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TWI897885B - Optical glass and optical components - Google Patents

Optical glass and optical components

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Publication number
TWI897885B
TWI897885B TW109133262A TW109133262A TWI897885B TW I897885 B TWI897885 B TW I897885B TW 109133262 A TW109133262 A TW 109133262A TW 109133262 A TW109133262 A TW 109133262A TW I897885 B TWI897885 B TW I897885B
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content
glass
tio2
mass
optical
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TW109133262A
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Chinese (zh)
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TW202114956A (en
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桑谷俊伍
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日商Ｈｏｙａ股份有限公司
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Priority claimed from JP2019175787A external-priority patent/JP7685820B2/en
Priority claimed from JP2020002064A external-priority patent/JP7481847B2/en
Priority claimed from JP2020125251A external-priority patent/JP7555747B2/en
Application filed by 日商Ｈｏｙａ股份有限公司 filed Critical 日商Ｈｏｙａ股份有限公司
Publication of TW202114956A publication Critical patent/TW202114956A/en
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Publication of TWI897885B publication Critical patent/TWI897885B/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—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
    • 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
    • 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

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Glass Compositions (AREA)

Abstract

本發明提供基於溫度變化的相對折射率溫度係數(dn/dT)低、平均線性熱膨脹係數大的光學玻璃、以及由上述光學玻璃製成的光學元件。本發明的光學玻璃的折射率nd為1.63~1.80，阿貝數νd為22~34，Nb 2O 5的含量為25~55質量%，WO 3的含量小於30質量%，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為36~60質量%，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.10以下，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下，且滿足(A)或(B)。 The present invention provides optical glass having a low relative refractive index temperature coefficient (dn/dT) based on temperature change and a large average linear thermal expansion coefficient, and an optical element made of the optical glass. The optical glass of the present invention has a refractive index nd of 1.63-1.80, an Abbe number νd of 22-34, a Nb 2 O 5 content of 25-55 mass%, a WO 3 content of less than 30 mass%, a 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 ] of 36-60 mass%. The total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 is 2.5% by mass relative to that 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 The mass ratio of the total O content [(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 TiO 2 content 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, and (A) or (B) is satisfied.

Description

光學玻璃及光學元件Optical glass and optical components

本發明涉及一種光學玻璃及光學元件。The present invention relates to optical glass and optical components.

安裝至車載用光學儀器的光學元件、或者安裝至投影儀、影印機、雷射印表機及廣播用器材等這樣的產生熱的光學儀器的光學元件在溫度變化大的環境中使用。如果折射率等光學特性因溫度變化而變動，則會對光學系統的成像特性等帶來影響。Optical components installed in automotive optical instruments, or in heat-generating optical instruments such as projectors, copiers, laser printers, and broadcasting equipment, are used in environments subject to significant temperature fluctuations. Temperature fluctuations in optical properties, such as refractive index, can affect the imaging characteristics of the optical system.

這裡，已知藉由將相對折射率溫度係數(dn/dT)成為負的光學元件與成為正的光學元件組合，可以降低溫度變化對光學系統的成像特性等的影響。It is known that by combining an optical element with a negative relative refractive index temperature coefficient (dn/dT) with an optical element with a positive relative refractive index temperature coefficient (dn/dT), the effects of temperature changes on the imaging characteristics of an optical system can be reduced.

相對折射率溫度係數(dn/dT)表示相對於溫度變化的折射率變化。對於溫度上升時折射率變低的光學元件而言，相對折射率溫度係數成為負。相反，對於溫度上升時折射率變高的光學元件而言，相對折射率溫度係數成為正。The relative refractive index temperature coefficient (dn/dT) indicates the change in refractive index relative to temperature. For optical components whose refractive index decreases as temperature rises, the relative refractive index temperature coefficient is negative. Conversely, for optical components whose refractive index increases as temperature rises, the relative refractive index temperature coefficient is positive.

此外，在玻璃的熔融溫度及成型溫度高的情況下，除了生產性差以外，熔融步驟中的玻璃熔融器具(例如，坩堝、熔融玻璃的攪拌器具等)被侵蝕，經濟性也差。因此，需要一種液相溫度LT低、即玻璃的熔融溫度及成型溫度低的玻璃。Furthermore, high melting and forming temperatures not only reduce productivity but also corrode glass melting equipment (e.g., crucibles, stirring tools for the molten glass) during the melting step, leading to poor economic efficiency. Therefore, there is a need for glass with a low liquidus temperature (LT), meaning a low melting and forming temperature.

專利文獻1中公開了一種相對折射率溫度係數(dn/dT)成為負的光學玻璃。然而，已知在專利文獻1的玻璃中，液相溫度LT高，生產性及經濟性差。Patent Document 1 discloses an optical glass having a negative relative refractive index temperature coefficient (dn/dT). However, the glass of Patent Document 1 has a high liquidus temperature (LT), resulting in poor productivity and economic efficiency.

此外，光學元件的平均線性熱膨脹係數在進行光學設計時是重要的。在將低折射率低分散玻璃材料和高折射率高分散玻璃材料組合的情況下，玻璃材料的平均線性熱膨脹係數之差越小，接合越好。例如，對於含有氟的低折射率低分散玻璃材料而言，通常平均線性熱膨脹係數大。因此，要求與其組合的高折射率高分散玻璃材料也具有高的平均線性熱膨脹係數。專利文獻2中公開的光學玻璃為高折射率，但低分散且平均線性熱膨脹係數小。因此，需要一種高折射率高分散且平均線性熱膨脹係數大的光學玻璃。 ［現有技術文獻］ ［專利文獻］ Furthermore, the average linear thermal expansion coefficient of optical components is important in optical design. When combining a low-refractive-index, low-dispersion glass material with a high-refractive-index, high-dispersion glass material, the smaller the difference in the average linear thermal expansion coefficients of the glass materials, the better the bonding. For example, low-refractive-index, low-dispersion glass materials containing fluorine generally have a large average linear thermal expansion coefficient. Therefore, the high-refractive-index, high-dispersion glass material used in combination with them is required to also have a high average linear thermal expansion coefficient. The optical glass disclosed in Patent Document 2 has a high refractive index but low dispersion and a low average linear thermal expansion coefficient. Therefore, there is a need for an optical glass with a high refractive index, high dispersion, and a large average linear thermal expansion coefficient. [Prior Art Document] [Patent Document]

專利文獻1：日本特開2019-1697號公報 專利文獻2：日本特開2007-106611號公報 Patent Document 1: Japanese Patent Application Publication No. 2019-1697 Patent Document 2: Japanese Patent Application Publication No. 2007-106611

［發明要解決的問題］[Problem to be solved by the invention]

因此，本發明的目的在於，提供一種基於溫度變化的相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃、以及由上述光學玻璃製成的光學元件。 ［解決問題的方法］ Therefore, an object of the present invention is to provide an optical glass having a low relative refractive index temperature coefficient (dn/dT) due to temperature changes and a large average linear thermal expansion coefficient, and an optical element made from such optical glass. [Solution]

本發明的主旨如下所述。 (1)一種光學玻璃，其折射率nd為1.63~1.80， 阿貝數νd為22~34， Nb 2O 5的含量為25~55質量%， WO 3的含量小於30質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為36~60質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.10以下， TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下， 且滿足下述(A)或(B)： (A) P 2O 5的含量為20~36質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.50以下， B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為8.0質量%以下； (B) P 2O 5的含量為25~38質量%， Al 2O 3的含量小於5質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為7.0質量%以下， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。 The gist of the present invention is as follows. (1) An optical glass having a refractive index nd of 1.63-1.80, an Abbe number νd of 22-34, a Nb 2 O 5 content of 25-55 mass%, a WO 3 content of less than 30 mass%, a 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 ] of 36-60 mass%, and a total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 relative to 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 The mass ratio of the total content of O [(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, and the following (A) or (B) is satisfied: (A) The content of P 2 O 5 is 20-36 mass%, the total content of P 2 O 5 , B 2 O 3 and SiO 2 is 20-36 mass% relative to the total content of Li 2 O, Na 2 O and K 2 The mass ratio of the total content of O and Cs2O [ ( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is less than 1.50 , the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is 0.05-0.39, and the total content of MgO , CaO, SrO and BaO [MgO + CaO + SrO + BaO] is less than 8.0 mass%; (B) the content of P2O5 is 25-38 mass%, the content of Al2O3 is less than 5 mass%, and the total content of P2O5 , B2O3 and SiO2 relative to the content of Li2O , Na2O , K2O and Cs2O is 1.50-1.50 . The mass ratio of the total O content [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] is 1.80 or less, the total content of MgO, CaO, SrO and BaO [MgO+CaO+SrO+BaO] is 7.0 mass% or less, and the mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 +Ta2O5 ) ] is 0.25 or more.

(2)根據(1)所述的光學玻璃，其中，P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.00以上。 (2) The optical glass according to (1), wherein the mass ratio of the total content of P2O5, B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O ) ] is 1.00 or more.

(3)根據(1)或(2)所述的光學玻璃，其中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]為0.50以上。 (3) The optical glass according to (1) or (2), wherein the mass ratio of the total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 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 [(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 0.50 or more.

(4)一種光學玻璃，其中， P 2O 5的含量為25~50質量%， TiO 2的含量為10~50質量%， Nb 2O 5含量為5~30質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60質量%， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下， 且滿足下述(A)或(B)： (A) WO 3的含量為7質量%以下； (B) 實質上不含F。 (4) An optical glass, wherein the content of P2O5 is 25-50 mass%, the content of TiO2 is 10-50 mass%, the content of Nb2O5 is 5-30 mass% , the total content of TiO2, Nb2O5, WO3, Bi2O3 and Ta2O5 [TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] is 35-60 mass % , the mass ratio of the content of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 / ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] is 0.25 or more, and P2 The mass ratio of the combined content of O 5 , B 2 O 3 , and SiO 2 to the combined content 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, and the following (A) or (B) is met: (A) The WO 3 content is 7 mass% or less; (B) F is substantially absent.

(5)一種光學玻璃，其中， P 2O 5的含量為25~50質量%， Nb 2O 5含量為14~40質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60質量%， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上， B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39， Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]為10質量%以上， Na 2O的含量相對於K 2O的含量的質量比[Na 2O/K 2O]為1.50以上。 (5) An optical glass, wherein the content of P2O5 is 25-50 mass%, the content of Nb2O5 is 14-40 mass%, the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] is 35-60 mass%, the mass ratio of the content of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 / ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] is 0.25 or more, and the content of B2O3 to P2O5 is 14-40 mass % . The mass ratio of the content of Li2O3 to P2O5 [ B2O3 / P2O5 ] is 0.05-0.39, the total content of Li2O , Na2O , K2O and Cs2O [ Li2O + Na2O + K2O + Cs2O ] is 10 mass% or more, and the mass ratio of the content of Na2O to the content of K2O [ Na2O / K2O ] is 1.50 or more.

(6)根據(5)所述的光學玻璃，其實質上不含F。(6) The optical glass according to (5), which does not substantially contain F.

(7)根據(1)、(2)、(4)~(6)中任一項所述的光學玻璃，其在100~300℃的平均線性熱膨脹係數α為100×10 -7~200×10 -7℃ -1。 (7) The optical glass according to any one of (1), (2), (4) to (6), wherein the average linear thermal expansion coefficient α at 100 to 300°C is 100×10 -7 to 200×10 -7 °C -1 .

(8)根據(1)、(2)、(4)~(6)中任一項所述的光學玻璃，其在He-Ne雷射的波長(633nm)下的相對折射率溫度係數dn/dT在20~40℃的範圍內為-0.1×10 -6~-13.0×10 -6℃ -1。 (8) The optical glass according to any one of (1), (2), (4) to (6), wherein the relative refractive index temperature coefficient dn/dT at the wavelength (633 nm) of the He-Ne laser is in the range of -0.1×10 -6 to -13.0×10 -6 ℃ -1 in the range of 20 to 40°C.

(9)一種光學元件，其由上述(1)~(8)中任一項所述的光學玻璃製成。 ［發明的效果］ (9) An optical element made of the optical glass described in any one of (1) to (8) above. [Effects of the Invention]

根據本發明，可以提供一種基於溫度變化的相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃、以及由上述光學玻璃製成的光學元件。According to the present invention, an optical glass having a low temperature-dependent relative refractive index temperature coefficient (dn/dT) and a large average linear thermal expansion coefficient, and an optical element made of the optical glass can be provided.

在本發明及本說明書中，只要沒有特別記載，光學玻璃的玻璃組成以氧化物基準表示。其中，「氧化物基準的玻璃組成」是指，按照玻璃原料在熔融時全部分解而在光學玻璃中以氧化物的形式存在的物質進行換算而得到的玻璃組成，各玻璃成分的表述按照習慣記載為SiO 2、TiO 2等。只要沒有特別記載，則玻璃成分的含量及合計含量為質量基準，「%」是指「質量%」。 In the present invention and this specification, unless otherwise specified, the glass composition of optical glass is expressed on an oxide basis. "Glass composition on an oxide basis" refers to the glass composition calculated based on the total amount of substances present as oxides in the optical glass after complete decomposition of the glass raw materials during melting. Individual glass components are conventionally expressed as SiO₂ , TiO₂ , etc. Unless otherwise specified, the content and total content of glass components are expressed by mass, and "%" means "mass %."

玻璃成分的含量可以藉由公知的方法、例如電感耦合電漿原子發射光譜法(ICP-AES)、電感耦合電漿質譜分析法(ICP-MS)等方法進行定量。另外，在本說明書及本發明中，構成成分的含量為0%是指，實質上不含該構成成分，允許以不可避免的雜質水準含有該成分。The content of glass components can be quantified by known methods, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). In this specification and the present invention, a 0% content of a component means that the component is substantially absent; however, the presence of the component as an unavoidable impurity level is permitted.

本說明書中，玻璃的熱穩定性及耐失透性都是指在玻璃中的結晶析出的難易度。特別地，熱穩定性是指熔融狀態的玻璃固化時結晶析出的難易度，耐失透性是指在再熱壓製時這樣的將固化後的玻璃再加熱時結晶析出的難易度。In this specification, the terms "thermal stability" and "devitrification resistance" of glass refer to the ease with which crystals form in the glass. Specifically, thermal stability refers to the ease with which crystals form when molten glass solidifies, while devitrification resistance refers to the ease with which crystals form when the solidified glass is reheated, such as during hot pressing.

另外，在本說明書中，只要沒有特別記載，折射率是指在氦的d射線(波長587.56nm)下的折射率nd。In this specification, unless otherwise specified, the refractive index refers to the refractive index nd under helium d-ray (wavelength 587.56 nm).

另外，阿貝數νd是被用作表示與分散相關的性質的值，由以下的數學式表示。其中，nF為藍色氫的F射線(波長486.13nm)下的折射率、nC為紅色氫的C射線(656.27nm)下的折射率。 νd＝(nd－1)/nF－nC…(1) The Abbe number νd is a value used to represent properties related to dispersion and is expressed by the following mathematical formula. Here, nF is the refractive index of blue hydrogen under F-rays (wavelength 486.13 nm), and nC is the refractive index of red hydrogen under C-rays (656.27 nm). νd＝(nd－1)/nF－nC…(1)

以下，將本發明的光學玻璃分成第1實施方式、第2實施方式、第3實施方式進行說明。Hereinafter, the optical glass of the present invention will be described by being divided into a first embodiment, a second embodiment, and a third embodiment.

第1實施方式 對第1實施方式的光學玻璃詳細地進行說明。 第1實施方式的光學玻璃的折射率nd為1.63~1.80， 阿貝數νd為22~34， Nb 2O 5的含量為25~55質量%， WO 3的含量小於30質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為36~60質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.10以下， TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下， 且滿足下述(A)或(B)： (A) P 2O 5的含量為20~36質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.50以下， B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為8.0質量%以下； (B) P 2O 5的含量為25~38質量%， Al 2O 3的含量小於5質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為7.0質量%以下， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。 First Embodiment The optical glass according to the first embodiment is described in detail. The optical glass of the first embodiment has a refractive index nd of 1.63 to 1.80, an Abbe number νd of 22 to 34, a Nb 2 O 5 content of 25 to 55 mass%, a WO 3 content of less than 30 mass%, a 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 ] of 36 to 60 mass%. The total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 , and Ta 2 O 5 is 2.5% by mass relative to that 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 The mass ratio of the total content of O [(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, and the following (A) or (B) is satisfied: (A) The content of P 2 O 5 is 20-36 mass%, the total content of P 2 O 5 , B 2 O 3 and SiO 2 is 20-36 mass% relative to the total content of Li 2 O, Na 2 O and K 2 The mass ratio of the total content of O and Cs2O [ ( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is less than 1.50 , the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is 0.05-0.39, and the total content of MgO , CaO, SrO and BaO [MgO + CaO + SrO + BaO] is less than 8.0 mass%; (B) the content of P2O5 is 25-38 mass%, the content of Al2O3 is less than 5 mass%, and the total content of P2O5 , B2O3 and SiO2 relative to the content of Li2O , Na2O , K2O and Cs2O is 1.50-1.50 . The mass ratio of the total O content [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] is 1.80 or less, the total content of MgO, CaO, SrO and BaO [MgO+CaO+SrO+BaO] is 7.0 mass% or less, and the mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 +Ta2O5 ) ] is 0.25 or more.

以下，只要沒有特別記載，第1實施方式的光學玻璃是指滿足上述(A)的第1實施方式的光學玻璃及滿足上述(B)的第1實施方式的光學玻璃。Hereinafter, unless otherwise specified, the optical glass of the first embodiment refers to the optical glass of the first embodiment satisfying the above-mentioned (A) and the optical glass of the first embodiment satisfying the above-mentioned (B).

在第1實施方式的光學玻璃中，折射率nd為1.63~1.80。折射率nd的下限可以為1.65、1.67或1.69，折射率nd的上限可以為1.79、1.78或1.77。In the optical glass of the first embodiment, the refractive index nd is 1.63 to 1.80. The lower limit of the refractive index nd can be 1.65, 1.67, or 1.69, and the upper limit of the refractive index nd can be 1.79, 1.78, or 1.77.

可以藉由適宜調整各玻璃成分的含量而使折射率nd為期望的值。具有相對地提高折射率nd的作用的成分(高折射率化成分)為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2、La 2O 3等。另一方面，具有相對地降低折射率nd的作用的成分(低折射率化成分)為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O等。因此，例如可以藉由增加TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]來提高折射率nd，可以藉由減少該質量比來降低折射率nd。 The refractive index nd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components that relatively increase the refractive index nd (refractive index-increasing components) include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , ZrO2 , and La2O3 . On the other hand, components that relatively decrease the refractive index nd (refractive index-lowering components) include P2O5 , SiO2 , B2O3 , Li2O , Na2O , and K2O . Therefore, for example, the refractive index nd can be increased by increasing the mass ratio of the total content of TiO2 , Nb2O5 , WO3, Bi2O3, and Ta2O5 relative to the total content of P2O5, B2O3, SiO2, Al2O3, Li2O, Na2O, K2O , and Cs2O [ ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] , and the refractive index nd can be lowered by reducing this mass ratio.

在第1實施方式的光學玻璃中，阿貝數νd為22~34。阿貝數νd的下限可以為22.5、23或23.5，阿貝數νd的上限可以為32、30或28。In the optical glass of the first embodiment, the Abbe number νd is 22 to 34. The lower limit of the Abbe number νd can be 22.5, 23, or 23.5, and the upper limit of the Abbe number νd can be 32, 30, or 28.

可以藉由適宜調整各玻璃成分的含量而使阿貝數νd為期望的值。阿貝數νd相對較低的成分、即高分散化成分為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2等。另一方面，阿貝數νd相對較高的成分、即低分散化成分為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O、La 2O 3、BaO、CaO、SrO等。 The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components with relatively low Abbe numbers νd, i.e. , highly dispersed components, include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , and ZrO2 . On the other hand, components with relatively high Abbe numbers νd, i.e., low dispersed components, include P2O5 , SiO2 , B2O3 , Li2O , Na2O , K2O , La2O3 , BaO, CaO, and SrO .

在第1實施方式的光學玻璃中，Nb 2O 5的含量為25~55%。Nb 2O 5的含量的下限較佳為27%，進一步以29%、31%、33%的順序更佳。另外，Nb 2O 5的含量的上限較佳為53%，進一步以51%、49%、47%的順序更佳。 In the optical glass of the first embodiment, the Nb2O5 content is 25-55%. The lower limit of the Nb2O5 content is preferably 27%, more preferably 29%, 31%, and 33%, in this order. Furthermore, the upper limit of the Nb2O5 content is preferably 53%, more preferably 51%, 49%, and 47%, in this order.

Nb 2O 5是有助於高折射率化及高分散化的成分。因此，藉由將Nb 2O 5的含量設為上述範圍，可以得到具有期望的光學常數的光學玻璃。另一方面，Nb 2O 5的含量過多時，存在玻璃的著色增強的擔憂。 Nb2O5 contributes to a higher refractive index and higher dispersion. Therefore, by setting the Nb2O5 content within the above range, an optical glass with desired optical constants can be obtained. On the other hand, if the Nb2O5 content is too high, there is a concern that the glass may be overly colored.

在第1實施方式的光學玻璃中，WO 3的含量小於30%。WO 3的含量的上限較佳為20%，進一步以15%、10%、5%的順序更佳。較佳WO 3的含量少的情況，其下限較佳為0%。WO 3的含量也可以為0%。 In the optical glass of the first embodiment, the WO 3 content is less than 30%. The upper limit of the WO 3 content is preferably 20%, and more preferably 15%, 10%, and 5%, in that order. When the WO 3 content is low, the lower limit is preferably 0%. The WO 3 content may also be 0%.

藉由將WO 3的含量設為上述範圍，可以提高透射率，而且可以抑制玻璃的比重的增大。另外，可以降低相對折射率溫度係數(dn/dT)。 By setting the WO3 content within the above range, the transmittance can be improved while suppressing an increase in the specific gravity of the glass. In addition, the relative refractive index temperature coefficient (dn/dT) can be reduced.

在第1實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為36~60%。該合計含量的下限較佳為38%，進一步以40%、41%、42%的順序更佳。另外，該合計含量的上限較佳為58%，進一步以56%、54%、52%的順序更佳。 In the optical glass of the first embodiment, the total content of TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ ( TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ) is 36% to 60%. The lower limit of this total content is preferably 38 %, more preferably 40%, 41%, and 42 % , in that order. The upper limit of this total content is preferably 58 %, more preferably 56%, 54%, and 52%, in that order.

TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5是有助於玻璃的高分散化的成分。因此，藉由將合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]設為上述範圍，可以得到具有期望的光學常數的光學玻璃。另外，玻璃的熱穩定性也可以改善。另一方面，該合計含量過多時，存在不能得到具有期望的光學常數的光學玻璃的擔憂，而且存在玻璃的熱穩定性降低、玻璃的著色增強的擔憂。 TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ are components that contribute to high dispersion in glass. Therefore, by setting the combined content [ TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ] within the above range, optical glass with desired optical constants can be obtained. Furthermore, the thermal stability of the glass can be improved. On the other hand, if the combined content is too high , optical glass with the desired optical constants may not be obtained, and there is a concern that the thermal stability of the glass may be reduced or that coloring of the glass may be enhanced.

在第1實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.10以下。該質量比的上限較佳為1.07，進一步以1.04、1.02、1.00的順序更佳。另外，該質量比的下限更佳為0.50，進一步以0.55、0.60、0.65的順序更佳。 In the optical glass of the first embodiment, the mass ratio of the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 to the total content of P2O5 , B2O3 , SiO2 , Al2O3 , Li2O , Na2O , K2O , and Cs2O [ ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] is 1.10 or less. The upper limit of the mass ratio is preferably 1.07, more preferably 1.04, 1.02, and 1.00, in that order. The lower limit of the mass ratio is more preferably 0.50, more preferably 0.55, 0.60, and 0.65, in that order.

藉由將質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，可得到具有期望的光學常數的光學玻璃。 By setting the mass ratio [( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] within the above range, an optical glass having desired optical constants can be obtained.

在第1實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下。 In the optical glass of the first embodiment, 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.

藉由將質量比[TiO 2/(P 2O 5＋B 2O 3)]設為上述範圍，可得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /(P 2 O 5 +B 2 O 3 )] within the above range, an optical glass having desired optical constants and high thermal stability can be obtained.

第1實施方式的光學玻璃如上所述，滿足(A)或(B)。首先，對(A)進行詳細敘述。As described above, the optical glass of the first embodiment satisfies (A) or (B). First, (A) will be described in detail.

第1實施方式的光學玻璃可以滿足下述要件： (A) P 2O 5的含量為20~36質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.50以下， B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為8.0質量%以下。 The optical glass of the first embodiment can meet the following requirements: (A) the P2O5 content is 20-36% by mass, the mass ratio of the total content of P2O5, B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [ ( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is 1.50 or less, the mass ratio of the B2O3 content to the P2O5 content [ B2O3 / P2O5 ] is 0.05-0.39, and the total content of MgO, CaO, SrO , and BaO [MgO + CaO + SrO + BaO] is 8.0% by mass or less.

在滿足上述(A)的第1實施方式的光學玻璃中，P 2O 5的含量為20~36%。P 2O 5的含量的下限較佳為21%，進一步以22%、23%、24%的順序更佳。另外，P 2O 5的含量的上限較佳為35%，進一步以34%、33%、32%的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the P₂O₅ content is 20-36%. The lower limit of the P₂O₅ content is preferably 21%, more preferably 22%, 23%, and 24%, in this order. Furthermore, the upper limit of the P₂O₅ content is preferably 35%, more preferably 34%, 33%, and 32%, in this order.

P 2O 5是玻璃的網絡形成成分，是為了在玻璃中大量含有高分散成分的必要成分。藉由將P 2O 5的含量設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 P2O5 is a network - forming component of glass and is essential for containing a large amount of highly dispersed components in the glass. By setting the P2O5 content within the above range, an optical glass with high thermal stability and desired optical constants can be obtained.

在滿足上述(A)的第1實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.50以下。該質量比的上限較佳為1.47，進一步以1.44、1.42、1.40的順序更佳。另外，該質量比的下限較佳為1.00，進一步以1.05、1.08、1.10的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the mass ratio of the total content of P2O5 , B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O ) ] is 1.50 or less. The upper limit of this mass ratio is preferably 1.47 , more preferably 1.44, 1.42, and 1.40, in that order. The lower limit of this mass ratio is preferably 1.00, more preferably 1.05, 1.08, and 1.10, in that order.

藉由將質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，可得到熱穩定性高、相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃。 By setting the mass ratio [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] within the above range, an optical glass having high thermal stability, a low relative refractive index temperature coefficient ( dn/dT), and a large average linear thermal expansion coefficient can be obtained.

在滿足上述(A)的第1實施方式的光學玻璃中，B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39。該質量比的下限較佳為0.06，進一步以0.07、0.08、0.09的順序更佳。另外，該質量比的上限更佳為0.36，進一步以0.33、0.31、0.29的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is 0.05 to 0.39. The lower limit of this mass ratio is preferably 0.06, more preferably 0.07 , 0.08, and 0.09 , in that order. The upper limit of this mass ratio is more preferably 0.36, more preferably 0.33, 0.31, and 0.29, in that order.

藉由將質量比[B 2O 3/P 2O 5]設為上述範圍，可得到相對折射率溫度係數(dn/dT)低、平均線性熱膨脹係數大、耐失透性高、進而液相溫度LT低的光學玻璃。 By setting the mass ratio [B 2 O 3 /P 2 O 5 ] within the above range, an optical glass having a low relative refractive index temperature coefficient (dn/dT), a large average linear thermal expansion coefficient, high devitrification resistance, and a low liquidus temperature LT can be obtained.

在滿足上述(A)的第1實施方式的光學玻璃中，MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為8.0%以下。該合計含量的上限較佳為6%，進一步以5%、4%、3%的順序更佳。另外，該合計含量的下限較佳為0%。In the optical glass of the first embodiment satisfying the above (A), the total content of MgO, CaO, SrO, and BaO [MgO + CaO + SrO + BaO] is 8.0% or less. The upper limit of this total content is preferably 6%, and more preferably 5%, 4%, and 3% in that order. The lower limit of this total content is preferably 0%.

藉由將合計含量[MgO＋CaO＋SrO＋BaO]設為上述範圍，可以促進高分散化。By setting the total content [MgO + CaO + SrO + BaO] within the above range, high dispersion can be promoted.

另外，在滿足上述(A)的第1實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下。該質量比的上限較佳為0.47，進一步以0.44、0.42、0.40的順序更佳。另外，該質量比的下限更佳為0.00，進一步以0.03、0.06、0.08、0.10的順序更佳。 In the optical glass of the first embodiment satisfying (A) above, the mass ratio of the TiO2 content to the total content of P2O5 and B2O3 [ TiO2 / ( P2O5 + B2O3 )] is 0.50 or less. The upper limit of this mass ratio is preferably 0.47, more preferably 0.44 , 0.42 , and 0.40 , in that order. The lower limit of this mass ratio is more preferably 0.00, more preferably 0.03, 0.06, 0.08, and 0.10, in that order.

藉由將質量比[TiO 2/(P 2O 5＋B 2O 3)]設為上述範圍，可得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /(P 2 O 5 +B 2 O 3 )] within the above range, an optical glass having desired optical constants and high thermal stability can be obtained.

對於滿足上述(A)的第1實施方式的光學玻璃中的玻璃成分的含量及比率，以下示出非限定性的實例。Non-limiting examples of the contents and ratios of the glass components in the optical glass according to the first embodiment satisfying (A) above are shown below.

在滿足上述(A)的第1實施方式的光學玻璃中，B 2O 3的含量的上限較佳為10%，進一步以8%、7%、6%的順序更佳。另外，B 2O 3的含量的下限較佳為1%，進一步以1.5%、1.8%、2.0%的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the upper limit of the B2O3 content is preferably 10%, more preferably 8%, 7%, and 6% in this order. Furthermore, the lower limit of the B2O3 content is preferably 1%, more preferably 1.5%, 1.8%, and 2.0% in this order.

B 2O 3是玻璃的網絡形成成分，具有改善玻璃的熱穩定性的作用。另一方面，B 2O 3的含量多時，存在耐失透性降低的傾向。因此，B 2O 3的含量較佳為上述範圍。 B2O3 is a glass network-forming component that improves the thermal stability of glass. However, if the B2O3 content is high, devitrification resistance tends to decrease. Therefore, the B2O3 content is preferably within the above range.

在滿足上述(A)的第1實施方式的光學玻璃中，Al 2O 3的含量較佳為3%以下，進一步以2%以下、1%以下的順序更佳。Al 2O 3的含量也可以為0%。 In the optical glass of the first embodiment satisfying the above (A), the Al2O3 content is preferably 3% or less, more preferably 2% or less, and more preferably 1% or less. The Al2O3 content may be 0%.

Al 2O 3是具有改善玻璃的化學耐久性、耐候性的作用的玻璃成分，可以將其視為網絡形成成分。另一方面，Al 2O 3的含量變多時，玻璃的耐失透性降低。另外，容易發生玻璃化轉變溫度Tg上升、熱穩定性降低等問題。從避免這樣的問題的觀點考慮，Al 2O 3的含量的上限較佳為上述範圍。 Al₂O₃ is a glass component that improves the chemical durability and weather resistance of glass and can be considered a network-forming component. However, increasing the Al₂O₃ content reduces the glass's resistance to devitrification . It can also lead to problems such as an increase in the glass transition temperature (Tg) and a decrease in thermal stability. To avoid these problems, the upper limit of the Al₂O₃ content is preferably within the above range.

在滿足上述(A)的第1實施方式的光學玻璃中，TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]的下限較佳為0，進一步以0.02、0.04、0.06的順序更佳。另外，該質量比的上限較佳為0.50，進一步以0.45、0.40、0.35的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 / ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] is preferably 0 , more preferably in the order of 0.02, 0.04 , and 0.06 . The upper limit of this mass ratio is preferably 0.50, more preferably in the order of 0.45, 0.40 , and 0.35 .

TiO 2是在高折射率化成分中、高折射率化的作用特別大的成分。因此，從得到期望的光學常數的觀點考慮，質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]較佳為上述範圍。 TiO2 is a component that has a particularly large effect on increasing the refractive index among components that increase the refractive index. Therefore, from the perspective of obtaining desired optical constants, the mass ratio [TiO2/(TiO2+Nb2O5+WO3+Bi2O3+Ta2O5 ) ] is preferably within the above range .

在滿足上述(A)的第1實施方式的光學玻璃中，TiO 2的含量的下限較佳為0%，進一步以1%、2%、3%、4%的順序更佳。TiO 2的含量也可以為0%。另外，TiO 2的含量的上限較佳為15%，進一步以13%、11%、10%的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the lower limit of the TiO2 content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, and 4%. The TiO2 content may also be 0%. Furthermore, the upper limit of the TiO2 content is preferably 15%, and more preferably in the order of 13%, 11%, and 10%.

TiO 2特別有助於高分散化。另一方面，TiO 2比較容易增大玻璃的著色，而且存在容易使熔融性惡化的擔憂。因此，TiO 2的含量較佳為上述範圍。 TiO2 is particularly helpful for achieving high dispersion. However, TiO2 can easily increase the coloring of the glass and may also deteriorate its solubility. Therefore, the TiO2 content is preferably within the above range.

在滿足上述(A)的第1實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3及Bi 2O 3的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]的下限較佳為36%，進一步以38%、40%、41%、42%的順序更佳。另外，合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]的上限較佳為58%，進一步以56%、54%、52%的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the lower limit of the combined content of TiO2 , Nb2O5 , WO3 , and Bi2O3 [ TiO2 + Nb2O5 + WO3 + Bi2O3 ] is preferably 36%, more preferably 38%, 40%, 41 %, and 42 % in this order. Furthermore, the upper limit of the combined content [ TiO2 + Nb2O5 + WO3 + Bi2O3 ] is preferably 58%, more preferably 56%, 54%, and 52 % in this order.

TiO 2、Nb 2O 5、WO 3及Bi 2O 3有助於玻璃的高分散化，而且藉由適量含有，也具有改善玻璃的熱穩定性的作用。另一方面，也是增大玻璃的著色的成分。因此，合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]較佳為上述範圍。 TiO₂ , Nb₂O₅ , WO₃ , and Bi₂O₃ contribute to high dispersion in glass and, when included in appropriate amounts, improve the thermal stability of glass. On the other hand, they also contribute to the coloring of glass. Therefore, the combined content ( TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ ) is preferably within the above range.

在滿足上述(A)的第1實施方式的光學玻璃中，Na 2O的含量的下限較佳為6%，進一步以8%、9%、10%的順序更佳。另外，Na 2O的含量的上限較佳為30%，進一步以28%、26%、25%的順序更佳。 In the optical glass of the first embodiment satisfying (A) above, 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%, in that order.

Na 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Na 2O的含量變多時，耐失透性降低。因此，Na 2O的含量較佳為上述範圍。 Na2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Na2O content reduces devitrification resistance. Therefore, the Na2O content is preferably within the above range.

在滿足上述(A)的第1實施方式的光學玻璃中，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]的上限較佳為35%，進一步以33%、31%、30%的順序更佳。另外，該合計含量的下限較佳為10%，進一步以14%、17%、18%的順序更佳。 In the optical glass of the first embodiment satisfying the above (A), the upper limit of the total content of Li2O , Na2O , and K2O [ Li2O + Na2O + K2O ] is preferably 35%, more preferably 33%, 31%, and 30%, in that order. The lower limit of the total content is preferably 10%, more preferably 14%, 17%, and 18%, in that order.

Li 2O、Na 2O及K 2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]較佳為上述範圍。 Li2O , Na2O , and K2O all improve the thermal stability of glass. However, increasing their content may reduce chemical durability and weather resistance. Therefore, the combined content of Li2O , Na2O , and K2O ( Li2O + Na2O + K2O ) is preferably within the above range.

接下來，對(B)進行詳細敘述。Next, (B) is described in detail.

第1實施方式的光學玻璃可以滿足下述要件： (B) P 2O 5的含量為25~38質量%， Al 2O 3的含量小於5質量%， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下， MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為7.0質量%以下， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。 The optical glass of the first embodiment can meet the following requirements: (B) the content of P2O5 is 25-38% by mass, the content of Al2O3 is less than 5% by mass, the mass ratio of the total content of P2O5 , B2O3 and SiO2 to the total content of Li2O , Na2O , K2O and Cs2O [(P2O5 + B2O3 + SiO2) / (Li2O + Na2O + K2O + Cs2O ) ] 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 content of TiO2 is 25-38% by mass, the content of Al2O3 is less than 5% by mass, the mass ratio of the total content of P2O5 , B2O3 and SiO2 to the total content of Li2O, Na2O , K2O and Cs2O [ ( P2O5 + B2O3 + SiO2 ) / (Li2O + Na2O + K2O + Cs2O)] 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 , and the content of TiO2 is 25-38% by mass or less relative to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O The mass ratio of the total content of TiO 2 and Nb 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.

在滿足上述(B)的第1實施方式的光學玻璃中，P 2O 5的含量為25~38%。P 2O 5的含量的下限較佳為26%，進一步以27%、28%、29%、30%的順序更佳。另外，P 2O 5的含量的上限較佳為37%。 In the optical glass of the first embodiment satisfying the above (B), the P2O5 content is 25-38%. The lower limit of the P2O5 content is preferably 26%, and more preferably 27%, 28%, 29%, and 30%, in this order. Furthermore, the upper limit of the P2O5 content is preferably 37%.

P 2O 5是玻璃的網絡形成成分，是為了在玻璃中大量含有高分散成分的必要成分。藉由將P 2O 5的含量設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 P2O5 is a network - forming component of glass and is essential for containing a large amount of highly dispersed components in the glass. By setting the P2O5 content within the above range, an optical glass with high thermal stability and desired optical constants can be obtained.

在滿足上述(B)的第1實施方式的光學玻璃中，Al 2O 3的含量小於5%。Al 2O 3的含量較佳為3%以下，進一步以2%以下、1%以下的順序更佳。Al 2O 3的含量也可以為0%。 In the optical glass of the first embodiment satisfying (B) above, the Al2O3 content is less than 5%. The Al2O3 content is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less. The Al2O3 content may be 0%.

Al 2O 3是具有改善玻璃的化學耐久性、耐候性的作用的玻璃成分，可以將其視為網絡形成成分。另一方面，Al 2O 3的含量變多時，玻璃的耐失透性降低。另外，容易發生玻璃化轉變溫度Tg上升、熱穩定性降低等問題。從避免這樣的問題的觀點考慮，Al 2O 3的含量的上限較佳為上述範圍。 Al₂O₃ is a glass component that improves the chemical durability and weather resistance of glass and can be considered a network-forming component. However, increasing the Al₂O₃ content reduces the glass's resistance to devitrification . It can also lead to problems such as an increase in the glass transition temperature (Tg) and a decrease in thermal stability. To avoid these problems, the upper limit of the Al₂O₃ content is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下。該質量比的上限較佳為1.78，進一步以1.76、1.74的順序更佳。另外，該質量比的下限較佳為1.00，進一步以1.05、1.08、1.10的順序更佳。 In the optical glass of the first embodiment satisfying the above (B), the mass ratio of the total content of P2O5 , B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O ) ] is 1.80 or less. The upper limit of this mass ratio is preferably 1.78, more preferably 1.76, then 1.74. The lower limit of this mass ratio is preferably 1.00, more preferably 1.05, then 1.08, then 1.10.

藉由將質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，可得到熱穩定性高、相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃。 By setting the mass ratio [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] within the above range, an optical glass having high thermal stability, a low relative refractive index temperature coefficient ( dn/dT), and a large average linear thermal expansion coefficient can be obtained.

在滿足上述(B)的第1實施方式的光學玻璃中，MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為7.0%以下。該合計含量的上限較佳為6%，進一步以5%、4%、3%的順序更佳。另外，該合計含量的下限較佳為0%。In the optical glass of the first embodiment satisfying the above (B), the total content of MgO, CaO, SrO, and BaO [MgO + CaO + SrO + BaO] is 7.0% or less. The upper limit of this total content is preferably 6%, more preferably 5%, 4%, and 3%, in that order. The lower limit of this total content is preferably 0%.

藉由將合計含量[MgO＋CaO＋SrO＋BaO]設為上述範圍，可以促進高分散化。By setting the total content [MgO + CaO + SrO + BaO] within the above range, high dispersion can be promoted.

在滿足上述(B)的第1實施方式的光學玻璃中，TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。該質量比的下限較佳為0.26，進一步以0.27、0.28、0.29的順序更佳。另外，該質量比的上限較佳為0.50，進一步以0.45、0.40、0.35的順序更佳。 In the optical glass of the first embodiment satisfying the above (B), the mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] is 0.25 or greater. The lower limit of this mass ratio is preferably 0.26, more preferably in the order of 0.27 , 0.28 , and 0.29. The upper limit of this mass ratio is preferably 0.50, more preferably in the order of 0.45, 0.40, and 0.35.

TiO 2是高折射率化成分中、高折射率化的作用特別大的成分。因此，從得到期望的光學常數的觀點考慮，質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]較佳為上述範圍。 TiO2 is a component that has a particularly large effect on increasing the refractive index among components that increase the refractive index. Therefore , from the perspective of obtaining desired optical constants, the mass ratio [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] is preferably within the above range.

另外，在滿足上述(B)的第1實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]為0.50以下。該質量比的上限較佳為0.47，進一步以0.46、0.45的順序較佳。另外，該質量比的下限較佳為0.00，進一步以0.20、0.25、0.30、0.35的順序較佳。 In the optical glass of the first embodiment satisfying (B) above, the mass ratio of the TiO2 content to the total content of P2O5 and B2O3 [ TiO2 /( P2O5 + B2O3 )] is 0.50 or less. The upper limit of this mass ratio is preferably 0.47, more preferably 0.46, then 0.45 . The lower limit of this mass ratio is preferably 0.00, more preferably 0.20, 0.25, 0.30, then 0.35 .

藉由將質量比[TiO 2/(P 2O 5＋B 2O 3)]設為上述範圍，可得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /(P 2 O 5 +B 2 O 3 )] within the above range, an optical glass having desired optical constants and high thermal stability can be obtained.

對於滿足上述(B)的第1實施方式的光學玻璃中的玻璃成分的含量及比率，以下示出非限定性的實例。Non-limiting examples of the contents and ratios of the glass components in the optical glass according to the first embodiment satisfying (B) above are shown below.

在滿足上述(B)的第1實施方式的光學玻璃中，B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]的下限較佳為0。該質量比也可以為0。另外，該質量比的上限更佳為0.36，進一步以0.33、0.31、0.29的順序更佳。 In the optical glass of the first embodiment satisfying the above (B), the lower limit of the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is preferably 0. This mass ratio may be 0. The upper limit of this mass ratio is more preferably 0.36, and more preferably in the order of 0.33, 0.31, and 0.29 .

藉由將質量比[B 2O 3/P 2O 5]設為上述範圍，可得到相對折射率溫度係數(dn/dT)低、平均線性熱膨脹係數大、耐失透性高、而且液相溫度LT低的光學玻璃。 By setting the mass ratio [B 2 O 3 /P 2 O 5 ] within the above range, an optical glass having a low relative refractive index temperature coefficient (dn/dT), a large average linear thermal expansion coefficient, high devitrification resistance, and a low liquidus temperature LT can be obtained.

在滿足上述(B)的第1實施方式的光學玻璃中，B 2O 3的含量的上限較佳為10%，進一步以8%、7%、6%的順序更佳。另外，B 2O 3的含量的下限較佳為0%。B 2O 3的含量也可以為0%。 In the optical glass of the first embodiment satisfying the above (B), the upper limit of the B2O3 content is preferably 10%, more preferably 8%, 7%, and 6%. The lower limit of the B2O3 content is preferably 0%. The B2O3 content may also be 0%.

B 2O 3是玻璃的網絡形成成分，具有改善玻璃的熱穩定性的作用。另一方面，B 2O 3的含量多時，存在耐失透性降低的傾向。因此，B 2O 3的含量較佳為上述範圍。 B2O3 is a glass network-forming component that improves the thermal stability of glass. However, if the B2O3 content is high, devitrification resistance tends to decrease. Therefore, the B2O3 content is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，TiO 2的含量的下限較佳為0%，進一步以1%、2%、3%、4%、6%、8%、10%、12%的順序更佳。TiO 2的含量也可以為0%。另外，TiO 2的含量的上限較佳為15%。 In the optical glass of the first embodiment satisfying the above (B), the lower limit of the TiO2 content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, 4%, 6%, 8%, 10%, and 12%. The TiO2 content may also be 0%. In addition, the upper limit of the TiO2 content is preferably 15%.

TiO 2特別有助於高分散化。另一方面，TiO 2比較容易增大玻璃的著色，而且存在容易使熔融性惡化的擔憂。因此，TiO 2的含量較佳為上述範圍。 TiO2 is particularly helpful for achieving high dispersion. However, TiO2 can easily increase the coloring of the glass and may also deteriorate its solubility. Therefore, the TiO2 content is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3及Bi 2O 3的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]的下限較佳為36%，進一步以38%、40%、41%、42%的順序更佳。另外，合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]的上限較佳為58%，進一步以56%、54%、52%、50%、48%、46%的順序更佳。 In the optical glass of the first embodiment satisfying the above (B), the lower limit of the combined content of TiO2 , Nb2O5 , WO3 , and Bi2O3 [ TiO2 + Nb2O5 + WO3 + Bi2O3 ] is preferably 36%, more preferably 38%, 40%, 41%, and 42 % in this order. Furthermore, the upper limit of the combined content [ TiO2 + Nb2O5 + WO3 + Bi2O3 ] is preferably 58%, more preferably 56%, 54 %, 52%, 50%, 48%, and 46% in this order.

TiO 2、Nb 2O 5、WO 3及Bi 2O 3有助於玻璃的高分散化，而且藉由適量含有，還具有改善玻璃的熱穩定性的作用。另一方面，也是增大玻璃的著色的成分。因此，其合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3]較佳為上述範圍。 TiO₂ , Nb₂O₅ , WO₃ , and Bi₂O₃ contribute to high dispersion in glass and, when included in appropriate amounts, improve the thermal stability of glass. On the other hand, they also contribute to the coloring of glass. Therefore, their combined content ( TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ ) is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，Na 2O的含量的下限較佳為6%，進一步以8%、9%、10%的順序更佳。另外，Na 2O的含量的上限較佳為30%，進一步以28%、26%、25%、22%、20%、18%、17%的順序更佳。 In the optical glass of the first embodiment satisfying (B) above, the lower limit of the Na₂O content is preferably 6%, more preferably in the order of 8%, 9%, and 10%. Furthermore, the upper limit of the Na₂O content is preferably 30%, more preferably in the order of 28%, 26%, 25%, 22%, 20%, 18%, and 17%.

Na2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Na2O的含量變多時，耐失透性降低。因此，Na2O的含量較佳為上述範圍。 Na2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Na2O content reduces devitrification resistance. Therefore, the Na2O content is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，Li2O、Na2O及K2O的合計含量[Li2O+Na2O+K2O]的上限較佳為35%，進一步以33%、31%、30%、28%、27%、26%、25%的順序較佳。另外，該合計含量的下限較佳為10%，進一步以14%、17%、18%、20%的順序更佳。 In the optical glass of the first embodiment satisfying the above (B), the upper limit of the combined content of Li₂O , Na₂O , and K₂O [ Li₂O + Na₂O + K₂O ] is preferably 35%, more preferably 33%, 31%, 30%, 28%, 27%, 26%, and 25%, in this order. The lower limit of this combined content is preferably 10%, more preferably 14%, 17%, 18%, and 20%, in this order.

Li2O、Na2O及K2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li2O、Na2O及K2O的合計含量[Li2O+Na2O+K2O]較佳為上述範圍。 Li2O , Na2O , and K2O all improve the thermal stability of glass. However, increasing their content may reduce chemical durability and weather resistance. Therefore, the combined content of Li2O , Na2O , and K2O ( Li2O + Na2O + K2O ) is preferably within the above range.

在滿足上述(B)的第1實施方式的光學玻璃中，Nb2O5的含量為25~55%。Nb2O5的含量的下限較佳為27%、更佳為29%。另外，Nb2O5的含量的上限較佳為53%，進一步以51%、49%、47%、40%、35%、33%的順序較佳。 In the optical glass of the first embodiment satisfying the above (B), the Nb2O5 content is 25-55%. The lower limit of the Nb2O5 content is preferably 27%, more preferably 29%. Furthermore, the upper limit of the Nb2O5 content is preferably 53%, and more preferably 51%, 49%, 47%, 40%, 35%, and 33%, in this order.

Nb2O5是有助於高折射率化及高分散化的成分。因此，藉由將Nb2O5的含量設為上述範圍，可得到具有期望的光學常數的光學玻璃。另一方面，Nb2O5的含量過多時，存在玻璃的著色增強的擔憂。 Nb2O5 contributes to a higher refractive index and higher dispersion. Therefore, by setting the Nb2O5 content within the above range, an optical glass with desired optical constants can be obtained. On the other hand, if the Nb2O5 content is too high, there is a concern that the glass may be overly colored.

接下來，對第1實施方式的光學玻璃的特性進行說明。 Next, the characteristics of the optical glass of the first embodiment will be described.

在第1實施方式的光學玻璃中，100~300℃的平均線性熱膨脹係數α的下限較佳為100×10-7℃-1，進一步以105×10-7℃-1、110×10-7℃-1、115×10-7℃-1、120×10-7℃-1的順序更佳。另外，平均線性熱膨脹係數α的上限更佳為200×10-7℃-1，進一步以190×10-7℃-1、180×10-7℃-1、170×10-7℃-1、160×10-7℃-1的順序更佳。 In the optical glass of the first embodiment, the lower limit of the average linear thermal expansion coefficient α at 100-300°C is preferably 100× 10-7 °C -1 , more preferably in the order of 105× 10-7 °C -1 , 110× 10-7 °C -1 , 115× 10-7 °C -1 , and 120× 10-7 °C -1 . Furthermore, the upper limit of the average linear thermal expansion coefficient α is more preferably 200× 10-7 °C -1 , more preferably in the order of 190× 10-7 °C -1 , 180× 10-7 °C -1 , 170× 10-7 °C- 1 , and 160× 10-7 °C -1 .

藉由將100~300℃的平均線性熱膨脹係數α設為上述範圍，可以抑制玻璃隨著熱膨脹的折射率的變化、即抑制相對折射率溫度係數dn/dT的增大。 By setting the average linear thermal expansion coefficient α between 100°C and 300°C within the above range, the change in the glass's refractive index due to thermal expansion, that is, the increase in the relative refractive index temperature coefficient dn/dT, can be suppressed.

平均線性熱膨脹係數α基於JOGIS08-2003的規定來測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定溫度和試樣的伸長率。 The average linear thermal expansion coefficient α is measured according to JOGIS08-2003. The specimen is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN is applied to the specimen, which is heated at a constant rate of 4°C per minute. The temperature and elongation of the specimen are measured.

需要說明的是，在本說明書中，將平均線性熱膨脹係數α用[℃-1]的單位表示，但在使用[K-1]作為單位的情況下，平均線性熱膨脹係數α的數值也相同。 In this specification, the average linear thermal expansion coefficient α is expressed in units of [°C -1 ]. However, the value of the average linear thermal expansion coefficient α is the same even when [K -1 ] is used as the unit.

在第1實施方式的光學玻璃中，在He-Ne雷射的波長(633nm)下的相對折射率溫度係數dn/dT在20~40℃的範圍內較佳為-1.0×10-6~-10.0×10-6℃-1，進一步以-1.5×10-6~-9.0×10-6℃-1、-2.0×10-6~-8.0×10-6℃-1、-2.5×10-6~-7.0×10-6℃-1、-3.0×10-6~-6.5×10-6℃-1的順序更佳。 In the optical glass of the first embodiment, the relative refractive index temperature coefficient dn/dT at the wavelength (633 nm) of a He-Ne laser is preferably -1.0× 10-6 to -10.0× 10-6 °C -1 within the range of 20°C to 40°C, and more preferably in the order of -1.5× 10-6 to -9.0× 10-6 °C - 1, -2.0× 10-6 to -8.0× 10-6 °C -1 , -2.5× 10-6 to -7.0× 10-6 °C -1 , and -3.0 ×10-6 to -6.5× 10-6 °C -1 .

藉由將dn/dT設為上述範圍，並與dn/dT為正的光學元件組合，即使在光學元件的溫度大幅變動這樣的環境下，折射率的變動也小，因此，可以在更寬的溫度範圍中以高精度發揮期望的光學特性。 By setting dn/dT within the above range and combining it with an optical element with positive dn/dT, fluctuations in the refractive index are minimized even in environments where the optical element's temperature fluctuates significantly. This allows the desired optical characteristics to be exhibited with high precision over a wider temperature range.

相對折射率溫度係數dn/dT基於JOGIS18-2008的干涉法來測定。 The relative refractive index temperature coefficient dn/dT is measured using the interferometry method according to JOGIS18-2008.

需要說明的是，在第1實施方式中，將溫度係數dn/dT用[℃-1]的單位表示，但在使用[K-1]作為單位的情況下，溫度係數dn/dT的數值也相同。 In the first embodiment, the temperature coefficient dn/dT is expressed in units of [°C -1 ]. However, the value of the temperature coefficient dn/dT is the same even when [K -1 ] is used as the unit.

(玻璃成分) (Glass composition)

對於第1實施方式的光學玻璃中的除上述以外的玻璃成分的含量及比率，以下示出非限定性的實例。 The following are non-limiting examples of the contents and ratios of glass components other than those described above in the optical glass of the first embodiment.

在第1實施方式的光學玻璃中，SiO2的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。SiO2的含量也可以為0%。 In the optical glass of the first embodiment, the upper limit of the SiO2 content is preferably 5%, and more preferably in the order of 3%, 2%, and 1%. The SiO2 content may also be 0%.

需要說明的是，有時在玻璃的熔融中使用石英玻璃製坩堝等石英玻璃製的熔融器具。在該情況下，由於少量的SiO2從熔融器具熔入玻璃熔融物，因此，玻璃原料即使不含SiO2，製成的玻璃也會含有少量的SiO2。從石英玻璃製的熔融器具混入玻璃的SiO 2的量也取決於熔融條件，例如相對於全部玻璃成分的含量的合計為0.5~1質量%左右。在除SiO 2以外的玻璃成分的含有比為恆定的狀態下，SiO 2的量增加0.5~1質量%左右。需要說明的是，根據熔解條件，上述量會有增減。根據SiO 2的含量不同，折射率、阿貝數等光學特性會變化，因此，可對除SiO 2以外的玻璃成分的含量進行微調而得到具有期望的光學特性的光學玻璃。 It should be noted that quartz glass melting vessels, such as quartz glass crucibles, are sometimes used in glass melting. In these cases, a small amount of SiO₂ is incorporated into the glass melt from the melting vessel. Therefore, even if the glass raw materials do not contain SiO₂ , the resulting glass will contain a small amount of SiO₂ . The amount of SiO₂ that enters the glass from the quartz glass melting vessel depends on the melting conditions, but for example, it is approximately 0.5 to 1% by mass relative to the total content of all glass components. When the content of glass components other than SiO₂ remains constant, the amount of SiO₂ increases by approximately 0.5 to 1% by mass. It should be noted that this amount can vary depending on the melting conditions. Optical properties such as the refractive index and Abbe number vary depending on the SiO2 content. Therefore, the content of glass components other than SiO2 can be fine-tuned to obtain optical glass with desired optical properties.

SiO 2是玻璃的網絡形成成分，具有改善玻璃的熱穩定性、化學耐久性、耐候性、提高熔融玻璃的黏度、容易將熔融玻璃成型的作用。另一方面，SiO 2的含量多時，存在玻璃的耐失透性降低的傾向。因此，SiO 2的含量的上限較佳為上述範圍。 SiO₂ is a network-forming component of glass, improving its thermal stability, chemical durability, and weather resistance, increasing the viscosity of molten glass, and facilitating its shaping. However, high SiO₂ contents tend to reduce the glass's resistance to devitrification. Therefore, the upper limit of the SiO₂ content is preferably within the above range.

在第1實施方式中，Bi 2O 3的含量的上限較佳為15%，進一步以10%、7%、5%、3%的順序更佳。另外，Bi 2O 3的含量的下限較佳為0%。 In the first embodiment, the upper limit of the Bi 2 O 3 content is preferably 15%, more preferably 10%, 7%, 5%, and 3% in this order. Furthermore, the lower limit of the Bi 2 O 3 content is preferably 0%.

藉由適量含有Bi 2O 3，具有改善玻璃的熱穩定性的作用。另一方面，如果提高Bi 2O 3的含量，則玻璃的著色增大。因此，Bi 2O 3的含量較佳為上述範圍。 The inclusion of an appropriate amount of Bi 2 O 3 improves the thermal stability of the glass. On the other hand, increasing the Bi 2 O 3 content increases the coloration of the glass. Therefore, the Bi 2 O 3 content is preferably within the above range.

在第1實施方式的光學玻璃中，Ta 2O 5的含量的上限較佳為10%，進一步以7%、5%、3%的順序更佳。另外，Ta 2O 5的含量的下限較佳為0%。Ta 2O 5的含量也可以為0%。 In the optical glass of the first embodiment, the upper limit of the Ta2O5 content is preferably 10%, more preferably 7%, 5%, and 3%. In addition, the lower limit of the Ta2O5 content is preferably 0%. The Ta2O5 content may also be 0%.

Ta 2O 5是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。另一方面，Ta 2O 5提高折射率，使玻璃高分散化。另外，Ta 2O 5的含量變多時，玻璃的熱穩定性降低，使玻璃熔融時，容易產生玻璃原料的熔融殘留物。因此，Ta 2O 5的含量較佳為上述範圍。此外，Ta 2O 5與其它玻璃成分相比，是非常昂貴的成分，Ta 2O 5的含量變多時，玻璃的生產成本增大。此外，Ta 2O 5與其它玻璃成分相比，分子量大，因此，會增大玻璃的比重，其結果，增大光學元件的重量。 Ta2O5 is a glass component that improves the thermal stability and devitrification resistance of glass. It also increases the refractive index, making the glass highly dispersed. However, increasing the Ta2O5 content reduces the thermal stability of the glass, making it more likely to produce molten residue from the glass raw materials when the glass is melted. Therefore, the Ta2O5 content is preferably within the above range. Furthermore, Ta2O5 is very expensive compared to other glass components, and increasing its content increases the production cost of the glass. Furthermore, Ta2O5 has a higher molecular weight than other glass components, which increases the specific gravity of the glass, resulting in an increase in the weight of the optical element.

在第1實施方式的光學玻璃中，Li 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。Li 2O的含量的下限較佳為0%。Li 2O的含量也可以為0%。 In the optical glass of the first embodiment, 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 Li 2 O content may be 0%.

Li 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Li 2O的含量變多時，耐失透性降低。因此，Li 2O的含量較佳為上述範圍。 Li2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Li2O content reduces devitrification resistance. Therefore, the Li2O content is preferably within the above range.

在第1實施方式的光學玻璃中，K 2O的含量的下限較佳為1%，進一步以2%、3%、4%的順序更佳。另外，K 2O的含量的上限較佳為13%，進一步以12%、11%、10%的順序更佳。 In the optical glass of the first embodiment, the lower limit of the K 2 O content is preferably 1%, more preferably 2%, 3%, and 4% in that order. The upper limit of the K 2 O content is preferably 13%, more preferably 12%, 11%, and 10% in that order.

K 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熱穩定性的作用，而且具有增大平均線性熱膨脹係數的作用。另一方面，K 2O的含量變多時，熱穩定性降低、玻璃化時容易產生條紋。因此，K 2O的含量較佳為上述範圍。 K2O contributes to lowering the specific gravity of glass, improving its thermal stability and increasing its average linear thermal expansion coefficient. However, increasing the K2O content reduces thermal stability and increases the likelihood of striations during vitrification. Therefore, the K2O content is preferably within the above range.

在第1實施方式的光學玻璃中，Cs 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。另外，Cs 2O的含量的下限較佳為0%。Cs 2O的含量也可以為0%。 In the optical glass of the first embodiment, the upper limit of the Cs 2 O content is preferably 5%, more preferably 3%, 2%, and 1%. The lower limit of the Cs 2 O content is preferably 0%. The Cs 2 O content may also be 0%.

Cs 2O具有改善玻璃的熔融性的作用，但含量變多時，玻璃的熱穩定性、折射率nd降低，而且在熔解中，玻璃成分的揮發增加，變得不能得到期望的玻璃。因此，Cs 2O的含量較佳為上述範圍。 Cs2O improves the meltability of glass, but if its content increases, the thermal stability and refractive index nd of the glass decrease, and the volatility of glass components increases during melting, making it impossible to obtain the desired glass. Therefore, the Cs2O content is preferably within the above range.

在第1實施方式的光學玻璃中，MgO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，MgO的含量的下限較佳為0%。MgO的含量也可以為0%。In the optical glass of the first embodiment, the MgO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the MgO content is preferably 0%. The MgO content may also be 0%.

在第1實施方式的光學玻璃中，CaO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，CaO的含量的下限較佳為0%。CaO的含量也可以為0%。In the optical glass of the first embodiment, the CaO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the CaO content is preferably 0%. The CaO content may also be 0%.

在第1實施方式的光學玻璃中，SrO的含量較佳為6%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，SrO的含量的下限較佳為0%。In the optical glass of the first embodiment, the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less, in this order. The lower limit of the SrO content is preferably 0%.

在第1實施方式的光學玻璃中，BaO的含量較佳為8%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，BaO的含量的下限較佳為0%。In the optical glass of the first embodiment, the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less, in this order. The lower limit of the BaO content is preferably 0%.

MgO、CaO、SrO、BaO均為具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，這些玻璃成分的含量變多時，損害高分散性，而且玻璃的熱穩定性及耐失透性降低。因此，這些玻璃成分的各含量分別較佳為上述範圍。MgO, CaO, SrO, and BaO are all glass components that improve the thermal stability and devitrification resistance of glass. However, increasing the content of these glass components impairs high dispersibility and reduces the thermal stability and devitrification resistance of the glass. Therefore, the content of each of these glass components is preferably within the above-mentioned ranges.

在第1實施方式的光學玻璃中，ZnO的含量的上限較佳為10%，進一步以6%、4%、3%的順序更佳。較佳ZnO含量少的情況，其下限較佳為0%。ZnO的含量也可以為0%。In the optical glass of the first embodiment, the upper limit of the ZnO content is preferably 10%, and more preferably 6%, 4%, and 3% in that order. When the ZnO content is low, the lower limit is preferably 0%. The ZnO content may also be 0%.

ZnO是具有改善玻璃的熱穩定性的作用玻璃成分。然而，ZnO的含量過多時，玻璃的比重增大。而且，相對折射率溫度係數(dn/dT)變高。因此，ZnO的含量較佳為上述範圍。ZnO is a glass component that improves the thermal stability of glass. However, excessive ZnO content increases the specific gravity of the glass and the relative refractive index temperature coefficient (dn/dT). Therefore, the ZnO content is preferably within the above range.

在第1實施方式的光學玻璃中，ZrO 2的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，ZrO 2的含量的下限較佳為0%。 In the optical glass of the first embodiment, the ZrO2 content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the ZrO2 content is preferably 0%.

ZrO 2是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，ZrO 2的含量過多時，顯示出熱穩定性降低的傾向。因此，ZrO 2的含量較佳為上述範圍。 ZrO₂ is a glass component that improves the thermal stability and devitrification resistance of glass. However, excessive ZrO₂ content tends to reduce thermal stability. Therefore, the ZrO₂ content is preferably within the above range.

在第1實施方式的光學玻璃中，Sc 2O 3的含量的上限較佳為2%。另外，Sc 2O 3的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the Sc 2 O 3 content is preferably 2%. In addition, the lower limit of the Sc 2 O 3 content is preferably 0%.

在第1實施方式的光學玻璃中，HfO 2的含量的上限較佳為2%。另外，HfO 2的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the HfO 2 content is preferably 2%. In addition, the lower limit of the HfO 2 content is preferably 0%.

Sc 2O 3、HfO 2均具有提高折射率nd的作用，而且是昂貴的成分。因此，Sc 2O 3、HfO 2的各含量較佳為上述範圍。 Sc 2 O 3 and HfO 2 both have the effect of increasing the refractive index nd and are expensive components. Therefore, the content of each of Sc 2 O 3 and HfO 2 is preferably within the above range.

在第1實施方式的光學玻璃中，Lu 2O 3的含量的上限較佳為2%。另外，Lu 2O 3的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the Lu 2 O 3 content is preferably 2%. In addition, the lower limit of the Lu 2 O 3 content is preferably 0%.

Lu 2O 3具有提高折射率nd的作用。另外，其分子量大，因此也是增加玻璃的比重的玻璃成分。因此，Lu 2O 3的含量較佳為上述範圍。 Lu₂O₃ has the effect of increasing the refractive index nd. Furthermore, due to its high molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the Lu₂O₃ content is preferably within the above range.

在第1實施方式的光學玻璃中，GeO 2的含量的上限較佳為2%。另外，GeO 2的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the GeO 2 content is preferably 2%. In addition, the lower limit of the GeO 2 content is preferably 0%.

GeO 2具有提高折射率nd的作用，而且是在通常使用的玻璃成分中特別地昂貴的成分。因此，從降低玻璃的製造成本的觀點考慮，GeO 2的含量較佳為上述範圍。 GeO2 has the effect of increasing the refractive index nd and is a particularly expensive component among commonly used glass components. Therefore, from the perspective of reducing the production cost of glass, the GeO2 content is preferably within the above range.

在第1實施方式的光學玻璃中，La 2O 3的含量的上限較佳為2%。另外，La 2O 3的含量的下限較佳為0%。La 2O 3的含量也可以為0%。 In the optical glass of the first embodiment, the upper limit of the La 2 O 3 content is preferably 2%. In addition, the lower limit of the La 2 O 3 content is preferably 0%. The La 2 O 3 content may also be 0%.

La 2O 3的含量變多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，La 2O 3的含量較佳為上述範圍。 When the La2O3 content increases, the thermal stability and devitrification resistance of the glass decrease, and the glass becomes more likely to devitrify during production. Therefore, from the perspective of suppressing the decrease in thermal stability and devitrification resistance, the La2O3 content is preferably within the above range.

在第1實施方式的光學玻璃中，Gd 2O 3的含量的上限較佳為2%。另外，Gd 2O 3的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the Gd 2 O 3 content is preferably 2%. In addition, the lower limit of the Gd 2 O 3 content is preferably 0%.

Gd 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。另外，Gd 2O 3的含量過多時，玻璃的比重增大而不佳。因此，從良好地保持玻璃的熱穩定性及耐失透性、同時抑制比重的增大的觀點考慮，Gd 2O 3的含量較佳為上述範圍。 If the Gd₂O₃ content is too high, the thermal stability and devitrification resistance of the glass will decrease, making the glass more susceptible to devitrification during production. Furthermore, if the Gd₂O₃ content is too high, the specific gravity of the glass will increase, which is not desirable. Therefore, from the perspective of maintaining good thermal stability and devitrification resistance of the glass while suppressing an increase in specific gravity, the Gd₂O₃ content is preferably within the above range.

在第1實施方式的光學玻璃中，Y 2O 3的含量的上限較佳為2%。另外，Y 2O 3的含量的下限較佳為0%。Y 2O 3的含量也可以為0%。 In the optical glass of the first embodiment, the upper limit of the Y 2 O 3 content is preferably 2%. In addition, the lower limit of the Y 2 O 3 content is preferably 0%. The Y 2 O 3 content may also be 0%.

Y 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，Y 2O 3的含量較佳為上述範圍。 If the content of Y2O3 is too high, the thermal stability and devitrification resistance of the glass will decrease. Therefore, from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance, the content of Y2O3 is preferably within the above range.

在第1實施方式的光學玻璃中，Yb 2O 3的含量的上限較佳為2%。另外，Yb 2O 3的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the Yb 2 O 3 content is preferably 2%. In addition, the lower limit of the Yb 2 O 3 content is preferably 0%.

Yb 2O 3與La 2O 3、Gd 2O 3、Y 2O 3相比，分子量大，因此，會增大玻璃的比重。玻璃的比重增大時，光學元件的質量增大。例如，如果將質量大的透鏡導入自動對焦式的攝像透鏡，則自動對焦時，透鏡的驅動所需的電力增大，電池的消耗變得嚴重。因此，期望減少Yb 2O 3的含量，抑制玻璃的比重的增大。 Yb2O3 has a higher molecular weight than La2O3 , Gd2O3 , and Y2O3 , and therefore increases the specific gravity of glass. When the specific gravity of glass increases, the mass of the optical component increases. For example, if a heavy lens is incorporated into an autofocus camera lens, the power required to drive the lens increases during autofocus, significantly increasing battery drain. Therefore, it is desirable to reduce the Yb2O3 content to suppress the increase in the specific gravity of glass.

另外，Yb 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。從防止玻璃的熱穩定性的降低、抑制比重的增大的觀點考慮，Yb 2O 3的含量較佳為上述範圍。 In addition, if the content of Yb2O3 is too high, the thermal stability and devitrification resistance of the glass will be reduced. From the viewpoint of preventing the reduction of the thermal stability of the glass and suppressing the increase of the specific gravity, the content of Yb2O3 is preferably within the above range.

較佳為滿足上述(A)的第1實施方式的光學玻璃主要以上述的玻璃成分、即作為必要成分的P 2O 5、Nb 2O 5、B 2O 3、作為任意成分的WO 3、SiO 2、Al 2O 3、TiO 2、Bi 2O 3、Ta 2O 5、Li 2O、Na 2O、K 2O、Cs 2O、MgO、CaO、SrO、BaO、ZnO、ZrO 2、Sc 2O 3、HfO 2、Lu 2O 3、GeO 2、La 2O 3、Gd 2O 3、Y 2O 3、及Yb 2O 3構成，上述的玻璃成分的合計含量較佳為95%以上、更佳為98%以上、進一步較佳為99%以上、更進一步較佳為99.5%以上。 Preferably , the optical glass of the first embodiment satisfying the above-mentioned (A) mainly contains the above-mentioned glass components, namely, P2O5, Nb2O5, and B2O3 as essential components , and WO3, SiO2, Al2O3 , TiO2 , Bi2O3 , Ta2O5 , Li2O , Na2O , K2O , Cs2O , MgO , CaO, SrO , BaO , ZnO , ZrO2 , Sc2O3 , HfO2, Lu2O3, GeO2 , La2O3 , Gd2O3 , Y2O3 , and Yb2O3 as optional components . 3 , the total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and even more preferably 99.5% or more.

另外，較佳為滿足上述(B)的第1實施方式的光學玻璃主要以上述的玻璃成分、即作為必要成分的P 2O 5、Nb 2O 5、作為任意成分的B 2O 3、WO 3、SiO 2、Al 2O 3、TiO 2、Bi 2O 3、Ta 2O 5、Li 2O、Na 2O、K 2O、Cs 2O、MgO、CaO、SrO、BaO、ZnO、ZrO 2、Sc 2O 3、HfO 2、Lu 2O 3、GeO 2、La 2O 3、Gd 2O 3、Y 2O 3、及Yb 2O 3構成，上述的玻璃成分的合計含量較佳為95%以上、更佳為98%以上、進一步較佳為99%以上、更進一步較佳為99.5%以上。 In addition, it is preferred that the optical glass of the first embodiment satisfying the above- mentioned (B ) mainly contains the above-mentioned glass components, namely, P2O5 and Nb2O5 as essential components, and B2O3 , WO3 , SiO2 , Al2O3 , TiO2 , Bi2O3 , Ta2O5 , Li2O , Na2O, K2O , Cs2O , MgO, CaO , SrO , BaO , ZnO , ZrO2 , Sc2O3 , HfO2 , Lu2O3 , GeO2 , La2O3 , Gd2O3 , Y2O3 , and Yb2O3 as optional components . 3 , the total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and even more preferably 99.5% or more.

在第1實施方式的光學玻璃中，TeO 2的含量的上限較佳為2%。另外，TeO 2的含量的下限較佳為0%。 In the optical glass of the first embodiment, the upper limit of the TeO 2 content is preferably 2%. In addition, the lower limit of the TeO 2 content is preferably 0%.

由於TeO 2具有毒性，因此，較佳減少TeO 2的含量。因此，TeO 2的含量較佳為上述範圍。 Since TeO 2 is toxic, it is preferable to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably within the above range.

需要說明的是，第1實施方式的光學玻璃基本上由上述玻璃成分構成，但在不妨礙本發明的作用效果的範圍內，也可以含有其它成分。另外，在本發明中，不排除含有不可避免的雜質。It should be noted that the optical glass of the first embodiment is basically composed of the above-mentioned glass components, but other components may be included within the scope that does not hinder the effects of the present invention. In addition, the present invention does not exclude the inclusion of inevitable impurities.

＜其它成分組成＞ Pb、As、Cd、Tl、Be、Se均具有毒性。因此，較佳為第1實施方式的光學玻璃不含這些元素作為玻璃成分。 <Other Components> Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferred that the optical glass of the first embodiment does not contain these elements as glass components.

U、Th、Ra均為放射性元素。因此，較佳為第1實施方式的光學玻璃不含這些元素作為玻璃成分。U, Th, and Ra are all radioactive elements. Therefore, it is preferred that the optical glass of the first embodiment does not contain these elements as glass components.

V、Cr、Mn、Fe、Co、Ni、Cu、Pr、Nd、Pm、Sm、Eu、Tb、Dy、Ho、Er、Tm可以增大玻璃的著色、成為螢光的發生源。因此，較佳為第1實施方式的光學玻璃不含這些元素作為玻璃成分。V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, and Tm can enhance the coloration of glass and serve as a source of fluorescence. Therefore, it is preferred that the optical glass of the first embodiment does not contain these elements as glass components.

Sb(Sb 2O 3)、Ce(CeO 2)是作為澄清劑發揮功能的可以任意添加的元素。其中，Sb(Sb 2O 3)是澄清效果大的澄清劑。然而，Sb(Sb 2O 3)的氧化性強，如果增加Sb(Sb 2O 3)的添加量，則由於由Sb離子導致的光吸收，玻璃的著色增大而不佳。另外，將玻璃熔融時，如果熔融物中存在Sb，則促進構成玻璃熔融坩堝的鉑對熔融物的溶出，玻璃中的鉑濃度變高。在玻璃中，鉑以離子的形式存在時，由於光的吸收，玻璃的著色增大。另外，在玻璃中，鉑以固體物質的形式存在時，成為光的散射源，會降低玻璃的品質。Ce(CeO 2)與Sb(Sb 2O 3)相比，澄清效果小。如果大量添加Ce(CeO 2)，則玻璃的著色增強。因此，在添加澄清劑的情況下，較佳為一邊注意添加量一邊添加Sb(Sb 2O 3)。 Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are elements that can be added arbitrarily, functioning as clarifiers. Of these, Sb (Sb 2 O 3 ) is the most effective clarifier. However, Sb (Sb 2 O 3 ) is highly oxidizing, and increasing the amount of Sb (Sb 2 O 3 ) added increases the coloration of the glass due to light absorption by Sb ions, resulting in poor quality. Furthermore, when melting glass, the presence of Sb in the melt promotes the dissolution of platinum, which constitutes the glass's crucible, into the melt, increasing the platinum concentration in the glass. When platinum exists in the form of ions in the glass, light absorption increases the coloration of the glass. Furthermore, when platinum exists in the form of solid matter in the glass, it becomes a source of light scattering, reducing the quality of the glass. Ce (CeO 2 ) has a smaller clarification effect than Sb (Sb 2 O 3 ). If a large amount of Ce (CeO 2 ) is added, the coloring of the glass will be enhanced. Therefore, when adding a clarifier, it is better to add Sb (Sb 2 O 3 ) while paying attention to the amount of addition.

將Sb 2O 3的含量設為外加比例表示。即，將除Sb 2O 3及CeO 2以外的全部玻璃成分的合計含量設為100質量%時，Sb 2O 3的含量較佳小於1質量%、更佳小於0.1質量%，進一步以小於0.05質量%、小於0.03質量%、小於0.02質量%的順序較佳。Sb 2O 3的含量也可以為0質量%。 The Sb2O3 content is expressed as an added percentage. That is, when the total content of all glass components excluding Sb2O3 and CeO2 is set to 100 mass%, the Sb2O3 content is preferably less than 1 mass%, more preferably less than 0.1 mass%, and further preferably less than 0.05 mass%, less than 0.03 mass%, and less than 0.02 mass%. The Sb2O3 content may also be 0 mass%.

將CeO 2的含量也設為外加比例表示。即，將除CeO 2、Sb 2O 3以外的全部玻璃成分的合計含量設為100質量%時，CeO 2的含量較佳小於2質量%、更佳小於1質量%、進一步較佳小於0.5質量%、更進一步較佳小於0.1質量%的範圍。CeO 2的含量也可以為0質量%。藉由將CeO 2的含量設為上述範圍，可以改善玻璃的澄清性。 The CeO2 content is also expressed as an added percentage. That is, when the total content of all glass components excluding CeO2 and Sb2O3 is set to 100 mass%, the CeO2 content is preferably less than 2 mass%, more preferably less than 1 mass%, further preferably less than 0.5 mass%, and even more preferably less than 0.1 mass%. The CeO2 content may also be 0 mass%. By setting the CeO2 content within the above range, the clarity of the glass can be improved.

(玻璃特性) ＜玻璃化轉變溫度Tg＞ 第1實施方式的光學玻璃的玻璃化轉變溫度Tg較佳為570℃以下，進一步以560℃以下、550℃以下、540℃以下、530℃以下的順序更佳。 (Glass Properties) <Glass Transition Temperature (Tg)> The glass transition temperature (Tg) of the optical glass of the first embodiment is preferably 570°C or lower, and more preferably 560°C or lower, 550°C or lower, 540°C or lower, and 530°C or lower, in that order.

藉由使玻璃化轉變溫度Tg的上限滿足上述範圍，可以抑制玻璃的成型溫度及退火溫度的上升，可以降低熱對壓製成型用設備及退火設備的損傷。另外，藉由使玻璃化轉變溫度Tg的下限滿足上述範圍，容易在保持期望的阿貝數、折射率的同時良好地保持玻璃的熱穩定性。By ensuring that the upper limit of the glass transition temperature (Tg) falls within the above range, increases in the glass forming and annealing temperatures can be suppressed, reducing thermal damage to press-forming and annealing equipment. Furthermore, by ensuring that the lower limit of the glass transition temperature (Tg) falls within the above range, it is easier to maintain the desired Abbe number and refractive index while also maintaining good thermal stability of the glass.

＜玻璃的比重＞ 在第1實施方式的光學玻璃中，比重較佳為3.60以下，進一步以3.50以下、3.40以下的順序更佳。如果能夠減少玻璃的比重，則可以減少透鏡的重量。其結果，可以降低搭載透鏡的相機透鏡的自動對焦驅動的消耗電力。 <Glass Specific Gravity> In the optical glass of the first embodiment, the specific gravity is preferably 3.60 or less, more preferably 3.50 or less, and even more preferably 3.40 or less. Reducing the specific gravity of the glass can reduce the weight of the lens. Consequently, the power consumption of the autofocus drive of a camera lens equipped with the lens can be reduced.

＜玻璃的透光性＞ 第1實施方式的光學玻璃的透光性可以藉由著色度λ5來評價。 對於厚度10.0mm±0.1mm的玻璃試樣，在波長200~700nm的範圍內測定分光透射率，將外部透射率成為5%的波長設為λ5。 <Glass Transmittance> The light transmittance of the optical glass of the first embodiment can be evaluated using the chromaticity λ5. For glass samples with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured within the wavelength range of 200 to 700 nm. The wavelength at which the external transmittance reaches 5% was defined as λ5.

第1實施方式的光學玻璃的λ5較佳為400nm以下，更佳為380nm以下、進一步較佳為370nm以下。The λ5 of the optical glass according to the first embodiment is preferably 400 nm or less, more preferably 380 nm or less, and even more preferably 370 nm or less.

藉由使用將λ5短波長化後的光學玻璃，可以提供可實現適宜的顏色再現的光學元件。By using optical glass with a shorter wavelength of λ5, it is possible to provide optical elements that achieve appropriate color reproduction.

(光學玻璃的製造) 本發明的實施方式的光學玻璃以達到上述預定組成的方式調配玻璃原料，利用調配的玻璃原料、按照公知的玻璃製造方法製作即可。例如，調配多種化合物，充分混合而製成批原料，將批原料放入石英坩堝、或鉑坩堝中進行粗熔解(rough melt)。將粗熔解得到的熔融物驟冷、粉碎，製作碎玻璃。進一步將碎玻璃放入鉑坩堝中進行加熱、再熔融(remelt)，製成熔融玻璃，進一步在進行了澄清、均質化後，將熔融玻璃成型，進行緩慢冷卻，得到光學玻璃。熔融玻璃的成型、緩慢冷卻採用公知的方法即可。 (Optical Glass Production) The optical glass according to the embodiments of the present invention is produced by blending glass raw materials to achieve the predetermined composition described above. These blended glass raw materials are then produced using known glass production methods. For example, a plurality of compounds are blended and thoroughly mixed to form a batch of raw materials. The batch of raw materials is then placed in a quartz crucible or a platinum crucible for rough melting. The resulting melt is then quenched and pulverized to produce cullet. The cullet is then heated and remelted in a platinum crucible to produce molten glass. After further clarification and homogenization, the molten glass is shaped and slowly cooled to produce optical glass. Molten glass shaping and slow cooling can be performed using known methods.

需要說明的是，只要能在玻璃中導入期望的玻璃成分、並使其達到期望的含量，則對調配批原料時使用的化合物就沒有特別限定，作為這樣的化合物，可列舉氧化物、碳酸鹽、硝酸鹽、氫氧化物、氟化物等。It should be noted that as long as the desired glass components can be introduced into the glass and the desired content is achieved, there is no particular limitation on the compounds used when preparing the batch raw materials. Examples of such compounds include oxides, carbonates, nitrates, hydroxides, fluorides, etc.

(光學元件等製造) 使用本發明的實施方式的光學玻璃製作光學元件時，採用公知的方法即可。例如，將玻璃原料熔融，製成熔融玻璃，將該熔融玻璃注入鑄模而成型為板狀，製作由本發明的光學玻璃形成的玻璃材料。將得到的玻璃材料適當地切割、磨削、研磨，製作適於壓製成型的大小、形狀的碎片。將碎片加熱、軟化，藉由公知的方法進行壓製成型(再熱壓)，製作近似於光學元件的形狀的光學元件坯料。對光學元件坯料進行退火，藉由公知的方法進行磨削、研磨而製作光學元件。 (Manufacturing of Optical Components, etc.) Optical components using the optical glass according to embodiments of the present invention can be manufactured using known methods. For example, glass raw materials are melted to form molten glass, which is then poured into a mold and formed into a plate to produce a glass material comprising the optical glass of the present invention. The resulting glass material is then appropriately cut, ground, and polished to produce fragments of a size and shape suitable for press molding. The fragments are then heated and softened, and then press molded (re-hot-pressed) using known methods to produce an optical component blank having a shape similar to that of the optical component. The optical component blank is then annealed and then ground and polished using known methods to produce the optical component.

根據使用目的，可以在製作的光學元件的光學功能面塗佈防反射膜、全反射膜等。Depending on the intended use, the optical functional surface of the manufactured optical element can be coated with an anti-reflection film, a total reflection film, etc.

作為光學元件，可示例出球面透鏡等各種透鏡、棱鏡、繞射光柵等。Examples of optical elements include various lenses such as spherical lenses, prisms, and diffraction gratings.

第2實施方式 對第2實施方式的光學玻璃詳細地進行說明。 第2實施方式的光學玻璃的P 2O 5的含量為25~50質量%， TiO 2的含量為10~50質量%， Nb 2O 5含量為5~30質量%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60質量%， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上， P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下， 且滿足下述(A)或(B)： (A) WO 3的含量為7質量%以下； (B) 實質上不含F。 Second Embodiment The optical glass according to the second embodiment will be described in detail. The optical glass of the second embodiment has a P2O5 content of 25-50 mass%, a TiO2 content of 10-50 mass%, a Nb2O5 content of 5-30 mass%, a total content of TiO2, Nb2O5, WO3, Bi2O3 , and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] of 35-60 mass%, a mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 / ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] of 0.25 or more , and a P2O5 content of 10-50 mass % . 5. The mass ratio of the combined content of B2O3 and SiO2 to the combined content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is 1.80 or less , and the following (A) or (B) is met: (A) the WO3 content is 7% by mass or less; (B) it contains substantially no F.

以下，只要沒有特別記載，第2實施方式的光學玻璃是指滿足上述(A)的第2實施方式的光學玻璃及滿足上述(B)的第2實施方式的光學玻璃。Hereinafter, unless otherwise specified, the optical glass of the second embodiment refers to the optical glass of the second embodiment satisfying the above (A) and the optical glass of the second embodiment satisfying the above (B).

在第2實施方式的光學玻璃中，P 2O 5的含量為25~50%。P 2O 5的含量的下限較佳為27%，進一步以29%、31%、32%的順序更佳。另外，P 2O 5的含量的上限較佳為42%，進一步以40%、38%、37%、36%的順序更佳。 In the optical glass of the second embodiment, the P₂O₅ content is 25% to 50%. The lower limit of the P₂O₅ content is preferably 27%, more preferably 29%, 31%, and 32%, in that order. Furthermore, the upper limit of the P₂O₅ content is preferably 42%, more preferably 40%, 38%, 37%, and 36%, in that order.

P 2O 5是玻璃的網絡形成成分，是為了在玻璃中大量含有高分散成分的必要成分。藉由將P 2O 5的含量設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 P2O5 is a network - forming component of glass and is essential for containing a large amount of highly dispersed components in the glass. By setting the P2O5 content within the above range, an optical glass with high thermal stability and desired optical constants can be obtained.

在第2實施方式的光學玻璃中，TiO 2的含量為10~50%。TiO 2的含量的下限較佳為12%，進一步以14%、15%、16%、17%的順序更佳。另外，TiO 2的含量的上限較佳為40%，進一步以35%、30%、28%、26%、24%、23%的順序更佳。 In the optical glass of the second embodiment, the TiO2 content is 10-50%. The lower limit of the TiO2 content is preferably 12%, and more preferably in the order of 14%, 15%, 16%, and 17%. Furthermore, the upper limit of the TiO2 content is preferably 40%, and more preferably in the order of 35%, 30%, 28%, 26%, 24%, and 23%.

TiO 2特別有助於高分散化。另一方面，TiO 2比較容易增大玻璃的著色，而且存在容易使熔融性惡化的擔憂。因此，TiO 2的含量較佳為上述範圍。 TiO2 is particularly helpful for achieving high dispersion. However, TiO2 can easily increase the coloring of the glass and may also deteriorate its solubility. Therefore, the TiO2 content is preferably within the above range.

在第2實施方式的光學玻璃中，Nb 2O 5的含量為5~30%。Nb 2O 5的含量的下限較佳為10%，進一步以12%、14%、16%、17%、18%的順序更佳。另外，Nb 2O 5的含量的上限較佳為28%，進一步以27%、26%、25%的順序更佳。 In the optical glass of the second embodiment, the Nb2O5 content is 5-30%. The lower limit of the Nb2O5 content is preferably 10%, and more preferably in the order of 12%, 14%, 16%, 17%, and 18%. The upper limit of the Nb2O5 content is preferably 28%, and more preferably in the order of 27%, 26%, and 25%.

Nb 2O 5是有助於高折射率化及高分散化的成分。因此，藉由將Nb 2O 5的含量設為上述範圍，可得到具有期望的光學常數的光學玻璃。另一方面，Nb 2O 5的含量過多時，存在玻璃的著色增強的擔憂。 Nb2O5 contributes to a higher refractive index and higher dispersion. Therefore, by setting the Nb2O5 content within the above range, an optical glass with desired optical constants can be obtained. On the other hand, if the Nb2O5 content is too high, there is a concern that the glass may be overly colored.

在第2實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60%。該合計含量的下限較佳為36%，進一步以37%、38%、39%的順序更佳。另外，該合計含量的上限較佳為55%，進一步以50%、47%、45%、44%的順序更佳。 In the optical glass of the second embodiment, the total content of TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ ( TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ) is 35% to 60%. The lower limit of this total content is preferably 36 %, more preferably 37%, 38 %, and 39%, in that order. The upper limit of this total content is preferably 55 %, more preferably 50%, 47%, 45%, and 44%, in that order.

TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5是有助於玻璃的高分散化的成分。因此，藉由將合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]設為上述範圍，可得到具有期望的光學常數的光學玻璃。而且，還可以改善玻璃的熱穩定性。另一方面，該合計含量過多時，存在不能得到具有期望的光學常數的光學玻璃的擔憂，而且，存在玻璃的熱穩定性降低、玻璃的著色變強的擔憂。 TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ are components that contribute to high dispersion in glass. Therefore, by setting the combined content [ TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ] within the above range, optical glass with desired optical constants can be obtained. Furthermore, the thermal stability of the glass can be improved. On the other hand, if the combined content is too high , optical glass with the desired optical constants may not be obtained, and there is a concern that the thermal stability of the glass may be reduced or that the glass may have strong coloring.

在第2實施方式的光學玻璃中，TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。該質量比的下限較佳為0.30，進一步以0.32、0.34、0.36、0.38、0.40的順序更佳。另外，該質量比的上限較佳為0.65，進一步以0.60、0.58、0.56的順序更佳。 In the optical glass of the second embodiment, the mass ratio of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] [ TiO2 / (TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] is 0.25 or greater. The lower limit of this mass ratio is preferably 0.30, more preferably 0.32, 0.34, 0.36 , 0.38 , and 0.40 , in this order. The upper limit of this mass ratio is preferably 0.65, more preferably 0.60 , 0.58, and 0.56, in this order .

TiO 2是高折射率化成分中，高分散化的作用特別大的成分。因此，從得到期望的光學常數的觀點考慮，質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]較佳為上述範圍。 TiO2 is a component that has a particularly great effect on dispersion among components that increase the refractive index. Therefore, from the perspective of obtaining desired optical constants, the mass ratio [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] is preferably within the above range.

在第2實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]為1.80以下。該質量比的上限較佳為1.75，進一步以1.73、1.72、1.71、1.70的順序更佳。另外，該質量比的下限較佳為1.20，進一步以1.30、1.35、1.38、1.40的順序更佳。 In the optical glass of the second embodiment, the mass ratio of the total content of P2O5, B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is 1.80 or less. The upper limit of this mass ratio is preferably 1.75, more preferably 1.73, 1.72, 1.71, and 1.70, in that order. The lower limit of this mass ratio is preferably 1.20, more preferably 1.30, 1.35, 1.38, and 1.40, in that order.

藉由將質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，可得到熱穩定性高、相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃。 By setting the mass ratio [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] within the above range, an optical glass having high thermal stability, a low relative refractive index temperature coefficient ( dn/dT), and a large average linear thermal expansion coefficient can be obtained.

在滿足上述(A)的第2實施方式的光學玻璃中，WO 3的含量為7%以下。WO 3的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。較佳為WO 3的含量少的情況，其下限較佳為0%。WO 3的含量也可以為0%。 In the optical glass of the second embodiment satisfying (A) above, the WO 3 content is 7% or less. The upper limit of the WO 3 content is preferably 5%, more preferably 3%, 2%, and 1% in that order. When the WO 3 content is low, the lower limit is preferably 0%. The WO 3 content may also be 0%.

在滿足上述(B)的第2實施方式的光學玻璃中，WO 3的含量較佳為15%以下，其上限以10%、5%、3%的順序更佳。較佳WO 3的含量少的情況，其下限較佳為0%。WO 3的含量也可以為0%。 In the optical glass of the second embodiment satisfying the above (B), the WO3 content is preferably 15% or less, with the upper limit being more preferably 10%, 5%, and 3%, in that order. When the WO3 content is low, the lower limit is preferably 0%. The WO3 content may also be 0%.

藉由將WO 3的含量設為上述範圍，可以提高透射率，而且可以抑制玻璃的比重的增大。另外，可以降低相對折射率溫度係數(dn/dT)。 By setting the WO3 content within the above range, the transmittance can be improved while suppressing an increase in the specific gravity of the glass. In addition, the relative refractive index temperature coefficient (dn/dT) can be reduced.

在滿足上述(A)的第2實施方式的光學玻璃中，氟F的含量較佳為3%以下，其上限以1%、0.5%、0.3%的順序更佳。較佳為F的含量少的情況，其下限較佳為0%。F的含量也可以為0%。In the optical glass of the second embodiment satisfying the above (A), the fluorine (F) content is preferably 3% or less, with the upper limit being more preferably 1%, 0.5%, and 0.3%, in that order. When the F content is low, the lower limit is preferably 0%. The F content may also be 0%.

滿足上述(B)的第2實施方式的光學玻璃實質上不含氟F。The optical glass of the second embodiment satisfying the above-mentioned (B) contains substantially no fluorine F.

藉由將F的含量設為上述範圍，可以抑制玻璃在熔解中的揮發，可以抑制折射率的變動、條紋。By setting the F content within the above range, volatility of the glass during melting can be suppressed, and fluctuations in the refractive index and the formation of striations can be suppressed.

對於第2實施方式的光學玻璃中的除上述以外的玻璃成分的含量及比率，以下示出非限定性的實例。The following are non-limiting examples of the contents and ratios of the glass components other than those described above in the optical glass of the second embodiment.

在第2實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]較佳為1.10以下。該質量比的上限較佳為1.00，進一步以0.95、0.90、0.85、0.82、0.80的順序更佳。另外，該質量比的下限更佳為0.50，進一步以0.55、0.60、0.62、0.64的順序更佳。 In the optical glass of the second embodiment, the mass ratio of the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 to the total content of P2O5 , B2O3 , SiO2 , Al2O3 , Li2O , Na2O , K2O , and Cs2O [ ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] is preferably 1.10 or less . The upper limit of the mass ratio is preferably 1.00, and more preferably in the order of 0.95, 0.90, 0.85, 0.82, and 0.80. The lower limit of the mass ratio is more preferably 0.50, and more preferably in the order of 0.55, 0.60, 0.62, and 0.64.

藉由將質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，容易得到具有期望的光學常數的光學玻璃。 By setting the mass ratio [( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] within the above range, optical glass having desired optical constants can be easily obtained.

在第2實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]較佳為0.70以下。該質量比的上限較佳為0.68，進一步以0.67、0.66、0.65的順序更佳。該質量比的下限較佳為0.25，進一步以0.35、0.40、0.45的順序更佳。 In the optical glass of the second embodiment, the mass ratio of TiO2 to the total content of P2O5 and B2O3 [ TiO2 / ( P2O5 + B2O3 )] is preferably 0.70 or less. The upper limit of this mass ratio is preferably 0.68, more preferably 0.67 , 0.66, and 0.65, in that order. The lower limit of this mass ratio is preferably 0.25, more preferably 0.35, 0.40, and 0.45, in that order.

藉由將質量比[TiO 2/(P 2O 5＋B 2O 3)]設為上述範圍，容易得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /(P 2 O 5 +B 2 O 3 )] within the above range, it is easy to obtain an optical glass having desired optical constants and high thermal stability.

在第2實施方式的光學玻璃中，B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]較佳為0.39以下。該質量比的上限更佳為0.20，進一步以0.15、0.12、0.10、0.08、0.07、0.06的順序更佳。 In the optical glass of the second embodiment, the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is preferably 0.39 or less. The upper limit of this mass ratio is more preferably 0.20, and more preferably in the order of 0.15 , 0.12, 0.10, 0.08, 0.07, and 0.06.

藉由將質量比[B 2O 3/P 2O 5]設為上述範圍，容易得到具有期望的光學常數、熱穩定性高、且耐失透性高的光學玻璃。 By setting the mass ratio [B 2 O 3 /P 2 O 5 ] within the above range, it is easy to obtain an optical glass having desired optical constants, high thermal stability, and high resistance to devitrification.

在第2實施方式的光學玻璃中，MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為8.0%以下。該合計含量的上限較佳為6%，進一步以5%、4%、3%的順序更佳。另外，該合計含量的下限較佳為0%。In the optical glass of the second embodiment, the total content of MgO, CaO, SrO, and BaO (MgO + CaO + SrO + BaO) is 8.0% or less. The upper limit of this total content is preferably 6%, and more preferably 5%, 4%, and 3% in that order. The lower limit of this total content is preferably 0%.

藉由將合計含量[MgO＋CaO＋SrO＋BaO]設為上述範圍，可以促進高分散化。By setting the total content [MgO + CaO + SrO + BaO] within the above range, high dispersion can be promoted.

在第2實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5的含量的質量比[TiO 2/P 2O 5]的上限較佳為0.70，進一步以0.68、0.66、0.65的順序更佳。該質量比的下限較佳為0.25，進一步以0.35、0.40、0.45的順序更佳。 In the optical glass of the second embodiment, the upper limit of the mass ratio of TiO2 to P2O5 [ TiO2 / P2O5 ] is preferably 0.70, more preferably in the order of 0.68 , 0.66, and 0.65. The lower limit of this mass ratio is preferably 0.25, more preferably in the order of 0.35, 0.40, and 0.45 .

藉由將質量比[TiO 2/P 2O 5]設為上述範圍，容易得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /P 2 O 5 ] within the above range, it is easy to obtain an optical glass having desired optical constants and high thermal stability.

在第2實施方式的光學玻璃中，B 2O 3的含量的上限較佳為10%，進一步以7%、5%、3%、2%的順序更佳。B 2O 3的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the B2O3 content is preferably 10%, more preferably 7%, 5%, 3%, and 2% in this order. The B2O3 content may also be 0%.

B 2O 3是玻璃的網絡形成成分，具有改善玻璃的熱穩定性的作用。另一方面，B 2O 3的含量多時，存在耐失透性降低的傾向。因此，B 2O 3的含量較佳為上述範圍。 B2O3 is a glass network-forming component that improves the thermal stability of glass. However, if the B2O3 content is high, devitrification resistance tends to decrease. Therefore, the B2O3 content is preferably within the above range.

在第2實施方式的光學玻璃中，Al 2O 3的含量較佳為3%以下，進一步以2%以下、1%以下的順序更佳。Al 2O 3的含量也可以為0%。 In the optical glass of the second embodiment, the Al 2 O 3 content is preferably 3% or less, more preferably 2% or less, and more preferably 1% or less. The Al 2 O 3 content may be 0%.

Al 2O 3是具有改善玻璃的化學耐久性、耐候性的作用的玻璃成分，可以將其視為網絡形成成分。另一方面，Al 2O 3的含量變多時，玻璃的耐失透性降低。另外，容易發生玻璃化轉變溫度Tg上升、熱穩定性降低等問題。從避免這樣的問題的觀點考慮，Al 2O 3的含量的上限較佳為上述範圍。 Al₂O₃ is a glass component that improves the chemical durability and weather resistance of glass and can be considered a network-forming component. However, increasing the Al₂O₃ content reduces the glass's resistance to devitrification . It can also lead to problems such as an increase in the glass transition temperature (Tg) and a decrease in thermal stability. To avoid these problems, the upper limit of the Al₂O₃ content is preferably within the above range.

在第2實施方式的光學玻璃中，SiO 2的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。SiO 2的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the SiO2 content is preferably 5%, and more preferably in the order of 3%, 2%, and 1%. The SiO2 content may also be 0%.

需要說明的是，有時在玻璃的熔融中使用石英玻璃製坩堝等石英玻璃製的熔融器具。該情況下，由於少量的SiO 2從熔融器具熔入玻璃熔融物，因此，即使玻璃原料不含SiO 2，製成的玻璃中也會含有少量的SiO 2。從石英玻璃製的熔融器具混入玻璃的SiO 2的量也取決於熔融條件，例如相對於全部玻璃成分的含量的合計為0.5~1質量%左右。在除SiO 2以外的玻璃成分的含有比為恆定的狀態下，SiO 2的量增加0.5~1質量%左右。需要說明的是，根據熔解條件，上述量會有增減。根據SiO 2的含量不同，折射率、阿貝數等光學特性發生變化，因此，可對除SiO 2以外的玻璃成分的含量進行微調而得到具有期望的光學特性的光學玻璃。 It should be noted that quartz glass melting vessels, such as quartz glass crucibles, are sometimes used to melt glass. In this case, a small amount of SiO₂ is incorporated into the molten glass from the melting vessel. Therefore, even if the glass raw materials do not contain SiO₂ , the resulting glass will contain a small amount of SiO₂ . The amount of SiO₂ that enters the glass from the quartz glass melting vessel depends on the melting conditions, but for example, it is approximately 0.5 to 1% by mass relative to the total content of all glass components. When the content of glass components other than SiO₂ remains constant, the amount of SiO₂ increases by approximately 0.5 to 1% by mass. It should be noted that this amount can vary depending on the melting conditions. Optical properties such as the refractive index and Abbe number vary depending on the SiO2 content. Therefore, the content of glass components other than SiO2 can be fine-tuned to obtain optical glass with desired optical properties.

SiO 2是玻璃的網絡形成成分，具有改善玻璃的熱穩定性、化學耐久性、耐候性、提高熔融玻璃的黏度、容易將熔融玻璃成型的作用。另一方面，SiO 2的含量多時，存在玻璃的耐失透性降低的傾向。因此，SiO 2的含量的上限較佳為上述範圍。 SiO₂ is a network-forming component of glass, improving its thermal stability, chemical durability, and weather resistance, increasing the viscosity of molten glass, and facilitating its shaping. However, high SiO₂ contents tend to reduce the glass's resistance to devitrification. Therefore, the upper limit of the SiO₂ content is preferably within the above range.

在第2實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量[P 2O 5＋B 2O 3＋SiO 2]的上限較佳為45%，進一步以42%、40%、38%的順序更佳。該合計含量的下限較佳為25%，進一步以28%、30%、32%的順序更佳。 In the optical glass of the second embodiment, the upper limit of the combined content of P2O5 , B2O3 , and SiO2 [ P2O5 + B2O3 + SiO2 ] is preferably 45%, more preferably 42%, 40%, and 38%, in that order. The lower limit of the combined content is preferably 25%, more preferably 28%, 30%, and 32%, in that order.

藉由將合計含量[P 2O 5＋B 2O 3＋SiO 2]設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 By setting the total content [P 2 O 5 +B 2 O 3 +SiO 2 ] within the above range, an optical glass having high thermal stability and desired optical constants can be obtained.

在第2實施方式的光學玻璃中，Bi 2O 3的含量的上限較佳為15%，進一步以10%、7%、5%、3%的順序更佳。另外，Bi 2O 3的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the Bi2O3 content is preferably 15%, more preferably 10%, 7%, 5%, and 3% in this order. The lower limit of the Bi2O3 content is preferably 0%.

藉由適量含有Bi 2O 3，具有改善玻璃的熱穩定性的作用。另一方面，提高Bi 2O 3的含量時，玻璃的著色增大。因此，Bi 2O 3的含量較佳為上述範圍。 The inclusion of an appropriate amount of Bi 2 O 3 improves the thermal stability of the glass. On the other hand, increasing the Bi 2 O 3 content increases the coloration of the glass. Therefore, the Bi 2 O 3 content is preferably within the above range.

在第2實施方式的光學玻璃中，Ta 2O 5的含量的上限較佳為10%，進一步以7%、5%、3%的順序更佳。另外，Ta 2O 5的含量的下限較佳為0%。Ta 2O 5的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the Ta2O5 content is preferably 10%, more preferably 7%, 5%, and 3%. In addition, the lower limit of the Ta2O5 content is preferably 0%. The Ta2O5 content may also be 0%.

Ta 2O 5是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。另一方面，Ta 2O 5使折射率上升，使玻璃高分散化。另外，Ta 2O 5的含量變多時，玻璃的熱穩定性降低，將玻璃熔融時，容易產生玻璃原料的熔融殘留物。因此，Ta 2O 5的含量較佳為上述範圍。此外，Ta 2O 5與其它玻璃成分相比，是非常昂貴的成分，Ta 2O 5的含量變多時，玻璃的生產成本增大。此外，Ta 2O 5與其它玻璃成分相比分子量大，因此會增大玻璃的比重，其結果，增大光學元件的重量。 Ta2O5 is a glass component that improves the thermal stability and devitrification resistance of glass. On the other hand, Ta2O5 increases the refractive index, making the glass highly dispersed. Furthermore, increasing the Ta2O5 content reduces the thermal stability of the glass, and melting the glass can easily produce molten residues from the glass raw materials. Therefore, the Ta2O5 content is preferably within the above range. Furthermore, Ta2O5 is very expensive compared to other glass components, and increasing its content increases the production cost of the glass. Furthermore, Ta2O5 has a higher molecular weight than other glass components, which increases the specific gravity of the glass, resulting in an increase in the weight of the optical element.

在第2實施方式的光學玻璃中，Li 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。Li 2O的含量的下限較佳為0%。Li 2O的含量也可以為0%。 In the optical glass of the second embodiment, 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 Li 2 O content may be 0%.

Li 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Li 2O的含量變多時，耐失透性降低。因此，Li 2O的含量較佳為上述範圍。 Li2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Li2O content reduces devitrification resistance. Therefore, the Li2O content is preferably within the above range.

在第2實施方式的光學玻璃中，Na 2O的含量的下限較佳為6%，進一步以10%、12%、13%的順序更佳。另外，Na 2O的含量的上限較佳為30%，進一步以22%、20%、19%、18%的順序更佳。 In the optical glass of the second embodiment, the lower limit of the Na 2 O content is preferably 6%, more preferably in the order of 10%, 12%, and 13%. The upper limit of the Na 2 O content is preferably 30%, more preferably in the order of 22%, 20%, 19%, and 18%.

Na 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Na 2O的含量變多時，耐失透性降低。因此，Na 2O的含量較佳為上述範圍。 Na2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Na2O content reduces devitrification resistance. Therefore, the Na2O content is preferably within the above range.

在第2實施方式的光學玻璃中，K 2O的含量的下限較佳為1%，進一步以2%、3%、4%的順序更佳。另外，K 2O的含量的上限較佳為13%，進一步以12%、11%、10%的順序更佳。 In the optical glass of the second embodiment, the lower limit of the K 2 O content is preferably 1%, more preferably 2%, 3%, and 4% in that order. The upper limit of the K 2 O content is preferably 13%, more preferably 12%, 11%, and 10% in that order.

K 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熱穩定性的作用，而且具有增大平均線性熱膨脹係數的作用。另一方面，K 2O的含量變多時，熱穩定性降低，玻璃化時變多容易產生條紋。因此，K 2O的含量較佳為上述範圍。 K2O contributes to lowering the specific gravity of glass, improving its thermal stability and increasing its average linear thermal expansion coefficient. However, increasing the K2O content reduces thermal stability and increases the likelihood of striations during vitrification. Therefore, the K2O content is preferably within the above range.

在第2實施方式的光學玻璃中，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]的上限較佳為35%，進一步以30%、28%、26%、25%的順序更佳。另外，該合計含量的下限較佳為10%，進一步以14%、18%、19%、20%的順序更佳。 In the optical glass of the second embodiment, the upper limit of the total content of Li2O , Na2O , and K2O [ Li2O + Na2O + K2O ] is preferably 35%, more preferably 30%, 28%, 26%, and 25%, in this order. The lower limit of this total content is preferably 10%, more preferably 14%, 18%, 19%, and 20%, in this order.

Li 2O、Na 2O及K 2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]較佳為上述範圍。 Li2O , Na2O , and K2O all improve the thermal stability of glass. However, increasing their content may reduce chemical durability and weather resistance. Therefore, the combined content of Li2O , Na2O , and K2O ( Li2O + Na2O + K2O ) is preferably within the above range.

在第2實施方式的光學玻璃中，Cs 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。另外，Cs 2O的含量的下限較佳為0%。Cs 2O的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the Cs 2 O content is preferably 5%, more preferably 3%, 2%, and 1%. The lower limit of the Cs 2 O content is preferably 0%. The Cs 2 O content may also be 0%.

Cs 2O具有改善玻璃的熔融性的作用，但其含量變多時，玻璃的熱穩定性、折射率nd降低，而且在熔解中，玻璃成分的揮發增加，變得不能得到期望的玻璃。因此，Cs 2O的含量較佳為上述範圍。 Cs2O improves the meltability of glass, but if its content increases, the thermal stability and refractive index nd of the glass decrease, and the volatility of glass components increases during melting, making it impossible to obtain the desired glass. Therefore, the Cs2O content is preferably within the above range.

在第2實施方式的光學玻璃中，Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]的上限較佳為35%，進一步以30%、28%、26%、25%的順序更佳。另外，該合計含量的下限較佳為10%，進一步以14%、18%、19%、20%的順序更佳。 In the optical glass of the second embodiment, the upper limit of the total content of Li2O , Na2O , K2O , and Cs2O [ Li2O + Na2O + K2O + Cs2O ] is preferably 35%, more preferably 30%, 28%, 26%, and 25%, in that order. The lower limit of the total content is preferably 10%, more preferably 14%, 18%, 19%, and 20%, in that order.

Li 2O、Na 2O、K 2O及Cs 2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]較佳為上述範圍。 Li₂O , Na₂O , K₂O , and Cs₂O all improve the thermal stability of glass. However, increasing their content can reduce chemical durability and weather resistance. Therefore, the combined content of Li₂O , Na₂O , K₂O , and Cs₂O ( Li₂O + Na₂O + K₂O + Cs₂O ) is preferably within the above range.

在第2實施方式的光學玻璃中，MgO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，MgO的含量的下限較佳為0%。MgO的含量也可以為0%。In the optical glass of the second embodiment, the MgO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the MgO content is preferably 0%. The MgO content may also be 0%.

在第2實施方式的光學玻璃中，CaO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，CaO的含量的下限較佳為0%。CaO的含量也可以為0%。In the optical glass of the second embodiment, the CaO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the CaO content is preferably 0%. The CaO content may also be 0%.

在第2實施方式的光學玻璃中，SrO的含量較佳為6%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，SrO的含量的下限較佳為0%。In the optical glass of the second embodiment, the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less in this order. The lower limit of the SrO content is preferably 0%.

在第2實施方式的光學玻璃中，BaO的含量較佳為8%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，BaO的含量的下限較佳為0%。In the optical glass of the second embodiment, the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less in this order. The lower limit of the BaO content is preferably 0%.

MgO、CaO、SrO、BaO均為具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，這些玻璃成分的含量變多時，損害高分散性，另外，玻璃的熱穩定性及耐失透性降低。因此，這些玻璃成分的各含量分別較佳為上述範圍。MgO, CaO, SrO, and BaO are all glass components that improve the thermal stability and devitrification resistance of glass. However, increasing the content of these glass components impairs high dispersibility and reduces the thermal stability and devitrification resistance of the glass. Therefore, the content of each of these glass components is preferably within the above-mentioned ranges.

在第2實施方式的光學玻璃中，ZnO的含量的上限較佳為10%，進一步以6%、4%、3%的順序更佳。較佳ZnO含量少的情況，其下限較佳為0%。ZnO的含量也可以為0%。In the optical glass of the second embodiment, the upper limit of the ZnO content is preferably 10%, and more preferably 6%, 4%, and 3% in that order. When the ZnO content is low, the lower limit is preferably 0%. The ZnO content may also be 0%.

ZnO是具有改善玻璃的熱穩定性的作用的玻璃成分。然而，ZnO的含量過多時，玻璃的比重增大。而且，相對折射率溫度係數(dn/dT)變高。因此，ZnO的含量較佳為上述範圍。ZnO is a glass component that improves the thermal stability of glass. However, excessive ZnO content increases the specific gravity of the glass and the relative refractive index temperature coefficient (dn/dT). Therefore, the ZnO content is preferably within the above range.

在第2實施方式的光學玻璃中，ZrO 2的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，ZrO 2的含量的下限較佳為0%。 In the optical glass of the second embodiment, the ZrO2 content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the ZrO2 content is preferably 0%.

ZrO 2是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，ZrO 2的含量過多時，顯示出熱穩定性降低的傾向。因此，ZrO 2的含量較佳為上述範圍。 ZrO₂ is a glass component that improves the thermal stability and devitrification resistance of glass. However, excessive ZrO₂ content tends to reduce thermal stability. Therefore, the ZrO₂ content is preferably within the above range.

在第2實施方式的光學玻璃中，Sc 2O 3的含量的上限較佳為2%。另外，Sc 2O 3的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the Sc 2 O 3 content is preferably 2%. In addition, the lower limit of the Sc 2 O 3 content is preferably 0%.

在第2實施方式的光學玻璃中，HfO 2的含量的上限較佳為2%。另外，HfO 2的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the HfO 2 content is preferably 2%. In addition, the lower limit of the HfO 2 content is preferably 0%.

Sc 2O 3、HfO 2均具有提高折射率nd的作用，而且是昂貴的成分。因此，Sc 2O 3、HfO 2的各含量較佳為上述範圍。 Sc 2 O 3 and HfO 2 both have the effect of increasing the refractive index nd and are expensive components. Therefore, the content of each of Sc 2 O 3 and HfO 2 is preferably within the above range.

在第2實施方式的光學玻璃中，Lu 2O 3的含量的上限較佳為2%。另外，Lu 2O 3的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the Lu 2 O 3 content is preferably 2%. In addition, the lower limit of the Lu 2 O 3 content is preferably 0%.

Lu 2O 3具有提高折射率nd的作用。另外，其分子量大，因此也是增加玻璃的比重的玻璃成分。因此，Lu 2O 3的含量較佳為上述範圍。 Lu₂O₃ has the effect of increasing the refractive index nd. Furthermore, due to its high molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the Lu₂O₃ content is preferably within the above range.

在第2實施方式的光學玻璃中，GeO 2的含量的上限較佳為2%。另外，GeO 2的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the GeO 2 content is preferably 2%. In addition, the lower limit of the GeO 2 content is preferably 0%.

GeO 2具有提高折射率nd的作用，而且是在通常使用的玻璃成分中特別地昂貴的成分。因此，從降低玻璃的製造成本的觀點考慮，GeO 2的含量較佳為上述範圍。 GeO2 has the effect of increasing the refractive index nd and is a particularly expensive component among commonly used glass components. Therefore, from the perspective of reducing the production cost of glass, the GeO2 content is preferably within the above range.

在第2實施方式的光學玻璃中，La 2O 3的含量的上限較佳為2%。另外，La 2O 3的含量的下限較佳為0%。La 2O 3的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the La 2 O 3 content is preferably 2%. In addition, the lower limit of the La 2 O 3 content is preferably 0%. The La 2 O 3 content may also be 0%.

La 2O 3的含量變多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，La 2O 3的含量較佳為上述範圍。 When the La2O3 content increases, the thermal stability and devitrification resistance of the glass decrease, and the glass becomes more likely to devitrify during production. Therefore, from the perspective of suppressing the decrease in thermal stability and devitrification resistance, the La2O3 content is preferably within the above range.

在第2實施方式的光學玻璃中，Gd 2O 3的含量的上限較佳為2%。另外，Gd 2O 3的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the content of Gd 2 O 3 is preferably 2%. In addition, the lower limit of the content of Gd 2 O 3 is preferably 0%.

Gd 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。另外，Gd 2O 3的含量過多時，玻璃的比重增大而不佳。因此，從良好地保持玻璃的熱穩定性及耐失透性、同時抑制比重的增大的觀點考慮，Gd 2O 3的含量較佳為上述範圍。 If the Gd₂O₃ content is too high, the thermal stability and devitrification resistance of the glass will decrease, making the glass more susceptible to devitrification during production. Furthermore, if the Gd₂O₃ content is too high, the specific gravity of the glass will increase, which is not desirable. Therefore, from the perspective of maintaining good thermal stability and devitrification resistance of the glass while suppressing an increase in specific gravity, the Gd₂O₃ content is preferably within the above range.

在第2實施方式的光學玻璃中，Y 2O 3的含量的上限較佳為2%。另外，Y 2O 3的含量的下限較佳為0%。Y 2O 3的含量也可以為0%。 In the optical glass of the second embodiment, the upper limit of the Y 2 O 3 content is preferably 2%. In addition, the lower limit of the Y 2 O 3 content is preferably 0%. The Y 2 O 3 content may also be 0%.

Y 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，Y 2O 3的含量較佳為上述範圍。 If the content of Y2O3 is too high, the thermal stability and devitrification resistance of the glass will decrease. Therefore, from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance, the content of Y2O3 is preferably within the above range.

在第2實施方式的光學玻璃中，Yb 2O 3的含量的上限較佳為2%。另外，Yb 2O 3的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the Yb 2 O 3 content is preferably 2%. In addition, the lower limit of the Yb 2 O 3 content is preferably 0%.

Yb 2O 3與La 2O 3、Gd 2O 3、Y 2O 3相比，分子量大，因此會增大玻璃的比重。玻璃的比重增大時，光學元件的質量增大。例如，如果將質量大的透鏡導入自動對焦式的攝像透鏡，則自動對焦時，透鏡的驅動所需的電力增大，電池的消耗變得嚴重。因此，期望減少Yb 2O 3的含量，抑制玻璃的比重的增大。 Yb2O3 has a higher molecular weight than La2O3 , Gd2O3 , and Y2O3 , thus increasing the specific gravity of glass. As the specific gravity of glass increases, the mass of optical components increases. For example, if a heavy lens is incorporated into an autofocus camera lens, the power required to drive the lens increases during autofocus, significantly increasing battery drain. Therefore, it is desirable to reduce the Yb2O3 content to suppress the increase in the specific gravity of glass.

另外，Yb 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。從防止玻璃的熱穩定性的降低、抑制比重的增大的觀點考慮，Yb 2O 3的含量較佳為上述範圍。 In addition, if the content of Yb2O3 is too high, the thermal stability and devitrification resistance of the glass will be reduced. From the viewpoint of preventing the reduction of the thermal stability of the glass and suppressing the increase of the specific gravity, the content of Yb2O3 is preferably within the above range.

較佳為第2實施方式的光學玻璃主要以上述的玻璃成分、即作為必要成分的P 2O 5、TiO 2、Nb 2O 5、作為任意成分的WO 3、B 2O 3、Al 2O 3、SiO 2、Bi 2O 3、Ta 2O 5、Li 2O、Na 2O、K 2O、Cs 2O、MgO、CaO、SrO、BaO、ZnO、ZrO 2、Sc 2O 3、HfO 2、Lu 2O 3、GeO 2、La 2O 3、Gd 2O 3、Y 2O 3、及Yb 2O 3構成，上述的玻璃成分的合計含量較佳為95%以上、更佳為98%以上、進一步較佳為99%以上、更進一步較佳為99.5%以上。 The optical glass preferably according to the second embodiment mainly comprises the above-mentioned glass components , namely, P2O5 , TiO2 , and Nb2O5 as essential components, and WO3, B2O3 , Al2O3 , SiO2 , Bi2O3 , Ta2O5 , Li2O , Na2O , K2O , Cs2O , MgO , CaO, SrO , BaO, ZnO , ZrO2 , Sc2O3 , HfO2 , Lu2O3 , GeO2 , La2O3 , Gd2O3 , Y2O3 , and Yb2O3 as optional components . 3 , the total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and even more preferably 99.5% or more.

在第2實施方式的光學玻璃中，TeO 2的含量的上限較佳為2%。另外，TeO 2的含量的下限較佳為0%。 In the optical glass of the second embodiment, the upper limit of the TeO 2 content is preferably 2%. In addition, the lower limit of the TeO 2 content is preferably 0%.

由於TeO 2具有毒性，因此，較佳為減少TeO 2的含量。因此，TeO 2的含量較佳為上述範圍。 Since TeO 2 is toxic, it is preferable to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably within the above range.

需要說明的是，較佳為第2實施方式的光學玻璃基本上由上述玻璃成分構成，但在不妨礙本發明的作用效果的範圍內，也可以含有其它成分。另外，在本發明中，不排除含有不可避免的雜質。It should be noted that the optical glass of the second embodiment is preferably composed essentially of the above-mentioned glass components, but may also contain other components within the scope that does not impair the effects of the present invention. In addition, the present invention does not exclude the inclusion of unavoidable impurities.

＜其它成分組成＞ Pb、As、Cd、Tl、Be、Se均具有毒性。因此，較佳為第2實施方式的光學玻璃不含這些元素作為玻璃成分。 <Other Components> Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferred that the optical glass of the second embodiment does not contain these elements as glass components.

U、Th、Ra均為放射性元素。因此，較佳為第2實施方式的光學玻璃不含這些元素作為玻璃成分。U, Th, and Ra are all radioactive elements. Therefore, it is preferred that the optical glass of the second embodiment does not contain these elements as glass components.

V、Cr、Mn、Fe、Co、Ni、Cu、Pr、Nd、Pm、Sm、Eu、Tb、Dy、Ho、Er、Tm可以增大玻璃的著色、成為螢光的發生源。因此，較佳為第2實施方式的光學玻璃不含這些元素作為玻璃成分。V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, and Tm can enhance the coloration of glass and serve as a source of fluorescence. Therefore, it is preferred that the optical glass of the second embodiment does not contain these elements as glass components.

Sb(Sb 2O 3)、Ce(CeO 2)是作為澄清劑發揮功能的可以任意添加的元素。其中，Sb(Sb 2O 3)是澄清效果大的澄清劑。然而，Sb(Sb 2O 3)的氧化性強，如果增加Sb(Sb 2O 3)的添加量，則由於由Sb離子導致的光吸收，玻璃的著色增大而不佳。另外，將玻璃熔融時，如果熔融物中存在Sb，則會促進構成玻璃熔融坩堝的鉑對熔融物的溶出，玻璃中的鉑濃度變高。在玻璃中，鉑以離子的形式存在時，由於光的吸收，玻璃的著色增大。另外，在玻璃中，鉑以固體物質的形式存在時，成為光的散射源，會降低玻璃的品質。Ce(CeO 2)與Sb(Sb 2O 3)相比，澄清效果小。如果大量添加Ce(CeO 2)，則玻璃的著色增強。因此，在添加澄清劑的情況下，較佳為一邊注意添加量一邊添加Sb(Sb 2O 3)。 Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are elements that can be added arbitrarily, functioning as clarifiers. Of these, Sb (Sb 2 O 3 ) is the most effective clarifier. However, Sb (Sb 2 O 3 ) is highly oxidizing, and increasing the amount of Sb (Sb 2 O 3 ) added increases the coloration of the glass due to light absorption by Sb ions, resulting in poor quality. Furthermore, when melting glass, the presence of Sb in the melt promotes the dissolution of platinum, which constitutes the glass's crucible, into the melt, increasing the platinum concentration in the glass. When platinum exists in the form of ions in the glass, light absorption increases the coloration of the glass. Furthermore, when platinum exists in the form of solid matter in the glass, it becomes a source of light scattering, reducing the quality of the glass. Ce (CeO 2 ) has a smaller clarification effect than Sb (Sb 2 O 3 ). If a large amount of Ce (CeO 2 ) is added, the coloring of the glass will be enhanced. Therefore, when adding a clarifier, it is better to add Sb (Sb 2 O 3 ) while paying attention to the amount of addition.

將Sb 2O 3的含量設為外加比例表示。即，將除Sb 2O 3及CeO 2以外的全部玻璃成分的合計含量設為100質量%時，Sb 2O 3的含量較佳小於1質量%、更佳小於0.1質量%。進一步以小於0.05質量%、小於0.03質量%、小於0.02質量%、小於0.01%的順序較佳。Sb 2O 3的含量也可以為0質量%。 The Sb2O3 content is expressed as an added percentage. Specifically, when the total content of all glass components excluding Sb2O3 and CeO2 is taken as 100% by mass, the Sb2O3 content is preferably less than 1% by mass, more preferably less than 0.1% by mass. Further preferably, the Sb2O3 content is less than 0.05% by mass, less than 0.03% by mass, less than 0.02% by mass, and less than 0.01% by mass, in that order. The Sb2O3 content may also be 0% by mass.

將CeO 2的含量也設為外加比例表示。即，將除CeO 2、Sb 2O 3以外的全部玻璃成分的合計含量設為100質量%時，CeO 2的含量較佳小於2質量%、更佳小於1質量%、進一步較佳小於0.5質量%、更進一步較佳小於0.1質量%的範圍。CeO 2的含量也可以為0質量%。藉由將CeO 2的含量設為上述範圍，可以改善玻璃的澄清性。 The CeO2 content is also expressed as an added percentage. That is, when the total content of all glass components excluding CeO2 and Sb2O3 is set to 100 mass%, the CeO2 content is preferably less than 2 mass%, more preferably less than 1 mass%, further preferably less than 0.5 mass%, and even more preferably less than 0.1 mass%. The CeO2 content may also be 0 mass%. By setting the CeO2 content within the above range, the clarity of the glass can be improved.

(玻璃特性) 接下來，對第2實施方式的光學玻璃的特性進行說明。 (Glass Properties) Next, the properties of the optical glass of the second embodiment will be described.

＜折射率nd＞ 在第2實施方式的光學玻璃中，折射率nd較佳為1.63~1.80。折射率nd的下限可以為1.65、1.67、1.69、1.71或1.73，折射率nd的上限可以為1.79、1.78或1.77。 <Refractive Index nd> In the optical glass of the second embodiment, the refractive index nd is preferably 1.63 to 1.80. The lower limit of the refractive index nd can be 1.65, 1.67, 1.69, 1.71, or 1.73, and the upper limit of the refractive index nd can be 1.79, 1.78, or 1.77.

可以藉由適宜調整各玻璃成分的含量而使折射率nd為期望的值。具有相對地提高折射率nd的作用的成分(高折射率化成分)為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2、La 2O 3等。另一方面，具有相對地降低折射率nd的作用的成分(低折射率化成分)為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O等。 The refractive index nd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components that relatively increase the refractive index nd (refractive index-increasing components) include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , ZrO2 , and La2O3 . On the other hand, components that relatively decrease the refractive index nd (refractive index-lowering components) include P2O5 , SiO2 , B2O3 , Li2O , Na2O , and K2O .

＜阿貝數νd＞ 在第2實施方式的光學玻璃中，阿貝數νd較佳為20~30。阿貝數νd的下限可以為22、22.5、23或23.2，阿貝數νd的上限可以為28、26或25。 <Abbe Number νd> In the optical glass of the second embodiment, the Abbe number νd is preferably 20 to 30. The lower limit of the Abbe number νd can be 22, 22.5, 23, or 23.2, and the upper limit of the Abbe number νd can be 28, 26, or 25.

可以藉由適宜調整各玻璃成分的含量而使阿貝數νd為期望的值。阿貝數νd相對較低的成分、即高分散化成分為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2等。另一方面，阿貝數νd相對較高的成分、即低分散化成分為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O、La 2O 3、BaO、CaO、SrO等。 The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components with relatively low Abbe numbers νd, i.e. , highly dispersed components, include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , and ZrO2 . On the other hand, components with relatively high Abbe numbers νd, i.e., low dispersed components, include P2O5 , SiO2 , B2O3 , Li2O , Na2O , K2O , La2O3 , BaO, CaO, and SrO .

＜平均線性熱膨脹係數α＞ 在第2實施方式的光學玻璃中，100~300℃的平均線性熱膨脹係數α的下限較佳為100×10 -7℃ -1，進一步以105×10 -7℃ -1、110×10 -7℃ -1、115×10 -7℃ -1、120×10 -7℃-1的順序更佳。另外，平均線性熱膨脹係數α的上限更佳為200×10-7℃-1，進一步以190×10-7℃-1、180×10-7℃-1、170×10-7℃-1、160×10-7℃-1、150×10-7℃-1、145×10-7℃-1的順序更佳。 <Average Linear Thermal Expansion Coefficient α> In the optical glass of the second embodiment, the lower limit of the average linear thermal expansion coefficient α at 100-300°C is preferably 100× 10-7 °C -1 , more preferably in the order of 105× 10-7 °C -1 , 110× 10-7 °C -1 , 115× 10-7 °C -1 , and 120× 10-7 °C -1 . The upper limit of the average linear thermal expansion coefficient α is more preferably 200× 10-7 °C -1 , and more preferably in the order of 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 , and 145× 10-7 °C -1 .

藉由將100~300℃的平均線性熱膨脹係數α設為上述範圍，可以抑制玻璃伴隨著熱膨脹的折射率的變化、即抑制相對折射率溫度係數dn/dT的增大。 By setting the average linear thermal expansion coefficient α between 100°C and 300°C within the above range, the change in the glass's refractive index associated with thermal expansion, that is, the increase in the relative refractive index temperature coefficient dn/dT, can be suppressed.

平均線性熱膨脹係數α基於JOGIS08-2003的規定來測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定溫度和試樣的伸長率。 The average linear thermal expansion coefficient α is measured according to JOGIS08-2003. The specimen is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN is applied to the specimen, which is heated at a constant rate of 4°C per minute. The temperature and elongation of the specimen are measured.

需要說明的是，在本說明書中，將平均線性熱膨脹係數α用[℃-1]的單位表示，但在使用[K-1]作為單位的情況下，平均線性熱膨脹係數α的數值也相同。 In this specification, the average linear thermal expansion coefficient α is expressed in units of [°C -1 ]. However, the value of the average linear thermal expansion coefficient α is the same even when [K -1 ] is used as the unit.

<相對折射率溫度係數dn/dT> <Relative refractive index temperature coefficient dn/dT>

在第2實施方式的光學玻璃中，He-Ne雷射的波長(633nm)下的相對折射率溫度係數dn/dT在20~40℃的範圍內較佳為-1.0×10-6~-13.0×10-6℃-1，進一步以-1.0×10-6~-10.0×10-6℃-1、-1.5×10-6~-9.0×10-6℃-1、-2.0×10-6~-8.0×10-6℃-1、-2.5×10-6~-7.0×10-6℃-1、-3.0×10-6~-6.5×10-6℃-1的順序更佳。 In the optical glass of the second embodiment, the relative refractive index temperature coefficient dn/dT at the wavelength (633 nm) of a He-Ne laser is preferably -1.0× 10-6 to -13.0× 10-6 °C -1 within the range of 20°C to 40°C, and more preferably in the order of -1.0× 10-6 to -10.0× 10-6 °C -1 , -1.5× 10-6 to -9.0× 10-6 °C -1 , -2.0× 10-6 to -8.0× 10-6 °C -1 , -2.5× 10-6 to -7.0× 10-6 °C -1 , and -3.0× 10-6 to -6.5× 10-6 °C -1 .

藉由將dn/dT設為上述範圍，並與dn/dT為正的光學元件組合，即使在光學元件的溫度大幅變動這樣的環境中，折射率的變動也小，因此，可以在更寬的溫度範圍中以高精度發揮期望的光學特性。 By setting dn/dT within the above range and combining it with an optical element with positive dn/dT, fluctuations in the refractive index are minimized even in environments where the optical element's temperature fluctuates significantly. This allows the desired optical characteristics to be exhibited with high precision over a wider temperature range.

相對折射率溫度係數dn/dT基於JOGIS18-2008的干涉法來測定。 The relative refractive index temperature coefficient dn/dT is measured using the interferometry method according to JOGIS18-2008.

需要說明的是，在本說明書中，將溫度係數dn/dT用[℃-1]的單位表示，但在使用[K-1]作為單位的情況下，溫度係數dn/dT的數值也相同。 In this specification, the temperature coefficient dn/dT is expressed in units of [°C -1 ]. However, the value of the temperature coefficient dn/dT is the same even when [K -1 ] is used as the unit.

<玻璃化轉變溫度Tg> <Glass transition temperature Tg>

第2實施方式的光學玻璃的玻璃化轉變溫度Tg較佳為600℃以下，進一步以590℃以下、580℃以下、570℃以下、560℃以下的順序更佳。 The glass transition temperature (Tg) of the optical glass of the second embodiment is preferably 600°C or lower, and more preferably 590°C or lower, 580°C or lower, 570°C or lower, and 560°C or lower, in this order.

藉由使玻璃化轉變溫度Tg的上限滿足上述範圍，可以抑制玻璃的成型溫度及退火溫度的上升，可以降低熱對壓製成型用設備及退火設備的損傷。另外，藉由使玻璃化轉變溫度Tg的下限滿足上述範圍，容易在保持期望的阿貝數、折射率的同時良好地保持玻璃的熱穩定性。By ensuring that the upper limit of the glass transition temperature (Tg) falls within the above range, increases in the glass forming and annealing temperatures can be suppressed, reducing thermal damage to press-forming and annealing equipment. Furthermore, by ensuring that the lower limit of the glass transition temperature (Tg) falls within the above range, it is easier to maintain the desired Abbe number and refractive index while also maintaining good thermal stability of the glass.

＜玻璃的比重＞ 在第2實施方式的光學玻璃中，比重較佳為3.40以下，進一步以3.30以下、3.20以下的順序更佳。如果能夠減少玻璃的比重，則可以減少透鏡的重量。其結果，可以降低搭載透鏡的相機透鏡的自動對焦驅動的消耗電力。 <Glass Specific Gravity> In the optical glass of the second embodiment, the specific gravity is preferably 3.40 or less, more preferably 3.30 or less, and even more preferably 3.20 or less. Reducing the specific gravity of the glass can reduce the weight of the lens. Consequently, the power consumption of the autofocus drive of a camera lens equipped with the lens can be reduced.

＜玻璃的透光性＞ 第2實施方式的光學玻璃的透光性可以藉由著色度λ5來評價。 對於厚度10.0mm±0.1mm的玻璃試樣，在波長200~700nm的範圍內測定分光透射率，將外部透射率成為5%的波長設為λ5。 <Glass Transmittance> The light transmittance of the optical glass of the second embodiment can be evaluated using the chromaticity λ5. For glass samples with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured within the wavelength range of 200 to 700 nm. The wavelength at which the external transmittance reaches 5% was defined as λ5.

第2實施方式的光學玻璃的λ5較佳為400nm以下，更佳為390nm以下、進一步較佳為385nm以下。The λ5 of the optical glass according to the second embodiment is preferably 400 nm or less, more preferably 390 nm or less, and even more preferably 385 nm or less.

藉由使用將λ5短波長化後的光學玻璃，可以提供可實現適宜的顏色再現的光學元件。By using optical glass with a shorter wavelength of λ5, it is possible to provide optical elements that achieve appropriate color reproduction.

對於第2實施方式的光學玻璃的製造及光學元件等製造，可以設為與第1實施方式相同。The production of the optical glass and the production of the optical elements of the second embodiment can be the same as those of the first embodiment.

第3實施方式 對第3實施方式的光學玻璃詳細地進行說明。 第3實施方式的光學玻璃的P 2O 5的含量為25~50%， Nb 2O 5含量為14~40%， TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60%， TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上， B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39， Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]為10%以上， Na 2O的含量相對於K 2O的含量的質量比[Na 2O/K 2O]為1.50以上。 Third Embodiment The optical glass according to the third embodiment will be described in detail. The optical glass according to the third embodiment has a P2O5 content of 25-50%, a Nb2O5 content of 14-40%, a total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] of 35-60%, a mass ratio of the TiO2 content to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [TiO2/ ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] of 0.25 or more, and a mass ratio of the B2O3 content to the P2O5 content [ B2O3 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] of 0.25 or more . 2 O 3 /P 2 O 5 ] is 0.05~0.39, 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, and the mass ratio of the Na 2 O content to the K 2 O content [Na 2 O/K 2 O] is 1.50 or more.

在第3實施方式的光學玻璃中，P 2O 5的含量為25~50%。P 2O 5的含量的下限較佳為26%，進一步以26.5%、26.7%的順序更佳。另外，P 2O 5的含量的上限較佳為42%，進一步以40%、38%、37%、36%的順序更佳。 In the optical glass of the third embodiment, the P₂O₅ content is 25% to 50%. The lower limit of the P₂O₅ content is preferably 26%, more preferably 26.5%, and more preferably 26.7%. The upper limit of the P₂O₅ content is preferably 42%, more preferably 40%, 38%, 37%, and 36%.

P 2O 5是玻璃的網絡形成成分，是為了在玻璃中大量含有高分散成分的必要成分。藉由將P 2O 5的含量設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 P2O5 is a network-forming component of glass and is essential for containing a large amount of highly dispersed components in the glass. By setting the P2O5 content within the above range, an optical glass with high thermal stability and desired optical constants can be obtained.

在第3實施方式的光學玻璃中，Nb 2O 5的含量為14~40%。Nb 2O 5的含量的下限較佳為16%，進一步以17%、18%、19%、20%的順序更佳。另外，Nb 2O 5的含量的上限較佳為38%，進一步以36%、34%、32%的順序更佳。 In the optical glass of the third embodiment, the Nb2O5 content is 14-40%. The lower limit of the Nb2O5 content is preferably 16%, more preferably 17%, 18%, 19%, and 20%, in this order. Furthermore, the upper limit of the Nb2O5 content is preferably 38%, more preferably 36%, 34%, and 32%, in this order.

Nb 2O 5是有助於高折射率化及高分散化的成分。因此，藉由將Nb 2O 5的含量設為上述範圍，可得到具有期望的光學常數的光學玻璃。另一方面，Nb 2O 5的含量過多時，存在玻璃的著色增強的擔憂。 Nb2O5 contributes to a higher refractive index and higher dispersion. Therefore, by setting the Nb2O5 content within the above range, an optical glass with desired optical constants can be obtained. On the other hand, if the Nb2O5 content is too high, there is a concern that the glass may be overly colored.

在第3實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]為35~60%。該合計含量的下限較佳為36%，進一步以37%、38%、39%的順序更佳。另外，該合計含量的上限較佳為55%，進一步以50%、48%、47%、46%的順序更佳。 In the optical glass of the third embodiment, the total content of TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ ( TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ) is 35% to 60%. The lower limit of this total content is preferably 36 %, more preferably 37%, 38 %, and 39%, in that order. The upper limit of this total content is preferably 55 %, more preferably 50%, 48%, 47%, and 46%, in that order.

TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5是有助於玻璃的高分散化的成分。因此，藉由將合計含量[TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5]設為上述範圍，可得到具有期望的光學常數的光學玻璃，而且，還可以改善玻璃的熱穩定性。另一方面，該合計含量過多時，存在不能得到具有期望的光學常數的光學玻璃的擔憂，而且，存在玻璃的熱穩定性降低、玻璃的著色變強的擔憂。 TiO₂ , Nb₂O₅ , WO₃ , Bi₂O₃ , and Ta₂O₅ are components that contribute to high dispersion in glass. Therefore, by setting the combined content [ TiO₂ + Nb₂O₅ + WO₃ + Bi₂O₃ + Ta₂O₅ ] within the above range, optical glass with desired optical constants can be obtained, and the thermal stability of the glass can also be improved. On the other hand, if the combined content is too high , optical glass with the desired optical constants may not be obtained, and there is a concern that the thermal stability of the glass may be reduced, or that the glass may exhibit strong coloring.

在第3實施方式的光學玻璃中，TiO 2的含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量的質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]為0.25以上。該質量比的下限較佳為0.26，進一步以0.27、0.28、0.29、0.30的順序更佳。另外，該質量比的上限較佳為0.65，進一步以0.60、0.58、0.56、0.54、0.52、0.50、0.48的順序更佳。 In the optical glass of the third embodiment, the mass ratio of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 )] is 0.25 or greater. The lower limit of this mass ratio is preferably 0.26, more preferably 0.27, 0.28, 0.29 , and 0.30 , in that order. The upper limit of this mass ratio is preferably 0.65, more preferably 0.60, 0.58, 0.56, 0.54 , 0.52 , 0.50, and 0.48, in that order.

TiO 2是高折射率化成分中、高分散化的作用特別大的成分。因此，從得到期望的光學常數的觀點考慮，質量比[TiO 2/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)]較佳為上述範圍。 Among components that increase the refractive index, TiO2 has a particularly significant effect on high dispersion. Therefore, from the perspective of obtaining desired optical constants, the mass ratio [TiO2/(TiO2+Nb2O5+WO3+Bi2O3 + Ta2O5 ) ] is preferably within the above range.

在第3實施方式的光學玻璃中，B 2O 3的含量相對於P 2O 5的含量的質量比[B 2O 3/P 2O 5]為0.05~0.39。該質量比的上限較佳為0.30，進一步以0.25、0.22、0.20、0.19、0.18的順序更佳。另外，該質量比的下限較佳為0.06，進一步以0.07、0.08、0.09的順序更佳。 In the optical glass of the third embodiment, the mass ratio of the content of B2O3 to the content of P2O5 [ B2O3 / P2O5 ] is 0.05 to 0.39. The upper limit of this mass ratio is preferably 0.30, and more preferably in the order of 0.25 , 0.22, 0.20, 0.19, and 0.18. The lower limit of this mass ratio is preferably 0.06, and more preferably in the order of 0.07, 0.08, and 0.09.

藉由將質量比[B 2O 3/P 2O 5]設為上述範圍，容易得到具有期望的光學常數、熱穩定性高、且耐失透性高的光學玻璃。 By setting the mass ratio [B 2 O 3 /P 2 O 5 ] within the above range, it is easy to obtain an optical glass having desired optical constants, high thermal stability, and high resistance to devitrification.

在第3實施方式的光學玻璃中，Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]為10%以上。該合計含量的下限較佳為12%，進一步以14%、16%、17%的順序更佳。另外，該合計含量的上限較佳為35%，進一步以30%、28%、26%、25%的順序更佳。 In the optical glass of the third embodiment, the total content of Li₂O , Na₂O , K₂O , and Cs₂O [ Li₂O + Na₂O + K₂O + Cs₂O ] is 10% or greater. The lower limit of this total content is preferably 12%, more preferably 14%, 16%, and 17%, in that order. The upper limit of this total content is preferably 35%, more preferably 30%, 28%, 26%, and 25%, in that order.

Li 2O、Na 2O、K 2O及Cs 2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li 2O、Na 2O、K 2O及Cs 2O的合計含量[Li 2O＋Na 2O＋K 2O＋Cs 2O]較佳為上述範圍。 Li₂O , Na₂O , K₂O , and Cs₂O all improve the thermal stability of glass. However, increasing their content can reduce chemical durability and weather resistance. Therefore, the combined content of Li₂O , Na₂O , K₂O , and Cs₂O ( Li₂O + Na₂O + K₂O + Cs₂O ) is preferably within the above range.

在第3實施方式的光學玻璃中，Na 2O的含量相對於K 2O的含量的質量比[Na 2O/K 2O]為1.50以上。該質量比的下限較佳為1.70，進一步以1.90、2.10、2.30的順序更佳。另外，該質量比的上限較佳為10.0，進一步以8.50、7.50、7.00、6.50的順序更佳。 In the optical glass of the third embodiment, the mass ratio of the Na₂O content to the K₂O content [ Na₂O / K₂O ] is 1.50 or greater. The lower limit of this mass ratio is preferably 1.70, more preferably 1.90, 2.10, and 2.30, in that order. The upper limit of this mass ratio is preferably 10.0, more preferably 8.50, 7.50, 7.00, and 6.50, in that order.

Na 2O及K 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。然而，K 2O的含量變多時，熱穩定性、耐失透性、化學耐久性、耐候性降低。因此，質量比[Na 2O/K 2O]較佳為上述範圍。 Na₂O and K₂O contribute to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the K₂O content reduces thermal stability, devitrification resistance, chemical durability, and weather resistance. Therefore, the mass ratio [ Na₂O / K₂O ] is preferably within the above range.

對於第3實施方式的光學玻璃中的除上述以外的玻璃成分的含量及比率，以下示出非限定性的實例。The following are non-limiting examples of the contents and ratios of the glass components other than those described above in the optical glass of the third embodiment.

在第3實施方式的光學玻璃中，B 2O 3的含量的上限較佳為10%，進一步以9%、8%、7%、6%的順序更佳。 In the optical glass of the third embodiment, the upper limit of the B 2 O 3 content is preferably 10%, more preferably 9%, 8%, 7%, and 6% in this order.

B 2O 3是玻璃的網絡形成成分，具有改善玻璃的熱穩定性的作用。另一方面，B 2O 3的含量多時，存在耐失透性降低的傾向。因此，B 2O 3的含量較佳為上述範圍。 B2O3 is a glass network-forming component that improves the thermal stability of glass. However, if the B2O3 content is high, devitrification resistance tends to decrease. Therefore, the B2O3 content is preferably within the above range.

在第3實施方式的光學玻璃中，B 2O 3的含量相對於P 2O 5及B 2O 3的合計含量的質量比[B 2O 3/(P 2O 5＋B 2O 3)]的上限較佳為0.18，進一步以0.17、0.16、0.15的順序更佳。該質量比的下限較佳為0，進一步以0.01、0.03、0.05的順序更佳。 In the optical glass of the third embodiment, the upper limit of the mass ratio of the content of B2O3 to the total content of P2O5 and B2O3 [ B2O3 / ( P2O5 + B2O3 ) ] is preferably 0.18, more preferably in the order of 0.17, 0.16, and 0.15 . The lower limit of this mass ratio is preferably 0, more preferably in the order of 0.01, 0.03, and 0.05.

從改善玻璃的熱穩定性及耐失透性的觀點考慮，質量比[B 2O 3/(P 2O 5＋B 2O 3)]較佳為上述範圍。 From the viewpoint of improving the thermal stability and devitrification resistance of glass, the mass ratio [B 2 O 3 /(P 2 O 5 +B 2 O 3 )] is preferably within the above range.

在第3實施方式的光學玻璃中，Al 2O 3的含量較佳為3%以下，進一步以2%以下、1%以下的順序更佳。Al 2O 3的含量也可以為0%。 In the optical glass of the third embodiment, the Al 2 O 3 content is preferably 3% or less, more preferably 2% or less, and more preferably 1% or less. The Al 2 O 3 content may be 0%.

Al 2O 3是具有改善玻璃的化學耐久性、耐候性的作用的玻璃成分，可以將其視為網絡形成成分。另一方面，Al 2O 3的含量變多時，玻璃的耐失透性降低。另外，容易發生玻璃化轉變溫度Tg上升、熱穩定性降低等問題。從避免這樣的問題的觀點考慮，Al 2O 3的含量的上限較佳為上述範圍。 Al₂O₃ is a glass component that improves the chemical durability and weather resistance of glass and can be considered a network-forming component. However, increasing the Al₂O₃ content reduces the glass's resistance to devitrification . It can also lead to problems such as an increase in the glass transition temperature (Tg) and a decrease in thermal stability. To avoid these problems, the upper limit of the Al₂O₃ content is preferably within the above range.

在第3實施方式的光學玻璃中，SiO 2的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。SiO 2的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the SiO2 content is preferably 5%, and more preferably in the order of 3%, 2%, and 1%. The SiO2 content may also be 0%.

需要說明的是，有時在玻璃的熔融中使用石英玻璃製坩堝等石英玻璃製的熔融器具。在該情況下，由於少量的SiO 2從熔融器具熔入玻璃熔融物，因此，即使玻璃原料不含SiO 2，製成的玻璃也會含有少量的SiO 2。從石英玻璃製的熔融器具混入玻璃的SiO 2的量也取決於熔融條件，例如相對於全部玻璃成分的含量的合計為0.5~1質量%左右。在除SiO 2以外的玻璃成分的含有比為恆定的狀態下，SiO 2的量增加0.5~1質量%左右。需要說明的是，根據熔解條件，上述量會有增減。根據SiO 2的含量不同，折射率、阿貝數等光學特性會發生變化，因此，可對除SiO 2以外的玻璃成分的含量進行微調而得到具有期望的光學特性的光學玻璃。 It should be noted that quartz glass melting vessels, such as quartz glass crucibles, are sometimes used to melt glass. In these cases, a small amount of SiO₂ is incorporated into the glass melt from the melting vessel. Therefore, even if the glass starting materials do not contain SiO₂ , the resulting glass will contain a small amount of SiO₂ . The amount of SiO₂ that enters the glass from the quartz glass melting vessel depends on the melting conditions, but for example, it is approximately 0.5 to 1% by mass relative to the total content of all glass components. When the content of glass components other than SiO₂ remains constant, the amount of SiO₂ increases by approximately 0.5 to 1% by mass. It should be noted that this amount can vary depending on the melting conditions. Optical properties such as the refractive index and Abbe number vary depending on the SiO2 content. Therefore, by fine-tuning the content of glass components other than SiO2 , optical glass with desired optical properties can be obtained.

SiO 2是玻璃的網絡形成成分，具有改善玻璃的熱穩定性、化學耐久性、耐候性、提高熔融玻璃的黏度、容易將熔融玻璃成型的作用。另一方面，SiO 2的含量多時，存在玻璃的耐失透性降低的傾向。因此，SiO 2的含量的上限較佳為上述範圍。 SiO₂ is a network-forming component of glass, improving its thermal stability, chemical durability, and weather resistance, increasing the viscosity of molten glass, and facilitating its shaping. However, high SiO₂ contents tend to reduce the glass's resistance to devitrification. Therefore, the upper limit of the SiO₂ content is preferably within the above range.

在第3實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量[P 2O 5＋B 2O 3＋SiO 2]的上限較佳為50%，進一步以45%、43%、42%、41%的順序更佳。該合計含量的下限較佳為25%，進一步以27%、28%、29%的順序更佳。 In the optical glass of the third embodiment, the upper limit of the combined content of P2O5 , B2O3 , and SiO2 [ P2O5 + B2O3 + SiO2 ] is preferably 50%, more preferably 45%, 43 % , 42%, and 41% in this order. The lower limit of this combined content is preferably 25%, more preferably 27%, 28%, and 29% in this order.

藉由將合計含量[P 2O 5＋B 2O 3＋SiO 2]設為上述範圍，可得到熱穩定性高、且具有期望的光學常數的光學玻璃。 By setting the total content [P 2 O 5 +B 2 O 3 +SiO 2 ] within the above range, an optical glass having high thermal stability and desired optical constants can be obtained.

在第3實施方式的光學玻璃中，P 2O 5及B 2O 3的合計含量相對於P 2O 5、B 2O 3、SiO 2、及Al 2O 3的合計含量的質量比[(P 2O 5＋B 2O 3)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3)]的下限較佳為0.80，進一步以0.90、0.93、0.96、0.98的順序更佳。該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the total content of P2O5 and B2O3 to the total content of P2O5 , B2O3 , SiO2 , and Al2O3 [ ( P2O5 + B2O3 )/( P2O5 + B2O3 + SiO2 + Al2O3 )] is preferably 0.80 , more preferably 0.90, 0.93 , 0.96 , and 0.98 , in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到熱穩定性高、具有期望的光學常數的玻璃的觀點考慮，質量比[(P 2O 5＋B 2O 3)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3)]較佳為上述範圍。 From the viewpoint of obtaining glass having high thermal stability and desired optical constants, 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 within the above range.

在第3實施方式的光學玻璃中，TiO 2的含量的下限較佳為10%，進一步以11%、12%、13%的順序更佳。另外，TiO 2的含量的上限較佳為50%，進一步以40%、35%、30%、28%、26%、23%、21%的順序更佳。 In the optical glass of the third embodiment, the lower limit of the TiO2 content is preferably 10%, more preferably 11%, 12%, and 13% in this order. Furthermore, the upper limit of the TiO2 content is preferably 50%, more preferably 40%, 35%, 30%, 28%, 26%, 23%, and 21% in this order.

TiO 2顯著有助於高分散化。另一方面，TiO 2比較容易增大玻璃的著色，而且存在容易使熔融性惡化的擔憂。因此，TiO 2的含量較佳為上述範圍。 TiO2 significantly contributes to high dispersion. However, TiO2 tends to increase the coloration of the glass and may also deteriorate its solubility. Therefore, the TiO2 content is preferably within the above range.

在第3實施方式的光學玻璃中，WO 3的含量的上限較佳為15%，進一步以10%、5%、3%、2%、1%的順序更佳。較佳WO 3的含量少的情況，其下限較佳為0%。WO 3的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the WO 3 content is preferably 15%, and more preferably in the order of 10%, 5%, 3%, 2%, and 1%. When the WO 3 content is low, the lower limit is preferably 0%. The WO 3 content may also be 0%.

藉由將WO 3的含量設為上述範圍，可以提高透射率，而且可以抑制玻璃的比重的增大。另外，可以降低相對折射率溫度係數(dn/dT)。 By setting the WO3 content within the above range, the transmittance can be improved while suppressing an increase in the specific gravity of the glass. In addition, the relative refractive index temperature coefficient (dn/dT) can be reduced.

在第3實施方式的光學玻璃中，Bi 2O 3的含量的上限較佳為15%，進一步以10%、7%、5%、3%的順序更佳。另外，Bi 2O 3的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the Bi2O3 content is preferably 15%, more preferably 10%, 7%, 5%, and 3% in this order. The lower limit of the Bi2O3 content is preferably 0%.

藉由適量含有Bi 2O 3，具有改善玻璃的熱穩定性的作用。另一方面，如果提高Bi 2O 3的含量，則玻璃的著色增大。因此，Bi 2O 3的含量較佳為上述範圍。 The inclusion of an appropriate amount of Bi 2 O 3 improves the thermal stability of the glass. On the other hand, increasing the Bi 2 O 3 content increases the coloration of the glass. Therefore, the Bi 2 O 3 content is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5及B 2O 3的合計含量的質量比[TiO 2/(P 2O 5＋B 2O 3)]的上限較佳為0.70，進一步以0.66、0.64、0.62、0.60的順序更佳。該質量比的下限較佳為0.25，進一步以0.27、0.29、0.31的順序更佳。 In the optical glass of the third embodiment, the upper limit of the mass ratio of TiO2 to the total content of P2O5 and B2O3 [ TiO2 /( P2O5 + B2O3 )] is preferably 0.70, more preferably in the order of 0.66, 0.64 , 0.62 , and 0.60. The lower limit of this mass ratio is preferably 0.25, more preferably in the order of 0.27, 0.29 , and 0.31.

藉由將質量比[TiO 2/(P 2O 5＋B 2O 3)]設為上述範圍，容易得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /(P 2 O 5 +B 2 O 3 )] within the above range, it is easy to obtain an optical glass having desired optical constants and high thermal stability.

在第3實施方式的光學玻璃中，TiO 2的含量相對於P 2O 5的含量的質量比[TiO 2/P 2O 5]的上限較佳為0.70，進一步以0.66、0.64、0.62的順序更佳。該質量比的下限較佳為0.25，進一步以0.28、0.31、0.34的順序更佳。 In the optical glass of the third embodiment, the upper limit of the mass ratio of TiO2 to P2O5 [ TiO2 / P2O5 ] is preferably 0.70, more preferably 0.66, 0.64, and 0.62, in that order. The lower limit of this mass ratio is preferably 0.25, more preferably 0.28, 0.31, and 0.34, in that order.

藉由將質量比[TiO 2/P 2O 5]設為上述範圍，容易得到具有期望的光學常數、且熱穩定性高的光學玻璃。 By setting the mass ratio [TiO 2 /P 2 O 5 ] within the above range, it is easy to obtain an optical glass having desired optical constants and high thermal stability.

在第3實施方式的光學玻璃中，TiO 2及Nb 2O 5的合計含量[TiO 2＋Nb 2O 5]的下限較佳為35.0%，進一步以37.0%、39.0%、40.0%的順序更佳。另外，該合計含量的上限較佳為65.0%，進一步以60.0%、55.0%、50.0%、48.0%、46.0%的順序更佳。 In the optical glass of the third embodiment, the lower limit of the combined content of TiO2 and Nb2O5 [ TiO2 + Nb2O5 ] is preferably 35.0%, more preferably 37.0%, 39.0%, and 40.0%, in that order. The upper limit of the combined content is preferably 65.0%, more preferably 60.0%, 55.0%, 50.0%, 48.0%, and 46.0%, in that order.

從得到高折射率高分散、且玻璃的熱穩定性優異的玻璃的觀點考慮，該合計含量[TiO 2＋Nb 2O 5]較佳為上述範圍。 From the viewpoint of obtaining glass having a high refractive index and high dispersion and excellent thermal stability, the total content [TiO 2 + Nb 2 O 5 ] is preferably within the above range.

在第3實施方式的光學玻璃中，Nb 2O 5的含量相對於Nb 2O 5及WO 3的合計含量的質量比[Nb 2O 5/(Nb 2O 5＋WO 3)]的下限較佳為0.70，進一步以0.80、0.90、0.95的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the content of Nb2O5 to the total content of Nb2O5 and WO3 [ Nb2O5 /( Nb2O5 + WO3 )] is preferably 0.70, more preferably 0.80, 0.90 , and 0.95, in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到高折射率高分散、且抑制了相對折射率溫度係數(dn/dT)的上升的玻璃的觀點考慮，質量比[Nb 2O 5/(Nb 2O 5＋WO 3)]較佳為上述範圍。 From the viewpoint of obtaining glass having a high refractive index and high dispersion while suppressing an increase in the relative refractive index temperature coefficient (dn/dT), the mass ratio [Nb 2 O 5 /(Nb 2 O 5 +WO 3 )] is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2的含量相對於TiO 2及WO 3的合計含量的質量比[TiO 2/(TiO 2＋WO 3)]的下限較佳為0.70，進一步以0.80、0.90、0.95的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the TiO2 content to the total content of TiO2 and WO3 [ TiO2 /( TiO2 + WO3 )] is preferably 0.70, more preferably 0.80, 0.90, and 0.95, in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到高分散、且抑制了相對折射率溫度係數(dn/dT)的上升的玻璃的觀點考慮，質量比[TiO 2/(TiO 2＋WO 3)]較佳為上述範圍。 From the viewpoint of obtaining glass having high dispersion and suppressing an increase in the relative refractive index temperature coefficient (dn/dT), the mass ratio [TiO 2 /(TiO 2 +WO 3 )] is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2及Nb 2O 5的合計含量相對於TiO 2、Nb 2O 5、WO 3、及Bi 2O 3的合計含量的質量比[(TiO 2＋Nb 2O 5)/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3)]的下限較佳為0.70，進一步以0.80、0.90、0.95的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the total content of TiO2 and Nb2O5 to the total content of TiO2 , Nb2O5 , WO3 , and Bi2O3 [( TiO2 + Nb2O5 ) / ( TiO2 + Nb2O5 + WO3 + Bi2O3 )] is preferably 0.70, more preferably 0.80 , 0.90, and 0.95 , in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到高折射率高分散、且抑制了相對折射率溫度係數(dn/dT)的上升的玻璃的觀點考慮，質量比[(TiO 2＋Nb 2O 5)/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3)]較佳為上述範圍。 From the viewpoint of obtaining glass having a high refractive index and high dispersion while suppressing an increase in the relative refractive index temperature coefficient (dn/dT), the mass ratio [(TiO 2 + Nb 2 O 5 )/(TiO 2 + Nb 2 O 5 + WO 3 + Bi 2 O 3 )] is preferably within the above range.

在第3實施方式的光學玻璃中，Ta 2O 5的含量的上限較佳為10%，進一步以7%、5%、3%的順序更佳。另外，Ta 2O 5的含量的下限較佳為0%。Ta 2O 5的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the Ta2O5 content is preferably 10%, more preferably 7%, 5%, and 3%. In addition, the lower limit of the Ta2O5 content is preferably 0%. The Ta2O5 content may also be 0%.

Ta 2O 5是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。另一方面，Ta 2O 5使折射率上升，使玻璃高分散化。另外，Ta 2O 5的含量變多時，玻璃的熱穩定性降低、將玻璃熔融時，容易產生玻璃原料的熔融殘留物。因此，Ta 2O 5的含量較佳為上述範圍。此外，Ta 2O 5與其它玻璃成分相比，是非常昂貴的成分，Ta 2O 5的含量變多時，玻璃的生產成本增大。此外，Ta 2O 5與其它玻璃成分相比分子量大，因此會增大玻璃的比重，其結果，增大光學元件的重量。 Ta2O5 is a glass component that improves the thermal stability and devitrification resistance of glass. On the other hand, Ta2O5 increases the refractive index, making the glass highly dispersed. Furthermore, increasing the Ta2O5 content reduces the thermal stability of the glass and increases the likelihood of producing melt residues from the glass raw materials when the glass is melted. Therefore, the Ta2O5 content is preferably within the above range. Furthermore, Ta2O5 is very expensive compared to other glass components, and increasing its content increases the production cost of the glass . Furthermore, Ta2O5 has a higher molecular weight than other glass components, which increases the specific gravity of the glass, resulting in an increase in the weight of the optical element.

在第3實施方式的光學玻璃中，Li 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。Li 2O的含量的下限較佳為0%。Li 2O的含量也可以為0%。 In the optical glass of the third embodiment, 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 Li 2 O content may also be 0%.

Li 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Li 2O的含量變多時，耐失透性降低。因此，Li 2O的含量較佳為上述範圍。 Li2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Li2O content reduces devitrification resistance. Therefore, the Li2O content is preferably within the above range.

在第3實施方式的光學玻璃中，Na 2O的含量的下限較佳為6%，進一步以10%、12%、13%的順序更佳。另外，Na 2O的含量的上限較佳為30%，進一步以22%、20%、19%、18%的順序更佳。 In the optical glass of the third embodiment, the lower limit of the Na 2 O content is preferably 6%, more preferably 10%, 12%, and 13% in this order. The upper limit of the Na 2 O content is preferably 30%, more preferably 22%, 20%, 19%, and 18% in this order.

Na 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熔融性、並且增大平均線性熱膨脹係數的作用。另一方面，Na 2O的含量變多時，耐失透性降低。因此，Na 2O的含量較佳為上述範圍。 Na2O contributes to lowering the specific gravity of glass, improving its meltability and increasing its average linear thermal expansion coefficient. However, increasing the Na2O content reduces devitrification resistance. Therefore, the Na2O content is preferably within the above range.

在第3實施方式的光學玻璃中，K 2O的含量的下限較佳為1%，進一步以2%、3%、4%的順序更佳。另外，K 2O的含量的上限較佳為13%，進一步以12%、11%、10%的順序更佳。 In the optical glass of the third embodiment, the lower limit of the K 2 O content is preferably 1%, more preferably 2%, 3%, and 4% in this order. The upper limit of the K 2 O content is preferably 13%, more preferably 12%, 11%, and 10% in this order.

K 2O是有助於玻璃的低比重化的成分，具有改善玻璃的熱穩定性的作用。而且，具有增大平均線性熱膨脹係數的作用。另一方面，K 2O的含量變多時，熱穩定性、耐失透性、化學耐久性、耐候性降低。因此，K 2O的含量較佳為上述範圍。 K2O contributes to lowering the specific gravity of glass and improves its thermal stability. It also increases the average linear thermal expansion coefficient. However, increasing the K2O content can reduce thermal stability, devitrification resistance, chemical durability, and weather resistance. Therefore, the K2O content is preferably within the above range.

在第3實施方式的光學玻璃中，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]的上限較佳為35%，進一步以30%、28%、26%、25%的順序更佳。另外，該合計含量的下限較佳為10%，進一步以14%、15%、16%、17%的順序更佳。 In the optical glass of the third embodiment, the upper limit of the total content of Li2O , Na2O , and K2O [ Li2O + Na2O + K2O ] is preferably 35%, more preferably 30%, 28%, 26%, and 25%, in that order. The lower limit of the total content is preferably 10%, more preferably 14%, 15%, 16%, and 17%, in that order.

Li 2O、Na 2O及K 2O均具有改善玻璃的熱穩定性的作用。然而，它們的含量變多時，存在化學耐久性、耐候性降低的擔憂。因此，Li 2O、Na 2O及K 2O的合計含量[Li 2O＋Na 2O＋K 2O]較佳為上述範圍。 Li2O , Na2O , and K2O all improve the thermal stability of glass. However, increasing their content may reduce chemical durability and weather resistance. Therefore, the combined content of Li2O , Na2O , and K2O ( Li2O + Na2O + K2O ) is preferably within the above range.

在第3實施方式的光學玻璃中，Cs 2O的含量的上限較佳為5%，進一步以3%、2%、1%的順序更佳。另外，Cs 2O的含量的下限較佳為0%。Cs 2O的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the Cs 2 O content is preferably 5%, more preferably 3%, 2%, and 1%. The lower limit of the Cs 2 O content is preferably 0%. The Cs 2 O content may also be 0%.

Cs 2O具有改善玻璃的熔融性的作用，但含量變多時，玻璃的熱穩定性、折射率nd降低，而且在熔解中，玻璃成分的揮發增加，變得不能得到期望的玻璃。因此，Cs 2O的含量較佳為上述範圍。 Cs2O improves the meltability of glass, but if its content increases, the thermal stability and refractive index nd of the glass decrease, and the volatility of glass components increases during melting, making it impossible to obtain the desired glass. Therefore, the Cs2O content is preferably within the above range.

在第3實施方式的光學玻璃中，Na 2O的含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[Na 2O/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]的下限較佳為0.20，0.50、0.55、0.60、0.65的順序更佳。該質量比的上限較佳為0.98，進一步以0.95、0.92、0.90、0.88的順序更佳。 In the optical glass of the third embodiment, the mass ratio of the Na2O content to the total content of Li2O , Na2O , K2O , and Cs2O [ Na2O /( Li2O + Na2O + K2O + Cs2O )] is preferably 0.20, more preferably in the order of 0.50, 0.55, 0.60, and 0.65. The upper limit of this mass ratio is preferably 0.98, more preferably in the order of 0.95, 0.92, 0.90, and 0.88.

從得到耐失透性及熱穩定性優異的玻璃的觀點考慮，質量比[Na 2O/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]較佳為上述範圍。 From the viewpoint of obtaining glass excellent in devitrification resistance and thermal stability, the mass ratio [Na 2 O/(Li 2 O + Na 2 O + K 2 O + Cs 2 O)] is preferably within the above range.

在第3實施方式的光學玻璃中，P 2O 5、B 2O 3及SiO 2的合計含量相對於Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]的上限較佳為2.50，進一步以2.40、2.35、2.30、2.27、2.25的順序更佳。另外，該質量比的下限較佳為1.20，進一步以1.30、1.35、1.38、1.40的順序更佳。 In the optical glass of the third embodiment, the upper limit of the mass ratio of the total content of P2O5, B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [ ( P2O5 + B2O3 + SiO2) / ( Li2O + Na2O + K2O + Cs2O )] is preferably 2.50, more preferably 2.40, 2.35, 2.30 , 2.27, and 2.25, in that order. The lower limit of this mass ratio is preferably 1.20, more preferably 1.30 , 1.35, 1.38, and 1.40, in that order.

藉由將質量比[(P 2O 5＋B 2O 3＋SiO 2)/(Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，可得到熱穩定性高、相對折射率溫度係數(dn/dT)低、且平均線性熱膨脹係數大的光學玻璃。 By setting the mass ratio [( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] within the above range, an optical glass having high thermal stability, a low relative refractive index temperature coefficient ( dn/dT), and a large average linear thermal expansion coefficient can be obtained.

在第3實施方式的光學玻璃中，MgO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，MgO的含量的下限較佳為0%。MgO的含量也可以為0%。In the optical glass of the third embodiment, the MgO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the MgO content is preferably 0%. The MgO content may also be 0%.

在第3實施方式的光學玻璃中，CaO的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，CaO的含量的下限較佳為0%。CaO的含量也可以為0%。In the optical glass of the third embodiment, the CaO content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the CaO content is preferably 0%. The CaO content may also be 0%.

在第3實施方式的光學玻璃中，SrO的含量較佳為6%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，SrO的含量的下限較佳為0%。In the optical glass of the third embodiment, the SrO content is preferably 6% or less, more preferably 5% or less, 3% or less, and 1% or less, in this order. The lower limit of the SrO content is preferably 0%.

在第3實施方式的光學玻璃中，BaO的含量較佳為8%以下，進一步以5%以下、3%以下、1%以下的順序更佳。另外，BaO的含量的下限較佳為0%。In the optical glass of the third embodiment, the BaO content is preferably 8% or less, more preferably 5% or less, 3% or less, and 1% or less, in this order. The lower limit of the BaO content is preferably 0%.

在第3實施方式的光學玻璃中，MgO、CaO、SrO、及BaO的合計含量[MgO＋CaO＋SrO＋BaO]的上限較佳為8.0%，進一步以5.0%、4.0%、3.0%、1.5%、1.0%、0.5%的順序更佳。另外，該合計含量的下限較佳為0%。該合計含量也可以為0%。In the optical glass of the third embodiment, the upper limit of the total content of MgO, CaO, SrO, and BaO [MgO + CaO + SrO + BaO] is preferably 8.0%, and more preferably 5.0%, 4.0%, 3.0%, 1.5%, 1.0%, and 0.5%, in this order. The lower limit of this total content is preferably 0%. This total content may also be 0%.

MgO、CaO、SrO、BaO均為具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，這些玻璃成分的含量變多時，損害高分散性，另外，玻璃的熱穩定性及耐失透性降低。另外，BaO的含量過多時，玻璃的比重增大。因此，這些玻璃成分的各含量及合計含量較佳為上述範圍。MgO, CaO, SrO, and BaO are all glass components that improve the thermal stability and devitrification resistance of glass. However, increasing the content of these glass components impairs high dispersibility and reduces the thermal stability and devitrification resistance of the glass. Furthermore, excessive BaO content increases the specific gravity of the glass. Therefore, the individual and combined content of these glass components is preferably within the above ranges.

在第3實施方式的光學玻璃中，ZnO的含量的上限較佳為10%，進一步以6%、4%、3%的順序更佳。較佳為ZnO含量少的情況，其下限較佳為0%。ZnO的含量也可以為0%。In the optical glass of the third embodiment, the upper limit of the ZnO content is preferably 10%, and more preferably 6%, 4%, and 3% in that order. When the ZnO content is low, the lower limit is preferably 0%. The ZnO content may also be 0%.

ZnO是具有改善玻璃的熱穩定性的作用玻璃成分。然而，ZnO的含量過多時，玻璃的比重增大，而且，相對折射率溫度係數(dn/dT)變高。因此，ZnO的含量較佳為上述範圍。ZnO is a glass component that improves the thermal stability of glass. However, excessive ZnO content increases the specific gravity of the glass and the relative refractive index temperature coefficient (dn/dT). Therefore, the ZnO content is preferably within the above range.

在第3實施方式的光學玻璃中，Na 2O的含量相對於Na 2O及ZnO的合計含量的質量比[Na 2O/(Na 2O＋ZnO)]的下限較佳為0.50，進一步以0.60、0.70、0.90的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the lower limit of the mass ratio of the Na2O content to the total content of Na2O and ZnO [ Na2O /( Na2O + ZnO)] is preferably 0.50, more preferably 0.60, 0.70, and 0.90, in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從抑制玻璃的比重增大的、並且抑制相對折射率溫度係數(dn/dT)上升的觀點考慮，質量比[Na 2O/(Na 2O＋ZnO)]較佳為上述範圍。 From the viewpoint of suppressing an increase in the specific gravity of the glass and suppressing an increase in the relative refractive index temperature coefficient (dn/dT), the mass ratio [Na 2 O/(Na 2 O + ZnO)] is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2的含量相對於TiO 2及ZnO的合計含量的質量比[TiO 2/(TiO 2＋ZnO)]的下限較佳為0.70，進一步以0.80、0.90、0.95的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the TiO2 content to the total content of TiO2 and ZnO [ TiO2 /( TiO2 +ZnO)] is preferably 0.70, more preferably 0.80, 0.90, and 0.95, in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到高分散且抑制了相對折射率溫度係數(dn/dT)的上升的玻璃的觀點考慮，質量比[TiO 2/(TiO 2＋ZnO)]較佳為上述範圍。 From the viewpoint of obtaining glass having high dispersion and suppressing an increase in the relative refractive index temperature coefficient (dn/dT), the mass ratio [TiO 2 /(TiO 2 + ZnO)] is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2及Nb 2O 5的合計含量相對於TiO 2、Nb 2O 5、WO 3、Bi 2O 3及ZnO的合計含量的質量比[(TiO 2＋Nb 2O 5)/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋ZnO)]的下限較佳為0.70，進一步以0.80、0.90、0.95的順序更佳。另外，該質量比的上限較佳為1.00。該質量比也可以為1.00。 In the optical glass of the third embodiment, the mass ratio of the total content of TiO2 and Nb2O5 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and ZnO [(TiO2 + Nb2O5 ) / ( TiO2 + Nb2O5 + WO3 + Bi2O3 + ZnO)] is preferably 0.70, more preferably 0.80, 0.90, and 0.95 , in that order. The upper limit of this mass ratio is preferably 1.00. This mass ratio may also be 1.00.

從得到高折射率高分散、且抑制了相對折射率溫度係數(dn/dT)的上升的玻璃的觀點考慮，質量比[(TiO 2＋Nb 2O 5)/(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋ZnO)]較佳為上述範圍。 From the viewpoint of obtaining glass with high refractive index and high dispersion while suppressing the increase in the relative refractive index temperature coefficient (dn/ dT ), the mass ratio [( TiO2 + Nb2O5 )/( TiO2 + Nb2O5 + WO3 + Bi2O3 + ZnO)] is preferably within the above range.

在第3實施方式的光學玻璃中，TiO 2、Nb 2O 5、WO 3、Bi 2O 3及Ta 2O 5的合計含量相對於P 2O 5、B 2O 3、SiO 2、Al 2O 3、Li 2O、Na 2O、K 2O及Cs 2O的合計含量的質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]較佳為1.10以下。該質量比的上限較佳為1.00，進一步以0.95、0.90、0.85、0.82、0.80的順序更佳。另外，該質量比的下限更佳為0.50，進一步以0.60、0.65、0.68、0.70的順序更佳。 In the optical glass of the third embodiment, the mass ratio of the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 to the total content of P2O5 , B2O3 , SiO2 , Al2O3 , Li2O , Na2O , K2O , and Cs2O [ ( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] is preferably 1.10 or less . The upper limit of the mass ratio is preferably 1.00, and more preferably in the order of 0.95, 0.90, 0.85, 0.82, and 0.80. The lower limit of the mass ratio is more preferably 0.50, and more preferably in the order of 0.60, 0.65, 0.68, and 0.70.

藉由將質量比[(TiO 2＋Nb 2O 5＋WO 3＋Bi 2O 3＋Ta 2O 5)/(P 2O 5＋B 2O 3＋SiO 2＋Al 2O 3＋Li 2O＋Na 2O＋K 2O＋Cs 2O)]設為上述範圍，容易得到具有期望的光學常數的光學玻璃。 By setting the mass ratio [( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] within the above range, optical glass having desired optical constants can be easily obtained.

在第3實施方式的光學玻璃中，ZrO 2的含量較佳為5%以下，進一步以3%以下、1%以下的順序更佳。另外，ZrO 2的含量的下限較佳為0%。 In the optical glass of the third embodiment, the ZrO2 content is preferably 5% or less, more preferably 3% or less, and more preferably 1% or less. The lower limit of the ZrO2 content is preferably 0%.

ZrO 2是具有改善玻璃的熱穩定性及耐失透性的作用的玻璃成分。然而，ZrO 2的含量過多時，顯示出熱穩定性降低的傾向。因此，ZrO 2的含量較佳為上述範圍。 ZrO₂ is a glass component that improves the thermal stability and devitrification resistance of glass. However, excessive ZrO₂ content tends to reduce thermal stability. Therefore, the ZrO₂ content is preferably within the above range.

在第3實施方式的光學玻璃中，Sc 2O 3的含量的上限較佳為2%。另外，Sc 2O 3的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the Sc 2 O 3 content is preferably 2%. In addition, the lower limit of the Sc 2 O 3 content is preferably 0%.

在第3實施方式的光學玻璃中，HfO 2的含量的上限較佳為2%。另外，HfO 2的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the HfO 2 content is preferably 2%. In addition, the lower limit of the HfO 2 content is preferably 0%.

Sc 2O 3、HfO 2均具有提高折射率nd的作用，而且是昂貴的成分。因此，Sc 2O 3、HfO 2的各含量較佳為上述範圍。 Sc 2 O 3 and HfO 2 both have the effect of increasing the refractive index nd and are expensive components. Therefore, the content of each of Sc 2 O 3 and HfO 2 is preferably within the above range.

在第3實施方式的光學玻璃中，Lu 2O 3的含量的上限較佳為2%。另外，Lu 2O 3的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the Lu 2 O 3 content is preferably 2%. In addition, the lower limit of the Lu 2 O 3 content is preferably 0%.

Lu 2O 3具有提高折射率nd的作用。另外，其分子量大，因此也是增加玻璃的比重的玻璃成分。因此，Lu 2O 3的含量較佳為上述範圍。 Lu₂O₃ has the effect of increasing the refractive index nd. Furthermore, due to its high molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, the Lu₂O₃ content is preferably within the above range.

在第3實施方式的光學玻璃中，GeO 2的含量的上限較佳為2%。另外，GeO 2的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the GeO 2 content is preferably 2%. In addition, the lower limit of the GeO 2 content is preferably 0%.

GeO 2具有提高折射率nd的作用，而且是在通常使用的玻璃成分中特別地昂貴的成分。因此，從降低玻璃的製造成本的觀點考慮，GeO 2的含量較佳為上述範圍。 GeO2 has the effect of increasing the refractive index nd and is a particularly expensive component among commonly used glass components. Therefore, from the perspective of reducing the production cost of glass, the GeO2 content is preferably within the above range.

在第3實施方式的光學玻璃中，La 2O 3的含量的上限較佳為2%。另外，La 2O 3的含量的下限較佳為0%。La 2O 3的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the La 2 O 3 content is preferably 2%. In addition, the lower limit of the La 2 O 3 content is preferably 0%. The La 2 O 3 content may also be 0%.

La 2O 3的含量變多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，La 2O 3的含量較佳為上述範圍。 When the La2O3 content increases, the thermal stability and devitrification resistance of the glass decrease, and the glass becomes more likely to devitrify during production. Therefore, from the perspective of suppressing the decrease in thermal stability and devitrification resistance, the La2O3 content is preferably within the above range.

在第3實施方式的光學玻璃中，Gd 2O 3的含量的上限較佳為2%。另外，Gd 2O 3的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the content of Gd 2 O 3 is preferably 2%. In addition, the lower limit of the content of Gd 2 O 3 is preferably 0%.

Gd 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低，在製造中，玻璃變得容易失透。另外，Gd 2O 3的含量過多時，玻璃的比重增大而不佳。因此，從良好地保持玻璃的熱穩定性及耐失透性、同時抑制比重的增大的觀點考慮，Gd 2O 3的含量較佳為上述範圍。 If the Gd₂O₃ content is too high, the thermal stability and devitrification resistance of the glass will decrease, making the glass more susceptible to devitrification during production. Furthermore, if the Gd₂O₃ content is too high, the specific gravity of the glass will increase, which is not desirable. Therefore, from the perspective of maintaining good thermal stability and devitrification resistance of the glass while suppressing an increase in specific gravity, the Gd₂O₃ content is preferably within the above range.

在第3實施方式的光學玻璃中，Y 2O 3的含量的上限較佳為2%。另外，Y 2O 3的含量的下限較佳為0%。Y 2O 3的含量也可以為0%。 In the optical glass of the third embodiment, the upper limit of the Y 2 O 3 content is preferably 2%. In addition, the lower limit of the Y 2 O 3 content is preferably 0%. The Y 2 O 3 content may also be 0%.

Y 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。因此，從抑制熱穩定性及耐失透性的降低的觀點考慮，Y 2O 3的含量較佳為上述範圍。 If the content of Y2O3 is too high, the thermal stability and devitrification resistance of the glass will decrease. Therefore, from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance, the content of Y2O3 is preferably within the above range.

在第3實施方式的光學玻璃中，Yb 2O 3的含量的上限較佳為2%。另外，Yb 2O 3的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the Yb 2 O 3 content is preferably 2%. In addition, the lower limit of the Yb 2 O 3 content is preferably 0%.

Yb 2O 3與La 2O 3、Gd 2O 3、Y 2O 3相比分子量大，因此會增大玻璃的比重。玻璃的比重增大時，光學元件的質量增大。例如，如果將質量大的透鏡導入自動對焦式的攝像透鏡，則自動對焦時，透鏡的驅動所需的電力增大，電池的消耗變得嚴重。因此，期望降低Yb 2O 3的含量，抑制玻璃的比重的增大。 Yb2O3 has a higher molecular weight than La2O3 , Gd2O3 , and Y2O3 , and therefore increases the specific gravity of glass. When the specific gravity of glass increases, the mass of the optical component increases. For example, if a heavy lens is incorporated into an autofocus camera lens, the power required to drive the lens increases during autofocus, significantly increasing battery drain. Therefore, it is desirable to reduce the Yb2O3 content to suppress the increase in the specific gravity of glass.

另外，Yb 2O 3的含量過多時，玻璃的熱穩定性及耐失透性降低。從防止玻璃的熱穩定性的降低、抑制比重的增大的觀點考慮，Yb 2O 3的含量較佳為上述範圍。 In addition, if the content of Yb2O3 is too high, the thermal stability and devitrification resistance of the glass will be reduced. From the viewpoint of preventing the reduction of the thermal stability of the glass and suppressing the increase of the specific gravity, the content of Yb2O3 is preferably within the above range.

較佳為第3實施方式的光學玻璃主要以上述的玻璃成分、即作為必要成分的P 2O 5、Nb 2O 5、B 2O 3、TiO 2、Na 2O、K 2O、作為任意成分的Al 2O 3、SiO 2、WO 3、Bi 2O 3、Ta 2O 5、Li 2O、Cs 2O、MgO、CaO、SrO、BaO、ZnO、ZrO 2、Sc 2O 3、HfO 2、Lu 2O 3、GeO 2、La 2O 3、Gd 2O 3、Y 2O 3、及Yb 2O 3構成，上述的玻璃成分的合計含量較佳為95%以上、更佳為98%以上、進一步較佳為99%以上、更進一步較佳為99.5%以上。 The optical glass preferably according to the third embodiment mainly comprises the above-mentioned glass components , namely, P2O5 , Nb2O5 , B2O3 , TiO2 , Na2O , and K2O as essential components, and Al2O3 , SiO2 , WO3 , Bi2O3 , Ta2O5 , Li2O , Cs2O , MgO , CaO, SrO , BaO, ZnO, ZrO2 , Sc2O3 , HfO2 , Lu2O3 , GeO2 , La2O3 , Gd2O3 , Y2O3 , and Yb2O3 as optional components . 3 , the total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and even more preferably 99.5% or more.

在第3實施方式的光學玻璃中，TeO 2的含量的上限較佳為2%。另外，TeO 2的含量的下限較佳為0%。 In the optical glass of the third embodiment, the upper limit of the TeO 2 content is preferably 2%. In addition, the lower limit of the TeO 2 content is preferably 0%.

TeO 2具有毒性，因此，較佳為減少TeO 2的含量。因此，TeO 2的含量較佳為上述範圍。 TeO 2 is toxic, so it is better to reduce the content of TeO 2. Therefore, the content of TeO 2 is preferably within the above range.

在第3實施方式的光學玻璃中，氟F的含量較佳為3%以下，其上限以1%、0.5%、0.3%的順序更佳。較佳為F的含量少的情況，其下限較佳為0%。F的含量也可以為0%。另外，較佳為實質上不含氟F。In the optical glass of the third embodiment, the fluorine (F) content is preferably 3% or less, with the upper limit preferably being 1%, 0.5%, and 0.3%, respectively. When the F content is low, the lower limit is preferably 0%. The F content may be 0%. Furthermore, it is preferred that the glass contain substantially no fluorine (F).

藉由將F的含量設為上述範圍，可以抑制玻璃在熔解中的揮發，可以抑制折射率的變動、條紋。By setting the F content within the above range, volatility of the glass during melting can be suppressed, and fluctuations in the refractive index and the formation of striations can be suppressed.

需要說明的是，較佳為第3實施方式的光學玻璃基本上由上述玻璃成分構成，但也可以在不妨礙本發明的作用效果的範圍內含有其它成分。另外，在本發明中，不排除含有不可避免的雜質。It should be noted that the optical glass of the third embodiment is preferably composed essentially of the above-mentioned glass components, but may also contain other components within the scope that does not hinder the effects of the present invention. In addition, the present invention does not exclude the inclusion of inevitable impurities.

＜其它成分組成＞ Pb、As、Cd、Tl、Be、Se均具有毒性。因此，較佳為第3實施方式的光學玻璃不含這些元素作為玻璃成分。 <Other Components> Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferred that the optical glass of the third embodiment does not contain these elements as glass components.

U、Th、Ra均為放射性元素。因此，較佳為第3實施方式的光學玻璃不含這些元素作為玻璃成分。U, Th, and Ra are all radioactive elements. Therefore, it is preferred that the optical glass of the third embodiment does not contain these elements as glass components.

V、Cr、Mn、Fe、Co、Ni、Cu、Pr、Nd、Pm、Sm、Eu、Tb、Dy、Ho、Er、Tm可以增大玻璃的著色、成為螢光的發生源。因此，較佳為第3實施方式的光學玻璃不含這些元素作為玻璃成分。V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, and Tm can enhance the coloration of glass and serve as a source of fluorescence. Therefore, it is preferred that the optical glass of the third embodiment does not contain these elements as glass components.

Sb(Sb 2O 3)、Ce(CeO 2)是作為澄清劑發揮功能的可以任意添加的元素。其中，Sb(Sb 2O 3)是澄清效果大的澄清劑。然而，Sb(Sb 2O 3)的氧化性強，如果增大Sb(Sb 2O 3)的添加量，則由於由Sb離子導致的光吸收，玻璃的著色增大而不佳。另外，將玻璃熔融時，如果熔融物中存在Sb，則會促進構成玻璃熔融坩堝的鉑對熔融物的溶出，玻璃中的鉑濃度變高。在玻璃中，鉑以離子的形式存在時，由於光的吸收，玻璃的著色增大。另外，在玻璃中，鉑以固體物質的形式存在時，成為光的散射源，會降低玻璃的品質。Ce(CeO 2)與Sb(Sb 2O 3)相比，澄清效果小。如果大量添加Ce(CeO 2)，則玻璃的著色增強。因此，在添加澄清劑的情況下，較佳為一邊注意添加量一邊添加Sb(Sb 2O 3)。 Sb (Sb 2 O 3 ) and Ce (CeO 2 ) are elements that can be added arbitrarily, functioning as clarifiers. Of these, Sb (Sb 2 O 3 ) is the most effective clarifier. However, Sb (Sb 2 O 3 ) is highly oxidizing, and increasing the amount of Sb (Sb 2 O 3 ) added increases the coloration of the glass due to light absorption by Sb ions, resulting in poor quality. Furthermore, when melting glass, the presence of Sb in the melt promotes the dissolution of platinum, which constitutes the glass's crucible, into the melt, increasing the platinum concentration in the glass. When platinum exists in the form of ions in the glass, light absorption increases the coloration of the glass. Furthermore, when platinum exists in the form of solid matter in the glass, it becomes a source of light scattering, reducing the quality of the glass. Ce (CeO 2 ) has a smaller clarification effect than Sb (Sb 2 O 3 ). If a large amount of Ce (CeO 2 ) is added, the coloring of the glass will be enhanced. Therefore, when adding a clarifier, it is better to add Sb (Sb 2 O 3 ) while paying attention to the amount of addition.

將Sb 2O 3的含量設為外加比例表示。即，將除Sb 2O 3及CeO 2以外的全部玻璃成分的合計含量設為100質量%時，Sb 2O 3的含量較佳小於1質量%、更佳小於0.1質量%。進一步以小於0.05質量%、小於0.03質量%、小於0.02質量%、小於0.01%的順序較佳。Sb 2O 3的含量也可以為0質量%。 The Sb2O3 content is expressed as an added percentage. Specifically, when the total content of all glass components excluding Sb2O3 and CeO2 is taken as 100% by mass, the Sb2O3 content is preferably less than 1% by mass, more preferably less than 0.1% by mass. Further preferably, the Sb2O3 content is less than 0.05% by mass, less than 0.03% by mass, less than 0.02% by mass, and less than 0.01% by mass, in that order. The Sb2O3 content may also be 0% by mass.

將CeO 2的含量也設為外加比例表示。即，將除CeO 2、Sb 2O 3以外的全部玻璃成分的合計含量設為100質量%時，CeO 2的含量較佳小於2質量%、更佳小於1質量%、進一步較佳小於0.5質量%、更進一步較佳小於0.1質量%的範圍。CeO 2的含量也可以為0質量%。藉由將CeO 2的含量設為上述範圍，從而可以改善玻璃的澄清性。 The CeO2 content is also expressed as an added percentage. That is, when the total content of all glass components excluding CeO2 and Sb2O3 is set to 100% by mass, the CeO2 content is preferably less than 2% by mass, more preferably less than 1% by mass, further preferably less than 0.5% by mass, and even more preferably less than 0.1% by mass. The CeO2 content may also be 0% by mass. By setting the CeO2 content within the above range, the clarity of the glass can be improved.

(玻璃特性) 接下來，對第3實施方式的光學玻璃的特性進行說明。 (Glass Properties) Next, the properties of the optical glass of the third embodiment will be described.

＜折射率nd＞ 在第3實施方式的光學玻璃中，折射率nd較佳為1.63~1.80。折射率nd的下限可以為1.65、1.67、1.69、1.71或1.73，折射率nd的上限可以為1.79、1.78或1.77。 <Refractive Index nd> In the optical glass of the third embodiment, the refractive index nd is preferably 1.63 to 1.80. The lower limit of the refractive index nd can be 1.65, 1.67, 1.69, 1.71, or 1.73, and the upper limit of the refractive index nd can be 1.79, 1.78, or 1.77.

可以藉由適宜調整各玻璃成分的含量而使折射率nd為期望的值。具有相對地提高折射率nd的作用的成分(高折射率化成分)為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2、La 2O 3等。另一方面，具有相對地降低折射率nd的作用的成分(低折射率化成分)為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O等。 The refractive index nd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components that relatively increase the refractive index nd (refractive index-increasing components) include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , ZrO2 , and La2O3 . On the other hand, components that relatively decrease the refractive index nd (refractive index-lowering components) include P2O5 , SiO2 , B2O3 , Li2O , Na2O , and K2O .

＜阿貝數νd＞ 在第3實施方式的光學玻璃中，阿貝數νd較佳為20~30。阿貝數νd的下限可以為22、22.5、23或23.2，阿貝數νd的上限可以為28、26或25。 <Abbe Number νd> In the optical glass of the third embodiment, the Abbe number νd is preferably 20 to 30. The lower limit of the Abbe number νd can be 22, 22.5, 23, or 23.2, and the upper limit of the Abbe number νd can be 28, 26, or 25.

可以藉由適宜調整各玻璃成分的含量而使阿貝數νd為期望的值。阿貝數νd相對較低的成分、即高分散化成分為Nb 2O 5、TiO 2、WO 3、Bi 2O 3、Ta 2O 5、ZrO 2等。另一方面，阿貝數νd相對較高的成分、即低分散化成分為P 2O 5、SiO 2、B 2O 3、Li 2O、Na 2O、K 2O、La 2O 3、BaO、CaO、SrO等。 The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. Components with relatively low Abbe numbers νd, i.e. , highly dispersed components, include Nb2O5 , TiO2 , WO3 , Bi2O3 , Ta2O5 , and ZrO2 . On the other hand, components with relatively high Abbe numbers νd, i.e., low dispersed components, include P2O5 , SiO2 , B2O3 , Li2O , Na2O , K2O , La2O3 , BaO, CaO, and SrO .

<平均線性熱膨脹係數α> <Average linear thermal expansion coefficient α>

在第3實施方式的光學玻璃中，100~300℃的平均線性熱膨脹係數α的下限較佳為100×10-7℃-1，進一步以102×10-7℃-1、104×10-7℃-1、106×10-7℃-1、108×10-7℃-1的順序更佳。另外，平均線性熱膨脹係數α的上限更佳為200×10-7℃-1，進一步以190×10-7℃-1、180×10-7℃-1、170×10-7℃-1、160×10-7℃-1、150×10-7℃-1、145×10-7℃-1的順序更佳。 In the optical glass of the third embodiment, the lower limit of the average linear thermal expansion coefficient α at 100-300°C is preferably 100× 10-7 °C -1 , more preferably in the order of 102× 10-7 °C -1 , 104× 10-7 °C -1 , 106× 10-7 °C -1 , and 108× 10-7 °C -1 . Furthermore, the upper limit of the average linear thermal expansion coefficient α is more preferably 200× 10-7 °C -1 , more preferably in the order of 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 , and 145× 10-7 °C -1 .

藉由將100~300℃的平均線性熱膨脹係數α設為上述範圍，可以抑制折射率伴隨著玻璃的熱膨脹的變化、即抑制相對折射率溫度係數dn/dT的增大。 By setting the average linear thermal expansion coefficient α between 100°C and 300°C within the above range, the change in refractive index associated with thermal expansion of the glass, that is, the increase in the relative refractive index temperature coefficient dn/dT, can be suppressed.

平均線性熱膨脹係數α基於JOGIS08-2003的規定來測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定溫度和試樣的伸長率。 The average linear thermal expansion coefficient α is measured according to JOGIS08-2003. The specimen is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN is applied to the specimen, which is heated at a constant rate of 4°C per minute. The temperature and elongation of the specimen are measured.

需要說明的是，在本說明書中，將平均線性熱膨脹係數α用[℃-1]的單位表示，但在使用[K-1]作為單位的情況下，平均線性熱膨脹係數α的數值也相同。 In this specification, the average linear thermal expansion coefficient α is expressed in units of [°C -1 ]. However, the value of the average linear thermal expansion coefficient α is the same even when [K -1 ] is used as the unit.

<相對折射率溫度係數dn/dT> <Relative refractive index temperature coefficient dn/dT>

在第3實施方式的光學玻璃中，He-Ne雷射的波長(633nm)下的相對折射率溫度係數dn/dT在20~40℃的範圍內較佳為-1.0×10-6~-13.0×10-6℃-1，進一步以-1.0×10-6~-10.0×10-6℃-1、-1.3×10-6~-9.0×10-6℃-1、-1.3×10-6~-8.0×10-6℃-1、-1.5×10-6~-7.0×10-6℃-1、-1.6×10-6~-6.5×10-6℃-1的順序更佳。 In the optical glass of the third embodiment, the relative refractive index temperature coefficient dn/dT at the wavelength (633 nm) of a He-Ne laser is preferably -1.0× 10-6 to -13.0× 10-6 °C -1 within the range of 20°C to 40°C, and more preferably in the order of -1.0× 10-6 to -10.0× 10-6 °C -1 , -1.3× 10-6 to -9.0× 10-6 °C -1 , -1.3× 10-6 to -8.0× 10-6 °C -1 , -1.5× 10-6 to -7.0× 10-6 °C -1 , and -1.6× 10-6 to -6.5× 10-6 °C -1 .

藉由將dn/dT設為上述範圍，並與dn/dT為正的光學元件組合，即使在光學元件的溫度大幅變動這樣的環境中，折射率的變動也小，因此，可以在更寬的溫度範圍中以高精度發揮期望的光學特性。 By setting dn/dT within the above range and combining it with an optical element with positive dn/dT, fluctuations in the refractive index are minimized even in environments where the optical element's temperature fluctuates significantly. This allows the desired optical characteristics to be exhibited with high precision over a wider temperature range.

相對折射率溫度係數dn/dT基於JOGIS18-2008的干涉法來測定。 The relative refractive index temperature coefficient dn/dT is measured using the interferometry method according to JOGIS18-2008.

需要說明的是，在本說明書中，將溫度係數dn/dT用[℃-1]的單位表示，但在使用[K -1]作為單位的情況下，溫度係數dn/dT的數值也相同。 In this specification, the temperature coefficient dn/dT is expressed in units of [°C -1 ]. However, the value of the temperature coefficient dn/dT is the same even when [K -1 ] is used as the unit.

＜玻璃化轉變溫度Tg＞ 第3實施方式的光學玻璃的玻璃化轉變溫度Tg較佳為600℃以下，進一步以590℃以下、580℃以下、570℃以下、560℃以下的順序更佳。 <Glass Transition Temperature (Tg)> The glass transition temperature (Tg) of the optical glass of the third embodiment is preferably 600°C or lower, and more preferably 590°C or lower, 580°C or lower, 570°C or lower, and 560°C or lower, in that order.

藉由使玻璃化轉變溫度Tg的上限滿足上述範圍，可以抑制玻璃的成型溫度及退火溫度的上升，可以降低熱對壓製成型用設備及退火設備的損傷。另外，藉由使玻璃化轉變溫度Tg的下限滿足上述範圍，容易在保持期望的阿貝數、折射率的同時，良好地保持玻璃的熱穩定性。By ensuring that the upper limit of the glass transition temperature (Tg) falls within the above range, increases in the glass forming and annealing temperatures can be suppressed, reducing thermal damage to press-forming and annealing equipment. Furthermore, by ensuring that the lower limit of the glass transition temperature (Tg) falls within the above range, it is easier to maintain the desired Abbe number and refractive index while also maintaining good thermal stability of the glass.

＜玻璃的比重＞ 在第3實施方式的光學玻璃中，比重較佳為3.40以下，進一步以3.30以下、3.20以下的順序更佳。如果可以減少玻璃的比重，則可以減少透鏡的重量。其結果，可以降低搭載透鏡的相機透鏡的自動對焦驅動的消耗電力。 <Glass Specific Gravity> In the optical glass of the third embodiment, the specific gravity is preferably 3.40 or less, more preferably 3.30 or less, and even more preferably 3.20 or less. Reducing the specific gravity of the glass can reduce the weight of the lens. Consequently, the power consumption of the autofocus drive of a camera lens equipped with the lens can be reduced.

＜玻璃的透光性＞ 第3實施方式的光學玻璃的透光性可以藉由著色度λ5來評價。 對於厚度10.0mm±0.1mm的玻璃試樣，在波長200~700nm的範圍內測定分光透射率，將外部透射率成為5%的波長設為λ5。 <Light Transmittance of Glass> The light transmittance of the optical glass of the third embodiment can be evaluated using the chromaticity λ5. For glass samples with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured within the wavelength range of 200 to 700 nm. The wavelength at which the external transmittance reaches 5% was defined as λ5.

第3實施方式的光學玻璃的λ5較佳為400nm以下，更佳為390nm以下，進一步較佳為385nm以下。The λ5 of the optical glass according to the third embodiment is preferably 400 nm or less, more preferably 390 nm or less, and even more preferably 385 nm or less.

藉由使用將λ5短波長化後的光學玻璃，可以提供可實現適宜的顏色再現的光學元件。By using optical glass with a shorter wavelength of λ5, it is possible to provide optical elements that achieve appropriate color reproduction.

對於第3實施方式的光學玻璃的製造及光學元件等製造，設為與第1實施方式同樣。The production of optical glass and optical elements of the third embodiment are the same as those of the first embodiment.

以下，藉由實施例更具體地說明本發明，但本發明不僅限定於以下的實施例。需要說明的是，實施例1-1、1-2與第1實施方式對應，實施例2-1、2-2與第2實施方式對應，實施例3-1、3-2與第3實施方式對應。 The present invention is described in more detail below using examples, but the present invention is not limited to the following examples. It should be noted that Examples 1-1 and 1-2 correspond to the first embodiment, Examples 2-1 and 2-2 correspond to the second embodiment, and Examples 3-1 and 3-2 correspond to the third embodiment.

(實施例1-1) (Example 1-1)

[玻璃樣品的製作] [Glass Sample Preparation]

以成為具有表1-1~1-6中示出的試樣No.1~52的組成的玻璃的方式，稱量與各成分對應的化合物原料、即磷酸鹽、碳酸鹽、氧化物等原料，充分混合，製成了調配原料。將該調配原料投入鉑製坩堝，在大氣氣氛中加熱至900~1350℃，使其熔融，藉由攪拌使其均質化，進行澄清，得到了熔融玻璃。將該熔融玻璃鑄入成型模具，進行成型並緩慢冷卻，得到了塊狀的玻璃樣品。 To produce glasses having the compositions of Samples Nos. 1 to 52 shown in Tables 1-1 to 1-6, the compound raw materials corresponding to the respective components, namely phosphates, carbonates, oxides, etc., were weighed and thoroughly mixed to prepare the prepared raw materials. These prepared raw materials were placed in a platinum crucible and heated to 900-1350°C in an atmospheric atmosphere to melt. The mixture was homogenized by stirring and clarified to obtain molten glass. The molten glass was cast into a forming mold, shaped, and slowly cooled to obtain a block-shaped glass sample.

需要說明的是，可以將調配原料投入石英玻璃製坩堝，熔融後轉移至鉑製坩堝，進一步進行加熱，使其熔融，藉由攪拌使其均質化，進行澄清，將得到的熔融玻璃鑄入成型模具，進行成型、緩慢冷卻。 It should be noted that the raw materials can be placed in a quartz glass crucible, melted, and then transferred to a platinum crucible. They are further heated to melt, stirred to homogenize, and clarified. The resulting molten glass is then cast into a mold, formed, and slowly cooled.

[玻璃樣品的評價] [Evaluation of glass samples]

對於得到的玻璃樣品，藉由以下示出的方法測定玻璃組成、比重、折射率nd、阿貝數νd、λ5、玻璃化轉變溫度Tg、相對折射率溫度係數dn/dT、平均線性熱膨脹係數α，將結果示於表1-1、1-2、1-4。 The glass composition, specific gravity, refractive index nd, Abbe number νd, λ5, glass transition temperature Tg, relative refractive index temperature coefficient dn/dT, and average linear thermal expansion coefficient α of the obtained glass samples were measured using the methods described below. The results are shown in Tables 1-1, 1-2, and 1-4.

〔1〕玻璃組成 [1] Glass composition

對於得到的玻璃樣品，藉由電感耦合電漿原子發射光譜法(ICP-AES)測定了各玻璃成分的含量。 The contents of various glass components in the obtained glass samples were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

〔2〕比重 〔2〕Specific gravity

基於日本光學硝子工業會標準JOGIS-05進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-05.

〔3〕折射率nd及阿貝數νd 〔3〕Refractive index nd and Abbe number νd

基於日本光學硝子工業會標準JOGIS-01進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-01.

〔4〕λ5 〔4〕λ5

將玻璃樣品加工成厚度10mm、且具有相互平行且經光學研磨的平面，測定 在波長280nm~700nm的波長區的分光透射率。將垂直入射至經光學研磨的一個平面的光線的強度設為強度A，將從另一個平面出射的光線的強度設為強度B，計算出了分光透射率B/A。將分光透射率為5%的波長設為λ5。需要說明的是，分光透射率中也包括試樣表面的光線的反射損失。 A glass sample with a thickness of 10 mm and parallel, optically polished flat surfaces was processed. Spectral transmittance was measured in the wavelength range of 280 nm to 700 nm. The intensity of light perpendicularly incident on one optically polished surface was defined as intensity A, and the intensity of light emitted from the other surface was defined as intensity B. The spectral transmittance B/A was calculated. The wavelength at which the spectral transmittance reached 5% was defined as λ5. Note that the spectral transmittance also includes reflection loss from the sample surface.

〔5〕玻璃化轉變溫度Tg [5] Glass transition temperature Tg

玻璃化轉變溫度Tg使用NETZSCH JAPAN公司製造的差示掃描量熱分析裝置(DSC3300SA)，以升溫速度10℃/分進行了測定。 The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN Co., Ltd. at a heating rate of 10°C/min.

〔6〕相對折射率溫度係數dn/dT的測定 〔6〕Determination of relative refractive index temperature coefficient dn/dT

對於得到的玻璃樣品，基於JOGIS18-2008的干涉法進行了測定。光源使用波長633nm的He-Ne雷射，在溫度-70~150℃的範圍內連續地測定。測定結果中，將20℃~40℃的範圍的dn/dT值示於表1-1、1-2、1-4。 The resulting glass samples were measured using the interferometry method described in JOGIS 18-2008. A 633nm He-Ne laser was used as the light source, and measurements were performed continuously over a temperature range of -70°C to 150°C. The dn/dT values for the 20°C to 40°C range are shown in Tables 1-1, 1-2, and 1-4.

〔7〕平均線性熱膨脹係數α的測定 [7] Determination of the average linear thermal expansion coefficient α

100~300℃的平均線性熱膨脹係數α基於JOGIS08-2003的規定進行了測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定了溫度和試樣的伸長率。 The average linear thermal expansion coefficient α from 100 to 300°C was measured according to JOGIS08-2003. The specimen was a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN was applied to the specimen, and the temperature and elongation were measured by heating at a constant rate of 4°C per minute.

[表1-1] [Table 1-1]

[表1-2] [Table 1-2]

[表1-3] [Table 1-3]

[表1-4] [Table 1-4]

[表1-5] [Table 1-5]

[表1-6] [Table 1-6]

(實施例1-2) 對實施例1中得到的玻璃樣品切斷、磨削，製作了碎片。將碎片藉由再熱壓製而壓製成型，製作了光學元件坯料。對光學元件坯料進行精密退火，以成為所需的折射率的方式精密地調整了折射率後，藉由公知的方法進行磨削、研磨，由此得到雙凸透鏡、雙凹透鏡、平凸透鏡、平凹透鏡、凹彎月透鏡、凸彎月透鏡等各種透鏡。 (Example 1-2) The glass sample obtained in Example 1 was cut and ground to produce fragments. The fragments were then hot-pressed and pressed into shapes to produce optical element blanks. The optical element blanks were precision annealed to precisely adjust the refractive index to the desired value. The resulting materials were then ground and polished using known methods to produce various lenses, including biconvex, biconcave, plano-convex, plano-concave, concave meniscus, and convex meniscus.

(實施例2-1) [玻璃樣品的製作] 以成為具有表2-1中示出的試樣No.2-1~2-8的組成的玻璃的方式，稱量與各成分對應的化合物原料、即磷酸鹽、碳酸鹽、氧化物等原料，充分混合，製成了調配原料。將該調配原料投入鉑製坩堝，在大氣氣氛中加熱至900~1350℃，使其熔融，藉由攪拌使其均質化，進行澄清，得到了熔融玻璃。將該熔融玻璃鑄入成型模具，進行成型並緩慢冷卻，得到了塊狀的玻璃樣品。 (Example 2-1) [Glass Sample Preparation] To produce glasses having the compositions of Samples Nos. 2-1 to 2-8 shown in Table 2-1, the compound raw materials corresponding to the respective components, namely, phosphates, carbonates, oxides, etc., were weighed and thoroughly mixed to prepare a raw material blend. This raw material blend was placed in a platinum crucible and heated to 900-1350°C in an atmospheric atmosphere to melt. The mixture was homogenized by stirring and clarified to obtain molten glass. This molten glass was cast into a forming mold, shaped, and slowly cooled to obtain a block-shaped glass sample.

需要說明的是，可以將調配原料投入石英玻璃製坩堝，熔融後轉移至鉑製坩堝，進一步進行加熱，使其熔融，藉由攪拌使其均質化，進行澄清，將得到的熔融玻璃鑄入成型模具，進行成型、緩慢冷卻。 It should be noted that the raw materials can be placed in a quartz glass crucible, melted, and then transferred to a platinum crucible. They are further heated to melt, stirred to homogenize, and clarified. The resulting molten glass is then cast into a mold, formed, and slowly cooled.

[玻璃樣品的評價] [Evaluation of glass samples]

對於得到的玻璃樣品，藉由以下示出的方法測定了玻璃組成、折射率nd、阿貝數νd、λ5、玻璃化轉變溫度Tg、平均線性熱膨脹係數α、相對折射率溫度係數dn/dT、比重，將結果示於表2-3。 The glass composition, refractive index nd, Abbe number νd, λ5, glass transition temperature Tg, average linear thermal expansion coefficient α, relative refractive index temperature coefficient dn/dT, and specific gravity of the obtained glass samples were measured using the methods described below. The results are shown in Table 2-3.

〔1〕玻璃組成 [1] Glass composition

對於得到的玻璃樣品，藉由電感耦合電漿原子發射光譜法(ICP-AES)測定了各玻璃成分的含量。需要說明的是，在表2-3所示的No.2-1~2-8的全部玻璃樣品中，F的含量為0%。 The content of each glass component in the resulting glass samples was measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES). It should be noted that the F content in all glass samples No. 2-1 to 2-8 shown in Table 2-3 was 0%.

〔2〕比重 〔2〕Specific gravity

基於日本光學硝子工業會標準JOGIS-05進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-05.

〔3〕折射率nd及阿貝數νd 〔3〕Refractive index nd and Abbe number νd

基於日本光學硝子工業會標準JOGIS-01進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-01.

〔4〕λ5 〔4〕λ5

將玻璃樣品加工成厚度10mm、且具有相互平行且經光學研磨的平面，測定在波長280nm~700nm的波長區的分光透射率。將垂直入射至經光學研磨的一個平面的光線的強度設為強度A，將從另一個平面出射的光線的強度設為強度B，計算出了分光透射率B/A。將分光透射率為5%的波長設為λ5。需要說明的是，分光透射率中也包括試樣表面的光線的反射損失。 A glass sample with a thickness of 10 mm and parallel, optically polished flat surfaces was processed. Spectral transmittance was measured over the wavelength range of 280 nm to 700 nm. The intensity of light incident perpendicularly on one optically polished surface was defined as intensity A, and the intensity of light emitted from the other surface was defined as intensity B. The spectral transmittance B/A was calculated. The wavelength at which the spectral transmittance reached 5% was defined as λ5. Note that the spectral transmittance also includes reflection loss from the sample surface.

〔5〕玻璃化轉變溫度Tg [5] Glass transition temperature Tg

玻璃化轉變溫度Tg使用NETZSCH JAPAN公司製造的差示掃描量熱分析裝置(DSC3300SA)，以升溫速度10℃/分進行了測定。 The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN Co., Ltd. at a heating rate of 10°C/min.

〔6〕相對折射率溫度係數dn/dT的測定 〔6〕Determination of relative refractive index temperature coefficient dn/dT

對於得到的玻璃樣品，基於JOGIS18-2008的干涉法進行了測定。光源使用波長633nm的He-Ne雷射，在溫度-70~150℃的範圍內連續地測定。測定結果中，將20℃~40℃的範圍的dn/dT值示於表2-3。 The resulting glass samples were measured using the interferometry method described in JOGIS 18-2008. A 633nm He-Ne laser was used as the light source, and measurements were performed continuously over a temperature range of -70°C to 150°C. The dn/dT values for the 20°C to 40°C range are shown in Table 2-3.

〔7〕平均線性熱膨脹係數α的測定 [7] Determination of the average linear thermal expansion coefficient α

100~300℃的平均線性熱膨脹係數α基於JOGIS08-2003的規定進行了測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定了溫度和試樣的伸長率。 The average linear thermal expansion coefficient α from 100 to 300°C was measured according to JOGIS08-2003. The specimen was a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN was applied to the specimen, and the temperature and elongation were measured by heating at a constant rate of 4°C per minute.

[表2-1] [Table 2-1]

[表2-2] [Table 2-2]

[表2-3] [Table 2-3]

(實施例2-2) 對實施例2-1中得到的玻璃樣品切斷、磨削，製作了碎片。將碎片藉由再熱壓製而壓製成型，製作了光學元件坯料。對光學元件坯料進行精密退火，以成為所需的折射率的方式精密地調整了折射率後，藉由公知的方法進行磨削、研磨，由此得到雙凸透鏡、雙凹透鏡、平凸透鏡、平凹透鏡、凹彎月透鏡、凸彎月透鏡等各種透鏡。 (Example 2-2) The glass sample obtained in Example 2-1 was cut and ground to produce fragments. The fragments were then hot-pressed and pressed into shapes to produce optical element blanks. The optical element blanks were precision annealed to precisely adjust the refractive index to the desired value. The resulting materials were then ground and polished using known methods to produce various lenses, including biconvex, biconcave, plano-convex, plano-concave, concave meniscus, and convex meniscus.

(實施例3-1) [玻璃樣品的製作] 以成為具有表3-1中示出的試樣No.3-1~3-8的組成的玻璃的方式，稱量與各成分對應的化合物原料、即磷酸鹽、碳酸鹽、氧化物等原料，充分混合，製成了調配原料。將該調配原料投入鉑製坩堝，在大氣氣氛中加熱至900~1350℃，使其熔融，藉由攪拌使其均質化，進行澄清，得到了熔融玻璃。將該熔融玻璃鑄入成型模具，進行成型並緩慢冷卻，得到了塊狀的玻璃樣品。 需要說明的是，可以將調配原料投入石英玻璃製坩堝，熔融後轉移至鉑製坩堝，進一步進行加熱，使其熔融，藉由攪拌使其均質化，進行澄清，將得到的熔融玻璃鑄入成型模具，進行成型、緩慢冷卻。 (Example 3-1) [Glass Sample Preparation] To produce glasses having the compositions of Samples Nos. 3-1 to 3-8 shown in Table 3-1, the compound raw materials corresponding to the respective components, namely, phosphates, carbonates, oxides, etc., were weighed and thoroughly mixed to prepare a raw material blend. This raw material blend was placed in a platinum crucible and heated to 900-1350°C in an atmospheric atmosphere to melt. The mixture was homogenized by stirring and clarified to obtain molten glass. This molten glass was cast into a forming mold, shaped, and slowly cooled to obtain a block-shaped glass sample. It should be noted that the raw materials can be placed in a quartz glass crucible, melted, and then transferred to a platinum crucible. They are further heated to melt, stirred to homogenize, and clarified. The resulting molten glass is then cast into a mold, formed, and slowly cooled.

[玻璃樣品的評價] [Evaluation of glass samples]

對於得到的玻璃樣品，藉由以下示出的方法測定了玻璃組成、折射率nd、阿貝數νd、λ5、玻璃化轉變溫度Tg、平均線性熱膨脹係數α、相對折射率溫度係數dn/dT、比重，將結果示於表3-1。 The glass composition, refractive index nd, Abbe number νd, λ5, glass transition temperature Tg, average linear thermal expansion coefficient α, relative refractive index temperature coefficient dn/dT, and specific gravity of the obtained glass samples were measured using the methods described below. The results are shown in Table 3-1.

〔1〕玻璃組成 [1] Glass composition

對於得到的玻璃樣品，藉由電感耦合電漿原子發射光譜法(ICP-AES)測定了各玻璃成分的含量。需要說明的是，在表3-1所示的No.3-1~3-8的全部玻璃樣品中，F的含量為0%。 The contents of various glass components in the resulting glass samples were measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES). It should be noted that the F content in all glass samples No. 3-1 to 3-8 shown in Table 3-1 was 0%.

〔2〕比重 〔2〕Specific gravity

基於日本光學硝子工業會標準JOGIS-05進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-05.

〔3〕折射率nd及阿貝數νd 〔3〕Refractive index nd and Abbe number νd

基於日本光學硝子工業會標準JOGIS-01進行了測定。 Measurements were performed based on the Japan Optical Glass Industries Association standard JOGIS-01.

〔4〕λ5 〔4〕λ5

將玻璃樣品加工成厚度10mm、且具有相互平行且經光學研磨的平面，測定在波長280nm~700nm的波長區的分光透射率。將垂直入射至經光學研磨的一個平面的光線的強度設為強度A，將從另一個平面出射的光線的強度設為強度B，計算出了分光透射率B/A。將分光透射率為5%的波長設為λ5。需要說明的是，分光透射率中也包括試樣表面的光線的反射損失。 A glass sample with a thickness of 10 mm and parallel, optically polished flat surfaces was processed. Spectral transmittance was measured over the wavelength range of 280 nm to 700 nm. The intensity of light incident perpendicularly on one optically polished surface was defined as intensity A, and the intensity of light emitted from the other surface was defined as intensity B. The spectral transmittance B/A was calculated. The wavelength at which the spectral transmittance reached 5% was defined as λ5. Note that the spectral transmittance also includes reflection loss from the sample surface.

〔5〕玻璃化轉變溫度Tg [5] Glass transition temperature Tg

玻璃化轉變溫度Tg使用熱機械分析裝置(TMA)(MAC Science製、TMA-4000S)，以升溫速度4℃/分進行了測定。 The glass transition temperature (Tg) was measured using a thermomechanical analyzer (TMA) (manufactured by MAC Science, TMA-4000S) at a heating rate of 4°C/min.

〔6〕相對折射率溫度係數dn/dT的測定 〔6〕Determination of relative refractive index temperature coefficient dn/dT

對於得到的玻璃樣品，基於JOGIS18-2008的干涉法進行了測定。光源使用波長633nm的He-Ne雷射，在溫度-70~150℃的範圍內連續地測定。測定結果中，將20℃~40℃的範圍的dn/dT值示於表3-1。 The resulting glass samples were measured using the interferometry method described in JOGIS 18-2008. A 633nm He-Ne laser was used as the light source, and measurements were performed continuously over a temperature range of -70°C to 150°C. The dn/dT values for the 20°C to 40°C range are shown in Table 3-1.

〔7〕平均線性熱膨脹係數α的測定 [7] Determination of the average linear thermal expansion coefficient α

100~300℃的平均線性熱膨脹係數α基於JOGIS08-2003的規定進行了測定。其中，將試樣設為長度20mm±0.5mm、直徑5mm±0.5mm的圓桿，在對試樣施加了98mN的負載的狀態下，藉由以每分鐘4℃的恆定速度上升的方式加熱，測定了溫度和試樣的伸長率。 The average linear thermal expansion coefficient α from 100 to 300°C was measured according to JOGIS08-2003. The specimen was a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. A load of 98 mN was applied to the specimen, and the temperature and elongation were measured by heating at a constant rate of 4°C per minute.

(實施例3-2) (Example 3-2)

對實施例3-1中得到的玻璃樣品切斷、磨削，製作了碎片。將碎片藉由再熱壓製而壓製成型，製作了光學元件坯料。對光學元件坯料進行精密退火，以成為所需的折射率的方式精密地調整了折射率後，藉由公知的方法進行磨削、研磨，由此得到雙凸透鏡、雙凹透鏡、平凸透鏡、平凹透鏡、凹彎月透鏡、凸彎月透鏡等各種透鏡。 The glass sample obtained in Example 3-1 was cut and ground to produce fragments. The fragments were then hot-pressed and pressed into shapes to produce optical element blanks. The optical element blanks were precision annealed to precisely adjust the refractive index to the desired value. They were then ground and polished using known methods to produce various lenses, including biconvex, biconcave, plano-convex, plano-concave, concave meniscus, and convex meniscus.

應該理解的是，本次公開的實施方式全部是示例性的，並不構成限制。本發明的範圍由申請專利範圍所示，而不是上述的說明界定，旨在包括與申請專利範圍均等的含義及範圍內的全部變更。It should be understood that the embodiments disclosed herein are exemplary only and are not intended to be limiting. The scope of the present invention is indicated by the claims, not by the foregoing description, and is intended to include all modifications within the meaning and scope equivalent to those in the claims.

例如，藉由對上述示例出的玻璃組成進行了說明書中記載的組成調整，可製作本發明的一態樣的光學玻璃。 另外，當然可以將說明書中示例出的或作為較佳的範圍記載的事項中的2個以上任意組合。 For example, by adjusting the composition of the glass compositions exemplified above as described in the specification, optical glass according to one embodiment of the present invention can be produced. Of course, any combination of two or more of the items exemplified or described as preferred ranges in the specification can be used.

無。without.

無。without.

Claims (9)

一種光學玻璃，其折射率nd為1.63~1.80，阿貝數νd為22~34，Nb2O5的含量為25~55質量%，WO3的含量小於30質量%，TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量[TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5]為36~60質量%，TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量相對於P2O5、B2O3、SiO2、Al2O3、Li2O、Na2O、K2O及Cs2O的合計含量的質量比[(TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5)/(P2O5＋B2O3＋SiO2＋Al2O3＋Li2O＋Na2O＋K2O＋Cs2O)]為1.10以下，TiO2的含量相對於P2O5及B2O3的合計含量的質量比[TiO2/(P2O5＋B2O3)]為0.50以下，K2O的含量為4.81質量%以上，TiO2的含量為15質量%以下，且滿足下述(B)：(B) P2O5的含量為25~38質量%，Al2O3的含量小於5質量%，P2O5、B2O3及SiO2的合計含量相對於Li2O、Na2O、K2O及Cs2O的合計含量的質量比[(P2O5＋B2O3＋SiO2)/(Li2O＋Na2O＋K2O＋Cs2O)]為1.80以下，MgO、CaO、SrO及BaO的合計含量[MgO＋CaO＋SrO＋BaO]為7.0質量%以下，TiO2的含量相對於TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量的質量比[TiO2/(TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5)]為0.25以上，TiO2的含量相對於P2O5及B2O3的合計含量的質量比[TiO2/(P2O5＋B2O3)]為0.47以下。An optical glass having a refractive index nd of 1.63-1.80, an Abbe number νd of 22-34, a Nb 2 O 5 content of 25-55 mass%, a WO 3 content of less than 30 mass%, a 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 ] of 36-60 mass%, and a total content of TiO 2 , Nb 2 O 5 , WO 3 , Bi 2 O 3 and Ta 2 O 5 relative to 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 The mass ratio of the total content of O [(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 TiO 2 content 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 K 2 O content is 4.81 mass% or more, the TiO 2 content is 15 mass% or less, and the following (B) is satisfied: (B) the P 2 O 5 content is 25-38 mass%, the Al 2 O 3 content is less than 5 mass%, and the P 2 The mass ratio of the total content of O 5 , B 2 O 3 and SiO 2 to the total content 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 mass % or less, and 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 [TiO 2 /(TiO 2 ＋Nb 2 O 5 ＋WO 3 ＋Bi 2 O 3 ＋Ta 2 O 5 )] is 0.25 or more, and 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 0.47 or less. 如請求項1所述的光學玻璃，其中，P2O5、B2O3及SiO2的合計含量相對於Li2O、Na2O、K2O及Cs2O的合計含量的質量比[(P2O5＋B2O3＋SiO2)/(Li2O＋Na2O＋K2O＋Cs2O)]為1.00以上。The optical glass according to claim 1, wherein a mass ratio of the total content of P2O5 , B2O3 , and SiO2 to the total content of Li2O , Na2O , K2O , and Cs2O [ ( P2O5 + B2O3 + SiO2 )/( Li2O + Na2O + K2O + Cs2O )] is 1.00 or greater. 如請求項1或2所述的光學玻璃，其中，TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量相對於P2O5、B2O3、SiO2、Al2O3、Li2O、Na2O、K2O及Cs2O的合計含量的質量比[(TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5)/(P2O5＋B2O3＋SiO2＋Al2O3＋Li2O＋Na2O＋K2O＋Cs2O)]為0.50以上。 The optical glass according to claim 1 or 2, wherein the mass ratio of the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 , and Ta2O5 to the total content of P2O5 , B2O3 , SiO2 , Al2O3 , Li2O , Na2O , K2O , and Cs2O [( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) / ( P2O5 + B2O3 + SiO2 + Al2O3 + Li2O + Na2O + K2O + Cs2O ) ] is 0.50 or more . 一種光學玻璃，其中，P2O5的含量為25~50質量%，TiO2的含量為10~50質量%，Nb2O5含量為5~30質量%，TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量[TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5]為35~60質量%，TiO2的含量相對於TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量的質量比[TiO2/(TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5)]為0.25以上，P2O5、B2O3及SiO2的合計含量相對於Li2O、Na2O、K2O及Cs2O的合計含量的質量比[(P2O5＋B2O3＋SiO2)/(Li2O＋Na2O＋K2O＋Cs2O)]為1.75以下，Na2O的含量為13質量%以上，且滿足下述(A)或(B)：(A) WO3的含量為7質量%以下；(B) 實質上不含F。An optical glass, wherein the content of P2O5 is 25-50 mass%, the content of TiO2 is 10-50 mass%, the content of Nb2O5 is 5-30 mass%, the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] is 35-60 mass%, the mass ratio of the content of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 / (TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] is 0.25 or more, and the content of P2O5 is 25-50 mass%, the content of TiO2 is 10-50 mass % , the content of Nb2O5 is 5-30 mass % , the content of TiO2 is 35-60 mass % , the content of Nb2O5 is 10-50 mass %, the content of Nb2O5 is 5-3 ... 5. The mass ratio of the combined content of B2O3 and SiO2 to the combined content of Li2O , Na2O , K2O , and Cs2O [( P2O5 + B2O3 + SiO2 ) / ( Li2O + Na2O + K2O + Cs2O )] is 1.75 or less, the content of Na2O is 13 mass% or more, and the following (A) or (B) are met: (A) the content of WO3 is 7 mass% or less ; (B) F is substantially absent. 一種光學玻璃，其中，P2O5的含量為25~50質量%，Nb2O5含量為14~40質量%，TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量[TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5]為35~60質量%，TiO2的含量相對於TiO2、Nb2O5、WO3、Bi2O3及Ta2O5的合計含量的質量比[TiO2/(TiO2＋Nb2O5＋WO3＋Bi2O3＋Ta2O5)]為0.25以上，B2O3的含量相對於P2O5的含量的質量比[B2O3/P2O5]為0.05~0.39，Li2O、Na2O、K2O及Cs2O的合計含量[Li2O＋Na2O＋K2O＋Cs2O]為10質量%以上，Na2O的含量相對於K2O的含量的質量比[Na2O/K2O]為1.50以上，TiO2的含量相對於P2O5及B2O3的合計含量的質量比[TiO2/(P2O5＋B2O3)]為0.62以下，Na2O的含量為13質量%以上。An optical glass, wherein the content of P2O5 is 25-50 mass%, the content of Nb2O5 is 14-40 mass%, the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ] is 35-60 mass%, the mass ratio of the content of TiO2 to the total content of TiO2 , Nb2O5 , WO3 , Bi2O3 and Ta2O5 [ TiO2 /( TiO2 + Nb2O5 + WO3 + Bi2O3 + Ta2O5 ) ] is 0.25 or more, and the content of B2O3 to P2O5 is 14-40 mass% . The mass ratio of the content of Li2O to that of K2O [ B2O3 / P2O5 ] is 0.05-0.39, the total content of Li2O , Na2O , K2O and Cs2O [ Li2O + Na2O + K2O + Cs2O ] is 10 mass% or more, the mass ratio of the content of Na2O to the content of K2O [ Na2O / K2O ] is 1.50 or more, the mass ratio of the content of TiO2 to the total content of P2O5 and B2O3 [ TiO2 /( P2O5 + B2O3 )] is 0.62 or less, and the content of Na2O is 13 mass % or more. 如請求項5所述的光學玻璃，其實質上不含F。The optical glass as described in claim 5, which is substantially free of F. 如請求項1、2、4~6中任一項所述的光學玻璃，其在100~300℃的平均線性熱膨脹係數α為100×10-7~200×10-7℃-1。The optical glass according to any one of claims 1, 2, and 4 to 6, wherein the average linear thermal expansion coefficient α at 100 to 300°C is 100×10 -7 to 200×10 -7 °C -1 . 如請求項1、2、4~6中任一項所述的光學玻璃，其在He-Ne雷射的波長(633nm)下的相對折射率溫度係數dn/dT在20~40℃的範圍內為-0.1×10-6~-13.0×10-6℃-1。The optical glass according to any one of claims 1, 2, 4 to 6, wherein the relative refractive index temperature coefficient dn/dT at the wavelength (633 nm) of a He-Ne laser is in the range of -0.1×10 -6 to -13.0×10 -6 °C -1 within the range of 20°C to 40°C. 一種光學元件，其由如請求項1~8中任一項所述的光學玻璃製成。An optical element is made of the optical glass as described in any one of claims 1 to 8.
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