of P 2 O 5 is preferably 21%, more preferably 22%, 23%, and 24%.
  • the upper limit of the content of P 2 O 5 is preferably 35%, more preferably 34%, 33%, and 32% in that order.
  • P 2 O 5 is a network-forming component of glass, and is an essential component for containing a large amount of highly dispersed components in glass. By setting the content of P 2 O 5 in the above range, an optical glass having high thermal stability and a desired optical constant can be obtained.
  • the mass ratio of the content [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.50 or less.
  • the upper limit of the mass ratio is preferably 1.47, and more preferably 1.44, 1.42, and 1.40 in that order.
  • the lower limit of the mass ratio is preferably 1.00, more preferably 1.05, 1.08, and 1.10.
  • the thermal stability is high and the temperature coefficient of relative refractive index ( An optical glass having a low dn / dT) and a large average coefficient of linear thermal expansion can be obtained.
  • the mass ratio of the content of B 2 O 3 to the content of P 2 O 5 [B 2 O 3 / P 2 O 5] 0.05 ⁇ It is 0.39.
  • the lower limit of the mass ratio is preferably 0.06, more preferably 0.07, 0.08, 0.09.
  • the upper limit of the mass ratio is more preferably 0.36, and further preferably 0.33, 0.31 and 0.29.
  • the mass ratio [B 2 O 3 / P 2 O 5 ] in the above range the temperature coefficient of relative refractive index (dn / dT) is low, the average coefficient of linear thermal expansion is large, and the devitrification resistance is high. Further, an optical glass having a low liquidus temperature LT can be obtained.
  • the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO and BaO is 8.0% or less.
  • the upper limit of the total content is preferably 6%, more preferably 5%, 4%, and 3%.
  • the lower limit of the total content is preferably 0%.
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B). 2 O 3 )] is 0.50 or less.
  • the upper limit of the mass ratio is preferably 0.47, more preferably 0.44, 0.42, 0.40 in that order.
  • the lower limit of the mass ratio is more preferably 0.00, and further preferably 0.03, 0.06, 0.08, 0.10.
  • Non-limiting examples of the content and ratio of the glass component in the optical glass according to the first embodiment satisfying the above (A) are shown below.
  • the upper limit of the content of B 2 O 3 is preferably 10%, more preferably 8%, 7%, and 6%.
  • the lower limit of the content of B 2 O 3 is preferably 1%, more preferably 1.5%, 1.8%, and 2.0% in that order.
  • B 2 O 3 is a network-forming component of glass and has a function of improving the thermal stability of glass.
  • the content of B 2 O 3 is preferably in the above range.
  • the content of Al 2 O 3 is preferably 3% or less, more preferably 2% or less and 1% or less.
  • the content of Al 2 O 3 may be 0%.
  • Al 2 O 3 is a glass component having a function of improving the chemical durability and weather resistance of glass, and can be considered as a network forming component.
  • the content of Al 2 O 3 increases, the devitrification resistance of the glass decreases.
  • problems such as an increase in the glass transition temperature Tg and a decrease in thermal stability are likely to occur.
  • the upper limit of the content of Al 2 O 3 is preferably in the above range.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [
  • the lower limit of TiO 2 / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 )] is preferably 0, and more preferably 0.02, 0.04, and 0.06.
  • the upper limit of the mass ratio is preferably 0.50, and more preferably 0.45, 0.40, and 0.35.
  • TiO 2 is a component having a particularly large effect of increasing the refractive index among the components for increasing the refractive index. Therefore, from the viewpoint of obtaining a desired optical constant, the mass ratio [TiO 2 / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 )] is preferably in the above range.
  • the lower limit of the TiO 2 content is preferably 0%, more preferably 1%, 2%, 3%, and 4%.
  • the content of TiO 2 may be 0%.
  • the upper limit of the TiO 2 content is preferably 15%, more preferably 13%, 11%, and 10%.
  • TiO 2 greatly contributes to high dispersion. On the other hand, TiO 2 tends to increase the coloring of the glass relatively easily, and may deteriorate the meltability. Therefore, the content of TiO 2 is preferably in the above range.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ]
  • the lower limit is preferably 36%, more preferably 38%, 40%, 41%, and 42% in that order.
  • the upper limit of the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ] is preferably 58%, more preferably 56%, 54%, and 52%.
  • TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 contribute to high dispersion of glass, and also have a function of improving the thermal stability of glass by containing an appropriate amount. On the other hand, it is also a component that increases the coloring of glass. Therefore, the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ] is preferably in the above range.
  • the lower limit of the Na 2 O content is preferably 6%, more preferably 8%, 9%, and 10% in that order.
  • the upper limit of the Na 2 O content is preferably 30%, more preferably 28%, 26%, and 25%.
  • Na 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Na 2 O content is preferably in the above range.
  • the upper limit of the total content [Li 2 O + Na 2 O + K 2 O] of Li 2 O, Na 2 O and K 2 O is preferably 35%. Further, it is more preferable in the order of 33%, 31%, and 30%.
  • the lower limit of the total content is preferably 10%, more preferably 14%, 17%, and 18%.
  • Li 2 O, Na 2 O and K 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O and K 2 O [Li 2 O + Na 2 O + K 2 O] is preferably in the above range.
  • the optical glass according to the first embodiment is (B)
  • the content of P 2 O 5 is 25 to 38% by mass, and the content is 25 to 38% by mass.
  • the content of Al 2 O 3 is less than 5% by mass
  • Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the total content of MgO, CaO, SrO and BaO [MgO + CaO + SrO + BaO] is 7.0% by mass or less.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 0.25 or more, Can meet the requirements of.
  • the content of P 2 O 5 is 25 to 38 percent.
  • the lower limit of the content of P 2 O 5 is preferably 26%, more preferably 27%, 28%, 29% and 30%.
  • the upper limit of the content of P 2 O 5 is preferably 37%.
  • P 2 O 5 is a network-forming component of glass, and is an essential component for containing a large amount of highly dispersed components in glass. By setting the content of P 2 O 5 in the above range, an optical glass having high thermal stability and a desired optical constant can be obtained.
  • the content of Al 2 O 3 is less than 5%.
  • the content of Al 2 O 3 is preferably 3% or less, more preferably 2% or less and 1% or less.
  • the content of Al 2 O 3 may be 0%.
  • Al 2 O 3 is a glass component having a function of improving the chemical durability and weather resistance of glass, and can be considered as a network forming component.
  • the content of Al 2 O 3 increases, the devitrification resistance of the glass decreases.
  • problems such as an increase in the glass transition temperature Tg and a decrease in thermal stability are likely to occur.
  • the upper limit of the content of Al 2 O 3 is preferably in the above range.
  • the mass ratio of the content [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the upper limit of the mass ratio is preferably 1.78, and more preferably 1.76 and 1.74.
  • the lower limit of the mass ratio is preferably 1.00, more preferably 1.05, 1.08, and 1.10.
  • the thermal stability is high and the temperature coefficient of relative refractive index ( An optical glass having a low dn / dT) and a large average coefficient of linear thermal expansion can be obtained.
  • the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO and BaO is 7.0% or less.
  • the upper limit of the total content is preferably 6%, more preferably 5%, 4%, and 3%.
  • the lower limit of the total content is preferably 0%.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 0.25 or more.
  • the lower limit of the mass ratio is preferably 0.26, more preferably 0.27, 0.28, 0.29 in that order.
  • the upper limit of the mass ratio is preferably 0.50, and more preferably 0.45, 0.40, and 0.35.
  • TiO 2 is a component having a particularly large effect of increasing the refractive index among the components for increasing the refractive index. Therefore, from the viewpoint of obtaining a desired optical constant, the mass ratio [TiO 2 / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 )] is preferably in the above range.
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B). 2 O 3 )] is 0.50 or less.
  • the upper limit of the mass ratio is preferably 0.47, and more preferably 0.46 and 0.45 in that order.
  • the lower limit of the mass ratio is preferably 0.00, and more preferably 0.20, 0.25, 0.30, and 0.35 in that order.
  • Non-limiting examples of the content and ratio of the glass component in the optical glass according to the first embodiment satisfying the above (B) are shown below.
  • the lower limit of the content of the mass ratio of B 2 O 3 to the content of P 2 O 5 [B 2 O 3 / P 2 O 5] are preferably Is 0.
  • the mass ratio may be 0.
  • the upper limit of the mass ratio is more preferably 0.36, and further preferably 0.33, 0.31 and 0.29.
  • the mass ratio [B 2 O 3 / P 2 O 5 ] in the above range the temperature coefficient of relative refractive index (dn / dT) is low, the average coefficient of linear thermal expansion is large, and the devitrification resistance is high. Further, an optical glass having a low liquidus temperature LT can be obtained.
  • the upper limit of the content of B 2 O 3 is preferably 10%, more preferably 8%, 7%, and 6%.
  • the lower limit of the content of B 2 O 3 is preferably 0%.
  • the content of B 2 O 3 may be 0%.
  • B 2 O 3 is a network-forming component of glass and has a function of improving the thermal stability of glass.
  • the content of B 2 O 3 is preferably in the above range.
  • the lower limit of the content of TiO 2 is preferably 0%, and further 1%, 2%, 3%, 4%, 6%, 8 %, 10%, and 12% are more preferable.
  • the content of TiO 2 may be 0%.
  • the upper limit of the TiO 2 content is preferably 15%.
  • TiO 2 greatly contributes to high dispersion. On the other hand, TiO 2 tends to increase the coloring of the glass relatively easily, and may deteriorate the meltability. Therefore, the content of TiO 2 is preferably in the above range.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ]
  • the lower limit is preferably 36%, more preferably 38%, 40%, 41%, and 42% in that order.
  • the upper limit of the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ] is preferably 58%, further 56%, 54%, 52%, 50%, 48%, 46%. More preferred in order.
  • TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 contribute to high dispersion of glass, and also have a function of improving the thermal stability of glass by containing an appropriate amount. On the other hand, it is also a component that increases the coloring of glass. Therefore, the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 ] is preferably in the above range.
  • the lower limit of the Na 2 O content is preferably 6%, more preferably 8%, 9%, and 10%.
  • the upper limit of the Na 2 O content is preferably 30%, and more preferably 28%, 26%, 25%, 22%, 20%, 18%, and 17% in that order.
  • Na 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Na 2 O content is preferably in the above range.
  • the upper limit of the total content [Li 2 O + Na 2 O + K 2 O] of Li 2 O, Na 2 O and K 2 O is preferably 35%. Further, 33%, 31%, 30%, 28%, 27%, 26%, and 25% are preferable in this order.
  • the lower limit of the total content is preferably 10%, more preferably 14%, 17%, 18%, and 20%.
  • Li 2 O, Na 2 O and K 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O and K 2 O [Li 2 O + Na 2 O + K 2 O] is preferably in the above range.
  • the content of Nb 2 O 5 in the optical glass according to the first embodiment satisfying the above (B) is 25 to 55%.
  • the lower limit of the content of Nb 2 O 5 is preferably 27%, more preferably 29%.
  • the upper limit of the content of Nb 2 O 5 is preferably 53%, and more preferably 51%, 49%, 47%, 40%, 35%, and 33% in that order.
  • Nb 2 O 5 is a component that contributes to high refractive index and high dispersion. Therefore, by setting the content of Nb 2 O 5 in the above range, an optical glass having a desired optical constant can be obtained. On the other hand, if the content of Nb 2 O 5 is too large, the coloring of the glass may be strengthened.
  • the lower limit of the average coefficient of linear thermal expansion ⁇ of 100 to 300 ° C. is preferably 100 ⁇ 10 -7 ° C. -1 , and further 105 ⁇ 10 -7 ° C. -1 , 110. It is more preferable in the order of ⁇ 10 -7 ° C -1 , 115 ⁇ 10 -7 ° C -1 , and 120 ⁇ 10 -7 ° C -1.
  • the upper limit of the average coefficient of linear thermal expansion ⁇ is more preferably 200 ⁇ 10 -7 °C -1 , and further 190 ⁇ 10 -7 °C -1 , 180 ⁇ 10 -7 °C -1 , 170 ⁇ 10 ⁇ . It is more preferable in the order of 7 ° C -1 and 160 ⁇ 10 -7 ° C -1.
  • the average coefficient of linear expansion ⁇ is measured based on the provisions of JOBIS08-2003. However, the sample shall be a round bar with a length of 20 mm ⁇ 0.5 mm and a diameter of 5 mm ⁇ 0.5 mm, and with a load of 98 mN applied to the sample, it shall be heated so as to rise at a constant rate of 4 ° C. And measure the elongation of the sample.
  • the average coefficient of linear expansion ⁇ is expressed in the unit of [° C -1 ], but the numerical value of the average coefficient of linear expansion ⁇ is the same even when [K -1] is used as the unit.
  • the temperature coefficient dn / dT of the relative refractive index at the wavelength (633 nm) of the He—Ne laser is in the range of 20 to 40 ° C., preferably ⁇ 1.0 ⁇ 10-6 to. -10.0 x 10 -6 ° C -1 , and further -1.5 x 10 -6 to -9.0 x 10 -6 ° C -1 , -2.0 x 10 -6 to -8.0.
  • the temperature coefficient dn / dT of the relative refractive index is measured based on the interferometry of JOBIS18-2008.
  • the temperature coefficient dn / dT is expressed in the unit of [° C-1 ], but the numerical value of the temperature coefficient dn / dT is the same even when [K -1] is used as the unit. ..
  • Glass component Non-limiting examples of the content and ratio of glass components other than the above in the optical glass according to the first embodiment are shown below.
  • the upper limit of the content of SiO 2 is preferably 5%, more preferably 3%, 2%, and 1%.
  • the content of SiO 2 may be 0%.
  • a quartz glass melting device such as a quartz glass crucible may be used to melt the glass.
  • the glass frit is produced be free of SiO 2 contains a small amount of SiO 2.
  • the amount of SiO 2 mixed into the glass from the quartz glass melting device depends on the melting conditions, but is, for example, about 0.5 to 1% by mass with respect to the total content of all glass components.
  • the amount of SiO 2 increases by about 0.5 to 1% by mass while the content ratio of the glass component other than SiO 2 remains constant. The above amount may increase or decrease depending on the melting conditions. Since the optical characteristics such as the refractive index and the Abbe number change depending on the content of SiO 2, the content of the glass component other than SiO 2 is finely adjusted to obtain an optical glass having desired optical characteristics.
  • SiO 2 is a network-forming component of glass, and has a function of improving thermal stability, chemical durability, and weather resistance of glass, increasing the viscosity of molten glass, and facilitating molding of molten glass.
  • the upper limit of the content of SiO 2 is preferably in the above range.
  • the upper limit of the content of Bi 2 O 3 is preferably 15%, more preferably 10%, 7%, 5%, and 3% in that order.
  • the lower limit of the Bi 2 O 3 content is preferably 0%.
  • Bi 2 O 3 has a function of improving the thermal stability of glass by containing an appropriate amount.
  • the content of Bi 2 O 3 is increased, the coloring of the glass is increased. Therefore, the content of Bi 2 O 3 is preferably in the above range.
  • the upper limit of the content of Ta 2 O 5 is preferably 10%, more preferably 7%, 5%, and 3%.
  • the lower limit of the content of Ta 2 O 5 is preferably 0%.
  • the content of Ta 2 O 5 may be 0%.
  • Ta 2 O 5 is a glass component having a function of improving the thermal stability and devitrification resistance of glass.
  • Ta 2 O 5 increases the refractive index and makes the glass highly dispersed. Further, when the content of Ta 2 O 5 is increased, the thermal stability of the glass is lowered, and when the glass is melted, the unmelted residue of the glass raw material is likely to occur. Therefore, the content of Ta 2 O 5 is preferably in the above range.
  • Ta 2 O 5 is an extremely expensive component as compared with other glass components, and as the content of Ta 2 O 5 increases, the production cost of glass increases. Further, since Ta 2 O 5 has a larger molecular weight than other glass components, it increases the specific gravity of the glass, and as a result, increases the weight of the optical element.
  • the upper limit of the Li 2 O content is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Li 2 O content is preferably 0%.
  • the content of Li 2 O may be 0%.
  • Li 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Li 2 O content is preferably in the above range.
  • the lower limit of K 2 O content is preferably 1%, even 2%, 3%, preferably by 4% order.
  • the upper limit of the content of K 2 O is preferably 13%, further 12%, 11%, preferably by 10% order.
  • K 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the thermal stability of glass. It also has the function of increasing the average coefficient of linear thermal expansion.
  • the content of K 2 O is within the above range.
  • the upper limit of the content of Cs 2 O is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Cs 2 O content is preferably 0%.
  • the content of Cs 2 O may be 0%.
  • Cs 2 O has a function of improving the meltability of glass, but when the content is increased, the thermal stability and refractive index nd of the glass are lowered, and the volatilization of the glass component is increased during melting. The desired glass cannot be obtained. Therefore, the content of Cs 2 O is preferably in the above range.
  • the content of MgO is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the MgO content is preferably 0%.
  • the content of MgO may be 0%.
  • the CaO content is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the CaO content is preferably 0%.
  • the CaO content may be 0%.
  • the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the SrO content is preferably 0%.
  • the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the BaO content is preferably 0%.
  • MgO, CaO, SrO, and BaO are all glass components having a function of improving the thermal stability and devitrification resistance of glass.
  • the content of these glass components is increased, the high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass are lowered. Therefore, the content of each of these glass components is preferably in the above range.
  • the upper limit of the ZnO content is preferably 10%, more preferably 6%, 4%, and 3%.
  • the ZnO content is preferably low, and the lower limit thereof is preferably 0%.
  • the ZnO content may be 0%.
  • ZnO is a glass component having a function of improving the thermal stability of glass.
  • the ZnO content is too high, the specific gravity of the glass increases. Further, the temperature coefficient (dn / dT) of the relative refractive index becomes high. Therefore, the ZnO content is preferably in the above range.
  • the content of ZrO 2 is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the ZrO 2 content is preferably 0%.
  • ZrO 2 is a glass component having a function of improving the thermal stability and devitrification resistance of glass. However, if the content of ZrO 2 is too high, the thermal stability tends to decrease. Therefore, the content of ZrO 2 is preferably in the above range.
  • the upper limit of the Sc 2 O 3 content is preferably 2%.
  • the lower limit of the Sc 2 O 3 content is preferably 0%.
  • the upper limit of the HfO 2 content is preferably 2%.
  • the lower limit of the HfO 2 content is preferably 0%.
  • Sc 2 O 3 and HfO 2 both have a function of increasing the refractive index nd and are expensive components. Therefore, the contents of Sc 2 O 3 and HfO 2 are preferably in the above range.
  • the upper limit of the content of Lu 2 O 3 is preferably 2%.
  • the lower limit of the content of Lu 2 O 3 is preferably 0%.
  • Lu 2 O 3 has a function of increasing the refractive index nd. In addition, since it has a large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the content of Lu 2 O 3 is preferably in the above range.
  • the upper limit of the content of GeO 2 is preferably 2%.
  • the lower limit of the content of GeO 2 is preferably 0%.
  • GeO 2 has a function of increasing the refractive index nd, and is a prominently expensive component among commonly used glass components. Therefore, from the viewpoint of reducing the manufacturing cost of glass, the content of GeO 2 is preferably in the above range.
  • the upper limit of the content of La 2 O 3 is preferably 2%.
  • the lower limit of the content of La 2 O 3 is preferably 0%.
  • the content of La 2 O 3 may be 0%.
  • the content of La 2 O 3 is preferably in the above range from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance.
  • the upper limit of the content of Gd 2 O 3 is preferably 2%.
  • the lower limit of the content of Gd 2 O 3 is preferably 0%.
  • the content of Gd 2 O 3 is preferably in the above range from the viewpoint of suppressing an increase in specific gravity while maintaining good thermal stability and devitrification resistance of the glass.
  • the upper limit of the content of Y 2 O 3 is preferably 2%.
  • the lower limit of the content of Y 2 O 3 is preferably 0%.
  • the content of Y 2 O 3 may be 0%.
  • the content of Y 2 O 3 is preferably in the range.
  • the upper limit of the content of Yb 2 O 3 is preferably 2%.
  • the lower limit of the content of Yb 2 O 3 is preferably 0%.
  • Yb 2 O 3 Since Yb 2 O 3 has a larger molecular weight than La 2 O 3 , Gd 2 O 3 , and Y 2 O 3 , it increases the specific gravity of glass. As the specific gravity of glass increases, the mass of the optical element increases. For example, if a lens having a large mass is incorporated into an autofocus type imaging lens, the power required to drive the lens during autofocus increases, and the battery consumption increases. Therefore, it is desirable to reduce the content of Yb 2 O 3 to suppress the increase in the specific gravity of the glass.
  • the content of Yb 2 O 3 is preferably in the above range from the viewpoint of preventing a decrease in thermal stability of the glass and suppressing an increase in specific gravity.
  • the optical glass according to the first embodiment satisfying the above (A) is mainly composed of the above-mentioned glass components, that is, P 2 O 5 , Nb 2 O 5 , B 2 O 3 as essential components, and WO 3 , SiO 2 as optional components.
  • the optical glass according to the first embodiment satisfying the above (B) is mainly composed of the above-mentioned glass components, that is, P 2 O 5 and Nb 2 O 5 as essential components, and B 2 O 3 and WO 3 as optional components.
  • the total content is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, still more preferably 99.5% or more.
  • the upper limit of the content of TeO 2 is preferably 2%.
  • the lower limit of the content of TeO 2 is preferably 0%.
  • TeO 2 Since TeO 2 is toxic, it is preferable to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably in the above range.
  • the optical glass according to the first embodiment is basically composed of the above glass components, but it is also possible to contain other components as long as the effects of the present invention are not impaired. Further, in the present invention, the inclusion of unavoidable impurities is not excluded.
  • the optical glass according to the first embodiment does not contain these elements as a glass component.
  • the optical glass according to the first embodiment does not contain these elements as a glass component.
  • the optical glass according to the first embodiment does not contain these elements as a glass component.
  • Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are arbitrarily addable elements that function as fining agents.
  • Sb (Sb 2 O 3 ) is a fining agent having a large fining effect.
  • Sb (Sb 2 O 3 ) is highly oxidizing, and if the amount of Sb (Sb 2 O 3 ) added is increased, the coloration of the glass increases due to light absorption by Sb ions, which is not preferable. Further, when the glass is melted, if Sb is present in the melt, the elution of platinum constituting the glass melting crucible into the melt is promoted, and the platinum concentration in the glass becomes high.
  • the content of Sb 2 O 3 is indicated by external division. That is, when the total content of all glass components other than Sb 2 O 3 and CeO 2 is 100% by mass, the content of Sb 2 O 3 is preferably less than 1% by mass, more preferably 0.1% by mass. Is less than. Further, is preferable in the order of less than 0.05% by mass, less than 0.03% by mass, and less than 0.02% by mass.
  • the content of Sb 2 O 3 may be 0% by mass.
  • the content of CeO 2 is also indicated by external division. That is, when the total content of all glass components other than CeO 2 and Sb 2 O 3 is 100% by mass, the content of CeO 2 is preferably less than 2% by mass, more preferably less than 1% by mass, and even more preferably. Is in the range of less than 0.5% by mass, more preferably less than 0.1% by mass.
  • the content of CeO 2 may be 0% by mass.
  • the glass transition temperature Tg of the optical glass according to the first embodiment is preferably 570 ° C. or lower, more preferably 560 ° C. or lower, 550 ° C. or lower, 540 ° C. or lower, and 530 ° C. or lower.
  • the upper limit of the glass transition temperature Tg satisfies the above range, it is possible to suppress an increase in the glass molding temperature and the annealing temperature, and it is possible to reduce thermal damage to the press molding equipment and the annealing equipment. Further, when the lower limit of the glass transition temperature Tg satisfies the above range, it becomes easy to maintain good thermal stability of the glass while maintaining a desired Abbe number and refractive index.
  • the specific gravity is preferably 3.60 or less, and more preferably 3.50 or less and 3.40 or less. If the specific gravity of the glass can be reduced, the weight of the lens can be reduced. As a result, the power consumption of the autofocus drive of the camera lens on which the lens is mounted can be reduced.
  • the light transmittance of the optical glass according to the first embodiment can be evaluated by the degree of coloring ⁇ 5.
  • the spectral transmittance of a glass sample having a thickness of 10.0 mm ⁇ 0.1 mm is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance is 5% is defined as ⁇ 5.
  • the ⁇ 5 of the optical glass according to the first embodiment is preferably 400 nm or less, more preferably 380 nm or less, and further preferably 370 nm or less.
  • the optical glass according to the embodiment of the present invention may be produced by blending a glass raw material so as to have the above-mentioned predetermined composition and using the blended glass raw material according to a known glass manufacturing method. For example, a plurality of types of compounds are mixed and sufficiently mixed to obtain a batch raw material, and the batch raw material is placed in a quartz crucible or a platinum crucible for rough melting. The melt obtained by crude melting is rapidly cooled and crushed to prepare a cullet. Further, the cullet is placed in a platinum crucible, heated and remelted to obtain molten glass, and after further clarification and homogenization, the molten glass is formed and slowly cooled to obtain an optical glass. A known method may be applied to the molding and slow cooling of the molten glass.
  • the compound used when preparing the batch raw material is not particularly limited, and examples of such a compound include oxides and carbonates. Examples thereof include salts, nitrates, hydroxides and fluorides.
  • a known method may be applied. For example, a glass raw material is melted to obtain molten glass, and the molten glass is poured into a mold to form a plate shape to produce a glass material made of optical glass according to the present invention. The obtained glass material is appropriately cut, ground, and polished to produce a cut piece having a size and shape suitable for press molding. The cut piece is heated and softened, and press-molded (reheat-pressed) by a known method to produce an optical element blank that approximates the shape of the optical element. An optical element blank is annealed and ground and polished by a known method to produce an optical element.
  • the optical functional surface of the manufactured optical element may be coated with an antireflection film, a total reflection film, or the like, depending on the purpose of use.
  • optical elements include various lenses such as spherical lenses, prisms, and diffraction gratings.
  • the optical glass according to the second embodiment will be described in detail.
  • the optical glass according to the second embodiment is The content of P 2 O 5 is 25 to 50% by mass,
  • the content of TiO 2 is 10 to 50% by mass,
  • the Nb 2 O 5 content is 5 to 30% by mass,
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 35 to 60% by mass.
  • Mass ratio of TiO 2 content to total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 / (TIO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3) + Ta 2 O 5 )] is 0.25 or more, Mass ratio of total contents of P 2 O 5 , B 2 O 3 and SiO 2 to total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [(P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the following (A) or (B) is satisfied.
  • (A) The content of WO 3 is 7% by mass or less.
  • the optical glass according to the second embodiment means the optical glass according to the second embodiment satisfying the above (A) and the optical glass according to the second embodiment satisfying the above (B). And.
  • the content of P 2 O 5 is 25-50%.
  • the lower limit of the content of P 2 O 5 is preferably 27%, more preferably 29%, 31%, and 32% in that order.
  • the upper limit of the content of P 2 O 5 is preferably 42%, more preferably 40%, 38%, 37%, and 36%.
  • P 2 O 5 is a network-forming component of glass, and is an essential component for containing a large amount of highly dispersed components in glass. By setting the content of P 2 O 5 in the above range, an optical glass having high thermal stability and a desired optical constant can be obtained.
  • the content of TiO 2 is 10 to 50%.
  • the lower limit of the TiO 2 content is preferably 12%, more preferably 14%, 15%, 16%, and 17% in that order.
  • the upper limit of the TiO 2 content is preferably 40%, more preferably 35%, 30%, 28%, 26%, 24%, and 23%.
  • TiO 2 greatly contributes to high dispersion. On the other hand, TiO 2 tends to increase the coloring of the glass relatively easily, and may deteriorate the meltability. Therefore, the content of TiO 2 is preferably in the above range.
  • the content of Nb 2 O 5 is 5 to 30%.
  • the lower limit of the content of Nb 2 O 5 is preferably 10%, more preferably 12%, 14%, 16%, 17%, and 18%.
  • the upper limit of the content of Nb 2 O 5 is preferably 28%, more preferably 27%, 26%, and 25%.
  • Nb 2 O 5 is a component that contributes to high refractive index and high dispersion. Therefore, by setting the content of Nb 2 O 5 in the above range, an optical glass having a desired optical constant can be obtained. On the other hand, if the content of Nb 2 O 5 is too large, the coloring of the glass may be strengthened.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 35 to 60%.
  • the lower limit of the total content is preferably 36%, more preferably 37%, 38%, and 39%.
  • the upper limit of the total content is preferably 55%, more preferably 50%, 47%, 45%, and 44%.
  • TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 are components that contribute to high dispersion of glass. Therefore, by setting the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] in the above range, an optical glass having a desired optical constant can be obtained. In addition, the thermal stability of the glass can be improved. On the other hand, if the total content is too large, an optical glass having a desired optical constant may not be obtained, the thermal stability of the glass may be lowered, and the coloring of the glass may be strengthened.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O
  • the mass ratio of the content of TiO 2 to 5 ] is 0.25 or more.
  • the lower limit of the mass ratio is preferably 0.30, and more preferably 0.32, 0.34, 0.36, 0.38, 0.40 in that order.
  • the upper limit of the mass ratio is preferably 0.65, more preferably 0.60, 0.58, 0.56 in that order.
  • TiO 2 is a component having a particularly large effect of high dispersion. Therefore, from the viewpoint of obtaining a desired optical constant, the mass ratio [TiO 2 / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 )] is preferably in the above range.
  • the mass ratio of the total contents of P 2 O 5 , B 2 O 3 and SiO 2 to the total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [ (P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is 1.80 or less.
  • the upper limit of the mass ratio is preferably 1.75, and more preferably 1.73, 1.72, 1.71, and 1.70.
  • the lower limit of the mass ratio is preferably 1.20, and more preferably 1.30, 1.35, 1.38, and 1.40 in that order.
  • the thermal stability is high and the temperature coefficient of relative refractive index ( An optical glass having a low dn / dT) and a large average coefficient of linear thermal expansion can be obtained.
  • the content of WO 3 is 7% or less.
  • the upper limit of the content of WO 3 is preferably 5%, more preferably 3%, 2%, and 1%.
  • the content of WO 3 is preferably low, and the lower limit thereof is preferably 0%.
  • the content of WO 3 may be 0%.
  • the content of WO 3 is preferably 15% or less, and the upper limit thereof is more preferably 10%, 5%, and 3%.
  • the content of WO 3 is preferably low, and the lower limit thereof is preferably 0%.
  • the content of WO 3 may be 0%.
  • the transmittance can be increased and the increase in the specific gravity of the glass can be suppressed. Further, the temperature coefficient (dn / dT) of the relative refractive index can be lowered.
  • the content of fluorine F is preferably 3% or less, and the upper limit thereof is more preferably 1%, 0.5%, and 0.3%. ..
  • the content of F is preferably small, and the lower limit thereof is preferably 0%.
  • the content of F may be 0%.
  • optical glass according to the second embodiment satisfying the above (B) does not substantially contain fluorine F.
  • Non-limiting examples of the content and ratio of glass components other than the above in the optical glass according to the second embodiment are shown below.
  • the upper limit of the mass ratio is preferably 1.00, more preferably 0.95, 0.90, 0.85, 0.82, 0.80.
  • the lower limit of the mass ratio is more preferably 0.50, and further preferably 0.55, 0.60, 0.62, 0.64.
  • the mass ratio of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 [TiO 2 / (P 2 O 5 + B 2 O 3 )] is 0. It is preferably 70 or less.
  • the upper limit of the mass ratio is preferably 0.68, more preferably 0.67, 0.66, 0.65.
  • the lower limit of the mass ratio is preferably 0.25, more preferably 0.35, 0.40, 0.45 in that order.
  • the mass ratio of the content of B 2 O 3 to the content of P 2 O 5 [B 2 O 3 / P 2 O 5] is preferably at 0.39 or less.
  • the upper limit of the mass ratio is more preferably 0.20, and further preferably 0.15, 0.12, 0.10, 0.08, 0.07, 0.06 in that order.
  • the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO and BaO is 8.0% or less.
  • the upper limit of the total content is preferably 6%, more preferably 5%, 4%, and 3%.
  • the lower limit of the total content is preferably 0%.
  • the upper limit of the mass ratio of the content of TiO 2 [TiO 2 / P 2 O 5] to the content of P 2 O 5 is preferably 0.70, more 0 It is more preferable in the order of .68, 0.66, 0.65.
  • the lower limit of the mass ratio is preferably 0.25, more preferably 0.35, 0.40, 0.45 in that order.
  • the upper limit of the content of B 2 O 3 is preferably 10%, more preferably 7%, 5%, 3%, and 2%.
  • the content of B 2 O 3 may be 0%.
  • B 2 O 3 is a network-forming component of glass and has a function of improving the thermal stability of glass.
  • the content of B 2 O 3 is preferably in the above range.
  • the content of Al 2 O 3 is preferably 3% or less, more preferably 2% or less and 1% or less.
  • the content of Al 2 O 3 may be 0%.
  • Al 2 O 3 is a glass component having a function of improving the chemical durability and weather resistance of glass, and can be considered as a network forming component.
  • the content of Al 2 O 3 increases, the devitrification resistance of the glass decreases.
  • problems such as an increase in the glass transition temperature Tg and a decrease in thermal stability are likely to occur.
  • the upper limit of the content of Al 2 O 3 is preferably in the above range.
  • the upper limit of the content of SiO 2 is preferably 5%, more preferably 3%, 2%, and 1%.
  • the content of SiO 2 may be 0%.
  • a quartz glass melting device such as a quartz glass crucible may be used to melt the glass.
  • the glass frit is produced be free of SiO 2 contains a small amount of SiO 2.
  • the amount of SiO 2 mixed into the glass from the quartz glass melting device depends on the melting conditions, but is, for example, about 0.5 to 1% by mass with respect to the total content of all glass components.
  • the amount of SiO 2 increases by about 0.5 to 1% by mass while the content ratio of the glass component other than SiO 2 remains constant. The above amount may increase or decrease depending on the melting conditions. Since the optical characteristics such as the refractive index and the Abbe number change depending on the content of SiO 2, the content of the glass component other than SiO 2 is finely adjusted to obtain an optical glass having desired optical characteristics.
  • SiO 2 is a network-forming component of glass, and has a function of improving thermal stability, chemical durability, and weather resistance of glass, increasing the viscosity of molten glass, and facilitating molding of molten glass.
  • the upper limit of the content of SiO 2 is preferably in the above range.
  • the upper limit of the total content [P 2 O 5 + B 2 O 3 + SiO 2 ] of P 2 O 5 , B 2 O 3 and SiO 2 is preferably 45%, and further. Is more preferable in the order of 42%, 40%, and 38%.
  • the lower limit of the total content is preferably 25%, more preferably 28%, 30%, and 32%.
  • the upper limit of the content of Bi 2 O 3 is preferably 15%, more preferably 10%, 7%, 5%, and 3%.
  • the lower limit of the Bi 2 O 3 content is preferably 0%.
  • Bi 2 O 3 has a function of improving the thermal stability of glass by containing an appropriate amount.
  • the content of Bi 2 O 3 is increased, the coloring of the glass is increased. Therefore, the content of Bi 2 O 3 is preferably in the above range.
  • the upper limit of the content of Ta 2 O 5 is preferably 10%, more preferably 7%, 5%, and 3%.
  • the lower limit of the content of Ta 2 O 5 is preferably 0%.
  • the content of Ta 2 O 5 may be 0%.
  • Ta 2 O 5 is a glass component having a function of improving the thermal stability and devitrification resistance of glass.
  • Ta 2 O 5 increases the refractive index and makes the glass highly dispersed. Further, when the content of Ta 2 O 5 is increased, the thermal stability of the glass is lowered, and when the glass is melted, the unmelted residue of the glass raw material is likely to occur. Therefore, the content of Ta 2 O 5 is preferably in the above range.
  • Ta 2 O 5 is an extremely expensive component as compared with other glass components, and as the content of Ta 2 O 5 increases, the production cost of glass increases. Further, since Ta 2 O 5 has a larger molecular weight than other glass components, it increases the specific gravity of the glass, and as a result, increases the weight of the optical element.
  • the upper limit of the Li 2 O content is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Li 2 O content is preferably 0%.
  • the content of Li 2 O may be 0%.
  • Li 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Li 2 O content is preferably in the above range.
  • the lower limit of the Na 2 O content is preferably 6%, more preferably 10%, 12%, and 13% in that order.
  • the upper limit of the Na 2 O content is preferably 30%, more preferably 22%, 20%, 19%, and 18%.
  • Na 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Na 2 O content is preferably in the above range.
  • the lower limit of the K 2 O content is preferably 1%, more preferably 2%, 3%, and 4%.
  • the upper limit of the content of K 2 O is preferably 13%, further 12%, 11%, preferably by 10% order.
  • K 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the thermal stability of glass. It also has the function of increasing the average coefficient of linear thermal expansion.
  • the content of K 2 O is within the above range.
  • the upper limit of the total content [Li 2 O + Na 2 O + K 2 O] of Li 2 O, Na 2 O and K 2 O is preferably 35%, further 30%. 28%, 26%, and 25% are more preferable in this order.
  • the lower limit of the total content is preferably 10%, more preferably 14%, 18%, 19%, and 20%.
  • Li 2 O, Na 2 O and K 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O and K 2 O [Li 2 O + Na 2 O + K 2 O] is preferably in the above range.
  • the upper limit of the content of Cs 2 O is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Cs 2 O content is preferably 0%.
  • the content of Cs 2 O may be 0%.
  • Cs 2 O has a function of improving the meltability of glass, but when the content is increased, the thermal stability and refractive index nd of the glass are lowered, and the volatilization of the glass component is increased during melting. The desired glass cannot be obtained. Therefore, the content of Cs 2 O is preferably in the above range.
  • the upper limit of the total content [Li 2 O + Na 2 O + K 2 O + Cs 2 O] of Li 2 O, Na 2 O, K 2 O and Cs 2 O is preferably 35%. Further, 30%, 28%, 26%, and 25% are more preferable in this order.
  • the lower limit of the total content is preferably 10%, more preferably 14%, 18%, 19%, and 20%.
  • Li 2 O, Na 2 O, K 2 O and Cs 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O, K 2 O and Cs 2 O [Li 2 O + Na 2 O + K 2 O + Cs 2 O] is preferably in the above range.
  • the content of MgO is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the MgO content is preferably 0%.
  • the content of MgO may be 0%.
  • the CaO content is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the CaO content is preferably 0%.
  • the CaO content may be 0%.
  • the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the SrO content is preferably 0%.
  • the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the BaO content is preferably 0%.
  • MgO, CaO, SrO, and BaO are all glass components having a function of improving the thermal stability and devitrification resistance of glass.
  • the content of these glass components is increased, the high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass are lowered. Therefore, the content of each of these glass components is preferably in the above range.
  • the upper limit of the ZnO content is preferably 10%, more preferably 6%, 4%, and 3%.
  • the ZnO content is preferably low, and the lower limit thereof is preferably 0%.
  • the ZnO content may be 0%.
  • ZnO is a glass component having a function of improving the thermal stability of glass.
  • the ZnO content is too high, the specific gravity of the glass increases. Further, the temperature coefficient (dn / dT) of the relative refractive index becomes high. Therefore, the ZnO content is preferably in the above range.
  • the content of ZrO 2 is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the ZrO 2 content is preferably 0%.
  • ZrO 2 is a glass component having a function of improving the thermal stability and devitrification resistance of glass. However, if the content of ZrO 2 is too high, the thermal stability tends to decrease. Therefore, the content of ZrO 2 is preferably in the above range.
  • the upper limit of the content of Sc 2 O 3 is preferably 2%.
  • the lower limit of the Sc 2 O 3 content is preferably 0%.
  • the upper limit of the HfO 2 content is preferably 2%.
  • the lower limit of the HfO 2 content is preferably 0%.
  • Sc 2 O 3 and HfO 2 both have a function of increasing the refractive index nd and are expensive components. Therefore, the contents of Sc 2 O 3 and HfO 2 are preferably in the above range.
  • the upper limit of the content of Lu 2 O 3 is preferably 2%.
  • the lower limit of the content of Lu 2 O 3 is preferably 0%.
  • Lu 2 O 3 has a function of increasing the refractive index nd. In addition, since it has a large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the content of Lu 2 O 3 is preferably in the above range.
  • the upper limit of the content of GeO 2 is preferably 2%.
  • the lower limit of the content of GeO 2 is preferably 0%.
  • GeO 2 has a function of increasing the refractive index nd, and is a prominently expensive component among commonly used glass components. Therefore, from the viewpoint of reducing the manufacturing cost of glass, the content of GeO 2 is preferably in the above range.
  • the upper limit of the content of La 2 O 3 is preferably 2%.
  • the lower limit of the content of La 2 O 3 is preferably 0%.
  • the content of La 2 O 3 may be 0%.
  • the content of La 2 O 3 is preferably in the above range from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance.
  • the upper limit of the content of Gd 2 O 3 is preferably 2%.
  • the lower limit of the content of Gd 2 O 3 is preferably 0%.
  • the content of Gd 2 O 3 is preferably in the above range from the viewpoint of suppressing an increase in specific gravity while maintaining good thermal stability and devitrification resistance of the glass.
  • the upper limit of the content of Y 2 O 3 is preferably 2%.
  • the lower limit of the content of Y 2 O 3 is preferably 0%.
  • the content of Y 2 O 3 may be 0%.
  • the content of Y 2 O 3 is preferably in the range.
  • the upper limit of the content of Yb 2 O 3 is preferably 2%.
  • the lower limit of the content of Yb 2 O 3 is preferably 0%.
  • Yb 2 O 3 Since Yb 2 O 3 has a larger molecular weight than La 2 O 3 , Gd 2 O 3 , and Y 2 O 3 , it increases the specific gravity of glass. As the specific gravity of glass increases, the mass of the optical element increases. For example, if a lens having a large mass is incorporated into an autofocus type imaging lens, the power required to drive the lens during autofocus increases, and the battery consumption increases. Therefore, it is desirable to reduce the content of Yb 2 O 3 to suppress the increase in the specific gravity of the glass.
  • the content of Yb 2 O 3 is preferably in the above range from the viewpoint of preventing a decrease in thermal stability of the glass and suppressing an increase in specific gravity.
  • the optical glass according to the second embodiment mainly contains the above-mentioned glass components, that is, P 2 O 5 , TiO 2 , Nb 2 O 5 as essential components, and WO 3 , B 2 O 3 , Al 2 O 3 , as optional components.
  • SiO 2 , Bi 2 O 3 , Ta 2 O 5 Li 2 O, Na 2 O, K 2 O, Cs 2 O, MgO, CaO, SrO, BaO, ZnO, ZrO 2 , Sc 2 O 3 , HfO 2 , It is preferably composed of Lu 2 O 3 , GeO 2 , La 2 O 3 , Gd 2 O 3 , Y 2 O 3 , and Yb 2 O 3 , and the total content of the above-mentioned glass components is 95% or more. Is preferable, 98% or more is preferable, 99% or more is further preferable, and 99.5% or more is further preferable.
  • the upper limit of the content of TeO 2 is preferably 2%.
  • the lower limit of the content of TeO 2 is preferably 0%.
  • TeO 2 Since TeO 2 is toxic, it is preferable to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably in the above range.
  • the optical glass according to the second embodiment is basically composed of the above glass components, but it is also possible to contain other components as long as the effects of the present invention are not impaired. Further, in the present invention, the inclusion of unavoidable impurities is not excluded.
  • the optical glass according to the second embodiment does not contain these elements as a glass component.
  • the optical glass according to the second embodiment does not contain these elements as a glass component.
  • Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are arbitrarily addable elements that function as fining agents.
  • Sb (Sb 2 O 3 ) is a fining agent having a large fining effect.
  • Sb (Sb 2 O 3 ) is highly oxidizing, and if the amount of Sb (Sb 2 O 3 ) added is increased, the coloration of the glass increases due to light absorption by Sb ions, which is not preferable. Further, when the glass is melted, if Sb is present in the melt, the elution of platinum constituting the glass melting crucible into the melt is promoted, and the platinum concentration in the glass becomes high.
  • the content of Sb 2 O 3 is indicated by external division. That is, when the total content of all glass components other than Sb 2 O 3 and CeO 2 is 100% by mass, the content of Sb 2 O 3 is preferably less than 1% by mass, more preferably 0.1% by mass. Is less than. Further, is preferably less than 0.05% by mass, less than 0.03% by mass, less than 0.02% by mass, and less than 0.01% in this order.
  • the content of Sb 2 O 3 may be 0% by mass.
  • the content of CeO 2 is also indicated by external division. That is, when the total content of all glass components other than CeO 2 and Sb 2 O 3 is 100% by mass, the content of CeO 2 is preferably less than 2% by mass, more preferably less than 1% by mass, and even more preferably. Is in the range of less than 0.5% by mass, more preferably less than 0.1% by mass.
  • the content of CeO 2 may be 0% by mass.
  • the refractive index nd is preferably 1.63 to 1.80.
  • the lower limit of the refractive index nd may be 1.65, 1.67, 1.69, 1.71 or 1.73, and the upper limit of the refractive index nd may be 1.79, 1.78, or 1.77.
  • the refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components having the function of relatively increasing the refractive index nd are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2 , La 2 O 3, etc. Is.
  • the components having a function of relatively lowering the refractive index nd are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O and the like. is there.
  • the Abbe number ⁇ d is preferably 20 to 30.
  • the lower limit of the Abbe number ⁇ d may be 22, 22.5, 23, or 23.2, and the upper limit of the Abbe number ⁇ d may be 28, 26, or 25.
  • the Abbe number ⁇ d can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components that relatively lower the Abbe number ⁇ d, that is, the highly dispersed components, are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2, and the like.
  • the components that relatively increase the Abbe number ⁇ d, that is, the low dispersion components are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O, La 2 O 3 , BaO, CaO, SrO and the like.
  • the lower limit of the average coefficient of linear thermal expansion ⁇ at 100 to 300 ° C. is preferably 100 ⁇ 10 -7 ° C -1 , and further 105 ⁇ 10 -7 ° C -1 , 110. ⁇ 10 -7 °C -1, 115 ⁇ 10 -7 °C -1, preferably in the order of 120 ⁇ 10 -7 °C -1.
  • the upper limit of the average coefficient of linear thermal expansion ⁇ is more preferably 200 ⁇ 10 -7 °C -1 , and further 190 ⁇ 10 -7 °C -1 , 180 ⁇ 10 -7 °C -1 , 170 ⁇ 10 ⁇ . 7 ° C -1 , 160 ⁇ 10 -7 ° C -1 , 150 ⁇ 10 -7 ° C -1 , 145 ⁇ 10 -7 ° C -1 are more preferable.
  • the average coefficient of linear expansion ⁇ is measured based on the provisions of JOBIS08-2003. However, the sample shall be a round bar with a length of 20 mm ⁇ 0.5 mm and a diameter of 5 mm ⁇ 0.5 mm, and with a load of 98 mN applied to the sample, it shall be heated so as to rise at a constant rate of 4 ° C. And measure the elongation of the sample.
  • the average coefficient of linear expansion ⁇ is expressed in the unit of [° C -1 ], but the numerical value of the average coefficient of linear expansion ⁇ is the same even when [K -1] is used as the unit.
  • the temperature coefficient dn / dT of the relative refractive index at the wavelength (633 nm) of the He—Ne laser is in the range of 20 to 40 ° C., preferably ⁇ 1.0 ⁇ 10-6 to.
  • the order is ⁇ 3.0 ⁇ 10 -6 to ⁇ 6.5 ⁇ 10 -6 ° C -1.
  • the temperature coefficient dn / dT of the relative refractive index is measured based on the interferometry of JOBIS18-2008.
  • the temperature coefficient dn / dT is expressed in the unit of [° C-1 ], but the numerical value of the temperature coefficient dn / dT is the same even when [K -1] is used as the unit.
  • the glass transition temperature Tg of the optical glass according to the second embodiment is preferably 600 ° C. or lower, more preferably 590 ° C. or lower, 580 ° C. or lower, 570 ° C. or lower, and 560 ° C. or lower.
  • the upper limit of the glass transition temperature Tg satisfies the above range, it is possible to suppress an increase in the glass molding temperature and the annealing temperature, and it is possible to reduce thermal damage to the press molding equipment and the annealing equipment. Further, when the lower limit of the glass transition temperature Tg satisfies the above range, it becomes easy to maintain good thermal stability of the glass while maintaining a desired Abbe number and refractive index.
  • the specific gravity is preferably 3.40 or less, more preferably 3.30 or less, and 3.20 or less. If the specific gravity of the glass can be reduced, the weight of the lens can be reduced. As a result, the power consumption of the autofocus drive of the camera lens on which the lens is mounted can be reduced.
  • the light transmittance of the optical glass according to the second embodiment can be evaluated by the degree of coloring ⁇ 5.
  • the spectral transmittance of a glass sample having a thickness of 10.0 mm ⁇ 0.1 mm is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance is 5% is defined as ⁇ 5.
  • the ⁇ 5 of the optical glass according to the second embodiment is preferably 400 nm or less, more preferably 390 nm or less, and further preferably 385 nm or less.
  • the production of the optical glass and the production of the optical element and the like according to the second embodiment can be the same as those of the first embodiment.
  • the optical glass according to the third embodiment will be described in detail.
  • the optical glass according to the third embodiment is The content of P 2 O 5 is 25 to 50%, The Nb 2 O 5 content is 14-40%, The total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] is 35 to 60%.
  • Mass ratio of TiO 2 content to total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 [TiO 2 / (TIO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3) + Ta 2 O 5 )] is 0.25 or more, P 2 O 5 mass ratio of the content of B 2 O 3 to the content of [B 2 O 3 / P 2 O 5] is 0.05 to 0.39
  • the total content of Li 2 O, Na 2 O, K 2 O and Cs 2 O [Li 2 O + Na 2 O + K 2 O + Cs 2 O] is 10% or more.
  • K 2 O weight ratio of Na 2 O content to the content of [Na 2 O / K 2 O ] is 1.50 or more.
  • the content of P 2 O 5 is 25-50%.
  • the lower limit of the content of P 2 O 5 is preferably 26%, more preferably 26.5% and 26.7 in that order.
  • the upper limit of the content of P 2 O 5 is preferably 42%, more preferably 40%, 38%, 37%, and 36%.
  • P 2 O 5 is a network-forming component of glass, and is an essential component for containing a large amount of highly dispersed components in glass. By setting the content of P 2 O 5 in the above range, an optical glass having high thermal stability and a desired optical constant can be obtained.
  • the content of Nb 2 O 5 is 14 to 40%.
  • the lower limit of the content of Nb 2 O 5 is preferably 16%, more preferably 17%, 18%, 19%, and 20% in that order.
  • the upper limit of the content of Nb 2 O 5 is preferably 38%, more preferably 36%, 34%, and 32% in that order.
  • Nb 2 O 5 is a component that contributes to high refractive index and high dispersion. Therefore, by setting the content of Nb 2 O 5 in the above range, an optical glass having a desired optical constant can be obtained. On the other hand, if the content of Nb 2 O 5 is too large, the coloring of the glass may be strengthened.
  • the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 35 to 60%.
  • the lower limit of the total content is preferably 36%, more preferably 37%, 38%, and 39%.
  • the upper limit of the total content is preferably 55%, more preferably 50%, 48%, 47%, and 46%.
  • TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 are components that contribute to high dispersion of glass. Therefore, by setting the total content [TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 ] in the above range, an optical glass having a desired optical constant can be obtained. In addition, the thermal stability of the glass can be improved. On the other hand, if the total content is too large, an optical glass having a desired optical constant may not be obtained, the thermal stability of the glass may be lowered, and the coloring of the glass may be strengthened.
  • the mass ratio of the content of TiO 2 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 0.25 or more.
  • the lower limit of the mass ratio is preferably 0.26, more preferably 0.27, 0.28, 0.29, 0.30 in that order.
  • the upper limit of the mass ratio is preferably 0.65, and more preferably 0.60, 0.58, 0.56, 0.54, 0.52, 0.50, 0.48. ..
  • TiO 2 is a component having a particularly large effect of high dispersion. Therefore, from the viewpoint of obtaining a desired optical constant, the mass ratio [TiO 2 / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + Ta 2 O 5 )] is preferably in the above range.
  • the mass ratio of the content of B 2 O 3 to the content of P 2 O 5 [B 2 O 3 / P 2 O 5] is 0.05 to 0.39.
  • the upper limit of the mass ratio is preferably 0.30, and more preferably 0.25, 0.22, 0.20, 0.19, and 0.18.
  • the lower limit of the mass ratio is preferably 0.06, and more preferably 0.07, 0.08, and 0.09.
  • the total content [Li 2 O + Na 2 O + K 2 O + Cs 2 O] of Li 2 O, Na 2 O, K 2 O and Cs 2 O is 10% or more.
  • the lower limit of the total content is preferably 12%, more preferably 14%, 16%, and 17% in that order.
  • the upper limit of the total content is preferably 35%, more preferably 30%, 28%, 26%, and 25%.
  • Li 2 O, Na 2 O, K 2 O and Cs 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O, K 2 O and Cs 2 O [Li 2 O + Na 2 O + K 2 O + Cs 2 O] is preferably in the above range.
  • K 2 O weight ratio of Na 2 O content to the content of [Na 2 O / K 2 O ] is 1.50 or more.
  • the lower limit of the mass ratio is preferably 1.70, more preferably 1.90, 2.10 and 2.30 in that order.
  • the upper limit of the mass ratio is preferably 10.0, and more preferably 8.50, 7.50, 7.00, and 6.50.
  • Na 2 O and K 2 O are components that contribute to lowering the specific gravity of glass, and have a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the mass ratio [Na 2 O / K 2 O] is preferably in the above range.
  • Non-limiting examples of the content and ratio of glass components other than the above in the optical glass according to the third embodiment are shown below.
  • the upper limit of the content of B 2 O 3 is preferably 10%, more preferably 9%, 8%, 7%, and 6%.
  • B 2 O 3 is a network-forming component of glass and has a function of improving the thermal stability of glass.
  • the content of B 2 O 3 is preferably in the above range.
  • P 2 O 5 and B 2 O total mass ratio of the content of B 2 O 3 to the content of 3 [B 2 O 3 / ( P 2 O 5 + B 2 O 3) ] Is preferably 0.18, more preferably 0.17, 0.16, 0.15 in that order.
  • the lower limit of the mass ratio is preferably 0, more preferably 0.01, 0.03, 0.05.
  • the mass ratio [B 2 O 3 / (P 2 O 5 + B 2 O 3 )] is preferably in the above range.
  • the content of Al 2 O 3 is preferably 3% or less, more preferably 2% or less and 1% or less.
  • the content of Al 2 O 3 may be 0%.
  • Al 2 O 3 is a glass component having a function of improving the chemical durability and weather resistance of glass, and can be considered as a network forming component.
  • the content of Al 2 O 3 increases, the devitrification resistance of the glass decreases.
  • problems such as an increase in the glass transition temperature Tg and a decrease in thermal stability are likely to occur.
  • the upper limit of the content of Al 2 O 3 is preferably in the above range.
  • the upper limit of the content of SiO 2 is preferably 5%, more preferably 3%, 2%, and 1%.
  • the content of SiO 2 may be 0%.
  • a quartz glass melting device such as a quartz glass crucible may be used to melt the glass.
  • the glass frit is produced be free of SiO 2 contains a small amount of SiO 2.
  • the amount of SiO 2 mixed into the glass from the quartz glass melting device depends on the melting conditions, but is, for example, about 0.5 to 1% by mass with respect to the total content of all glass components.
  • the amount of SiO 2 increases by about 0.5 to 1% by mass while the content ratio of the glass component other than SiO 2 remains constant. The above amount may increase or decrease depending on the melting conditions. Since the optical characteristics such as the refractive index and the Abbe number change depending on the content of SiO 2, the content of the glass component other than SiO 2 is finely adjusted to obtain an optical glass having desired optical characteristics.
  • SiO 2 is a network-forming component of glass, and has a function of improving thermal stability, chemical durability, and weather resistance of glass, increasing the viscosity of molten glass, and facilitating molding of molten glass.
  • the upper limit of the content of SiO 2 is preferably in the above range.
  • the upper limit of the total content [P 2 O 5 + B 2 O 3 + SiO 2 ] of P 2 O 5 , B 2 O 3 and SiO 2 is preferably 50%, and further. Is more preferred in the order of 45%, 43%, 42%, 41%.
  • the lower limit of the total content is preferably 25%, more preferably 27%, 28%, and 29%.
  • the mass ratio of the total content of P 2 O 5 and B 2 O 3 to the total content of P 2 O 5 , B 2 O 3 , SiO 2 , and Al 2 O 3 [
  • the lower limit of (P 2 O 5 + B 2 O 3 ) / (P 2 O 5 + B 2 O 3 + SiO 2 + Al 2 O 3 )] is preferably 0.80, and further 0.90, 0.93, It is more preferable in the order of 0.96 and 0.98.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [(P 2 O 5 + B 2 O 3 ) / (P 2 O 5 + B 2 O 3 + SiO 2 + Al 2 O 3 )) ] Is preferably in the above range.
  • the lower limit of the TiO 2 content is preferably 10%, more preferably 11%, 12%, and 13% in that order.
  • the upper limit of the TiO 2 content is preferably 50%, more preferably 40%, 35%, 30%, 28%, 26%, 23%, and 21%.
  • TiO 2 greatly contributes to high dispersion. On the other hand, TiO 2 tends to increase the coloring of the glass relatively easily, and may deteriorate the meltability. Therefore, the content of TiO 2 is preferably in the above range.
  • the upper limit of the content of WO 3 is preferably 15%, more preferably 10%, 5%, 3%, 2%, and 1%.
  • the content of WO 3 is preferably low, and the lower limit thereof is preferably 0%.
  • the content of WO 3 may be 0%.
  • the transmittance can be increased and the increase in the specific gravity of the glass can be suppressed. Further, the temperature coefficient (dn / dT) of the relative refractive index can be lowered.
  • the upper limit of the content of Bi 2 O 3 is preferably 15%, more preferably 10%, 7%, 5%, and 3%.
  • the lower limit of the Bi 2 O 3 content is preferably 0%.
  • Bi 2 O 3 has a function of improving the thermal stability of glass by containing an appropriate amount.
  • the content of Bi 2 O 3 is increased, the coloring of the glass is increased. Therefore, the content of Bi 2 O 3 is preferably in the above range.
  • the upper limit of the mass ratio [TiO 2 / (P 2 O 5 + B 2 O 3 )] of the content of TiO 2 to the total content of P 2 O 5 and B 2 O 3 is , Preferably 0.70, and more preferably 0.66, 0.64, 0.62, 0.60.
  • the lower limit of the mass ratio is preferably 0.25, more preferably 0.27, 0.29, 0.31 in that order.
  • the upper limit of the mass ratio of the content of TiO 2 [TiO 2 / P 2 O 5] to the content of P 2 O 5 is preferably 0.70, more 0 It is more preferable in the order of .66, 0.64, 0.62.
  • the lower limit of the mass ratio is preferably 0.25, more preferably 0.28, 0.31 and 0.34.
  • the lower limit of the total content [TiO 2 + Nb 2 O 5 ] of TiO 2 and Nb 2 O 5 is preferably 35.0%, and further 37.0% and 39. It is more preferable in the order of 0.0% and 40.0%.
  • the upper limit of the total content is preferably 65.0%, more preferably 60.0%, 55.0%, 50.0%, 48.0%, and 46.0%.
  • the total content [TiO 2 + Nb 2 O 5 ] is preferably in the above range.
  • the lower limit of the mass ratio of the content of Nb 2 O 5 to the total content of Nb 2 O 5 and WO 3 is , It is preferably 0.70, and more preferably 0.80, 0.90, 0.95 in that order.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [Nb 2 O 5 / (Nb 2 O 5 + WO 3 )] is It is preferably in the above range.
  • the lower limit of the mass ratio of the content of TiO 2 to the total content of TiO 2 and WO 3 is preferably 0.70. Further, it is more preferable in the order of 0.80, 0.90, 0.95.
  • the upper limit of the mass ratio is preferably 1.00. The mass ratio may be 1.00.
  • the mass ratio [TiO 2 / (TiO 2 + WO 3 )] is preferably in the above range. ..
  • the mass ratio of the total content of TiO 2 and Nb 2 O 5 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 [(TiO 2 + Nb).
  • the lower limit of 2 O 5 ) / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 )] is preferably 0.70, and more preferably 0.80, 0.90, and 0.95.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [(TiO 2 + Nb 2 O 5 ) / (TiO 2 + Nb 2 O) 5 + WO 3 + Bi 2 O 3 )] is preferably in the above range.
  • the upper limit of the content of Ta 2 O 5 is preferably 10%, more preferably 7%, 5%, and 3%.
  • the lower limit of the content of Ta 2 O 5 is preferably 0%.
  • the content of Ta 2 O 5 may be 0%.
  • Ta 2 O 5 is a glass component having a function of improving the thermal stability and devitrification resistance of glass.
  • Ta 2 O 5 increases the refractive index and makes the glass highly dispersed. Further, when the content of Ta 2 O 5 is increased, the thermal stability of the glass is lowered, and when the glass is melted, the unmelted residue of the glass raw material is likely to occur. Therefore, the content of Ta 2 O 5 is preferably in the above range.
  • Ta 2 O 5 is an extremely expensive component as compared with other glass components, and as the content of Ta 2 O 5 increases, the production cost of glass increases. Further, since Ta 2 O 5 has a larger molecular weight than other glass components, it increases the specific gravity of the glass, and as a result, increases the weight of the optical element.
  • the upper limit of the Li 2 O content is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Li 2 O content is preferably 0%.
  • the content of Li 2 O may be 0%.
  • Li 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Li 2 O content is preferably in the above range.
  • the lower limit of the Na 2 O content is preferably 6%, more preferably 10%, 12%, and 13% in that order.
  • the upper limit of the Na 2 O content is preferably 30%, more preferably 22%, 20%, 19%, and 18%.
  • Na 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the meltability of glass and increasing the average coefficient of linear thermal expansion.
  • the Na 2 O content is preferably in the above range.
  • the lower limit of K 2 O content is preferably 1%, even 2%, 3%, preferably by 4% order.
  • the upper limit of the content of K 2 O is preferably 13%, further 12%, 11%, preferably by 10% order.
  • K 2 O is a component that contributes to lowering the specific gravity of glass, and has a function of improving the thermal stability of glass. It also has the function of increasing the average coefficient of linear thermal expansion. On the other hand, when the K 2 O content increases, the thermal stability, devitrification resistance, chemical durability, weather resistance decreases. Therefore, it is preferable that the content of K 2 O is within the above range.
  • the upper limit of the total content [Li 2 O + Na 2 O + K 2 O] of Li 2 O, Na 2 O and K 2 O is preferably 35%, further 30%. 28%, 26%, and 25% are more preferable in this order.
  • the lower limit of the total content is preferably 10%, more preferably 14%, 15%, 16%, and 17%.
  • Li 2 O, Na 2 O and K 2 O all have a function of improving the thermal stability of glass. However, if these contents are high, the chemical durability and weather resistance may be lowered. Therefore, the total content of Li 2 O, Na 2 O and K 2 O [Li 2 O + Na 2 O + K 2 O] is preferably in the above range.
  • the upper limit of the content of Cs 2 O is preferably 5%, more preferably 3%, 2%, and 1%.
  • the lower limit of the Cs 2 O content is preferably 0%.
  • the content of Cs 2 O may be 0%.
  • Cs 2 O has a function of improving the meltability of glass, but when the content is increased, the thermal stability and refractive index nd of the glass are lowered, and the volatilization of the glass component is increased during melting. The desired glass cannot be obtained. Therefore, the content of Cs 2 O is preferably in the above range.
  • the mass ratio of the content of Na 2 O to the total content of Li 2 O, Na 2 O, K 2 O and Cs 2 O [Na 2 O / (Li 2 O + Na 2 O + K).
  • the lower limit of 2 O + Cs 2 O)] is preferably 0.20, more preferably 0.50, 0.55, 0.60, 0.65.
  • the upper limit of the mass ratio is preferably 0.98, more preferably 0.95, 0.92, 0.90, 0.88.
  • the mass ratio [Na 2 O / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is preferably in the above range.
  • the mass ratio of the total contents of P 2 O 5 , B 2 O 3 and SiO 2 to the total contents of Li 2 O, Na 2 O, K 2 O and Cs 2 O [
  • the upper limit of (P 2 O 5 + B 2 O 3 + SiO 2 ) / (Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is preferably 2.50, and further 2.40, 2.35, 2.30. It is more preferable in the order of 2.27 and 2.25.
  • the lower limit of the mass ratio is preferably 1.20, and more preferably 1.30, 1.35, 1.38, and 1.40 in that order.
  • the thermal stability is high and the temperature coefficient of relative refractive index ( An optical glass having a low dn / dT) and a large average coefficient of linear thermal expansion can be obtained.
  • the content of MgO is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the MgO content is preferably 0%.
  • the content of MgO may be 0%.
  • the CaO content is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the CaO content is preferably 0%.
  • the CaO content may be 0%.
  • the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the SrO content is preferably 0%.
  • the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less.
  • the lower limit of the BaO content is preferably 0%.
  • the upper limit of the total content [MgO + CaO + SrO + BaO] of MgO, CaO, SrO, and BaO is preferably 8.0%, and further 5.0% and 4.0%. , 3.0%, 1.5%, 1.0%, 0.5% in that order.
  • the lower limit of the total content is preferably 0%.
  • the total content may be 0%.
  • MgO, CaO, SrO, and BaO are all glass components having a function of improving the thermal stability and devitrification resistance of glass.
  • the content of these glass components is increased, the high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass are lowered.
  • the BaO content is too large, the specific gravity of the glass increases. Therefore, each content and total content of these glass components are preferably in the above range.
  • the upper limit of the ZnO content is preferably 10%, more preferably 6%, 4%, and 3%.
  • the ZnO content is preferably low, and the lower limit thereof is preferably 0%.
  • the ZnO content may be 0%.
  • ZnO is a glass component having a function of improving the thermal stability of glass.
  • the ZnO content is too high, the specific gravity of the glass increases. Further, the temperature coefficient (dn / dT) of the relative refractive index becomes high. Therefore, the ZnO content is preferably in the above range.
  • the lower limit of the mass ratio [Na 2 O / (Na 2 O + Zn O)] of the content of Na 2 O to the total content of Na 2 O and Zn O is preferably 0.50. Yes, more preferably in the order of 0.60, 0.70, 0.90.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [Na 2 O / (Na 2 O + Zn O)] is in the above range from the viewpoint of suppressing an increase in the specific gravity of the glass and suppressing an increase in the temperature coefficient (dn / dT) of the relative refractive index. Is preferable.
  • the lower limit of the mass ratio [TiO 2 / (TiO 2 + ZnO)] of the content of TiO 2 to the total content of TiO 2 and ZnO is preferably 0.70, and further. Is more preferable in the order of 0.80, 0.90, 0.95.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [TiO 2 / (TiO 2 + ZnO)] is preferably in the above range.
  • the mass ratio of the total content of TiO 2 and Nb 2 O 5 to the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Zn O [(TIO 2).
  • the lower limit of [+ Nb 2 O 5 ) / (TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 + ZnO)] is preferably 0.70, and further in the order of 0.80, 0.90, 0.95. preferable.
  • the upper limit of the mass ratio is preferably 1.00.
  • the mass ratio may be 1.00.
  • the mass ratio [(TiO 2 + Nb 2 O 5 ) / (TiO 2 + Nb 2 O) 5 + WO 3 + Bi 2 O 3 + ZnO)] is preferably in the above range.
  • the upper limit of the mass ratio is preferably 1.00, more preferably 0.95, 0.90, 0.85, 0.82, 0.80.
  • the lower limit of the mass ratio is more preferably 0.50, and further preferably 0.60, 0.65, 0.68, 0.70 in that order.
  • the content of ZrO 2 is preferably 5% or less, more preferably 3% or less and 1% or less.
  • the lower limit of the ZrO 2 content is preferably 0%.
  • ZrO 2 is a glass component having a function of improving the thermal stability and devitrification resistance of glass. However, if the content of ZrO 2 is too high, the thermal stability tends to decrease. Therefore, the content of ZrO 2 is preferably in the above range.
  • the upper limit of the Sc 2 O 3 content is preferably 2%.
  • the lower limit of the Sc 2 O 3 content is preferably 0%.
  • the upper limit of the HfO 2 content is preferably 2%.
  • the lower limit of the HfO 2 content is preferably 0%.
  • Sc 2 O 3 and HfO 2 both have a function of increasing the refractive index nd and are expensive components. Therefore, the contents of Sc 2 O 3 and HfO 2 are preferably in the above range.
  • the upper limit of the content of Lu 2 O 3 is preferably 2%.
  • the lower limit of the content of Lu 2 O 3 is preferably 0%.
  • Lu 2 O 3 has a function of increasing the refractive index nd. In addition, since it has a large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the content of Lu 2 O 3 is preferably in the above range.
  • the upper limit of the content of GeO 2 is preferably 2%.
  • the lower limit of the content of GeO 2 is preferably 0%.
  • GeO 2 has a function of increasing the refractive index nd, and is a prominently expensive component among commonly used glass components. Therefore, from the viewpoint of reducing the manufacturing cost of glass, the content of GeO 2 is preferably in the above range.
  • the upper limit of the content of La 2 O 3 is preferably 2%.
  • the lower limit of the content of La 2 O 3 is preferably 0%.
  • the content of La 2 O 3 may be 0%.
  • the content of La 2 O 3 is preferably in the above range from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance.
  • the upper limit of the content of Gd 2 O 3 is preferably 2%.
  • the lower limit of the content of Gd 2 O 3 is preferably 0%.
  • the content of Gd 2 O 3 is preferably in the above range from the viewpoint of suppressing an increase in specific gravity while maintaining good thermal stability and devitrification resistance of the glass.
  • the upper limit of the content of Y 2 O 3 is preferably 2%.
  • the lower limit of the content of Y 2 O 3 is preferably 0%.
  • the content of Y 2 O 3 may be 0%.
  • the content of Y 2 O 3 is preferably in the range.
  • the upper limit of the content of Yb 2 O 3 is preferably 2%.
  • the lower limit of the content of Yb 2 O 3 is preferably 0%.
  • Yb 2 O 3 Since Yb 2 O 3 has a larger molecular weight than La 2 O 3 , Gd 2 O 3 , and Y 2 O 3 , it increases the specific gravity of glass. As the specific gravity of glass increases, the mass of the optical element increases. For example, if a lens having a large mass is incorporated into an autofocus type imaging lens, the power required to drive the lens during autofocus increases, and the battery consumption increases. Therefore, it is desirable to reduce the content of Yb 2 O 3 to suppress the increase in the specific gravity of the glass.
  • the content of Yb 2 O 3 is preferably in the above range from the viewpoint of preventing a decrease in thermal stability of the glass and suppressing an increase in specific gravity.
  • the optical glass according to the third embodiment mainly contains the above-mentioned glass components, that is, P 2 O 5 , Nb 2 O 5 , B 2 O 3 , TiO 2 , Na 2 O, K 2 O as essential components, and optional components.
  • the upper limit of the content of TeO 2 is preferably 2%.
  • the lower limit of the content of TeO 2 is preferably 0%.
  • TeO 2 Since TeO 2 is toxic, it is preferable to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably in the above range.
  • the content of fluorine F is preferably 3% or less, and the upper limit thereof is more preferably 1%, 0.5%, and 0.3%.
  • the content of F is preferably small, and the lower limit thereof is preferably 0%.
  • the content of F may be 0%. Also, preferably, it does not substantially contain fluorine F.
  • the optical glass according to the third embodiment is basically composed of the above glass components, but other components may be contained as long as the effects of the present invention are not impaired. Further, in the present invention, the inclusion of unavoidable impurities is not excluded.
  • the optical glass according to the third embodiment does not contain these elements as a glass component.
  • the optical glass according to the third embodiment does not contain these elements as a glass component.
  • the optical glass according to the third embodiment does not contain these elements as a glass component.
  • Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are arbitrarily addable elements that function as fining agents.
  • Sb (Sb 2 O 3 ) is a fining agent having a large fining effect.
  • Sb (Sb 2 O 3 ) is highly oxidizing, and if the amount of Sb (Sb 2 O 3 ) added is increased, the coloration of the glass increases due to light absorption by Sb ions, which is not preferable. Further, when the glass is melted, if Sb is present in the melt, the elution of platinum constituting the glass melting crucible into the melt is promoted, and the platinum concentration in the glass becomes high.
  • the content of Sb 2 O 3 is indicated by external division. That is, when the total content of all glass components other than Sb 2 O 3 and CeO 2 is 100% by mass, the content of Sb 2 O 3 is preferably less than 1% by mass, more preferably 0.1% by mass. Is less than. Further, is preferably less than 0.05% by mass, less than 0.03% by mass, less than 0.02% by mass, and less than 0.01% in this order.
  • the content of Sb 2 O 3 may be 0% by mass.
  • the content of CeO 2 is also indicated by external division. That is, when the total content of all glass components other than CeO 2 and Sb 2 O 3 is 100% by mass, the content of CeO 2 is preferably less than 2% by mass, more preferably less than 1% by mass, and even more preferably. Is in the range of less than 0.5% by mass, more preferably less than 0.1% by mass.
  • the content of CeO 2 may be 0% by mass.
  • the refractive index nd is preferably 1.63 to 1.80.
  • the lower limit of the refractive index nd may be 1.65, 1.67, 1.69, 1.71 or 1.73, and the upper limit of the refractive index nd may be 1.79, 1.78, or 1.77.
  • the refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components having the function of relatively increasing the refractive index nd are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2 , La 2 O 3, etc. Is.
  • the components having a function of relatively lowering the refractive index nd are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O and the like. is there.
  • the Abbe number ⁇ d is preferably 20 to 30.
  • the lower limit of the Abbe number ⁇ d may be 22, 22.5, 23, or 23.2, and the upper limit of the Abbe number ⁇ d may be 28, 26, or 25.
  • the Abbe number ⁇ d can be set to a desired value by appropriately adjusting the content of each glass component.
  • the components that relatively lower the Abbe number ⁇ d, that is, the highly dispersed components, are Nb 2 O 5 , TiO 2 , WO 3 , Bi 2 O 3 , Ta 2 O 5 , ZrO 2, and the like.
  • the components that relatively increase the Abbe number ⁇ d, that is, the low dispersion components are P 2 O 5 , SiO 2 , B 2 O 3 , Li 2 O, Na 2 O, K 2 O, La 2 O 3 , BaO, CaO, SrO and the like.
  • the lower limit of the average coefficient of linear thermal expansion ⁇ at 100 to 300 ° C. is preferably 100 ⁇ 10 -7 ° C -1 , and further 102 ⁇ 10 -7 ° C -1 , 104. It is more preferable in the order of ⁇ 10 -7 ° C -1 , 106 ⁇ 10 -7 ° C -1 , and 108 ⁇ 10 -7 ° C -1.
  • the upper limit of the average coefficient of linear thermal expansion ⁇ is more preferably 200 ⁇ 10 -7 °C -1 , and further 190 ⁇ 10 -7 °C -1 , 180 ⁇ 10 -7 °C -1 , 170 ⁇ 10 ⁇ . 7 ° C -1 , 160 ⁇ 10 -7 ° C -1 , 150 ⁇ 10 -7 ° C -1 , 145 ⁇ 10 -7 ° C -1 are more preferable.
  • the average coefficient of linear expansion ⁇ is measured based on the provisions of JOBIS08-2003. However, the sample shall be a round bar with a length of 20 mm ⁇ 0.5 mm and a diameter of 5 mm ⁇ 0.5 mm, and with a load of 98 mN applied to the sample, it shall be heated so as to rise at a constant rate of 4 ° C. And measure the elongation of the sample.
  • the average coefficient of linear expansion ⁇ is expressed in the unit of [° C -1 ], but the numerical value of the average coefficient of linear expansion ⁇ is the same even when [K -1] is used as the unit.
  • the temperature coefficient dn / dT of the relative refractive index at the wavelength (633 nm) of the He—Ne laser is in the range of 20 to 40 ° C., preferably ⁇ 1.0 ⁇ 10-6 to.
  • the temperature coefficient dn / dT of the relative refractive index is measured based on the interferometry of JOBIS18-2008.
  • the temperature coefficient dn / dT is expressed in the unit of [° C-1 ], but the numerical value of the temperature coefficient dn / dT is the same even when [K -1] is used as the unit.
  • the glass transition temperature Tg of the optical glass according to the third embodiment is preferably 600 ° C. or lower, more preferably 590 ° C. or lower, 580 ° C. or lower, 570 ° C. or lower, and 560 ° C. or lower.
  • the upper limit of the glass transition temperature Tg satisfies the above range, it is possible to suppress an increase in the glass molding temperature and the annealing temperature, and it is possible to reduce thermal damage to the press molding equipment and the annealing equipment. Further, when the lower limit of the glass transition temperature Tg satisfies the above range, it becomes easy to maintain good thermal stability of the glass while maintaining a desired Abbe number and refractive index.
  • the specific gravity is preferably 3.40 or less, and more preferably 3.30 or less and 3.20 or less. If the specific gravity of the glass can be reduced, the weight of the lens can be reduced. As a result, the power consumption of the autofocus drive of the camera lens on which the lens is mounted can be reduced.
  • the light transmittance of the optical glass according to the third embodiment can be evaluated by the degree of coloring ⁇ 5.
  • the spectral transmittance of a glass sample having a thickness of 10.0 mm ⁇ 0.1 mm is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance is 5% is defined as ⁇ 5.
  • the ⁇ 5 of the optical glass according to the third embodiment is preferably 400 nm or less, more preferably 390 nm or less, and further preferably 385 nm or less.
  • the production of the optical glass and the production of the optical element and the like according to the third embodiment can be the same as those of the first embodiment.
  • Examples 1-1 and 1-2 correspond to the first embodiment
  • Examples 2-1 and 2-2 correspond to the second embodiment
  • Examples 3-1 and 3-2 correspond to the third embodiment. Corresponds to the embodiment.
  • Example 1-1 [Preparation of glass sample] The sample numbers shown in Tables 1-1 to 1-6.
  • Compound raw materials corresponding to each component that is, raw materials such as phosphates, carbonates, and oxides, were weighed and sufficiently mixed to prepare a compounding raw material so as to form a glass having a composition of 1 to 52.
  • the compounding raw material was put into a platinum crucible, heated to 900 to 1350 ° C. in an atmospheric atmosphere to melt, homogenized and clarified by stirring to obtain molten glass.
  • the molten glass was cast into a molding die, molded, and slowly cooled to obtain a block-shaped glass sample.
  • the compounding raw material is put into a quartz glass crucible, melted, then transferred to a platinum crucible, further heated to melt, homogenized by stirring, and clarified, and the obtained molten glass is cast into a molding die and molded. , May be slowly cooled.
  • the glass sample was processed so as to have a plane having a thickness of 10 mm, parallel to each other and optically polished, and the spectral transmittance in the wavelength range from 280 nm to 700 nm was measured.
  • the spectral transmittance B / A was calculated with the intensity of the light beam perpendicularly incident on one plane optically polished as the intensity A and the intensity of the light beam emitted from the other plane as the intensity B.
  • the wavelength at which the spectral transmittance is 5% was defined as ⁇ 5.
  • the spectral transmittance also includes the reflection loss of light rays on the sample surface.
  • Glass transition temperature Tg The glass transition temperature Tg was measured at a heating rate of 10 ° C./min using a differential scanning calorimetry device (DSC3300SA) manufactured by NETZSCH JAPAN.
  • Example 1-2 The glass sample obtained in Example 1 was cut and ground to prepare a cut piece. The cut piece was press-molded by a reheat press to prepare an optical element blank. The optical element blank is precisely annealed, the refractive index is precisely adjusted to the required refractive index, and then ground and polished by a known method to obtain a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, and a concave meniscus lens. , Various lenses such as convex meniscus lenses were obtained.
  • Example 2-1 [Preparation of glass sample] Sample No. shown in Table 2-1.
  • Compound raw materials corresponding to each component that is, raw materials such as phosphates, carbonates, and oxides, are weighed and sufficiently mixed with the compounding raw materials so as to form a glass having a composition of 2-1 to 2-8. did.
  • the compounding raw material was put into a platinum crucible, heated to 900 to 1350 ° C. in an atmospheric atmosphere to melt, homogenized and clarified by stirring to obtain molten glass.
  • the molten glass was cast into a molding die, molded, and slowly cooled to obtain a block-shaped glass sample.
  • the compounding raw material is put into a quartz glass crucible, melted, then transferred to a platinum crucible, further heated to melt, homogenized by stirring, and clarified, and the obtained molten glass is cast into a molding die and molded. , May be slowly cooled.
  • the glass sample was processed so as to have a plane having a thickness of 10 mm, parallel to each other and optically polished, and the spectral transmittance in the wavelength range from 280 nm to 700 nm was measured.
  • the spectral transmittance B / A was calculated with the intensity of the light beam perpendicularly incident on one plane optically polished as the intensity A and the intensity of the light beam emitted from the other plane as the intensity B.
  • the wavelength at which the spectral transmittance is 5% was defined as ⁇ 5.
  • the spectral transmittance also includes the reflection loss of light rays on the sample surface.
  • Glass transition temperature Tg The glass transition temperature Tg was measured at a heating rate of 10 ° C./min using a differential scanning calorimetry device (DSC3300SA) manufactured by NETZSCH JAPAN.
  • Example 2-2 The glass sample obtained in Example 2-1 was cut and ground to prepare a cut piece. The cut piece was press-molded by a reheat press to prepare an optical element blank. The optical element blank is precisely annealed, the refractive index is precisely adjusted to the required refractive index, and then ground and polished by a known method to obtain a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, and a concave meniscus lens. , Various lenses such as convex meniscus lenses were obtained.
  • Example 3-1 [Preparation of glass sample] Sample No. shown in Table 3-1.
  • Compound raw materials corresponding to each component that is, raw materials such as phosphates, carbonates, and oxides, are weighed and sufficiently mixed to prepare a mixed raw material so as to form a glass having a composition of 3-1 to 3-8. did.
  • the compounding raw material was put into a platinum crucible, heated to 900 to 1350 ° C. in an atmospheric atmosphere to melt, homogenized and clarified by stirring to obtain molten glass.
  • the molten glass was cast into a molding die, molded, and slowly cooled to obtain a block-shaped glass sample.
  • the compounding raw material is put into a quartz glass crucible, melted, then transferred to a platinum crucible, further heated to melt, homogenized by stirring, and clarified, and the obtained molten glass is cast into a molding die and molded. , May be slowly cooled.
  • the glass sample was processed so as to have a plane having a thickness of 10 mm, parallel to each other and optically polished, and the spectral transmittance in the wavelength range from 280 nm to 700 nm was measured.
  • the spectral transmittance B / A was calculated with the intensity of the light beam perpendicularly incident on one plane optically polished as the intensity A and the intensity of the light beam emitted from the other plane as the intensity B.
  • the wavelength at which the spectral transmittance is 5% was defined as ⁇ 5.
  • the spectral transmittance also includes the reflection loss of light rays on the sample surface.
  • Example 3-2 The glass sample obtained in Example 3-1 was cut and ground to prepare a cut piece.
  • the cut piece was press-molded by a reheat press to prepare an optical element blank.
  • the optical element blank is precisely annealed, the refractive index is precisely adjusted to the required refractive index, and then ground and polished by a known method to obtain a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, and a concave meniscus lens.
  • Various lenses such as convex meniscus lenses were obtained.
  • the optical glass according to one aspect of the present invention can be produced by adjusting the composition described in the specification with respect to the glass composition exemplified above.

Abstract

L'invention a pour but de fournir un verre optique présentant un faible coefficient de température de l'indice de réfraction relatif (dn/dT) de ce dernier en raison d'un changement de température et un coefficient moyen de dilatation thermique linéaire important, ainsi qu'un élément optique qui comprend le verre optique. Pour atteindre ce but, l'invention concerne un verre optique présentant un indice de réfraction nd de 1,63 à 1,80, un nombre d'Abbe νd de 22 à 34, une teneur en Nb2O5 de 25 à 55 % en masse, une teneur en WO3 inférieure à 30 % en masse, une teneur totale [TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5] en TiO2, Nb2O5, WO3, Bi2O3 et Ta2O5 de 36 à 60 % en masse, un rapport massique [(TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5)/(P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2P + K2O + Cs2O)] de la teneur totale en TiO2, Nb2O5, WO3, Bi2O3 et Ta2O5 à la teneur totale en P2O5, B2O3, SiO2, Al2O3, Li2O, Na2O, K2O et Cs2O de 1,10 ou moins, et un rapport massique [TiO2/(P2O5 + B2O3)] de la teneur en TiO2 à la teneur totale en P2O5 et B2O3 de 0,50 ou moins, et satisfaisant (A) ou (B).
PCT/JP2020/035992 2019-09-26 2020-09-24 Verre optique et élément optique WO2021060362A1 (fr)

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EP3943458A4 (fr) * 2019-03-18 2022-12-07 Hikari Glass Co., Ltd. Verre optique, élément optique, système optique, lentille interchangeable et dispositif optique

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JP2011230991A (ja) * 2010-04-30 2011-11-17 Ohara Inc 光学ガラス、プリフォーム、及び光学素子
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