WO2017002956A1 - Optical glass and optical element - Google Patents

Optical glass and optical element Download PDF

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Publication number
WO2017002956A1
WO2017002956A1 PCT/JP2016/069603 JP2016069603W WO2017002956A1 WO 2017002956 A1 WO2017002956 A1 WO 2017002956A1 JP 2016069603 W JP2016069603 W JP 2016069603W WO 2017002956 A1 WO2017002956 A1 WO 2017002956A1
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glass
sio
bao
zro
zno
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PCT/JP2016/069603
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French (fr)
Japanese (ja)
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佐藤　浩一
藤原　康裕
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Hoya株式会社
佐藤　浩一
藤原　康裕
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Application filed by Hoya株式会社, 佐藤　浩一, 藤原　康裕 filed Critical Hoya株式会社
Priority to JP2017526448A priority Critical patent/JP7040939B2/en
Priority to CN201680038274.7A priority patent/CN107922241A/en
Publication of WO2017002956A1 publication Critical patent/WO2017002956A1/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
    • C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
    • C03C3/068—Glass compositions containing silica with less than 40% silica by weight containing boron containing rare earths

Definitions

  • the present invention relates to an optical glass and an optical element.
  • Patent Documents 1 to 7 disclose optical glasses having a refractive index nd of 1.65 to 1.72 and an Abbe number ⁇ d of about 50 to 57. These glasses enter into a class having a low glass transition temperature among optical glasses and have a property of softening at a low temperature, that is, a low temperature softening property.
  • Glass with a low glass transition temperature is suitable as a material for producing optical elements by precision press molding.
  • the glass having the above optical characteristics contains a relatively large amount of B 2 O 3 for low dispersion, and contains a rare earth component such as La 2 O 3 in order to increase the refractive index while maintaining low dispersion. . Furthermore, in order to lower the glass transition temperature, a component having a function of lowering the glass transition temperature such as Li 2 O and ZnO is also included.
  • Gd 2 O 3 is a rare earth component, like La 2 O 3 , and has a function of increasing the refractive index while suppressing a decrease in the Abbe number.
  • Ta 2 O 5 has a function of increasing the refractive index and reduces the Abbe number as compared with rare earth oxides.
  • Ta 2 O 5 is relatively less than high refractive index components such as TiO 2 , Nb 2 O 5 , and WO 3. It is a component with a small decrease in Abbe number.
  • Gd 2 O 3 and Ta 2 O 5 are effective components in maintaining the thermal stability of the glass while maintaining high refractive index and low dispersibility.
  • Gd 2 O 3 is a heavy rare earth oxide with a large atomic weight of rare earth elements among rare earth oxides, and has a smaller amount of resources than light rare earth oxides, and there is a strong demand for reduction in the amount of use.
  • Ta 2 O 5 is a more expensive component than Gd 2 O 3 , and there is a strong demand for a reduction in the amount of use.
  • Gd 2 O 3 Ta 2 O 5 -rich glass can be produced stably in, Gd 2 O 3, Ta 2 O 5 resulting in greatly affected by whether supplied stably . Therefore, in order to supply glass stably, it is necessary to reduce the content of Gd 2 O 3 and Ta 2 O 5 .
  • the above glass contains a large amount of B 2 O 3 in order to achieve low dispersion. Therefore, the chemical durability is low, and when the glass is left in the air, the surface is likely to be deteriorated and cloudy.
  • the surface of the glass may be altered and white turbidity easily by washing the glass in order to remove dirt on the glass surface.
  • the glass is washed several times. For example, the surface of the preform is cleaned before precision press molding. After the washed preform is precision press-molded, the obtained lens is centered, and the lens is washed to remove cutting oil adhering to the surface during processing. Then, the lens is washed before the optical functional surface of the lens is coated with an optical thin film such as an antireflection film. By washing the glass several times in this way, white turbidity on the glass surface becomes significant.
  • Haze is an index indicating the degree of light scattering on the glass surface. It means that the larger the haze, the more light is scattered on the glass surface and the amount of light transmitted through the glass decreases. That is, a large haze indicates that the surface quality of the glass is deteriorated. Therefore, it is difficult to use such an optical element as a product as it is.
  • a cleaning aid builder
  • STPP sodium tripolyphosphate
  • the glass easily dissolves in the sodium tripolyphosphate solution (STPP solution), the latent scratches expand while the glass is immersed in the cleaning solution containing STPP, and the visible light is scattered. In such a state, the transparency of the glass surface is lost, making it unsuitable for an optical element.
  • STPP solution sodium tripolyphosphate solution
  • the chemical durability to STPP solution that is, the index of latent scratch resistance D STPP is introduced to evaluate the resistance to a cleaning liquid containing a cleaning aid.
  • a glass having a refractive index and an Abbe number in the above-mentioned range and a low glass transition temperature suitable for precision press molding has a problem that the latent scratch resistance D STPP is large and latent scratches are easily revealed by cleaning. .
  • the present invention solves such problems, and provides a glass suitable for manufacturing an optical element having a good surface quality by precision press molding while reducing the content of Gd 2 O 3 and Ta 2 O 5. It is another object of the present invention to provide a precision press-molding preform and optical element made of glass, and a method for producing the optical element.
  • the present invention provides the following means.
  • the contents of 2 O 3 , Gd 2 O 3 , Y 2 O 3 , ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 are set to C (SiO 2 ), C (B 2 O 3 ), C ( Al 2 O 3 ), C (Li 2 O), C (Na 2 O), C (K 2 O), C (MgO), C (CaO), C (SrO), C (BaO), C (ZnO ), C (La 2 O 3 ), C (Gd 2 O 3), C (Y 2 O 3), C (ZrO 2), C (Nb 2 O 5), C (WO 3) and C (Ta 2 O 5), Si
  • the present invention it is possible to provide a glass suitable for the production of an optical element having a good surface quality by precision press molding while reducing the content of Gd 2 O 3 and Ta 2 O 5.
  • a precision press-molding preform, an optical element, and a method for manufacturing the optical element can be provided.
  • the content of each glass component is expressed by mass%.
  • SiO 2, B 2 O 3 , Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3, Gd 2 O 3, Y 2 O 3 , ZrO 2 , Nb 2 O 5 , WO 3, and Ta 2 O 5 are represented by respective chemical formulas M (SiO 2 ), M (B 2 O 3 ), M (Al 2 O 3 ), M (Li 2 O ), M (Na 2 O), M (K 2 O), M (MgO), M (CaO), M (SrO), M (BaO), M (ZnO), M (La 2 O 3 ), M (Gd 2 O 3 ), M (Y 2 O 3 ), M (ZrO 2 ), M (Nb 2 O 5 ), M (WO 3 ) and M (Ta 2 O 5 ).
  • A1, A2, A3, and A4 are defined as follows using the content of the glass component and the chemical formula amount.
  • A1 ⁇ 550C (SiO 2 ) ⁇ 500C (B 2 O 3 ) ⁇ 450C (Al 2 O 3 ) + 100C (Li 2 O) ⁇ 280C (Na 2 O) ⁇ 300C (K 2 O) ⁇ 300C (MgO) — 100C (SrO) + 50C (ZnO ) + 200C (La 2 O 3) + 150C (Gd 2 O 3) + 250C (Y 2 O 3) + 250C (ZrO 2) + 400C (Nb 2 O 5) + 300C (WO 3) ⁇ ( 1)
  • A2 0.4C (SiO 2 ) + 0.8C (B 2 O 3 ) + 0.1C (Al 2 O 3 ) ⁇ 0.3C (Li 2 O) ⁇ 0.5C (Na 2 O) ⁇ 0.5C ( K 2 O) -0.3C (MgO) -0.2C (CaO) -0.3C (SrO) -0.05C (BaO) -0.6C (ZnO) -0.2C (La 2 O 3 )- 0.2C (Gd 2 O 3) -0.2C (Y 2 O 3) -C (ZrO 2) -2C (Nb 2 O 5) -2C (WO 3) ⁇ (2)
  • A3 20C (Li 2 O) + 12C (Na 2 O) + 10C (K 2 O) + 2C (ZnO) -2C (BaO) -3C (SiO 2) -3C (B 2 O 3) -3C (ZrO 2) - C (Ta 2 O 5 ) -2C (Al 2 O 3 ) (3)
  • A4 2 ⁇ ⁇ C (B 2 O 3 ) / M (B 2 O 3 ) ⁇ ⁇ [ ⁇ C (MgO) / M (MgO) ⁇ + ⁇ C (CaO) / M (CaO) ⁇ + ⁇ C ( SrO) / M (SrO) ⁇ + ⁇ C (BaO) / M (BaO) ⁇ + 2 ⁇ ⁇ C (Li 2 O) / M (Li 2 O) ⁇ + 2 ⁇ ⁇ C (Na 2 O) / M (Na 2 O) ⁇ + 2 ⁇ ⁇ C (K 2 O) / M (K 2 O) ⁇ ] / [ ⁇ C (SiO 2 ) / M (SiO 2 ) ⁇ + 2 ⁇ ⁇ C (Al 2 O 3 ) / M ( Al 2 O 3 ) ⁇ + 2 ⁇ ⁇ C (La 2 O 3 ) / M (La 2 O 3 ) ⁇ + 2 ⁇ ⁇ C (Gd 2 O 3
  • A1 is an index for determining the refractive index nd of the glass.
  • the coefficient of content of each glass component is a contribution to increase / decrease in the refractive index nd of each glass component.
  • the glass component having a positive coefficient has a function of increasing the refractive index nd, and the larger the coefficient, the larger the increase in the refractive index nd per unit mass% of the content of this component.
  • a glass component having a negative coefficient has a function of decreasing the refractive index nd.
  • Each coefficient is a value obtained experimentally.
  • FIG. 1 is a graph in which each glass of Example 1 is plotted with A1 on the horizontal axis and the refractive index nd on the vertical axis. As is clear from FIG. 1, there is a correlation between A1 and the refractive index n, and the refractive index increases and decreases as A1 increases and decreases.
  • A1 of the glass of the present embodiment is -18000 or more and -7000 or less.
  • a preferred lower limit of A1 is -17500, more preferably -17000.
  • the upper limit of A1 is preferably ⁇ 7500, more preferably ⁇ 8000, ⁇ 8100.
  • A2 is an index for determining the Abbe number ⁇ d of the glass.
  • the coefficient of the content of each glass component is the degree of contribution to the increase / decrease in the Abbe number ⁇ d of each glass component.
  • the glass component having a positive coefficient has a function of increasing the Abbe number ⁇ d, and the larger the coefficient, the larger the increase in the Abbe number ⁇ d per unit mass% of the content of this component.
  • a glass component having a negative coefficient has a function of decreasing the Abbe number ⁇ d, and the larger the absolute value of the coefficient, the larger the decrease in the Abbe number ⁇ d per unit mass% of the content of this component.
  • Each coefficient is a value obtained experimentally.
  • FIG. 2 is a graph plotting each glass of Example 1 with the Abbe number ⁇ d on the horizontal axis and A2 on the vertical axis. As is apparent from FIG. 2, there is a correlation between A2 and the Abbe number ⁇ , and the Abbe number ⁇ d increases and decreases as A2 increases and decreases.
  • A2 of the glass of the present embodiment is ⁇ 1 or more and 15 or less.
  • the preferred lower limit of A2 is -0.5, more preferably 0, 0.3, 0.5, 0.8.
  • the upper limit with preferable A2 is 14.5, More preferably, it is 14.3 and 14 order.
  • A3 is an index for determining the glass transition temperature Tg.
  • the content coefficient of each glass component is the degree of contribution to the rise and fall of the glass transition temperature Tg of each glass component.
  • the glass component having a positive coefficient has a function of lowering the glass transition temperature, and the larger the coefficient, the larger the amount of decrease in the glass transition temperature per unit mass% of the content of this component.
  • a glass component having a negative coefficient has a function of increasing the glass transition temperature. The larger the absolute value of the coefficient, the larger the increase in the glass transition temperature per unit mass% of the content of this component.
  • Each coefficient is a value obtained experimentally.
  • FIG. 3 is a graph in which each glass of Example 1 is plotted with A3 on the horizontal axis and the glass transition temperature Tg on the vertical axis. As is clear from FIG. 3, there is a correlation between A3 and the glass transition temperature, and the glass transition temperature increases and decreases as A3 increases and decreases.
  • FIG. 4 shows the glass transition temperature Tg of the glass used for precision press-molding on the vertical axis, the number of continuous precision press-molding on the vertical axis, and five types of glasses with different glass transition temperatures Tg.
  • the number of precision press moldings performed until the glass is fused to the molding surface of the press molding die and the shape of the molding surface cannot be accurately transferred to the glass is plotted.
  • FIG. 4 shows that the glass transition temperature is preferably 540 ° C. or lower in order to enable continuous precision press molding 10,000 times.
  • A3 of the glass of this embodiment is ⁇ 64 or more.
  • the preferred lower limit of A3 is ⁇ 62, more preferably ⁇ 60, ⁇ 58, and ⁇ 55 in order to reduce the glass transition temperature and mass-produce high-quality optical elements by precision press molding.
  • the upper limit of A3 is preferably 45, more preferably 43, 40, 37, 35, 32, 30, 28.
  • A4 is an index that determines the degree of erosion of the glass by the aqueous sodium tripolyphosphate solution (STPP solution), that is, the latent damage resistance of the glass.
  • STPP solution aqueous sodium tripolyphosphate solution
  • a disk-shaped glass sample having a diameter of 43.7 mm and a thickness of 5 mm is used. Two surfaces having a diameter of 43.7 mm are optically polished surfaces, and the total area of the two surfaces is 30 cm 2 .
  • STPP 0.01 mol / liter Na 5 P 3 O 10
  • the mass difference between the glass sample before and after the 1 hour immersion was divided by 30 cm 2 .
  • the value of [mg / (cm 2 ⁇ hr)] that is, the mass loss D STPP is used to evaluate the latent resistance.
  • the latent resistance is classified into five classes from the first grade to the fifth grade as shown in the table below.
  • FIG. 5 is a graph in which A4 is plotted on the horizontal axis and D STPP is plotted on the vertical axis, and each glass of Example 1 and each glass of the comparative example are plotted. 5 As is clear, there is a correlation between the A4 and D STPP, in accordance with an increase and decrease of A4, D STPP also increased or decreased.
  • A4 of the glass of the present embodiment is 0.58 or less.
  • Optical glass having a refractive index nd of 1.65 to 1.72 and an Abbe number ⁇ d of 50 to 57 has conventionally had a resistance to latent scratches of 3 to 5.
  • the scratching property can be set to first grade or second grade.
  • the upper limit of A4 is preferably 0.57, more preferably 0.56, 0.54, 0.52, 0. From the viewpoint of improving the latent scratch resistance and facilitating the production of an optical element having a high surface quality.
  • the order is 50, 0.48, 0.46, and 0.44.
  • the preferred lower limit of A4 is 0.10, more preferably 0.15, 0.17, 0 from the standpoint of maintaining the thermal stability of the glass, realizing the desired optical properties, and suppressing an increase in the glass transition temperature. .20, 0.22, 0.25.
  • the glass transition temperature is 540 ° C. or lower and the latent scratch resistance is second class. It was difficult to achieve both. If the glass transition temperature is set to 540 ° C. or lower, the latent scratch resistance becomes the third or fourth grade. On the other hand, if the resistance to latent scratches is to be second grade, the glass transition temperature rises and exceeds 540 ° C.
  • some glasses having optical characteristics in a range different from the above range have a glass transition temperature of 540 ° C. or lower and a latent scratch resistance of a second class.
  • the glass transition temperature is 540 ° C. or lower and the latent resistance is a second class characteristic.
  • the significance of achieving both is very great.
  • by setting A1, A2, A3, and A4 to predetermined values it is possible to provide an optical glass that has a low glass transition temperature and good latent scratch resistance as well as the above optical characteristics.
  • BaO reacts with carbon dioxide in the atmosphere and causes barium carbonate to be generated on the surface of the glass.
  • the production of barium carbonate reduces the transparency of the glass surface and reduces the performance of the optical element.
  • the content of BaO that is, C (BaO) is 10 or less.
  • the preferable upper limit of C (BaO) is 8, more preferably in the order of 6, 4, 3, 2, 1.
  • C (BaO) may be 0.
  • Gd 2 O 3 is an expensive component, and C (Gd 2 O 3 ) is 4 or less from the viewpoint of stably supplying glass.
  • a preferable upper limit of C (Gd 2 O 3 ) is 3.5, more preferably 3, 2.5, 2, 1.5, 1, 0.5, and 0.1. For the above reason, C (Gd 2 O 3 ) is most preferably 0.
  • Ta 2 O 5 is an expensive component, and C (Ta 2 O 5 ) is less than 3 because glass is stably supplied.
  • C (Ta 2 O 5 ) is preferably 2 or less, more preferably 1 or less, 0.5 or less, and 0.1 or less. For the above reason, C (Ta 2 O 5 ) is most preferably 0.
  • the atomic weight of Ta is the largest, followed by the atomic weight of Gd. That is, Ta increases the specific gravity of glass together with Gd.
  • the increase in the specific gravity of the glass is disadvantageous in reducing the weight of the optical element and forming the molten glass lump into a precision press-molding preform in a floating state.
  • the optical glass according to the present embodiment is preferably a glass containing B 2 O 3 , SiO 2 , La 2 O 3 , Y 2 O 3 , Li 2 O and ZnO as essential components.
  • B 2 O 3 is a glass network forming component and has a function of increasing the Abbe number ⁇ d. However, when the content of B 2 O 3 increases, the chemical durability of the glass decreases and the surface quality of the glass tends to decrease.
  • C (B 2 O 3 ) is preferably 21 or more.
  • a more preferred lower limit of C (B 2 O 3 ) is 23, and a more preferred lower limit is 24.
  • C (B 2 O 3 ) is preferably 31 or less from the viewpoint of maintaining chemical durability, suppressing deterioration of the surface quality of the glass, and suppressing increase in haze.
  • a more preferred upper limit of C (B 2 O 3 ) is 29, and a more preferred lower limit is 28.
  • SiO 2 is a glass network forming component and has a function of improving the chemical durability of the glass.
  • the content of SiO 2 is set to 0.30 or more times the content of B 2 O 3 , that is, C ( it is preferable that the SiO 2) and C (B 2 O 3) of 0.30 times or more.
  • C (SiO 2 ) is preferably 8 or more, more preferably 10 or more, further preferably 12 or more, and 13 or more. Is more preferable.
  • C (SiO 2 ) is preferably 18 or less, more preferably 16 or less, and even more preferably 15 or less.
  • La 2 O 3 has a function of increasing the refractive index nd. It also has the function of increasing chemical durability. Among the components for increasing the refractive index that serve to increase the refractive index, it is also a component that is relatively difficult to reduce the Abbe number ⁇ d. From the viewpoint of increasing the refractive index nd and maintaining chemical durability while maintaining low dispersibility, C (La 2 O 3 ) is preferably 18 or more.
  • C (La 2 O 3 ) Is preferably 30 or less. Further, suppressing the increase of the glass transition temperature, even over to provide suitable glass for precision press molding, it is preferable C (La 2 O 3) is 30 or less.
  • the more preferable lower limit of C (La 2 O 3 ) is 19, and the more preferable lower limit is 20, 22, and 24 in this order.
  • the more preferable upper limit of C (La 2 O 3 ) is 29, and the more preferable upper limit is 28.
  • Y 2 O 3 functions to increase the refractive index nd without significantly reducing the Abbe number ⁇ d.
  • the preferred lower limit of C (Y 2 O 3 ) is 5 and the more preferred lower limit is 7, 8 in order to suppress the decrease in the Abbe number ⁇ d to maintain low dispersibility and maintain the thermal stability of the glass.
  • the preferred upper limit of C (Y 2 O 3 ) is 17, a more preferred upper limit is 15, and a more preferred upper limit is 14.
  • Nb 2 O 5 functions to increase the refractive index nd and improve the thermal stability of the glass. It also has the function of improving the chemical durability of the glass. On the other hand, when the content of Nb 2 O 5 is too large, the thermal stability of the glass tends to decrease, the Abbe number ⁇ d decreases, and the glass tends to be highly dispersed. In addition, the glass tends to become more colored.
  • the upper limit of C (Nb 2 O 5 ) is preferably 5, more preferably 3, still more preferably 2, and still more preferably 1.
  • the lower limit of C (Nb 2 O 5 ) is preferably 0.
  • C (Nb 2 O 5 ) may be 0.
  • WO 3 has a function of lowering the glass transition temperature Tg. However, if the content of WO 3 is too large, the Abbe number ⁇ d decreases, making it difficult to achieve the required optical characteristics. Moreover, the coloring of glass increases.
  • the upper limit of C (WO 3 ) is preferably 5, more preferably 3, still more preferably 2, even more preferably 1. It is.
  • the lower limit of C (WO 3 ) is preferably 0.
  • C (WO 3 ) may be 0.
  • Al 2 O 3 is an essential component having a function of improving the chemical durability of glass and suppressing an increase in haze on the glass surface.
  • the preferable lower limit of C (Al 2 O 3 ) is 0.1, the more preferable lower limit is 0.3, and the more preferable lower limit is 0.00. 5.
  • the upper limit of Al 2 O 3 is preferably 8, more preferably 5 and even more preferably 3 in order to suppress the decrease in the refractive index nd and bring the refractive index of the glass into a desired range.
  • ZnO has the function of lowering the glass transition temperature and improving the meltability and chemical durability of the glass.
  • the preferable lower limit of C (ZnO) is 6 from the viewpoint of suppressing the rise of the glass transition temperature and making the glass suitable for precision press molding, and maintaining the meltability and suppressing the unmelted glass raw material.
  • the lower limit is more preferably 6.5, 7, and 8.
  • the upper limit of C (ZnO) is 18 and the more preferable upper limit is 16 and 14 in order to suppress the decrease in Abbe number and maintain low dispersibility.
  • Li 2 O functions to lower the glass transition temperature and improve the meltability of the glass.
  • the preferable lower limit of C (Li 2 O) is 1, and the more preferable lower limit is in the order of 2 and 3.
  • the preferable upper limit of C (Li 2 O) is 7, and the more preferable upper limit is 6.
  • C (SrO) is preferably 0 to 3.
  • C (SrO) can also be set to zero.
  • the ratio of C (Gd 2 O 3) in order to maintain the desired refractive index nd, Abbe number [nu] d, the thermal stability, for C (Y 2 O 3) ( C (Gd 2 O 3 ) / C (Y 2 O 3 )) is preferably less than 7. Further, by limiting the ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )), the chemical durability of the glass is improved and the haze on the glass surface can be reduced.
  • the more preferable range of the ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )) is less than 4, and the more preferable range is less than 1.
  • the ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )) may be zero.
  • ZrO 2 functions to increase the refractive index nd and improve chemical durability and thermal stability.
  • the Abbe number ⁇ d decreases and the dispersion tends to increase.
  • thermal stability and meltability tend to decrease. Therefore, it is preferable to set C (ZrO 2 ) to 0-8.
  • C (ZrO 2 ) is more preferably 0.1 or more, further preferably 0.5 or more, and 1 or more. Is more preferable.
  • C a (ZrO 2) to 7 or less, more preferably be 6 or less, still more preferably 5 or less.
  • CaO has the function of improving the meltability and adjusting the refractive index.
  • the refractive index nd decreases as the CaO content increases.
  • C (CaO) is preferably 8 or less, more preferably 6 or less, and even more preferably 5 or less.
  • C (CaO) can also be set to zero.
  • C (CaO) is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1 or more.
  • MgO may be contained in a small amount, but the thermal stability tends to decrease as the content increases.
  • C (MgO) is preferably 0 to 1.
  • C (MgO) can also be set to zero.
  • Na 2 O and K 2 O have a function of lowering the glass transition temperature and a function of improving the meltability, although not as much as Li 2 O.
  • C (Na 2 O) is 0 to 1.
  • C (K 2 O) is preferably 0 to 1.
  • C (Na 2 O) may be zero.
  • C (K 2 O) can also be set to zero.
  • Sb 2 O 3 may be contained as a refining agent in a small amount.
  • the content of Sb 2 O 3 exceeds 1% by mass, the coloring of the glass increases due to light absorption by Sb, or when the glass is precision press-molded, Sb on the glass surface is the molding surface of the press mold. The glass is fused to the molding surface of the press mold, or the molding surface is damaged. Further, the Abbe number ⁇ d decreases, which is not preferable for maintaining low dispersibility.
  • the content of Sb 2 O 3 is preferably 0 to 1% by mass, and more preferably 0 to 0.5% by mass.
  • the Sb 2 O 3 content may be 0% by mass.
  • the GeO 2 content is preferably 0 to 1% by mass
  • the Lu 2 O 3 content is preferably 0 to 1% by mass
  • the Ga 2 O 3 content is 0 to 1% by mass.
  • the content of In 2 O 3 is 0 to 1% by mass
  • the content of Sc 2 O 3 is preferably 0 to 1% by mass
  • the GeO 2 content can be 0% by mass
  • the Lu 2 O 3 content can be 0% by mass
  • the Ga 2 O 3 content can be 0% by mass
  • the content of 2 O 3 can be 0 mass%
  • the content of Sc 2 O 3 can be 0 mass%
  • the content of HfO 2 can be 0 mass%.
  • P 2 O 5 is a component that decreases the refractive index nd and is also a component that decreases the thermal stability of the glass. Therefore, the content of P 2 O 5 is preferably 0 to 3% by mass, more preferably 0 to 1% by mass, further preferably 0 to 0.1% by mass, and 0% by mass. It can also be.
  • TeO 2 is a component that increases the refractive index nd.
  • the content of TeO 2 is preferably 0 to 1% by mass, and 0 to 0.1% by mass. More preferably, it is more preferably 0% by mass.
  • U, Th, and Ra are all radioactive elements. Therefore, it is preferable not to contain these elements, that is, not to introduce these elements into the glass as glass components.
  • the element contained in the optical glass is not preferable. Therefore, it is preferable not to contain these elements, that is, not to introduce these elements into the glass as glass components.
  • SnO 2 is an optionally addable component that functions as a fining agent.
  • the content of SnO 2 added as a fining agent is 0 to 2% by mass.
  • the SnO 2 content may be 0 to 1% by mass, 0 to 0.5% by mass, 0 to 0.1% by mass, or 0% by mass.
  • F, Cl, Br, and I are components that are not necessary for achieving the object of the invention. Therefore, the contents of F, Cl, Br, and I may each be 0% by mass.
  • the content of these components is preferably 0 to 5% by mass, more preferably 0 to 3%, and more preferably 0 to 1% by mass. More preferred is 0 to 0.1% by mass.
  • the glass composition of the optical glass according to the present embodiment can be quantified by a method such as ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry).
  • the analysis value obtained by ICP-AES may include a measurement error of about ⁇ 5% of the analysis value, for example.
  • the content of the glass component is 0% or does not contain or is not introduced, which means that this component is not substantially contained. It means that it is about the impurity level or less.
  • the component having a small content can be quantified by a method such as ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Depending on the component to be quantified, it may be quantified by a method such as ion chromatography.
  • the glass according to an embodiment of the present invention is a high refractive index and low dispersion glass, and preferably has a refractive index nd of 1.65 to 1.72 and an Abbe number ⁇ d of 50 to 57.
  • the Abbe number ⁇ d By setting the Abbe number ⁇ d to 50 or more, an optical element having a chromatic aberration correction function can be provided in combination with a high dispersion glass having a small Abbe number.
  • the Abbe number ⁇ d By setting the Abbe number ⁇ d to 57 or less, it becomes easy to maintain both the low-temperature softening property and the thermal stability. Further, since an increase in the content of B 2 O 3 can be suppressed, the Abbe number ⁇ d is preferably set to 57 or less in order to maintain chemical durability.
  • the lower limit of the Abbe number ⁇ d is more preferably 50.5, still more preferably 51.0, still more preferably 52.0, and even more preferably 52.5. Further, the upper limit of the Abbe number ⁇ d is more preferably 56.0, still more preferably 55.0, still more preferably 54.0, and even more preferably 53.5.
  • this glass can be used as an optical element material effective for making the optical system compact and highly functional.
  • the refractive index nd is 1.72 or less, it is easy to maintain both low temperature softening and thermal stability.
  • the lower limit of the refractive index nd is more preferably 1.665, still more preferably 1.670, still more preferably 1.675, still more preferably 1.680, and still more preferably 1. 685.
  • the upper limit of the refractive index nd is more preferably 1.716, still more preferably 1.710, still more preferably 1.705, still more preferably 1.700, and still more preferably 1.695.
  • Glass transition temperature Tg Glass transition temperature Tg
  • a preferable range of the glass transition temperature is 540 ° C. or less.
  • highly accurate press molding can be performed without excessively increasing the temperature of the press mold during precision press molding. Therefore, consumption of the press mold can be reduced, and the life of the press mold can be extended.
  • precision press molding can be performed continuously 10,000 times or more using a SiC press mold.
  • the upper limit of the glass transition temperature is more preferably 538 ° C, further preferably 536 ° C, and further preferably 535 ° C.
  • the lower limit of the glass transition temperature is naturally determined by the glass composition, but when the glass transition temperature is excessively decreased, the refractive index nd tends to decrease or the thermal stability of the glass tends to decrease.
  • a disk-shaped glass sample having a diameter of 43.7 mm and a thickness of 5 mm is used. Two surfaces having a diameter of 43.7 mm are optically polished surfaces, and the total area of the two surfaces is 30 cm 2 .
  • the preferred range of the latent resistance D STPP is less than 0.20 mg / (cm 2 ⁇ hr), that is, first grade or second grade.
  • the latent scratch resistance D STPP is second grade. Improving the latent scratch resistance from grade 3 to grade 5 to grade 1 or grade 2 corresponds to the solution of the problems inherent in the high refractive index and low dispersion glass having the above optical properties, and is significant.
  • the upper limit of haze is preferably 0.9%, more preferably 0.8%, still more preferably 0.75%, and even more preferably 0.7%. More preferably, it is 0.6%, and still more preferably 0.5%.
  • the lower limit of haze is preferably 0%.
  • the optical glass according to the present embodiment for example, weighs compounds such as oxides, boric acid, anhydrous boric acid, carbonates, etc., mixes them well, uses them as batch materials, and puts the batch materials into a platinum crucible. It can be obtained by heating and melting in the atmosphere at, for example, a temperature of 1200 to 1350 ° C., clarifying and stirring the melt to obtain a homogeneous molten glass, pouring the molten glass into a mold, and slowly cooling it. .
  • Preform for precision press molding and its manufacture The glass produced as described above is cut, ground, and polished to produce a precision press-molding preform.
  • molten glass may be dropped, an upward wind pressure may be applied to the molten glass droplet, and the preform may be molded into a precision press-molding preform in a floating state.
  • a carbon film may be coated on the surface of the preform.
  • the precision press-molding preform is introduced into, for example, a SiC press-molding die, heated in a nitrogen atmosphere to soften the glass, and the glass is precision press-molded with the press-molding die. After the precision press molding is finished, the glass, that is, the precision press-molded product is taken out from the press mold and annealed.
  • aspherical lenses of various shapes such as biconcave, biconvex, concave meniscus, convex meniscus, planoconvex, and planoconcave are produced.
  • a lens manufactured by precision press molding is subjected to centering processing as necessary, or a coating such as an antireflection film is formed on the optical functional surface of the lens.
  • various optical elements such as a diffraction grating and a prism may be manufactured.
  • Example 1 Batch raw materials were prepared by weighing and thoroughly mixing compounds such as oxides and boric acid so as to have the compositions described in the example composition tables (Tables 2 to 4).
  • the batch raw material was put in a platinum crucible, and the whole crucible was heated to a temperature of 1200 to 1350 ° C., and the glass was melted and refined over 30 to 60 minutes. After the molten glass was agitated and homogenized, the molten glass was cast into a preheated mold and allowed to cool to near the glass transition temperature, and then the glass together with the mold was placed in an annealing furnace. Then, annealing was performed for about 1 hour near the glass transition temperature. After annealing, it was allowed to cool to room temperature in an annealing furnace.
  • the refractive index nd, Abbe number ⁇ d, glass transition temperature Tg, and haze of the obtained glass were measured by the following methods. Table 5 shows the measurement results.
  • (1) Refractive index nd, nF, nc, Abbe number ⁇ d Refractive indexes nd, nF, and nc of the glass obtained by lowering the temperature at a temperature lowering rate of ⁇ 30 ° C./hour were measured by the refractive index measurement method of the Japan Optical Glass Industry Association standard.
  • the Abbe number ⁇ d was calculated using the measured values of the refractive indexes nd, nF, and nc.
  • the obtained glass was processed into a flat plate shape of 18 mm ⁇ 22 mm ⁇ thickness 3 mm, and two flat surfaces were optically polished.
  • the optically polished glass sample was washed and dried.
  • the dried glass sample was put in an aqueous solution of SE18 detergent manufactured by Sonic Fellows (detergent concentration was 5 vol%) and immersed for 2 hours while applying ultrasonic waves. Then, the glass sample was taken out from the detergent aqueous solution, washed with water and dried.
  • a haze meter defined in “Japan Optical Glass Industry Standard JOGIS Optical Glass Chemical Durability Measurement Method (Surface Method) 07-1975”, the diffuse transmittance Td and the total light transmittance Tt were measured. Haze was calculated.
  • Example 2 Using various optical glasses obtained in Example 1, a precision press-molding preform was produced by a known method. This preform was heated and softened in a nitrogen atmosphere, and precision press-molded using a SiC press mold to make the glass into an aspheric lens shape. The molded glass was taken out from the press mold and annealed to prepare aspherical lenses made of various optical glasses prepared in Example 1. Defects such as white turbidity, bubbles and scratches were not observed on the surface of the aspherical lens thus produced.
  • glass No. 5 shows an enlarged image of the surface of the aspherical lens fabricated in 5. As is apparent from FIG. 6, no cloudiness or scratches are observed on the lens surface. Glass No. Even when a glass other than 5 was used, a lens having a high surface quality could be similarly produced.
  • a large number of precision press-molding preforms prepared using the various optical glasses obtained in Example 1 were prepared, and precision press molding was continuously performed using the same SiC press-molding die. Preforms made of any optical glass could be precision press-molded more than 10,000 times.
  • Example 1 The glass of Example 6 described in Patent Document 7 (Chinese Patent Application Publication No. 1014339929) has an A4 of 0.785, a weight loss D STPP of 0.47 mg / (cm 2 ⁇ hr), and has a latent resistance.
  • Example 1 The glass of Example 6 described in Patent Document 7 (Chinese Patent Application Publication No. 1014339929) has an A4 of 0.785, a weight loss D STPP of 0.47 mg / (cm 2 ⁇ hr), and has a latent resistance.
  • Example 1 The glass of Example 6 described in Patent Document 7 (Chinese Patent Application Publication No. 1014339929) has an A4 of 0.785, a weight loss D STPP of 0.47 mg / (cm 2 ⁇ hr), and has a latent resistance.
  • Example 1 The glass of Example 6 described in Patent Document 7 (Chinese Patent Application Publication No. 1014339929) has an A4 of 0.785, a weight loss D STPP of 0.47 mg
  • Example 2 The glass of Example 5 described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2000-016831) has A4 of 1.073, weight loss D STPP of 0.48 mg / (cm 2 ⁇ hr), and latent scratch resistance.
  • A4 of the glass of Example 11 of Patent Document 3 was 0.837, the mass reduction D STPP was 0.37 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 3.
  • A4 of the glass of Example 12 of Patent Document 3 was 0.727, the weight loss D STPP was 0.47 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 4.
  • Example 11 described in Patent Document 3 and the composition of Example 11 described in Patent Document 4 are the same composition.
  • the glass of Example 11 described in Patent Document 3 was treated in the same manner as in Example 1, and then the haze was measured in the same manner as in Example 1. The value was 1.1%.
  • Example 3 The A4 of the glass of Example 3 described in JP-A-5-201743 was 1.015, the weight loss D STPP was 0.45 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 4. .
  • the A4 of the glass of Example 6 of the same publication was 0.717, the weight loss D STPP was 0.50 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 4.
  • A4 of the glass of Example 8 of the publication was 0.702, the mass reduction D STPP was 0.26 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 3.
  • the A4 of the glass of Example 9 of the publication was 0.596, the weight loss D STPP was 0.25 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 3.
  • Example 4 The A4 of Example 2 described in JP-A-2010-076987 was 0.679, the weight loss D STPP was 0.37 mg / (cm 2 ⁇ hr), and the latent resistance was grade 3. A4 of Example 7 of the publication was 0.764, the mass loss D STPP was 0.25 mg / (cm 2 ⁇ hr), and the latent scratch resistance was grade 3.

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Abstract

Provided is a glass or the like suited for producing, through precision press molding, an optical element having fine surface quality while contained amounts of Gd2O3 and Ta2O5 are reduced. In this optical glass, in terms of oxides, when the contained amount of glass components expressed in mass% is represented as C(SiO2), C(B2O3), or the like, when the chemical formula weight of each component is represented as M(SiO2), M(B2O3), or the like, and when A1=-550C(SiO2)-500C(B2O3)-450C(Al2O3)+100C(Li2O)-280C(Na2O)-300C(K2O)-300C(MgO)-100C(SrO)+50C(ZnO)+200C(La2O3)+150C(Gd2O3)+250C(Y2O3)+250C(ZrO2)+400C(Nb2O5)+300C(WO3), A2=0.4C(SiO2)+0.8C(B2O3)+0.1C(Al2O3)-0.3C(Li2O)-0.5C(Na2O)-0.5C(K2O)-0.3C(MgO)-0.2C(CaO)-0.3C(SrO)-0.05C(BaO)-0.6C(ZnO)-0.2C(La2O3)-0.2C(Gd2O3)-0.2C(Y2O3)-C(ZrO2)-2C(Nb2O5)-2C(WO3), A3=20C(Li2O)+12C(Na2O)+10C(K2O)+2C(ZnO)-2C(BaO)-3C(SiO2)-3C(B2O3)-3C(ZrO2)-C(Ta2O5)-2C(Al2O3), and A4=2×{C(B2O3)/M(B2O3)}×[{C(MgO)/M(MgO)}+{C(CaO)/M(CaO)}+{C(SrO)/M(SrO)}+{C(BaO)/M(BaO)}+2×{C(Li2O)/M(Li2O)}+2×{C(Na2O)/M(Na2O)}+2×{C(K2O)/M(K2O)}]/[{C(SiO2)/M(SiO2)}+2×{C(Al2O3)/M(Al2O3)}+2×{C(La2O3)/M(La2O3)}+2×{C(Gd2O3)/M(Gd2O3)}+2×{C(Y2O3)/M(Y2O3)}+{C(ZrO2)/M(ZrO2)}+{C(ZnO)/M(ZnO)}+2×{C(Nb2O5)/M(Nb2O5)}] are defined, A1 ranges between -18000 to -7000, A2 ranges between -1 to 15, A3 is -64 or more, A4 is 0.58 or less, C(BaO) is 10 or less, C(Gd2O3) is 4 or less, and C(Ta2O5) is less than 3.

Description

光学ガラスおよび光学素子Optical glass and optical element
　本発明は、光学ガラスおよび光学素子に関する。 The present invention relates to an optical glass and an optical element.
　特許文献１～７には、屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７付近の光学ガラスが開示されている。これらのガラスは、光学ガラスの中でもガラス転移温度が低い部類に入り、低温で軟化する性質、すなわち、低温軟化性を有する。 Patent Documents 1 to 7 disclose optical glasses having a refractive index nd of 1.65 to 1.72 and an Abbe number νd of about 50 to 57. These glasses enter into a class having a low glass transition temperature among optical glasses and have a property of softening at a low temperature, that is, a low temperature softening property.
　ガラス転移温度が低いガラスは、精密プレス成形により光学素子を製造するための材料として適している。 Glass with a low glass transition temperature is suitable as a material for producing optical elements by precision press molding.
　上記光学特性を有するガラスは、低分散化のために比較的多くのＢ2Ｏ3を含み、低分散性を維持しつつ屈折率を高めるためにＬａ2Ｏ3等の希土類成分を含んでいる。さらに、ガラス転移温度を低下させるために、Ｌｉ2ＯやＺｎＯなどのガラス転移温度を低下させる働きを有する成分も含む。 The glass having the above optical characteristics contains a relatively large amount of B 2 O 3 for low dispersion, and contains a rare earth component such as La 2 O 3 in order to increase the refractive index while maintaining low dispersion. . Furthermore, in order to lower the glass transition temperature, a component having a function of lowering the glass transition temperature such as Li 2 O and ZnO is also included.
ＷＯ２００７／０９７３４５号公報WO2007 / 097345 特開２００３－０２０２４９号公報JP 2003-020249 A 特開２０００－０１６８３１号公報JP 2000-016831 A 特開２００１－１３０９２４号公報JP 2001-130924 A 特開２００７－２５４２２４号公報JP 2007-254224 A 特開２００７－０３１２５３号公報JP 2007-031253 A 中国専利出願公開第１０１４３９９２９号公報Chinese Patent Application Publication No. 1014339929
　ところで、高屈折率低分散特性と低温軟化性の両方を実現しようとすると、ガラスの熱的安定性が低下し、ガラスを製造する過程で、ガラス中に結晶が析出し、失透しやすくなる。 By the way, if it is going to realize both high refractive index low dispersion characteristic and low temperature softening property, the thermal stability of the glass is lowered, and in the process of producing the glass, crystals are likely to precipitate in the glass and easily devitrify. .
　そこで、特許文献１、２に記載されているガラスでは、熱的安定性を維持するために、ガラスに必須成分としてＧｄ2Ｏ3やＴａ2Ｏ5を導入し、耐失透性の改善を図っている。 Therefore, in the glasses described in Patent Documents 1 and 2, in order to maintain thermal stability, Gd 2 O 3 and Ta 2 O 5 are introduced as essential components in the glass to improve devitrification resistance. I am trying.
　Ｇｄ2Ｏ3は、Ｌａ2Ｏ3同様、希土類成分であり、アッベ数の減少を抑えつつ、屈折率を高める働きを有する。Ｔａ2Ｏ5は、屈折率を高める働きを有し、希土類酸化物と比べ、アッベ数を減少させるが、ＴｉＯ2、Ｎｂ2Ｏ5、ＷＯ3などの高屈折率化成分と比べ、比較的アッベ数の減少量が少ない成分である。このように、Ｇｄ2Ｏ3、Ｔａ2Ｏ5は、高屈折率低分散性を維持しつつ、ガラスの熱的安定性を維持する上で、有効な成分である。 Gd 2 O 3 is a rare earth component, like La 2 O 3 , and has a function of increasing the refractive index while suppressing a decrease in the Abbe number. Ta 2 O 5 has a function of increasing the refractive index and reduces the Abbe number as compared with rare earth oxides. However, Ta 2 O 5 is relatively less than high refractive index components such as TiO 2 , Nb 2 O 5 , and WO 3. It is a component with a small decrease in Abbe number. Thus, Gd 2 O 3 and Ta 2 O 5 are effective components in maintaining the thermal stability of the glass while maintaining high refractive index and low dispersibility.
　ところが、Ｇｄ2Ｏ3は、希土類酸化物の中でも希土類元素の原子量が大きい重希土類酸化物であり、軽希土類酸化物と比べてさらに資源量が乏しく、その使用量の削減が強く求められている。Ｔａ2Ｏ5は、Ｇｄ2Ｏ3よりもさらに高価な成分であり、その使用量の削減が強く求められている。Ｇｄ2Ｏ3、Ｔａ2Ｏ5を多く含むガラスを安定して生産できるか否かは、Ｇｄ2Ｏ3、Ｔａ2Ｏ5が安定して供給されるか否かによって大きな影響を受けてしまう。したがって、ガラスを安定して供給するには、Ｇｄ2Ｏ3、Ｔａ2Ｏ5の含有量を低減することが必要となっている。 However, Gd 2 O 3 is a heavy rare earth oxide with a large atomic weight of rare earth elements among rare earth oxides, and has a smaller amount of resources than light rare earth oxides, and there is a strong demand for reduction in the amount of use. . Ta 2 O 5 is a more expensive component than Gd 2 O 3 , and there is a strong demand for a reduction in the amount of use. Whether Gd 2 O 3, Ta 2 O 5 -rich glass can be produced stably in, Gd 2 O 3, Ta 2 O 5 resulting in greatly affected by whether supplied stably . Therefore, in order to supply glass stably, it is necessary to reduce the content of Gd 2 O 3 and Ta 2 O 5 .
　ところで、上記ガラスは、低分散化を図るため多量のＢ2Ｏ3を含有しているので、化学的耐久性が低く、ガラスを空気中に放置すると、表面が変質し、白濁しやすい。また、ガラス表面の汚れを除去するために、ガラスを洗浄することによっても表面が変質し、白濁しやすい。このようなガラスを用いて光学素子を作ると、光学素子の表面が変質して、光を散乱し、光学素子の性能が大幅に低下する。 By the way, the above glass contains a large amount of B 2 O 3 in order to achieve low dispersion. Therefore, the chemical durability is low, and when the glass is left in the air, the surface is likely to be deteriorated and cloudy. In addition, the surface of the glass may be altered and white turbidity easily by washing the glass in order to remove dirt on the glass surface. When an optical element is made using such glass, the surface of the optical element is altered, light is scattered, and the performance of the optical element is greatly reduced.
　ガラスからレンズなどの光学素子を製造する過程で何回かガラスを洗浄することになる。例えば、精密プレス成形を行う前にプリフォームの表面を洗浄する。洗浄したプリフォームを精密プレス成形した後、得られたレンズを芯取り加工するが、加工時に表面に付着した切削オイルを除去するためにレンズを洗浄する。そして、レンズの光学機能面に反射防止膜などの光学薄膜をコートする前にレンズを洗浄する。このようにガラスを数回にわたり洗浄することにより、ガラス表面の白濁が顕著になる。 In the process of manufacturing optical elements such as lenses from glass, the glass is washed several times. For example, the surface of the preform is cleaned before precision press molding. After the washed preform is precision press-molded, the obtained lens is centered, and the lens is washed to remove cutting oil adhering to the surface during processing. Then, the lens is washed before the optical functional surface of the lens is coated with an optical thin film such as an antireflection film. By washing the glass several times in this way, white turbidity on the glass surface becomes significant.
　例えば、特許文献３に実施例１１として記載されているガラスを用いて、プリフォームからレンズを製造する際の洗浄に見立てた洗浄テストを行った後、ガラス表面のヘイズを測定すると、その値は１．１％と大きな値を示す。 For example, using a glass described in Patent Document 3 as Example 11, after performing a cleaning test based on cleaning when manufacturing a lens from a preform, when measuring the haze of the glass surface, the value is A large value of 1.1% is shown.
　ヘイズは、ガラス表面における光の散乱の度合を示す指標である。ヘイズが大きいほど、ガラス表面において多くの光が散乱され、ガラスを透過する光量が減少することを意味している。すなわち、ヘイズが大きいということは、ガラスの表面品質が低下していることを示す。したがって、このような光学素子をそのまま製品として使用することは難しい。 Haze is an index indicating the degree of light scattering on the glass surface. It means that the larger the haze, the more light is scattered on the glass surface and the amount of light transmitted through the glass decreases. That is, a large haze indicates that the surface quality of the glass is deteriorated. Therefore, it is difficult to use such an optical element as a product as it is.
　ところで、ガラスを洗浄するとき、洗剤の洗浄力を高めるために洗浄助剤（ビルダー）を添加することが行われている。洗浄助剤の中で代表的なものには、トリポリリン酸ナトリウム（ＳＴＰＰ）と呼ばれる水軟化剤がある。 By the way, when glass is washed, a cleaning aid (builder) is added to increase the cleaning power of the detergent. A typical cleaning aid is a water softener called sodium tripolyphosphate (STPP).
　ガラス表面には可視光の波長よりも小さな傷が存在する。可視光の波長よりも小さな傷は光を散乱しないため、目視できない。このような傷を潜傷と呼んでいる。 * Scratches smaller than the wavelength of visible light exist on the glass surface. Scratches smaller than the wavelength of visible light are not visible because they do not scatter light. Such a wound is called a latent wound.
　ガラスがトリポリリン酸ナトリウム溶液（ＳＴＰＰ溶液）に溶けやすいと、ＳＴＰＰを含む洗浄液にガラスを浸しているうちに潜傷が拡大し、可視光を散乱するようになる。このような状態になると、ガラス表面の透明性が失われ、光学素子には適さなくなる。 If the glass easily dissolves in the sodium tripolyphosphate solution (STPP solution), the latent scratches expand while the glass is immersed in the cleaning solution containing STPP, and the visible light is scattered. In such a state, the transparency of the glass surface is lost, making it unsuitable for an optical element.
　光学ガラスの業界では、ＳＴＰＰ溶液に対する化学的耐久性、すなわち、耐潜傷性ＤSTPPという指標を導入して、洗浄助剤を含む洗浄液に対する耐性を評価している。 In the optical glass industry, the chemical durability to STPP solution, that is, the index of latent scratch resistance D STPP is introduced to evaluate the resistance to a cleaning liquid containing a cleaning aid.
　従来、上記範囲の屈折率、アッベ数を有し、精密プレス成形に好適なガラス転移温度が低いガラスは、耐潜傷性ＤSTPPが大きく、洗浄によって潜傷が顕在化しやすいという問題があった。 Conventionally, a glass having a refractive index and an Abbe number in the above-mentioned range and a low glass transition temperature suitable for precision press molding has a problem that the latent scratch resistance D STPP is large and latent scratches are easily revealed by cleaning. .
　本発明は、このような問題を解決し、Ｇｄ2Ｏ3、Ｔａ2Ｏ5の含有量を低減しつつ、精密プレス成形により、表面の品質の良い光学素子の製造に適したガラスを提供すること、このガラスからなる精密プレス成形用プリフォームおよび光学素子ならびに光学素子の製造方法を提供することを目的とする。 The present invention solves such problems, and provides a glass suitable for manufacturing an optical element having a good surface quality by precision press molding while reducing the content of Gd 2 O 3 and Ta 2 O 5. It is another object of the present invention to provide a precision press-molding preform and optical element made of glass, and a method for producing the optical element.
　本発明は上記課題を解決するため、以下の手段を提供する。
（１）酸化物基準において、質量％表示によるガラス成分ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の含有量をそれぞれＣ（ＳｉＯ2）、Ｃ（Ｂ2Ｏ3）、Ｃ（Ａｌ2Ｏ3）、Ｃ（Ｌｉ2Ｏ）、Ｃ（Ｎａ2Ｏ）、Ｃ（Ｋ2Ｏ）、Ｃ（ＭｇＯ）、Ｃ（ＣａＯ）、Ｃ（ＳｒＯ）、Ｃ（ＢａＯ）、Ｃ（ＺｎＯ）、Ｃ（Ｌａ2Ｏ3）、Ｃ（Ｇｄ2Ｏ3）、Ｃ（Ｙ2Ｏ3）、Ｃ（ＺｒＯ2）、Ｃ（Ｎｂ2Ｏ5）、Ｃ（ＷＯ3）およびＣ（Ｔａ2Ｏ5）、
　ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の各化学式量をそれぞれＭ（ＳｉＯ2）、Ｍ（Ｂ2Ｏ3）、Ｍ（Ａｌ2Ｏ3）、Ｍ（Ｌｉ2Ｏ）、Ｍ（Ｎａ2Ｏ）、Ｍ（Ｋ2Ｏ）、Ｍ（ＭｇＯ）、Ｍ（ＣａＯ）、Ｍ（ＳｒＯ）、Ｍ（ＢａＯ）、Ｍ（ＺｎＯ）、Ｍ（Ｌａ2Ｏ3）、Ｍ（Ｇｄ2Ｏ3）、Ｍ（Ｙ2Ｏ3）、Ｍ（ＺｒＯ2）、Ｍ（Ｎｂ2Ｏ5）、Ｍ（ＷＯ3）およびＭ（Ｔａ2Ｏ5）とし、
　Ａ１＝－５５０Ｃ（ＳｉＯ2）－５００Ｃ（Ｂ2Ｏ3）－４５０Ｃ（Ａｌ2Ｏ3）＋１００Ｃ（Ｌｉ2Ｏ）－２８０Ｃ（Ｎａ2Ｏ）－３００Ｃ（Ｋ2Ｏ）－３００Ｃ（ＭｇＯ）－１００Ｃ（ＳｒＯ）＋５０Ｃ（ＺｎＯ）＋２００Ｃ（Ｌａ2Ｏ3）＋１５０Ｃ（Ｇｄ2Ｏ3）＋２５０Ｃ（Ｙ2Ｏ3）＋２５０Ｃ（ＺｒＯ2）＋４００Ｃ（Ｎｂ2Ｏ5）＋３００Ｃ（ＷＯ3）、
　Ａ２＝０．４Ｃ（ＳｉＯ2）＋０．８Ｃ（Ｂ2Ｏ3）＋０．１Ｃ（Ａｌ2Ｏ3）－０．３Ｃ（Ｌｉ2Ｏ）－０．５Ｃ（Ｎａ2Ｏ）－０．５Ｃ（Ｋ2Ｏ）－０．３Ｃ（ＭｇＯ）－０．２Ｃ（ＣａＯ）－０．３Ｃ（ＳｒＯ）－０．０５Ｃ（ＢａＯ）－０．６Ｃ（ＺｎＯ）－０．２Ｃ（Ｌａ2Ｏ3）－０．２Ｃ（Ｇｄ2Ｏ3）－０．２Ｃ（Ｙ2Ｏ3）－Ｃ（ＺｒＯ2）－２Ｃ（Ｎｂ2Ｏ5）－２Ｃ（ＷＯ3）、
　Ａ３＝２０Ｃ（Ｌｉ2Ｏ）＋１２Ｃ（Ｎａ2Ｏ）＋１０Ｃ（Ｋ2Ｏ）＋２Ｃ（ＺｎＯ）－２Ｃ（ＢａＯ）－３Ｃ（ＳｉＯ2）－３Ｃ（Ｂ2Ｏ3）－３Ｃ（ＺｒＯ2）－Ｃ（Ｔａ2Ｏ5）－２Ｃ（Ａｌ2Ｏ3）、
　Ａ４＝２×｛Ｃ（Ｂ2Ｏ3）／Ｍ（Ｂ2Ｏ3）｝×［｛Ｃ（ＭｇＯ）／Ｍ（ＭｇＯ）｝＋｛Ｃ（ＣａＯ）／Ｍ（ＣａＯ）｝＋｛Ｃ（ＳｒＯ）／Ｍ（ＳｒＯ）｝＋｛Ｃ（ＢａＯ）／Ｍ（ＢａＯ）｝＋２×｛Ｃ（Ｌｉ2Ｏ）／Ｍ（Ｌｉ2Ｏ）｝＋２×｛Ｃ（Ｎａ2Ｏ）／Ｍ（Ｎａ2Ｏ）｝＋２×｛Ｃ（Ｋ2Ｏ）／Ｍ（Ｋ2Ｏ）｝］／［｛Ｃ（ＳｉＯ2）／Ｍ（ＳｉＯ2）｝＋２×｛Ｃ（Ａｌ2Ｏ3）／Ｍ（Ａｌ2Ｏ3）｝＋２×｛Ｃ（Ｌａ2Ｏ3）／Ｍ（Ｌａ2Ｏ3）｝＋２×｛Ｃ（Ｇｄ2Ｏ3）／Ｍ（Ｇｄ2Ｏ3）｝＋２×｛Ｃ（Ｙ2Ｏ3）／Ｍ（Ｙ2Ｏ3）｝＋｛Ｃ（ＺｒＯ2）／Ｍ（ＺｒＯ2）｝＋｛Ｃ（ＺｎＯ）／Ｍ（ＺｎＯ）｝＋２×｛Ｃ（Ｎｂ2Ｏ5）／Ｍ（Ｎｂ2Ｏ5）｝］、
としたとき、
　Ａ１が－１８０００以上かつ－７０００以下、
　Ａ２が－１以上１５以下、
　Ａ３が－６４以上、
　Ａ４が０．５８以下、
　Ｃ（ＢａＯ）が１０以下、
　Ｃ（Ｇｄ2Ｏ3）が４以下、
　Ｃ（Ｔａ2Ｏ5）が３未満、
である光学ガラス。 In order to solve the above-mentioned problems, the present invention provides the following means.
(1) On the oxide basis, glass components SiO 2 , B 2 O 3 , Al 2 O 3 , Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La by mass% display The contents of 2 O 3 , Gd 2 O 3 , Y 2 O 3 , ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 are set to C (SiO 2 ), C (B 2 O 3 ), C ( Al 2 O 3 ), C (Li 2 O), C (Na 2 O), C (K 2 O), C (MgO), C (CaO), C (SrO), C (BaO), C (ZnO ), C (La 2 O 3 ), C (Gd 2 O 3), C (Y 2 O 3), C (ZrO 2), C (Nb 2 O 5), C (WO 3) and C (Ta 2 O 5),
SiO 2, B 2 O 3, Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3, Gd 2 O 3, Y 2 O 3, The chemical formula amounts of ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 are respectively M (SiO 2 ), M (B 2 O 3 ), M (Al 2 O 3 ), M (Li 2 O), M (Na 2 O), M (K 2 O), M (MgO), M (CaO), M (SrO), M (BaO), M (ZnO), M (La 2 O 3 ), M (Gd 2 O 3 ), M (Y 2 O 3 ), M (ZrO 2 ), M (Nb 2 O 5 ), M (WO 3 ) and M (Ta 2 O 5 ),
A1 = −550C (SiO 2 ) −500C (B 2 O 3 ) −450C (Al 2 O 3 ) + 100C (Li 2 O) −280C (Na 2 O) −300C (K 2 O) −300C (MgO) — 100C (SrO) + 50C (ZnO ) + 200C (La 2 O 3) + 150C (Gd 2 O 3) + 250C (Y 2 O 3) + 250C (ZrO 2) + 400C (Nb 2 O 5) + 300C (WO 3),
A2 = 0.4C (SiO 2 ) + 0.8C (B 2 O 3 ) + 0.1C (Al 2 O 3 ) −0.3C (Li 2 O) −0.5C (Na 2 O) −0.5C ( K 2 O) -0.3C (MgO) -0.2C (CaO) -0.3C (SrO) -0.05C (BaO) -0.6C (ZnO) -0.2C (La 2 O 3 )- 0.2C (Gd 2 O 3) -0.2C (Y 2 O 3) -C (ZrO 2) -2C (Nb 2 O 5) -2C (WO 3),
A3 = 20C (Li 2 O) + 12C (Na 2 O) + 10C (K 2 O) + 2C (ZnO) -2C (BaO) -3C (SiO 2) -3C (B 2 O 3) -3C (ZrO 2) - C (Ta 2 O 5 ) -2C (Al 2 O 3 ),
A4 = 2 × {C (B 2 O 3 ) / M (B 2 O 3 )} × [{C (MgO) / M (MgO)} + {C (CaO) / M (CaO)} + {C ( SrO) / M (SrO)} + {C (BaO) / M (BaO)} + 2 × {C (Li 2 O) / M (Li 2 O)} + 2 × {C (Na 2 O) / M (Na 2 O)} + 2 × {C (K 2 O) / M (K 2 O)}] / [{C (SiO 2 ) / M (SiO 2 )} + 2 × {C (Al 2 O 3 ) / M ( Al 2 O 3 )} + 2 × {C (La 2 O 3 ) / M (La 2 O 3 )} + 2 × {C (Gd 2 O 3 ) / M (Gd 2 O 3 )} + 2 × {C (Y 2 O 3 ) / M (Y 2 O 3 )} + {C (ZrO 2 ) / M (ZrO 2 )} + {C (ZnO) / M (ZnO)} + 2 × {C (Nb 2 O 5 ) / M (Nb 2 O 5 )}],
When
A1 is -18000 or more and -7000 or less,
A2 is -1 or more and 15 or less,
A3 is -64 or more,
A4 is 0.58 or less,
C (BaO) is 10 or less,
C (Gd 2 O 3 ) is 4 or less,
C (Ta 2 O 5 ) is less than 3,
Optical glass that is.
（２）屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７である上記（１）に記載の光学ガラス。 (2) The optical glass according to (1), wherein the refractive index nd is 1.65 to 1.72, and the Abbe number νd is 50 to 57.
（３）ガラス転移温度が５４０℃以下である上記（１）または（２）のいずれかに記載の光学ガラス。 (3) Optical glass in any one of said (1) or (2) whose glass transition temperature is 540 degrees C or less.
（４）上記（１）～（３）のいずれかに記載の光学ガラスによりなるプレス成形用プリフォーム。 (4) A press-molding preform made of the optical glass according to any one of (1) to (3) above.
（５）上記（１）～（３）のいずれかに記載の光学ガラスよりなる光学素子。 (5) An optical element comprising the optical glass according to any one of (1) to (3) above.
　本発明によれば、Ｇｄ2Ｏ3、Ｔａ2Ｏ5の含有量を低減しつつ、精密プレス成形により、表面の品質の良い光学素子の製造に適したガラスを提供すること、このガラスからなる精密プレス成形用プリフォームおよび光学素子ならびに光学素子の製造方法を提供することができる。 According to the present invention, it is possible to provide a glass suitable for the production of an optical element having a good surface quality by precision press molding while reducing the content of Gd 2 O 3 and Ta 2 O 5. A precision press-molding preform, an optical element, and a method for manufacturing the optical element can be provided.
横軸にＡ１、縦軸に屈折率ｎｄをとり、本件実施例１の各ガラスをプロットしたグラフである。It is the graph which plotted each glass of this Example 1 by taking A1 on a horizontal axis and refractive index nd on a vertical axis | shaft. 横軸にアッベ数νｄ、縦軸にＡ２をとり、本件実施例１の各ガラスをプロットしたグラフである。The Abbe number νd is plotted on the horizontal axis and A2 is plotted on the vertical axis, and each glass of Example 1 is plotted. 横軸にＡ３、縦軸にガラス転移温度Ｔｇをとり、本件実施例１の各ガラスをプロットしたグラフである。It is the graph which plotted each glass of this Example 1 by taking A3 on a horizontal axis and taking glass transition temperature Tg on a vertical axis | shaft. ガラス転移温度と連続して精密プレス成形が可能な回数の関係を示すグラフである。It is a graph which shows the relationship between the glass transition temperature and the frequency | count in which precision press molding is possible continuously. 横軸にＡ４、縦軸にＤSTPPをとり、本件実施例１の各ガラスをプロットしたグラフである。It is the graph which plotted each glass of this Example 1 by taking AST on a horizontal axis and taking DSTPP on a vertical axis | shaft. 本件実施例１のガラスＮｏ．５を用いて、精密プレス成形により作製した非球面レンズの表面の拡大写真である。In this case, the glass No. 5 is an enlarged photograph of the surface of an aspheric lens produced by precision press molding.
　以下、本発明の実施形態について説明する。
　以下、ガラス組成を酸化物基準にて表記したとき、各ガラス成分の含有量を質量％により表示するものとする。 Hereinafter, embodiments of the present invention will be described.
Hereinafter, when the glass composition is expressed on an oxide basis, the content of each glass component is expressed by mass%.
　ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の含有量を、質量％表示で表したときの数値を、それぞれＣ（ＳｉＯ2）、Ｃ（Ｂ2Ｏ3）、Ｃ（Ａｌ2Ｏ3）、Ｃ（Ｌｉ2Ｏ）、Ｃ（Ｎａ2Ｏ）、Ｃ（Ｋ2Ｏ）、Ｃ（ＭｇＯ）、Ｃ（ＣａＯ）、Ｃ（ＳｒＯ）、Ｃ（ＢａＯ）、Ｃ（ＺｎＯ）、Ｃ（Ｌａ2Ｏ3）、Ｃ（Ｇｄ2Ｏ3）、Ｃ（Ｙ2Ｏ3）、Ｃ（ＺｒＯ2）、Ｃ（Ｎｂ2Ｏ5）、Ｃ（ＷＯ3）およびＣ（Ｔａ2Ｏ5）とする。
　仮に、Ｂ2Ｏ3の含有量が２０質量％のとき、Ｃ（Ｂ2Ｏ3）は２０であり、Ｌａ2Ｏ3の含有量が３０質量％のとき、Ｃ（Ｌａ2Ｏ3）は３０である。 SiO 2, B 2 O 3, Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3, Gd 2 O 3, Y 2 O 3, Numerical values when the contents of ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 are expressed in terms of mass% are respectively C (SiO 2 ), C (B 2 O 3 ), C (Al 2 O 3 ), C (Li 2 O), C (Na 2 O), C (K 2 O), C (MgO), C (CaO), C (SrO), C (BaO), C (ZnO), C (La 2 O 3 ), C (Gd 2 O 3 ), C (Y 2 O 3 ), C (ZrO 2 ), C (Nb 2 O 5 ), C (WO 3 ) and C (Ta 2 O 5 ).
Temporarily, when the content of B 2 O 3 is 20% by mass, C (B 2 O 3 ) is 20, and when the content of La 2 O 3 is 30% by mass, C (La 2 O 3 ) is 30.
　また、ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の各化学式量をそれぞれＭ（ＳｉＯ2）、Ｍ（Ｂ2Ｏ3）、Ｍ（Ａｌ2Ｏ3）、Ｍ（Ｌｉ2Ｏ）、Ｍ（Ｎａ2Ｏ）、Ｍ（Ｋ2Ｏ）、Ｍ（ＭｇＯ）、Ｍ（ＣａＯ）、Ｍ（ＳｒＯ）、Ｍ（ＢａＯ）、Ｍ（ＺｎＯ）、Ｍ（Ｌａ2Ｏ3）、Ｍ（Ｇｄ2Ｏ3）、Ｍ（Ｙ2Ｏ3）、Ｍ（ＺｒＯ2）、Ｍ（Ｎｂ2Ｏ5）、Ｍ（ＷＯ3）およびＭ（Ｔａ2Ｏ5）とする。 Further, SiO 2, B 2 O 3 , Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3, Gd 2 O 3, Y 2 O 3 , ZrO 2 , Nb 2 O 5 , WO 3, and Ta 2 O 5 are represented by respective chemical formulas M (SiO 2 ), M (B 2 O 3 ), M (Al 2 O 3 ), M (Li 2 O ), M (Na 2 O), M (K 2 O), M (MgO), M (CaO), M (SrO), M (BaO), M (ZnO), M (La 2 O 3 ), M (Gd 2 O 3 ), M (Y 2 O 3 ), M (ZrO 2 ), M (Nb 2 O 5 ), M (WO 3 ) and M (Ta 2 O 5 ).
　そして、ガラス成分の含有量、化学式量を用いて、Ａ１、Ａ２、Ａ３、Ａ４を次のように定義する。 And A1, A2, A3, and A4 are defined as follows using the content of the glass component and the chemical formula amount.
Ａ１＝－５５０Ｃ（ＳｉＯ2）－５００Ｃ（Ｂ2Ｏ3）－４５０Ｃ（Ａｌ2Ｏ3）＋１００Ｃ（Ｌｉ2Ｏ）－２８０Ｃ（Ｎａ2Ｏ）－３００Ｃ（Ｋ2Ｏ）－３００Ｃ（ＭｇＯ）－１００Ｃ（ＳｒＯ）＋５０Ｃ（ＺｎＯ）＋２００Ｃ（Ｌａ2Ｏ3）＋１５０Ｃ（Ｇｄ2Ｏ3）＋２５０Ｃ（Ｙ2Ｏ3）＋２５０Ｃ（ＺｒＯ2）＋４００Ｃ（Ｎｂ2Ｏ5）＋３００Ｃ（ＷＯ3）　・・・（１） A1 = −550C (SiO 2 ) −500C (B 2 O 3 ) −450C (Al 2 O 3 ) + 100C (Li 2 O) −280C (Na 2 O) −300C (K 2 O) −300C (MgO) — 100C (SrO) + 50C (ZnO ) + 200C (La 2 O 3) + 150C (Gd 2 O 3) + 250C (Y 2 O 3) + 250C (ZrO 2) + 400C (Nb 2 O 5) + 300C (WO 3) ··· ( 1)
Ａ２＝０．４Ｃ（ＳｉＯ2）＋０．８Ｃ（Ｂ2Ｏ3）＋０．１Ｃ（Ａｌ2Ｏ3）－０．３Ｃ（Ｌｉ2Ｏ）－０．５Ｃ（Ｎａ2Ｏ）－０．５Ｃ（Ｋ2Ｏ）－０．３Ｃ（ＭｇＯ）－０．２Ｃ（ＣａＯ）－０．３Ｃ（ＳｒＯ）－０．０５Ｃ（ＢａＯ）－０．６Ｃ（ＺｎＯ）－０．２Ｃ（Ｌａ2Ｏ3）－０．２Ｃ（Ｇｄ2Ｏ3）－０．２Ｃ（Ｙ2Ｏ3）－Ｃ（ＺｒＯ2）－２Ｃ（Ｎｂ2Ｏ5）－２Ｃ（ＷＯ3）　・・・（２） A2 = 0.4C (SiO 2 ) + 0.8C (B 2 O 3 ) + 0.1C (Al 2 O 3 ) −0.3C (Li 2 O) −0.5C (Na 2 O) −0.5C ( K 2 O) -0.3C (MgO) -0.2C (CaO) -0.3C (SrO) -0.05C (BaO) -0.6C (ZnO) -0.2C (La 2 O 3 )- 0.2C (Gd 2 O 3) -0.2C (Y 2 O 3) -C (ZrO 2) -2C (Nb 2 O 5) -2C (WO 3) ··· (2)
Ａ３＝２０Ｃ（Ｌｉ2Ｏ）＋１２Ｃ（Ｎａ2Ｏ）＋１０Ｃ（Ｋ2Ｏ）＋２Ｃ（ＺｎＯ）－２Ｃ（ＢａＯ）－３Ｃ（ＳｉＯ2）－３Ｃ（Ｂ2Ｏ3）－３Ｃ（ＺｒＯ2）－Ｃ（Ｔａ2Ｏ5）－２Ｃ（Ａｌ2Ｏ3）　・・・（３） A3 = 20C (Li 2 O) + 12C (Na 2 O) + 10C (K 2 O) + 2C (ZnO) -2C (BaO) -3C (SiO 2) -3C (B 2 O 3) -3C (ZrO 2) - C (Ta 2 O 5 ) -2C (Al 2 O 3 ) (3)
Ａ４＝２×｛Ｃ（Ｂ2Ｏ3）／Ｍ（Ｂ2Ｏ3）｝×［｛Ｃ（ＭｇＯ）／Ｍ（ＭｇＯ）｝＋｛Ｃ（ＣａＯ）／Ｍ（ＣａＯ）｝＋｛Ｃ（ＳｒＯ）／Ｍ（ＳｒＯ）｝＋｛Ｃ（ＢａＯ）／Ｍ（ＢａＯ）｝＋２×｛Ｃ（Ｌｉ2Ｏ）／Ｍ（Ｌｉ2Ｏ）｝＋２×｛Ｃ（Ｎａ2Ｏ）／Ｍ（Ｎａ2Ｏ）｝＋２×｛Ｃ（Ｋ2Ｏ）／Ｍ（Ｋ2Ｏ）｝］／［｛Ｃ（ＳｉＯ2）／Ｍ（ＳｉＯ2）｝＋２×｛Ｃ（Ａｌ2Ｏ3）／Ｍ（Ａｌ2Ｏ3）｝＋２×｛Ｃ（Ｌａ2Ｏ3）／Ｍ（Ｌａ2Ｏ3）｝＋２×｛Ｃ（Ｇｄ2Ｏ3）／Ｍ（Ｇｄ2Ｏ3）｝＋２×｛Ｃ（Ｙ2Ｏ3）／Ｍ（Ｙ2Ｏ3）｝＋｛Ｃ（ＺｒＯ2）／Ｍ（ＺｒＯ2）｝＋｛Ｃ（ＺｎＯ）／Ｍ（ＺｎＯ）｝＋２×｛Ｃ（Ｎｂ2Ｏ5）／Ｍ（Ｎｂ2Ｏ5）｝］　・・・（４） A4 = 2 × {C (B 2 O 3 ) / M (B 2 O 3 )} × [{C (MgO) / M (MgO)} + {C (CaO) / M (CaO)} + {C ( SrO) / M (SrO)} + {C (BaO) / M (BaO)} + 2 × {C (Li 2 O) / M (Li 2 O)} + 2 × {C (Na 2 O) / M (Na 2 O)} + 2 × {C (K 2 O) / M (K 2 O)}] / [{C (SiO 2 ) / M (SiO 2 )} + 2 × {C (Al 2 O 3 ) / M ( Al 2 O 3 )} + 2 × {C (La 2 O 3 ) / M (La 2 O 3 )} + 2 × {C (Gd 2 O 3 ) / M (Gd 2 O 3 )} + 2 × {C (Y 2 O 3 ) / M (Y 2 O 3 )} + {C (ZrO 2 ) / M (ZrO 2 )} + {C (ZnO) / M (ZnO)} + 2 × {C (Nb 2 O 5 ) / M (Nb 2 O 5 )}] (4)
　Ａ１は、ガラスの屈折率ｎｄを決める指標である。（１）式の右辺において、各ガラス成分の含有量の係数は、各ガラス成分の屈折率ｎｄの増減に及ぼす寄与度である。 A1 is an index for determining the refractive index nd of the glass. In the right side of the equation (1), the coefficient of content of each glass component is a contribution to increase / decrease in the refractive index nd of each glass component.
　係数がプラスのガラス成分は屈折率ｎｄを増加させる働きを有し、係数が大きいほど、この成分の含有量の単位質量％あたりの屈折率ｎｄの増加量が大きくなる。一方、係数がマイナスのガラス成分は屈折率ｎｄを減少させる働きを有し、係数の絶対値が大きいほど、この成分の含有量の単位質量％あたりの屈折率ｎｄの減少量が大きくなる。上記の各係数は、実験化学的に求めた値である。 The glass component having a positive coefficient has a function of increasing the refractive index nd, and the larger the coefficient, the larger the increase in the refractive index nd per unit mass% of the content of this component. On the other hand, a glass component having a negative coefficient has a function of decreasing the refractive index nd. The larger the absolute value of the coefficient, the larger the amount of decrease in the refractive index nd per unit mass% of the content of this component. Each coefficient is a value obtained experimentally.
　図１は、横軸にＡ１、縦軸に屈折率ｎｄをとり、本件実施例１の各ガラスをプロットしたグラフである。図１より明らかなように、Ａ１と屈折率ｎの間には相関があり、Ａ１の増減に伴い、屈折率も増減する。 FIG. 1 is a graph in which each glass of Example 1 is plotted with A1 on the horizontal axis and the refractive index nd on the vertical axis. As is clear from FIG. 1, there is a correlation between A1 and the refractive index n, and the refractive index increases and decreases as A1 increases and decreases.
　所望の屈折率ｎｄを実現する上から、本実施形態のガラスのＡ１は－１８０００以上かつ－７０００以下である。Ａ１の好ましい下限は－１７５００、より好ましくは－１７０００ある。Ａ１の好ましい上限は－７５００、より好ましくは－８０００、－８１００の順である。 From the standpoint of realizing the desired refractive index nd, A1 of the glass of the present embodiment is -18000 or more and -7000 or less. A preferred lower limit of A1 is -17500, more preferably -17000. The upper limit of A1 is preferably −7500, more preferably −8000, −8100.
　Ａ２は、ガラスのアッベ数νｄを決める指標である。(２)式の右辺において、各ガラス成分の含有量の係数は、各ガラス成分のアッベ数νｄの増減に及ぼす寄与度である。 A2 is an index for determining the Abbe number νd of the glass. In the right side of the equation (2), the coefficient of the content of each glass component is the degree of contribution to the increase / decrease in the Abbe number νd of each glass component.
　係数がプラスのガラス成分はアッベ数νｄを増加させる働きを有し、係数が大きいほど、この成分の含有量の単位質量％あたりのアッベ数νｄの増加量が大きくなる。一方、係数がマイナスのガラス成分はアッベ数νｄを減少させる働きを有し、係数の絶対値が大きいほど、この成分の含有量の単位質量％あたりのアッベ数νｄの減少量が大きくなる。上記の各係数は、実験化学的に求めた値である。 The glass component having a positive coefficient has a function of increasing the Abbe number νd, and the larger the coefficient, the larger the increase in the Abbe number νd per unit mass% of the content of this component. On the other hand, a glass component having a negative coefficient has a function of decreasing the Abbe number νd, and the larger the absolute value of the coefficient, the larger the decrease in the Abbe number νd per unit mass% of the content of this component. Each coefficient is a value obtained experimentally.
　図２は、横軸にアッベ数νｄ、縦軸にＡ２をとり、本件実施例１の各ガラスをプロットしたグラフである。図２より明らかなように、Ａ２とアッベ数νの間には相関があり、Ａ２の増減に伴い、アッベ数νｄも増減する。 FIG. 2 is a graph plotting each glass of Example 1 with the Abbe number νd on the horizontal axis and A2 on the vertical axis. As is apparent from FIG. 2, there is a correlation between A2 and the Abbe number ν, and the Abbe number νd increases and decreases as A2 increases and decreases.
　所望のアッベ数νｄを実現する上から、本実施形態のガラスのＡ２は－１以上かつ１５以下である。Ａ２の好ましい下限は－０．５、より好ましくは０、０．３、０．５、０．８の順である。Ａ２の好ましい上限は１４．５、より好ましくは１４．３、１４の順である。 In order to achieve the desired Abbe number νd, A2 of the glass of the present embodiment is −1 or more and 15 or less. The preferred lower limit of A2 is -0.5, more preferably 0, 0.3, 0.5, 0.8. The upper limit with preferable A2 is 14.5, More preferably, it is 14.3 and 14 order.
　Ａ３は、ガラスの転移温度Ｔｇを決める指標である。(３)式の右辺において、各ガラス成分の含有量の係数は、各ガラス成分のガラス転移温度Ｔｇの上昇下降に及ぼす寄与度である。 A3 is an index for determining the glass transition temperature Tg. In the right side of the equation (3), the content coefficient of each glass component is the degree of contribution to the rise and fall of the glass transition temperature Tg of each glass component.
　係数がプラスのガラス成分はガラス転移温度を下降させる働きを有し、係数が大きいほど、この成分の含有量の単位質量％あたりのガラス転移温度の下降量が大きくなる。一方、係数がマイナスのガラス成分はガラス転移温度を上昇させる働きを有し、係数の絶対値が大きいほど、この成分の含有量の単位質量％あたりのガラス転移温度の上昇量が大きくなる。上記の各係数は、実験化学的に求めた値である。 The glass component having a positive coefficient has a function of lowering the glass transition temperature, and the larger the coefficient, the larger the amount of decrease in the glass transition temperature per unit mass% of the content of this component. On the other hand, a glass component having a negative coefficient has a function of increasing the glass transition temperature. The larger the absolute value of the coefficient, the larger the increase in the glass transition temperature per unit mass% of the content of this component. Each coefficient is a value obtained experimentally.
　図３は、横軸にＡ３、縦軸にガラス転移温度Ｔｇをとり、本件実施例１の各ガラスをプロットしたグラフである。図３より明らかなように、Ａ３とガラス転移温度の間には相関があり、Ａ３の増減に伴い、ガラス転移温度が下降上昇する。 FIG. 3 is a graph in which each glass of Example 1 is plotted with A3 on the horizontal axis and the glass transition temperature Tg on the vertical axis. As is clear from FIG. 3, there is a correlation between A3 and the glass transition temperature, and the glass transition temperature increases and decreases as A3 increases and decreases.
　図４は、精密プレス成形に使用するガラスのガラス転移温度Ｔｇを縦軸、連続して精密プレス成形が可能な回数を縦軸にとり、ガラス転移温度Ｔｇが異なる５種のガラスについて、新しいＳｉＣ製のプレス成形型を用い、ガラスがプレス成形型の成形面に融着し、ガラスに成形面の形状を精密に転写できなくなるまで行った精密プレス成形の回数をプロットしたものである。 FIG. 4 shows the glass transition temperature Tg of the glass used for precision press-molding on the vertical axis, the number of continuous precision press-molding on the vertical axis, and five types of glasses with different glass transition temperatures Tg. The number of precision press moldings performed until the glass is fused to the molding surface of the press molding die and the shape of the molding surface cannot be accurately transferred to the glass is plotted.
　図４より、連続して１００００回の精密プレス成形を可能にするためには、ガラス転移温度が５４０℃以下であることが望まれる。図３により、このようなガラスを作製するために、本実施形態のガラスのＡ３は－６４以上である。 FIG. 4 shows that the glass transition temperature is preferably 540 ° C. or lower in order to enable continuous precision press molding 10,000 times. According to FIG. 3, in order to produce such glass, A3 of the glass of this embodiment is −64 or more.
　ガラス転移温度を低下させ、精密プレス成形により高品質の光学素子を量産する上から、Ａ３の好ましい下限は－６２、より好ましくは－６０、－５８、－５５の順である。一方、Ａ３を過剰に大きくすると、ガラスの熱的安定性が低下したり、化学的耐久性が低下する傾向が生じる。ガラスの熱的安定性、化学的安定性を維持する上から、Ａ３の好ましい上限は４５、より好ましくは４３、４０、３７、３５、３２、３０、２８の順である。 The preferred lower limit of A3 is −62, more preferably −60, −58, and −55 in order to reduce the glass transition temperature and mass-produce high-quality optical elements by precision press molding. On the other hand, if A3 is excessively increased, the thermal stability of the glass tends to decrease, or the chemical durability tends to decrease. In order to maintain the thermal stability and chemical stability of the glass, the upper limit of A3 is preferably 45, more preferably 43, 40, 37, 35, 32, 30, 28.
　Ａ４は、トリポリリン酸ナトリウム水溶液（ＳＴＰＰ溶液）によるガラスの侵蝕の度合、すなわち、ガラスの耐潜傷性を決める指標である。（４）式の右辺において、各ガラス成分の含有量の係数が大きいほど、この成分の含有量の単位質量％あたりのＳＴＰＰ溶液による侵蝕の度合が大きくなる、すなわち、耐潜傷性を低下させやすい。 A4 is an index that determines the degree of erosion of the glass by the aqueous sodium tripolyphosphate solution (STPP solution), that is, the latent damage resistance of the glass. In the right side of the formula (4), the greater the coefficient of content of each glass component, the greater the degree of erosion by the STPP solution per unit mass% of the content of this component, that is, the latent resistance is reduced. Cheap.
　耐潜傷性の評価には、例えば、直径４３．７ｍｍ、厚さ５ｍｍのディスク状のガラス試料を使用する。直径４３．７ｍｍの２つの面は光学研磨面になっており、２つの面の面積の合計は３０ｃｍ2である。このガラス試料を５０℃に保たれた０．０１モル／リットルのＮａ5Ｐ3Ｏ10（ＳＴＰＰ）水溶液中に１時間浸漬したとき、１時間浸漬前後のガラス試料の質量差を３０ｃｍ2で割った値［ｍｇ／（ｃｍ2・時）］、すなわち、質量減ＤSTPPの大小により耐潜傷性を評価する。 For the evaluation of the latent scratch resistance, for example, a disk-shaped glass sample having a diameter of 43.7 mm and a thickness of 5 mm is used. Two surfaces having a diameter of 43.7 mm are optically polished surfaces, and the total area of the two surfaces is 30 cm 2 . When this glass sample was immersed in a 0.01 mol / liter Na 5 P 3 O 10 (STPP) aqueous solution maintained at 50 ° C. for 1 hour, the mass difference between the glass sample before and after the 1 hour immersion was divided by 30 cm 2 . The value of [mg / (cm 2 · hr)], that is, the mass loss D STPP is used to evaluate the latent resistance.
　上記質量減ＤSTPPが小さいほど、耐潜傷性が優れていることを意味する。ＤSTPPの範囲によって、耐潜傷性は下表のように、１級から５級までの５つのクラスに分類される。
Figure JPOXMLDOC01-appb-T000001
 It means that the smaller the mass loss D STPP is, the better the latent scratch resistance is. Depending on the range of D STPP , the latent resistance is classified into five classes from the first grade to the fifth grade as shown in the table below.
Figure JPOXMLDOC01-appb-T000001
　Ａ４の増加に伴い、ＤSTPPも増加し、耐潜傷性が低下する。（４）式の右辺における各ガラス成分の含有量の係数は、実験化学的に求めた値である。 Along with the increase in A4, D STPP also increases, and the latent resistance is lowered. The coefficient of content of each glass component on the right side of the equation (4) is a value obtained experimentally.
　図５は、横軸にＡ４、縦軸にＤSTPPをとり、本件実施例１の各ガラスと、比較例の各ガラスをプロットしたグラフである。図５より明らかなように、Ａ４とＤSTPPの間には相関があり、Ａ４の増減に伴い、ＤSTPPも増減する。 FIG. 5 is a graph in which A4 is plotted on the horizontal axis and D STPP is plotted on the vertical axis, and each glass of Example 1 and each glass of the comparative example are plotted. 5 As is clear, there is a correlation between the A4 and D STPP, in accordance with an increase and decrease of A4, D STPP also increased or decreased.
　所望の耐潜傷性を実現する上から、本実施形態のガラスのＡ４は０．５８以下である。
　屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７である光学ガラスは、従来、耐潜傷性が３～５級であったが、Ａ４を調整することにより、耐潜傷性を１級または２級にすることができる。 In order to achieve the desired latent scratch resistance, A4 of the glass of the present embodiment is 0.58 or less.
Optical glass having a refractive index nd of 1.65 to 1.72 and an Abbe number νd of 50 to 57 has conventionally had a resistance to latent scratches of 3 to 5. However, by adjusting A4, The scratching property can be set to first grade or second grade.
　耐潜傷性を改善し、表面の品質が高い光学素子の製造を容易にする上から、Ａ４の好ましい上限は０．５７、より好ましくは０．５６、０．５４、０．５２、０．５０、０．４８、０．４６、０．４４の順である。一方、Ａ４を過剰に小さくすると、ガラスの熱的安定性が低下したり、所望の屈折率、アッベ数を実現することが難しくなったり、ガラス転移温度が上昇する傾向が生じる。ガラスの熱的安定性を維持し、所望の光学特性を実現し、ガラス転移温度の上昇を抑制する上から、Ａ４の好ましい下限は０．１０、より好ましくは０．１５、０．１７、０．２０、０．２２、０．２５の順である。 The upper limit of A4 is preferably 0.57, more preferably 0.56, 0.54, 0.52, 0. From the viewpoint of improving the latent scratch resistance and facilitating the production of an optical element having a high surface quality. The order is 50, 0.48, 0.46, and 0.44. On the other hand, when A4 is excessively small, the thermal stability of the glass is lowered, it is difficult to realize a desired refractive index and Abbe number, and the glass transition temperature tends to increase. The preferred lower limit of A4 is 0.10, more preferably 0.15, 0.17, 0 from the standpoint of maintaining the thermal stability of the glass, realizing the desired optical properties, and suppressing an increase in the glass transition temperature. .20, 0.22, 0.25.
　従来、屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７の範囲の光学特性を有するガラスにおいて、ガラス転移温度が５４０℃以下の特性と耐潜傷性が２級の特性を両立することが困難であった。ガラス転移温度を５４０℃以下にしようとすると、耐潜傷性が３級もしくは４級になってしまう。逆に、耐潜傷性を２級にしようとすると、ガラス転移温度が上昇し、５４０℃を超えてしまう。 Conventionally, in a glass having an optical characteristic with a refractive index nd of 1.65 to 1.72 and an Abbe number νd of 50 to 57, the glass transition temperature is 540 ° C. or lower and the latent scratch resistance is second class. It was difficult to achieve both. If the glass transition temperature is set to 540 ° C. or lower, the latent scratch resistance becomes the third or fourth grade. On the other hand, if the resistance to latent scratches is to be second grade, the glass transition temperature rises and exceeds 540 ° C.
　一方、上記範囲とは異なる範囲の光学特性を有するガラスでは、ガラス転移温度が５４０℃以下の特性と耐潜傷性が２級の特性を兼ね備えるものがある。 On the other hand, some glasses having optical characteristics in a range different from the above range have a glass transition temperature of 540 ° C. or lower and a latent scratch resistance of a second class.
　すなわち、屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７の範囲の光学特性を有するガラスにおいて、ガラス転移温度が５４０℃以下の特性と耐潜傷性が２級の特性の両立を図ることの意義は非常に大きい。
　本実施形態では、Ａ１、Ａ２、Ａ３、Ａ４を所定の値にすることにより、上記光学特性とともに、ガラス転移温度が低く、耐潜傷性も良好な光学ガラスを提供できる。 That is, in a glass having an optical characteristic in which the refractive index nd is 1.65 to 1.72 and the Abbe number νd is 50 to 57, the glass transition temperature is 540 ° C. or lower and the latent resistance is a second class characteristic. The significance of achieving both is very great.
In this embodiment, by setting A1, A2, A3, and A4 to predetermined values, it is possible to provide an optical glass that has a low glass transition temperature and good latent scratch resistance as well as the above optical characteristics.
　ＢａＯは、大気中の二酸化炭素と反応し、ガラスの表面に炭酸バリウムを生成する原因となる。炭酸バリウムの生成は、ガラス表面の透明性を低下させ、光学素子の性能を低下させる。ガラス表面の透明性を維持する上から、ＢａＯの含有量、すなわち、Ｃ（ＢａＯ）は１０以下である。Ｃ（ＢａＯ）の好ましい上限は８、より好ましくは６、４、３、２、１の順である。Ｃ（ＢａＯ）は０でもよい。 BaO reacts with carbon dioxide in the atmosphere and causes barium carbonate to be generated on the surface of the glass. The production of barium carbonate reduces the transparency of the glass surface and reduces the performance of the optical element. In order to maintain the transparency of the glass surface, the content of BaO, that is, C (BaO) is 10 or less. The preferable upper limit of C (BaO) is 8, more preferably in the order of 6, 4, 3, 2, 1. C (BaO) may be 0.
　Ｇｄ2Ｏ3は高価な成分であり、ガラスを安定して供給する上から、Ｃ（Ｇｄ2Ｏ3）は４以下である。Ｃ（Ｇｄ2Ｏ3）の好ましい上限は３.５、より好ましくは３、２.５、２、１．５、１、０．５、０．１の順である。上記の理由より、Ｃ（Ｇｄ2Ｏ3）が０であることが最も好ましい。 Gd 2 O 3 is an expensive component, and C (Gd 2 O 3 ) is 4 or less from the viewpoint of stably supplying glass. A preferable upper limit of C (Gd 2 O 3 ) is 3.5, more preferably 3, 2.5, 2, 1.5, 1, 0.5, and 0.1. For the above reason, C (Gd 2 O 3 ) is most preferably 0.
　Ｔａ2Ｏ5は高価な成分であり、ガラスを安定して供給する上から、Ｃ（Ｔａ2Ｏ5）は３未満である。Ｃ（Ｔａ2Ｏ5）は好ましくは２以下、さらに１以下、０．５以下、０．１以下の順により好ましい。上記の理由より、Ｃ（Ｔａ2Ｏ5）が０であることが最も好ましい。 Ta 2 O 5 is an expensive component, and C (Ta 2 O 5 ) is less than 3 because glass is stably supplied. C (Ta 2 O 5 ) is preferably 2 or less, more preferably 1 or less, 0.5 or less, and 0.1 or less. For the above reason, C (Ta 2 O 5 ) is most preferably 0.
（１）式～（４）式に現れるガラス成分の中で、Ｔａの原子量が最も大きく、次いでＧｄの原子量が大きい。すなわち、ＴａはＧｄとともにガラスの比重を増大させる。ガラスの比重増加は、光学素子を軽量化したり、熔融ガラス塊を浮上状態で精密プレス成形用プリフォームに成形する上で不利に働く。 Among the glass components appearing in the equations (1) to (4), the atomic weight of Ta is the largest, followed by the atomic weight of Gd. That is, Ta increases the specific gravity of glass together with Gd. The increase in the specific gravity of the glass is disadvantageous in reducing the weight of the optical element and forming the molten glass lump into a precision press-molding preform in a floating state.
　また、ガラス熔融中に軽い原料と重い原料が混在すると、重い原料、すなわち、Ｔａ原料やＧｄ原料が偏析してガラスの熔融性を低下させることがある。
　このように、ガラスを軽量化し、熔融性を改善する上でも、Ｃ（Ｇｄ2Ｏ3）、Ｃ（Ｔａ2Ｏ5）を上記のように制限することが好ましい。 In addition, when light and heavy raw materials are mixed during glass melting, heavy raw materials, that is, Ta raw materials and Gd raw materials may segregate, which may lower the meltability of the glass.
Thus, it is preferable to limit C (Gd 2 O 3 ) and C (Ta 2 O 5 ) as described above in order to reduce the weight of the glass and improve the meltability.
　本実施形態に係る光学ガラスとしては、必須の成分として、Ｂ2Ｏ3、ＳｉＯ2、Ｌａ2Ｏ3、Ｙ2Ｏ3、Ｌｉ2ＯおよびＺｎＯを含むガラスが好ましい。 The optical glass according to the present embodiment is preferably a glass containing B 2 O 3 , SiO 2 , La 2 O 3 , Y 2 O 3 , Li 2 O and ZnO as essential components.
　Ｂ2Ｏ3は、ガラスのネットワーク形成成分であり、アッベ数νｄを増加させる働きを有する。しかし、Ｂ2Ｏ3の含有量が多くなると、ガラスの化学的耐久性が低下し、ガラスの表面品質が低下しやすくなる。 B 2 O 3 is a glass network forming component and has a function of increasing the Abbe number νd. However, when the content of B 2 O 3 increases, the chemical durability of the glass decreases and the surface quality of the glass tends to decrease.
　アッベ数νｄの減少を抑制し、低分散性を維持する上から、Ｃ（Ｂ2Ｏ3）が２１以上であることが好ましい。Ｃ（Ｂ2Ｏ3）のより好ましい下限は２３、さらに好ましい下限は２４である。一方、化学的耐久性を維持し、ガラスの表面品質が低下を抑制し、ヘイズの増大を抑える上から、Ｃ（Ｂ2Ｏ3）が３１以下であることが好ましい。Ｃ（Ｂ2Ｏ3）のより好ましい上限は２９、さらに好ましい下限は２８である。 In order to suppress a decrease in the Abbe number νd and maintain low dispersibility, C (B 2 O 3 ) is preferably 21 or more. A more preferred lower limit of C (B 2 O 3 ) is 23, and a more preferred lower limit is 24. On the other hand, C (B 2 O 3 ) is preferably 31 or less from the viewpoint of maintaining chemical durability, suppressing deterioration of the surface quality of the glass, and suppressing increase in haze. A more preferred upper limit of C (B 2 O 3 ) is 29, and a more preferred lower limit is 28.
　ＳｉＯ2は、ガラスのネットワーク形成成分であり、ガラスの化学的耐久性を改善する働きを有する。Ｂ2Ｏ3の含有量の増加に伴い、低下する化学的耐久性を維持するために、ＳｉＯ2の含有量をＢ2Ｏ3の含有量の０．３０倍以上とする、すなわち、Ｃ（ＳｉＯ2）をＣ（Ｂ2Ｏ3）の０．３０倍以上とすることが好ましい。また、化学的耐久性をより改善する上で、Ｃ（ＳｉＯ2）を８以上にすることが好ましく、１０以上にすることがより好ましく、１２以上にすることがさらに好ましく、１３以上にすることが一層好ましい。一方、高屈折率特性を維持する上で、Ｃ（ＳｉＯ2）を１８以下にすることが好ましく、１６以下にすることがより好ましく、１５以下にすることがさらに好ましい。 SiO 2 is a glass network forming component and has a function of improving the chemical durability of the glass. In order to maintain the chemical durability that decreases as the content of B 2 O 3 increases, the content of SiO 2 is set to 0.30 or more times the content of B 2 O 3 , that is, C ( it is preferable that the SiO 2) and C (B 2 O 3) of 0.30 times or more. In order to further improve the chemical durability, C (SiO 2 ) is preferably 8 or more, more preferably 10 or more, further preferably 12 or more, and 13 or more. Is more preferable. On the other hand, in maintaining high refractive index characteristics, C (SiO 2 ) is preferably 18 or less, more preferably 16 or less, and even more preferably 15 or less.
　Ｌａ2Ｏ3は、屈折率ｎｄを高める働きを有する。また、化学的耐久性を高める働きも有する。そして、屈折率を高める働きをする高屈折率化成分の中でも、比較的、アッベ数νｄを減少させにくい成分でもある。低分散性を維持しつつ、屈折率ｎｄを高め、化学的耐久性を維持する上から、Ｃ（Ｌａ2Ｏ3）が１８以上であることが好ましい。 La 2 O 3 has a function of increasing the refractive index nd. It also has the function of increasing chemical durability. Among the components for increasing the refractive index that serve to increase the refractive index, it is also a component that is relatively difficult to reduce the Abbe number νd. From the viewpoint of increasing the refractive index nd and maintaining chemical durability while maintaining low dispersibility, C (La 2 O 3 ) is preferably 18 or more.
　ガラスの熱的安定性、すなわち、耐失透性を維持し、製造する過程でガラスを結晶化しにくくして、均質な光学ガラスを製造することを容易にする上から、Ｃ（Ｌａ2Ｏ3）が３０以下であることが好ましい。また、ガラス転移温度の上昇を抑え、精密プレス成形に好適なガラスを提供する上からも、Ｃ（Ｌａ2Ｏ3）が３０以下であることが好ましい。 From the viewpoint of maintaining the thermal stability of the glass, that is, devitrification resistance, making the glass difficult to crystallize in the manufacturing process, and facilitating the production of a homogeneous optical glass, C (La 2 O 3 ) Is preferably 30 or less. Further, suppressing the increase of the glass transition temperature, even over to provide suitable glass for precision press molding, it is preferable C (La 2 O 3) is 30 or less.
　Ｃ（Ｌａ2Ｏ3）のより好ましい下限は１９、さらに好ましい下限は２０、２２、２４の順である。一方、ガラスの熱的安定性を改善し、ガラス転移温度を低く保つ上から、Ｃ（Ｌａ2Ｏ3）のより好ましい上限は２９、さらに好ましい上限は２８である。 The more preferable lower limit of C (La 2 O 3 ) is 19, and the more preferable lower limit is 20, 22, and 24 in this order. On the other hand, from the viewpoint of improving the thermal stability of the glass and keeping the glass transition temperature low, the more preferable upper limit of C (La 2 O 3 ) is 29, and the more preferable upper limit is 28.
　Ｙ2Ｏ3は、アッベ数νｄを大きく減少させることなく、屈折率ｎｄを高める働きを有する。アッベ数νｄの減少を抑制して低分散性を維持し、ガラスの熱的安定性を維持する上から、Ｃ（Ｙ2Ｏ3）の好ましい下限は５であり、より好ましい下限は７、８の順である。
ガラスの熱的安定性を維持し、失透しにくいガラスとする上から、Ｃ（Ｙ2Ｏ3）の好ましい上限は１７であり、より好ましい上限は１５、さらに好ましい上限は１４である。 Y 2 O 3 functions to increase the refractive index nd without significantly reducing the Abbe number νd. The preferred lower limit of C (Y 2 O 3 ) is 5 and the more preferred lower limit is 7, 8 in order to suppress the decrease in the Abbe number νd to maintain low dispersibility and maintain the thermal stability of the glass. In the order.
From the standpoint of maintaining the thermal stability of the glass and making it difficult to devitrify, the preferred upper limit of C (Y 2 O 3 ) is 17, a more preferred upper limit is 15, and a more preferred upper limit is 14.
　Ｎｂ2Ｏ5は、屈折率ｎｄを高めるとともに、ガラスの熱的安定性を改善する働きを有する。また、ガラスの化学的耐久性を改善する働きも有する。一方、Ｎｂ2Ｏ5の含有量が多くなりすぎると、ガラスの熱的安定性が低下する傾向を示すとともに、アッベ数νｄが減少し、ガラスが高分散化する傾向を示す。また、ガラスの着色が強まる傾向がある。ガラスの熱的安定性を維持する上で、Ｃ（Ｎｂ2Ｏ5）の上限は、好ましくは５であり、より好ましくは３であり、さらに好ましくは２であり、一層好ましくは１である。Ｃ（Ｎｂ2Ｏ5）の下限は、好ましくは０である。Ｃ（Ｎｂ2Ｏ5）は０とすることもできる。 Nb 2 O 5 functions to increase the refractive index nd and improve the thermal stability of the glass. It also has the function of improving the chemical durability of the glass. On the other hand, when the content of Nb 2 O 5 is too large, the thermal stability of the glass tends to decrease, the Abbe number νd decreases, and the glass tends to be highly dispersed. In addition, the glass tends to become more colored. In order to maintain the thermal stability of the glass, the upper limit of C (Nb 2 O 5 ) is preferably 5, more preferably 3, still more preferably 2, and still more preferably 1. The lower limit of C (Nb 2 O 5 ) is preferably 0. C (Nb 2 O 5 ) may be 0.
　ＷＯ3は、ガラス転移温度Ｔｇを低下させる働きを有する。しかし、ＷＯ3の含有量が多くなりすぎると、アッベ数νｄが減少し、所要の光学特性の実現が困難になる。また、ガラスの着色が増大する。アッベ数νｄの減少を抑え、ガラスの着色増大を防ぐ上から、Ｃ（ＷＯ3）の上限は、好ましくは５であり、より好ましくは３であり、さらに好ましくは２であり、一層好ましくは１である。Ｃ（ＷＯ3）の下限は、好ましくは０である。Ｃ（ＷＯ3）は０とすることもできる。 WO 3 has a function of lowering the glass transition temperature Tg. However, if the content of WO 3 is too large, the Abbe number νd decreases, making it difficult to achieve the required optical characteristics. Moreover, the coloring of glass increases. In order to prevent the Abbe number νd from decreasing and prevent an increase in the coloration of the glass, the upper limit of C (WO 3 ) is preferably 5, more preferably 3, still more preferably 2, even more preferably 1. It is. The lower limit of C (WO 3 ) is preferably 0. C (WO 3 ) may be 0.
　Ａｌ2Ｏ3は、ガラスの化学的耐久性を改善し、ガラス表面のヘイズの増加を抑制する働きを有する必須成分である。化学的耐久性を維持し、ガラスの表面品質の低下を抑える上から、Ｃ（Ａｌ2Ｏ3）の好ましい下限は０．１であり、より好ましい下限は０．３、さらに好ましい下限は０．５である。屈折率ｎｄの低下を抑え、ガラスの屈折率を所望の範囲にする上から、Ａｌ2Ｏ3の好ましい上限は８、より好まし上限は５、さらに好ましい上限は３である。 Al 2 O 3 is an essential component having a function of improving the chemical durability of glass and suppressing an increase in haze on the glass surface. In order to maintain the chemical durability and suppress the deterioration of the surface quality of the glass, the preferable lower limit of C (Al 2 O 3 ) is 0.1, the more preferable lower limit is 0.3, and the more preferable lower limit is 0.00. 5. The upper limit of Al 2 O 3 is preferably 8, more preferably 5 and even more preferably 3 in order to suppress the decrease in the refractive index nd and bring the refractive index of the glass into a desired range.
　ＺｎＯは、ガラス転移温度を低下させるとともに、ガラスの熔融性、化学的耐久性を改善する働きを有する。ガラス転移温度の上昇を抑えて精密プレス成形に好適なガラスとする上から、そして、熔融性を維持し、ガラス原料の熔け残りを抑制する上から、Ｃ（ＺｎＯ）の好ましい下限は６であり、より好ましい下限は６．５、７、８の順である。アッベ数の減少を抑え、低分散性を維持する上から、Ｃ（ＺｎＯ）の好ましい上限は１８であり、より好ましい上限は１６、１４の順である。 ZnO has the function of lowering the glass transition temperature and improving the meltability and chemical durability of the glass. The preferable lower limit of C (ZnO) is 6 from the viewpoint of suppressing the rise of the glass transition temperature and making the glass suitable for precision press molding, and maintaining the meltability and suppressing the unmelted glass raw material. The lower limit is more preferably 6.5, 7, and 8. The upper limit of C (ZnO) is 18 and the more preferable upper limit is 16 and 14 in order to suppress the decrease in Abbe number and maintain low dispersibility.
　Ｌｉ2Ｏは、ガラス転移温度を低下させるとともに、ガラスの熔融性を改善する働きを有する。ガラス転移温度が上昇を抑制し、精密プレス成形に好適なガラスとする上から、Ｃ（Ｌｉ2Ｏ）の好ましい下限は１であり、より好ましい下限は２、３の順である。ガラスの化学的耐久性を維持し、ガラスの表面品質を良好にする上から、Ｃ（Ｌｉ2Ｏ）の好ましい上限は７、より好ましい上限は６である。 Li 2 O functions to lower the glass transition temperature and improve the meltability of the glass. From the viewpoint of suppressing the increase in the glass transition temperature and making the glass suitable for precision press molding, the preferable lower limit of C (Li 2 O) is 1, and the more preferable lower limit is in the order of 2 and 3. From the standpoint of maintaining the chemical durability of the glass and improving the surface quality of the glass, the preferable upper limit of C (Li 2 O) is 7, and the more preferable upper limit is 6.
　ＳｒＯを含有するガラスでは、ＢａＯを含有するガラスと同様、表面に存在するＳｒが大気中の二酸化炭素と結合し、ガラス表面に炭酸塩を生成する。この炭酸塩の生成が、ガラス表面の変質の一つの原因と考えられる。Ｃ（ＳｒＯ）およびＣ（ＢａＯ）の合計が５より多いと、ガラス表面が変質しやすくなる、すなわち、化学的耐久性が低下する。したがって、Ｃ（ＳｒＯ）およびＣ（ＢａＯ）の合計が５以下であることが好ましく、４以下とすることがより好ましく、３以下とすることがさらに好ましい。Ｃ（ＳｒＯ）およびＣ（ＢａＯ）の合計を０とすることもできる。 In a glass containing SrO, Sr present on the surface is combined with carbon dioxide in the atmosphere to produce carbonate on the glass surface, as in the glass containing BaO. The formation of this carbonate is considered to be one cause of the alteration of the glass surface. When the sum of C (SrO) and C (BaO) is more than 5, the glass surface is easily deteriorated, that is, the chemical durability is lowered. Therefore, the total of C (SrO) and C (BaO) is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. The sum of C (SrO) and C (BaO) may be zero.
　熱的安定性と化学的耐久性を維持する上で、Ｃ（ＳｒＯ）を０～３とすることが好ましい。Ｃ（ＳｒＯ）を０にすることもできる。 In order to maintain thermal stability and chemical durability, C (SrO) is preferably 0 to 3. C (SrO) can also be set to zero.
　Ｃ（Ｇｄ2Ｏ3）を制限しつつ、所望の屈折率ｎｄ、アッベ数νｄ、熱的安定性を維持するために、Ｃ（Ｙ2Ｏ3）に対するＣ（Ｇｄ2Ｏ3）の比（Ｃ（Ｇｄ2Ｏ3）／Ｃ（Ｙ2Ｏ3））を７未満とすることが好ましい。また、比（Ｃ（Ｇｄ2Ｏ3）／Ｃ（Ｙ2Ｏ3））を制限することにより、ガラスの化学的耐久性が改善され、ガラス表面のヘイズを減少させることもできる。 While limiting the C (Gd 2 O 3), the ratio of C (Gd 2 O 3) in order to maintain the desired refractive index nd, Abbe number [nu] d, the thermal stability, for C (Y 2 O 3) ( C (Gd 2 O 3 ) / C (Y 2 O 3 )) is preferably less than 7. Further, by limiting the ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )), the chemical durability of the glass is improved and the haze on the glass surface can be reduced.
　上記の理由より、比（Ｃ（Ｇｄ2Ｏ3）／Ｃ（Ｙ2Ｏ3））のより好ましい範囲は４未満、さらに好ましい範囲は１未満である。比（Ｃ（Ｇｄ2Ｏ3）／Ｃ（Ｙ2Ｏ3））を０にすることもできる。 For the above reason, the more preferable range of the ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )) is less than 4, and the more preferable range is less than 1. The ratio (C (Gd 2 O 3 ) / C (Y 2 O 3 )) may be zero.
　ＺｒＯ2は、屈折率ｎｄを高め、化学的耐久性や熱的安定性を改善する働きを有する。ＺｒＯ2の含有量が多くなると、アッベ数νｄが減少し、分散が高まる傾向を示す。また、熱的安定性、熔融性も低下する傾向を示す。そのため、Ｃ（ＺｒＯ2）を０～８にすることが好ましい。ガラスの化学的耐久性や熱的安定性を改善する上で、Ｃ（ＺｒＯ2）を０．１以上にすることがより好ましく、０．５以上にすることがさらに好ましく、１以上にすることが一層好ましい。一方、低分散性を維持する上から、Ｃ（ＺｒＯ2）を７以下にすることが好ましく、６以下にすることがより好ましく、５以下にすることがさらに好ましい。 ZrO 2 functions to increase the refractive index nd and improve chemical durability and thermal stability. When the content of ZrO 2 increases, the Abbe number νd decreases and the dispersion tends to increase. In addition, thermal stability and meltability tend to decrease. Therefore, it is preferable to set C (ZrO 2 ) to 0-8. In order to improve the chemical durability and thermal stability of the glass, C (ZrO 2 ) is more preferably 0.1 or more, further preferably 0.5 or more, and 1 or more. Is more preferable. On the other hand, from the viewpoint of maintaining low dispersion, it is preferable to C a (ZrO 2) to 7 or less, more preferably be 6 or less, still more preferably 5 or less.
　ＣａＯは、熔融性を改善し、屈折率を調整する働きを有する。しかし、ＣａＯの含有量が多くなると、屈折率ｎｄが減少する。高屈折率ガラスを得る上から、Ｃ（ＣａＯ）を８以下とすることが好ましく、６以下とすることがより好ましく、５以下とすることがさらに好ましい。なお、Ｃ（ＣａＯ）を０とすることもできる。ＣａＯの導入による熔融性の改善効果を得る上で、Ｃ（ＣａＯ）を０．１以上とすることが好ましく、０．５以上とすることがより好ましく、１以上とすることがさらに好ましい。 CaO has the function of improving the meltability and adjusting the refractive index. However, the refractive index nd decreases as the CaO content increases. From the viewpoint of obtaining a high refractive index glass, C (CaO) is preferably 8 or less, more preferably 6 or less, and even more preferably 5 or less. C (CaO) can also be set to zero. In obtaining the effect of improving the meltability by introducing CaO, C (CaO) is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1 or more.
　ＭｇＯは、少量であれば含有させてもよいが、その含有量が増加するにつれて、熱的安定性が低下する傾向を示す。熱的安定性を維持し、ガラスの失透を防止する上で、Ｃ（ＭｇＯ）を０～１にすることが好ましい。Ｃ（ＭｇＯ）を０にすることもできる。 MgO may be contained in a small amount, but the thermal stability tends to decrease as the content increases. In order to maintain thermal stability and prevent devitrification of the glass, C (MgO) is preferably 0 to 1. C (MgO) can also be set to zero.
　Ｎａ2Ｏ、Ｋ2Ｏは、Ｌｉ2Ｏほどではないが、ガラス転移温度を低下させる働きや熔融性を改善する働きを有する。しかし、これらの成分の含有量が多くなると、アッベ数νｄが低下し、高分散化する傾向が生じる。そのため、Ｃ（Ｎａ2Ｏ）を０～１とすることが好ましい。また、Ｃ（Ｋ2Ｏ）を０～１とすることが好ましい。Ｃ（Ｎａ2Ｏ）を０にすることもできる。また、Ｃ（Ｋ2Ｏ）を０にすることもできる。 Na 2 O and K 2 O have a function of lowering the glass transition temperature and a function of improving the meltability, although not as much as Li 2 O. However, when the content of these components increases, the Abbe number νd decreases and a tendency to high dispersion occurs. Therefore, it is preferable that C (Na 2 O) is 0 to 1. Also, C (K 2 O) is preferably 0 to 1. C (Na 2 O) may be zero. C (K 2 O) can also be set to zero.
　Ｓｂ2Ｏ3は、少量であれば、清澄剤として含有してもよい。しかし、Ｓｂ2Ｏ3の含有量が１質量％より多くなると、Ｓｂによる光吸収によりガラスの着色が増大したり、ガラスを精密プレス成形するときに、ガラス表面のＳｂがプレス成形型の成形面を酸化し、ガラスがプレス成形型の成形面に融着したり、成形面にダメージを与えたりする。また、アッベ数νｄが減少し、低分散性の維持にとって好ましくない。 Sb 2 O 3 may be contained as a refining agent in a small amount. However, when the content of Sb 2 O 3 exceeds 1% by mass, the coloring of the glass increases due to light absorption by Sb, or when the glass is precision press-molded, Sb on the glass surface is the molding surface of the press mold. The glass is fused to the molding surface of the press mold, or the molding surface is damaged. Further, the Abbe number νd decreases, which is not preferable for maintaining low dispersibility.
　したがって、Ｓｂ2Ｏ3の含有量は０～１質量％とすることが好ましく、０～０．５質量％とすることがより好ましい。Ｓｂ2Ｏ3の含有量が０質量％であってもよい。 Therefore, the content of Sb 2 O 3 is preferably 0 to 1% by mass, and more preferably 0 to 0.5% by mass. The Sb 2 O 3 content may be 0% by mass.
　ＧｅＯ2、Ｌｕ2Ｏ3、Ｇａ2Ｏ3、Ｉｎ2Ｏ3、Ｓｃ2Ｏ3、ＨｆＯ2は、いずれも屈折率ｎｄを高める働きを有する。しかし、これらの成分は高価であり、発明の目的を達成する上で必要な成分ではない。したがって、ＧｅＯ2の含有量を０～１質量％にすることが好ましく、Ｌｕ2Ｏ3の含有量を０～１質量％にすることが好ましく、Ｇａ2Ｏ3の含有量を０～１質量％にすることが好ましく、Ｉｎ2Ｏ3の含有量を０～１質量％にすることが好ましく、Ｓｃ2Ｏ3の含有量を０～１質量％にすることが好ましく、ＨｆＯ2の含有量を０～１質量％にすることが好ましい。ＧｅＯ2の含有量を０質量％にすることができ、Ｌｕ2Ｏ3の含有量を０質量％にすることができ、Ｇａ2Ｏ3の含有量を０質量％にすることができ、Ｉｎ2Ｏ3の含有量を０質量％にすることができ、Ｓｃ2Ｏ3の含有量を０質量％にすることができ、ＨｆＯ2の含有量を０質量％にすることができる。 GeO 2 , Lu 2 O 3 , Ga 2 O 3 , In 2 O 3 , Sc 2 O 3 , and HfO 2 all have a function of increasing the refractive index nd. However, these components are expensive and are not necessary components for achieving the object of the invention. Therefore, the GeO 2 content is preferably 0 to 1% by mass, the Lu 2 O 3 content is preferably 0 to 1% by mass, and the Ga 2 O 3 content is 0 to 1% by mass. %, Preferably the content of In 2 O 3 is 0 to 1% by mass, the content of Sc 2 O 3 is preferably 0 to 1% by mass, and the content of HfO 2 Is preferably 0 to 1% by mass. The GeO 2 content can be 0% by mass, the Lu 2 O 3 content can be 0% by mass, the Ga 2 O 3 content can be 0% by mass, The content of 2 O 3 can be 0 mass%, the content of Sc 2 O 3 can be 0 mass%, and the content of HfO 2 can be 0 mass%.
　Ｐ2Ｏ5は、屈折率ｎｄを低下させる成分であり、ガラスの熱的安定性を低下させる成分でもある。したがって、Ｐ2Ｏ5の含有量を０～３質量％にすることが好ましく、０～１質量％にすることがより好ましく、０～０．１質量％にすることがさらに好ましく、０質量％とすることもできる。 P 2 O 5 is a component that decreases the refractive index nd and is also a component that decreases the thermal stability of the glass. Therefore, the content of P 2 O 5 is preferably 0 to 3% by mass, more preferably 0 to 1% by mass, further preferably 0 to 0.1% by mass, and 0% by mass. It can also be.
　ＴｅＯ2は、屈折率ｎｄを高める成分であるが、環境への負荷を軽減する上から、ＴｅＯ2の含有量を０～１質量％にすることが好ましく、０～０．１質量％にすることがより好ましく、０質量％とすることがさらに好ましい。 TeO 2 is a component that increases the refractive index nd. However, in order to reduce the burden on the environment, the content of TeO 2 is preferably 0 to 1% by mass, and 0 to 0.1% by mass. More preferably, it is more preferably 0% by mass.
　Ｐｂ、Ａｓ、Ｃｄ、Ｔｌ、Ｂｅ、Ｓｅは、それぞれ毒性を有する。そのため、これらの元素を含有させないこと、すなわち、これら元素をガラス成分としてガラス中に導入しないことが好ましい。 * Pb, As, Cd, Tl, Be, and Se are each toxic. Therefore, it is preferable not to contain these elements, that is, not to introduce these elements into the glass as glass components.
　Ｕ、Ｔｈ、Ｒａはいずれも放射性元素である。そのため、これらの元素を含有させないこと、すなわち、これら元素をガラス成分としてガラス中に導入しないことが好ましい。 U, Th, and Ra are all radioactive elements. Therefore, it is preferable not to contain these elements, that is, not to introduce these elements into the glass as glass components.
　Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｐｒ，Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｃｅは、ガラスの着色を増大させたり、蛍光の発生源となり、光学ガラスに含有させる元素としては好ましくない。そのため、これらの元素を含有させないこと、すなわち、これら元素をガラス成分としてガラス中に導入しないことが好ましい。 V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Ce increase the coloration of the glass and become a source of fluorescence. The element contained in the optical glass is not preferable. Therefore, it is preferable not to contain these elements, that is, not to introduce these elements into the glass as glass components.
　ＳｎＯ2は清澄剤として機能する任意に添加可能な成分である。清澄剤として添加するＳｎＯ2の含有量は０～２質量％である。ＳｎＯ2の含有量は０～１質量％としてもよく、０～０．５質量％としてもよく、０～０．１質量％としてもよく、０質量％としてもよい。 SnO 2 is an optionally addable component that functions as a fining agent. The content of SnO 2 added as a fining agent is 0 to 2% by mass. The SnO 2 content may be 0 to 1% by mass, 0 to 0.5% by mass, 0 to 0.1% by mass, or 0% by mass.
　Ｆ、Ｃｌ、Ｂｒ、Ｉは、発明の目的を達成する上で必要としない成分である。したがって、Ｆ、Ｃｌ、Ｂｒ、Ｉの含有量はそれぞれ０質量％としてもよい。 F, Cl, Br, and I are components that are not necessary for achieving the object of the invention. Therefore, the contents of F, Cl, Br, and I may each be 0% by mass.
　Ｆ、Ｃｌ、Ｂｒ、Ｉを含有させる場合は、これら成分の含有量を０～５質量％にすることが好ましく、０～３％にすることがより好ましく、０～１質量％にすることがさらに好ましく、０～０．１質量％にすることが一層好ましい。 When F, Cl, Br, and I are contained, the content of these components is preferably 0 to 5% by mass, more preferably 0 to 3%, and more preferably 0 to 1% by mass. More preferred is 0 to 0.1% by mass.
　本実施形態に係る光学ガラスのガラス組成は、例えば、ＩＣＰ－ＡＥＳ（Inductively Coupled Plasma - Atomic Emission Spectrometry）などの方法により定量することができる。ＩＣＰ－ＡＥＳにより求められる分析値は、例えば、分析値の±５％程度の測定誤差を含んでいることがある。また、本明細書および本発明において、ガラスの構成成分の含有量が０％または含まないもしくは導入しないとは、この構成成分を実質的に含まないことを意味し、この構成成分の含有量が不純物レベル程度以下であることを指す。
　含有量が少ない成分の定量については、例えばＩＣＰ－ＭＳ（Inductively Coupled Plasma - Mass Spectrometry）などの方法により定量することができる。定量する成分によっては、イオンクロマトグラフ法などの方法により定量してもよい。 The glass composition of the optical glass according to the present embodiment can be quantified by a method such as ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). The analysis value obtained by ICP-AES may include a measurement error of about ± 5% of the analysis value, for example. In the present specification and the present invention, the content of the glass component is 0% or does not contain or is not introduced, which means that this component is not substantially contained. It means that it is about the impurity level or less.
The component having a small content can be quantified by a method such as ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Depending on the component to be quantified, it may be quantified by a method such as ion chromatography.
（ガラスの光学特性）
　本発明の実施態様に係るガラスは、高屈折率低分散ガラスであり、好ましくは、屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７である。 (Optical properties of glass)
The glass according to an embodiment of the present invention is a high refractive index and low dispersion glass, and preferably has a refractive index nd of 1.65 to 1.72 and an Abbe number νd of 50 to 57.
　アッベ数νｄを５０以上にすることにより、アッベ数の小さい高分散ガラスとの組合せにより、色収差補正機能を有する光学素子を提供することができる。一方、アッベ数νｄを５７以下にすることにより、低温軟化性の維持と熱的安定性の維持の両立が容易になる。また、Ｂ2Ｏ3の含有量の増大を抑えることができるので、化学的耐久性を維持する上でもアッベ数νｄを５７以下にすることが好ましい。 By setting the Abbe number νd to 50 or more, an optical element having a chromatic aberration correction function can be provided in combination with a high dispersion glass having a small Abbe number. On the other hand, by setting the Abbe number νd to 57 or less, it becomes easy to maintain both the low-temperature softening property and the thermal stability. Further, since an increase in the content of B 2 O 3 can be suppressed, the Abbe number νd is preferably set to 57 or less in order to maintain chemical durability.
　アッベ数νｄの下限は、より好ましくは５０．５であり、さらに好ましくは５１．０であり、一層好ましくは５２．０であり、より一層好ましくは５２．５である。またアッベ数νｄの上限は、より好ましくは５６．０であり、さらに好ましくは５５．０であり、一層好ましくは５４．０であり、より一層好ましくは５３．５である。 The lower limit of the Abbe number νd is more preferably 50.5, still more preferably 51.0, still more preferably 52.0, and even more preferably 52.5. Further, the upper limit of the Abbe number νd is more preferably 56.0, still more preferably 55.0, still more preferably 54.0, and even more preferably 53.5.
　ガラスの屈折率ｎｄを１．６５以上にすることにより、このガラスを、光学系のコンパクト化、高機能化に有効な光学素子材料とすることができる。一方、屈折率ｎｄを１．７２以下とすることにより、低温軟化性の維持と熱的安定性の維持の両立が容易になる。 By setting the refractive index nd of the glass to 1.65 or more, this glass can be used as an optical element material effective for making the optical system compact and highly functional. On the other hand, when the refractive index nd is 1.72 or less, it is easy to maintain both low temperature softening and thermal stability.
　屈折率ｎｄの下限は、より好ましくは１．６６５であり、さらに好ましくは１．６７０であり、一層好ましくは１．６７５であり、より一層好ましくは１．６８０であり、なお一層好ましくは１．６８５である。また、屈折率ｎｄの上限は、より好ましくは１．７１６であり、さらに好ましくは１．７１０であり、一層好ましくは１．７０５であり、より一層好ましくは１．７００であり、なお一層好ましくは１．６９５である。 The lower limit of the refractive index nd is more preferably 1.665, still more preferably 1.670, still more preferably 1.675, still more preferably 1.680, and still more preferably 1. 685. The upper limit of the refractive index nd is more preferably 1.716, still more preferably 1.710, still more preferably 1.705, still more preferably 1.700, and still more preferably 1.695.
（ガラス転移温度Ｔｇ）
　ガラス転移温度の好ましい範囲は５４０℃以下である。ガラス転移温度を５４０℃以下にすることにより、精密プレス成形のときにプレス成形型の温度を過剰に高くしなくても、高精度のプレス成形が可能になる。そのため、プレス成形型の消耗を低減することができ、プレス成形型の寿命を延ばすことができる。例えば、ガラス転移温度が５４０℃以下のガラスでは、ＳｉＣ製のプレス成形型を用いて、１００００回以上連続して精密プレス成形を行うことができる。 (Glass transition temperature Tg)
A preferable range of the glass transition temperature is 540 ° C. or less. By setting the glass transition temperature to 540 ° C. or lower, highly accurate press molding can be performed without excessively increasing the temperature of the press mold during precision press molding. Therefore, consumption of the press mold can be reduced, and the life of the press mold can be extended. For example, in a glass having a glass transition temperature of 540 ° C. or lower, precision press molding can be performed continuously 10,000 times or more using a SiC press mold.
　さらに、ガラス転移温度を低下させることにより、精密プレス成形のときにガラスとプレス成形型の成形面との反応を抑制することができ、プレス成形により得られる光学素子の表面品質を良好にすることができる。 Furthermore, by reducing the glass transition temperature, it is possible to suppress the reaction between the glass and the molding surface of the press mold during precision press molding, and to improve the surface quality of the optical element obtained by press molding. Can do.
　精密プレス成形による光学素子の量産性を改善する上から、ガラス転移温度の上限は、より好ましくは５３８℃であり、さらに好ましくは５３６℃であり、一層好ましくは５３５℃である。なお、ガラス転移温度の下限は、ガラス組成により自ずと定まるものであるが、ガラス転移温度を過剰に低下させると、屈折率ｎｄが低下したり、ガラスの熱的安定性が低下する傾向を示す。 In order to improve the mass productivity of the optical element by precision press molding, the upper limit of the glass transition temperature is more preferably 538 ° C, further preferably 536 ° C, and further preferably 535 ° C. The lower limit of the glass transition temperature is naturally determined by the glass composition, but when the glass transition temperature is excessively decreased, the refractive index nd tends to decrease or the thermal stability of the glass tends to decrease.
（耐潜傷性）
　直径４３．７ｍｍ、厚さ５ｍｍのディスク状のガラス試料を使用する。直径４３．７ｍｍの２つの面は光学研磨面になっており、２つの面の面積の合計は３０ｃｍ2である。このガラス試料を５０℃に保たれた０．０１モル／リットルのＮａ5Ｐ3Ｏ10（ＳＴＰＰ）水溶液中に１時間浸漬したときの単位面積あたりの質量減ＤSTPP、すなわち、１時間浸漬前後のガラス試料の質量差を３０ｃｍ2で割った値［ｍｇ／（ｃｍ2・時）］の大小により耐潜傷性を評価する。 (In latent resistance)
A disk-shaped glass sample having a diameter of 43.7 mm and a thickness of 5 mm is used. Two surfaces having a diameter of 43.7 mm are optically polished surfaces, and the total area of the two surfaces is 30 cm 2 . The mass loss per unit area D STPP when this glass sample was immersed in a 0.01 mol / liter Na 5 P 3 O 10 (STPP) aqueous solution kept at 50 ° C. for 1 hour, that is, before and after immersion for 1 hour the magnitude of the value of the mass difference of the glass sample was divided by 30 cm 2 of [mg / (hour cm 2 ·)] by evaluating the耐潜scratch resistance.
　耐潜傷性ＤSTPPの好ましい範囲は０．２０ｍｇ／（ｃｍ2・時）未満、すなわち、１級または２級である。屈折率、アッベ数、ガラス転移温度、熱的安定性を所望の範囲内に保つ上から、耐潜傷性ＤSTPPが２級であることがより好ましい。
　耐潜傷性を３～５級から１級または２級に改善することは、上記の光学特性を有する高屈折率低分散ガラスにおける固有の問題の解決に相当し、意義深いことである。 The preferred range of the latent resistance D STPP is less than 0.20 mg / (cm 2 · hr), that is, first grade or second grade. In order to keep the refractive index, Abbe number, glass transition temperature, and thermal stability within the desired ranges, it is more preferable that the latent scratch resistance D STPP is second grade.
Improving the latent scratch resistance from grade 3 to grade 5 to grade 1 or grade 2 corresponds to the solution of the problems inherent in the high refractive index and low dispersion glass having the above optical properties, and is significant.
（ヘイズ）
　まず、１８ｍｍ×２２ｍｍ×厚さ３ｍｍの平板形状のガラス試料を作製する。次に１８ｍｍ×２２ｍｍの２つの平面を光学研磨する。そして光学研磨したガラス試料を洗浄、乾燥させる。乾燥したガラス試料を、ソニックフェロー社製ＳＥ１８洗剤の水溶液（洗剤の濃度は５ｖｏｌ％）中に入れ、超音波をかけながら２時間浸漬する。その後、洗剤水溶液からガラス試料を取り出し、水洗いして乾燥させた後、ヘイズを測定する。上記洗浄テストはガラスの化学的耐久性を評価するための加速試験である。 (Haze)
First, a flat glass sample of 18 mm × 22 mm × thickness 3 mm is prepared. Next, two planes of 18 mm × 22 mm are optically polished. Then, the optically polished glass sample is washed and dried. The dried glass sample is placed in an aqueous solution of SE18 detergent manufactured by Sonic Fellows (detergent concentration is 5 vol%) and immersed for 2 hours while applying ultrasonic waves. Thereafter, a glass sample is taken out from the detergent aqueous solution, washed with water and dried, and then the haze is measured. The cleaning test is an accelerated test for evaluating the chemical durability of glass.
　「ヘイズ」は、ガラス表面の曇りの度合を表す値であり、数値が小さい程、ガラス表面の透明性が高いことを示す。具体的には、「日本光学硝子工業会規格ＪＯＧＩＳ　光学ガラスの化学的耐久性の測定方法（表面法）０７－１９７５」に定められているように、
　ヘイズ（％）＝（Ｔｄ／Ｔｔ）×１００
により算出される。ただし、Ｔｄは拡散透過率、Ｔｔは全光線透過率である。 “Haze” is a value representing the degree of cloudiness on the glass surface, and the smaller the value, the higher the transparency of the glass surface. Specifically, as defined in “Japan Optical Glass Industry Standard JOGIS Optical Glass Chemical Durability Measurement Method (Surface Method) 07-1975”,
Haze (%) = (Td / Tt) × 100
Is calculated by However, Td is diffuse transmittance and Tt is total light transmittance.
　そして、「日本光学硝子工業会規格ＪＯＧＩＳ　光学ガラスの化学的耐久性の測定方法（表面法）０７－１９７５」に定められたヘイズメーターを用い、Ｔｄ、Ｔｔを測定し、測定値を上記式に代入してヘイズを算出する。 Then, using a haze meter defined in “Japan Optical Glass Industry Association Standard JOGIS Optical Glass Chemical Durability Measurement Method (Surface Method) 07-1975”, Td and Tt were measured, and the measured values were expressed by the above formula. Substitute to calculate haze.
　本実施形態に係る光学ガラスにおいて、ヘイズの上限は、好ましくは０．９％であり、より好ましくは０．８％であり、さらに好ましくは０．７５％であり、一層好ましくは０．７％であり、より一層好ましくは０．６％であり、なお一層好ましくは０．５％である。ヘイズの下限は、好ましくは０％である。 In the optical glass according to the present embodiment, the upper limit of haze is preferably 0.9%, more preferably 0.8%, still more preferably 0.75%, and even more preferably 0.7%. More preferably, it is 0.6%, and still more preferably 0.5%. The lower limit of haze is preferably 0%.
（ガラスの製造）
　本実施形態に係る光学ガラスは、例えば、酸化物、ホウ酸、無水ホウ酸、炭酸塩などの化合物を秤量し、充分混合し、バッチ原料とし、バッチ原料を白金製の坩堝の中に入れて、大気中で、例えば、１２００～１３５０℃の温度で加熱、熔融し、熔融物を清澄、攪拌して均質な熔融ガラスとし、この熔融ガラスを鋳型に流し込み成形、徐冷して得ることができる。 (Manufacture of glass)
The optical glass according to the present embodiment, for example, weighs compounds such as oxides, boric acid, anhydrous boric acid, carbonates, etc., mixes them well, uses them as batch materials, and puts the batch materials into a platinum crucible. It can be obtained by heating and melting in the atmosphere at, for example, a temperature of 1200 to 1350 ° C., clarifying and stirring the melt to obtain a homogeneous molten glass, pouring the molten glass into a mold, and slowly cooling it. .
（精密プレス成形用プリフォームとその製造）
　上記のようにして作製したガラスを切断、研削、研磨して、精密プレス成形用プリフォームを作製する。別の方法として、熔融ガラスを滴下し、熔融ガラス滴に上向きの風圧を加え、浮上させた状態で精密プレス成形用プリフォームに成形してもよい。このようにして作製した精密プレス成形用プリフォームの表面を洗浄、乾燥させた後、例えば、プリフォームの表面に炭素膜をコートしてもよい。 (Preform for precision press molding and its manufacture)
The glass produced as described above is cut, ground, and polished to produce a precision press-molding preform. As another method, molten glass may be dropped, an upward wind pressure may be applied to the molten glass droplet, and the preform may be molded into a precision press-molding preform in a floating state. After the surface of the precision press-molding preform produced in this way is washed and dried, for example, a carbon film may be coated on the surface of the preform.
（光学素子とその製造）
　精密プレス成形用プリフォームを例えば、ＳｉＣ製のプレス成形型内に導入し、窒素雰囲気中で加熱して、ガラスを軟化させ、ガラスをプレス成形型で精密プレス成形する。精密プレス成形が終わった後、ガラス、すなわち、精密プレス成形品をプレス成形型から取り出し、アニールする。 (Optical elements and their manufacture)
The precision press-molding preform is introduced into, for example, a SiC press-molding die, heated in a nitrogen atmosphere to soften the glass, and the glass is precision press-molded with the press-molding die. After the precision press molding is finished, the glass, that is, the precision press-molded product is taken out from the press mold and annealed.
　このようにして、両凹、両凸、凹メニスカス、凸メニスカス、平凸、平凹など各種形状の非球面レンズを作製する。なお、精密プレス成形により作製したレンズに、必要に応じて芯取り加工を行ったり、レンズの光学機能面に反射防止膜などのコーティングを形成したりする。レンズ以外に、回折格子、プリズムなどの各種光学素子を作製してもよい。 In this way, aspherical lenses of various shapes such as biconcave, biconvex, concave meniscus, convex meniscus, planoconvex, and planoconcave are produced. A lens manufactured by precision press molding is subjected to centering processing as necessary, or a coating such as an antireflection film is formed on the optical functional surface of the lens. In addition to the lens, various optical elements such as a diffraction grating and a prism may be manufactured.
（実施例１）
　実施例組成表（表２～４）に記載されている組成を有するように、酸化物、ホウ酸などの化合物を秤量し、充分混合してバッチ原料を作製した。 (Example 1)
Batch raw materials were prepared by weighing and thoroughly mixing compounds such as oxides and boric acid so as to have the compositions described in the example composition tables (Tables 2 to 4).
　バッチ原料を白金坩堝中に入れ、１２００～１３５０℃の温度に坩堝ごと加熱し、３０～６０分かけてガラスを熔融、清澄した。熔融ガラスを攪拌して均質化した後、予熱した成形型に熔融ガラスを鋳込み、ガラス転移温度付近まで放冷してから直ちに、成形型ごとガラスをアニール炉内に入れた。それから、ガラス転移温度付近で約１時間アニールした。アニールした後、アニール炉内で室温まで放冷した。 The batch raw material was put in a platinum crucible, and the whole crucible was heated to a temperature of 1200 to 1350 ° C., and the glass was melted and refined over 30 to 60 minutes. After the molten glass was agitated and homogenized, the molten glass was cast into a preheated mold and allowed to cool to near the glass transition temperature, and then the glass together with the mold was placed in an annealing furnace. Then, annealing was performed for about 1 hour near the glass transition temperature. After annealing, it was allowed to cool to room temperature in an annealing furnace.
　このようにして作製したガラスを観察したところ、結晶の析出、泡、脈理、原料の熔け残り、着色は認められなかった。このようにして、均質性の高い光学ガラスを作るとこができた。 When the glass thus prepared was observed, no precipitation of crystals, bubbles, striae, unmelted raw materials, or coloring was observed. In this way, an optical glass with high homogeneity was made.
　得られたガラスの屈折率ｎｄ、アッベ数νｄ、ガラス転移温度Ｔｇ、ヘイズを次に示す方法で測定した。測定結果を表５に示す。
（１）屈折率ｎｄ、ｎＦ、ｎｃ、アッベ数νｄ
　降温速度－３０℃／時間で降温して得たガラスについて、日本光学硝子工業会規格の屈折率測定法により、屈折率ｎｄ、ｎＦ、ｎｃを測定した。屈折率ｎｄ、ｎＦ、ｎｃの各測定値を用いて、アッベ数νｄを算出した。 The refractive index nd, Abbe number νd, glass transition temperature Tg, and haze of the obtained glass were measured by the following methods. Table 5 shows the measurement results.
(1) Refractive index nd, nF, nc, Abbe number νd
Refractive indexes nd, nF, and nc of the glass obtained by lowering the temperature at a temperature lowering rate of −30 ° C./hour were measured by the refractive index measurement method of the Japan Optical Glass Industry Association standard. The Abbe number νd was calculated using the measured values of the refractive indexes nd, nF, and nc.
（２）ガラス転移温度Ｔｇ
　株式会社リガク製の熱機械分析装置を用いて、昇温速度を４℃／分にして測定した。 (2) Glass transition temperature Tg
Using a thermomechanical analyzer manufactured by Rigaku Corporation, the temperature increase rate was 4 ° C./min.
（３）耐潜傷性ＤSTPP
　得られたガラスを、２つの面の面積の合計が３０ｃｍ2の直径４３．７ｍｍ、厚さ５ｍｍのディスク状に加工し、その２つの面を光学研磨してガラス試料とした。このガラス試料を５０℃に保たれた０．０１モル／リットルのＮａ5Ｐ3Ｏ10（ＳＴＰＰ）水溶液中に１時間浸漬した。１時間浸漬前後のガラス試料の質量差を３０ｃｍ2で割った値［ｍｇ／（ｃｍ2・時）］を算出して、ＤSTPPとした。 (3) Scratch resistance D STPP
The obtained glass was processed into a disk shape having a diameter of 43.7 mm and a thickness of 5 mm with a total area of two surfaces of 30 cm 2 , and the two surfaces were optically polished to obtain a glass sample. This glass sample was immersed in a 0.01 mol / liter Na 5 P 3 O 10 (STPP) aqueous solution kept at 50 ° C. for 1 hour. It calculates a value obtained by dividing the mass difference of the glass samples of 1 hour before and after immersion in 30cm 2 [mg / (cm 2 pm ·)], and the D STPP.
（４）ヘイズ
　得られたガラスを、１８ｍｍ×２２ｍｍ×厚さ３ｍｍの平板形状に加工し、２つの平面を光学研磨した。光学研磨したガラス試料を洗浄、乾燥させた。乾燥したガラス試料を、ソニックフェロー社製ＳＥ１８洗剤の水溶液（洗剤の濃度は５ｖｏｌ％）中に入れ、超音波をかけながら２時間浸漬した。その後、洗剤水溶液からガラス試料を取り出し、水洗いして乾燥させた。「日本光学硝子工業会規格ＪＯＧＩＳ　光学ガラスの化学的耐久性の測定方法（表面法）０７－１９７５」に定められたヘイズメーターを用いて、拡散透過率Ｔｄおよび全光線透過率Ｔｔを測定し、ヘイズを算出した。 (4) Haze The obtained glass was processed into a flat plate shape of 18 mm × 22 mm × thickness 3 mm, and two flat surfaces were optically polished. The optically polished glass sample was washed and dried. The dried glass sample was put in an aqueous solution of SE18 detergent manufactured by Sonic Fellows (detergent concentration was 5 vol%) and immersed for 2 hours while applying ultrasonic waves. Then, the glass sample was taken out from the detergent aqueous solution, washed with water and dried. Using a haze meter defined in “Japan Optical Glass Industry Standard JOGIS Optical Glass Chemical Durability Measurement Method (Surface Method) 07-1975”, the diffuse transmittance Td and the total light transmittance Tt were measured. Haze was calculated.
（実施例２）
　実施例１で得られた各種光学ガラスを使用し、公知の方法により精密プレス成形用プリフォームを作製した。このプリフォームを窒素雰囲気中で加熱、軟化し、ＳｉＣ製のプレス成形型を用いて精密プレス成形し、ガラスを非球面レンズ形状にした。成形したガラスをプレス成形型から取り出し、アニールし、実施例１で作製した各種光学ガラスからなる非球面レンズを作製した。このようにして作製した非球面レンズの表面には白濁、泡、傷などの欠陥は認められなかった。 (Example 2)
Using various optical glasses obtained in Example 1, a precision press-molding preform was produced by a known method. This preform was heated and softened in a nitrogen atmosphere, and precision press-molded using a SiC press mold to make the glass into an aspheric lens shape. The molded glass was taken out from the press mold and annealed to prepare aspherical lenses made of various optical glasses prepared in Example 1. Defects such as white turbidity, bubbles and scratches were not observed on the surface of the aspherical lens thus produced.
　図６にガラスＮｏ．５で作製した非球面レンズの表面を拡大撮影した画像を示す。図６より明らかなように、レンズ表面には白濁、傷は認められない。ガラスＮｏ．５以外のガラスを使用しても、同様に表面品質の高いレンズを作製することができた。 In Fig. 6, glass No. 5 shows an enlarged image of the surface of the aspherical lens fabricated in 5. As is apparent from FIG. 6, no cloudiness or scratches are observed on the lens surface. Glass No. Even when a glass other than 5 was used, a lens having a high surface quality could be similarly produced.
　実施例１で得られた各種光学ガラスを用いて作製した精密プレス成形用プリフォームを多数用意し、同一のＳｉＣ製プレス成形型を用いて連続して精密プレス成形を行った。いずれの光学ガラスからなるプリフォームにおいても、１００００回を超える回数の精密プレス成形が可能であった。 A large number of precision press-molding preforms prepared using the various optical glasses obtained in Example 1 were prepared, and precision press molding was continuously performed using the same SiC press-molding die. Preforms made of any optical glass could be precision press-molded more than 10,000 times.
（比較例１）
　特許文献７（中国専利出願公開第１０１４３９９２９号）に記載の実施例６のガラスは、Ａ４が０．７８５、質量減ＤSTPPが０．４７ｍｇ／（ｃｍ2・時）であり、耐潜傷性は４級であった。 (Comparative Example 1)
The glass of Example 6 described in Patent Document 7 (Chinese Patent Application Publication No. 1014339929) has an A4 of 0.785, a weight loss D STPP of 0.47 mg / (cm 2 · hr), and has a latent resistance. Was grade 4.
（比較例２）
　特許文献３（特開２０００－０１６８３１号公報）に記載の実施例５のガラスは、Ａ４が１．０７３、質量減ＤSTPPが０．４８ｍｇ／（ｃｍ2・時）であり、耐潜傷性は４級であった。特許文献３の実施例１１のガラスのＡ４は０．８３７、質量減ＤSTPPが０．３７ｍｇ／（ｃｍ2・時）であり、耐潜傷性は３級であった。特許文献３の実施例１２のガラスのＡ４は０．７２７、質量減ＤSTPPが０．４７ｍｇ／（ｃｍ2・時）であり、耐潜傷性は４級であった。 (Comparative Example 2)
The glass of Example 5 described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2000-016831) has A4 of 1.073, weight loss D STPP of 0.48 mg / (cm 2 · hr), and latent scratch resistance. Was grade 4. A4 of the glass of Example 11 of Patent Document 3 was 0.837, the mass reduction D STPP was 0.37 mg / (cm 2 · hr), and the latent scratch resistance was grade 3. A4 of the glass of Example 12 of Patent Document 3 was 0.727, the weight loss D STPP was 0.47 mg / (cm 2 · hr), and the latent scratch resistance was grade 4.
　上記の特許文献３に記載の実施例１１の組成と特許文献４に記載の実施例１１の組成とは同一の組成である。特許文献３に記載の実施例１１のガラスについて実施例１と同様の処理を行った後、実施例１と同様の方法でヘイズを測定したところ、その値は１．１％であった。 The composition of Example 11 described in Patent Document 3 and the composition of Example 11 described in Patent Document 4 are the same composition. The glass of Example 11 described in Patent Document 3 was treated in the same manner as in Example 1, and then the haze was measured in the same manner as in Example 1. The value was 1.1%.
（比較例３）
　特開平５－２０１７４３号公報に記載の実施例３のガラスのＡ４は１．０１５、質量減ＤSTPPが０．４５ｍｇ／（ｃｍ2・時）であり、耐潜傷性は４級であった。同公報の実施例６のガラスのＡ４は０．７１７、質量減ＤSTPPが０．５０ｍｇ／（ｃｍ2・時）であり、耐潜傷性は４級であった。同公報の実施例８のガラスのＡ４は０．７０２、質量減ＤSTPPが０．２６ｍｇ／（ｃｍ2・時）であり、耐潜傷性は３級であった。同公報の実施例９のガラスのＡ４は０．５９６、質量減ＤSTPPが０．２５ｍｇ／（ｃｍ2・時）であり、耐潜傷性は３級であった。 (Comparative Example 3)
The A4 of the glass of Example 3 described in JP-A-5-201743 was 1.015, the weight loss D STPP was 0.45 mg / (cm 2 · hr), and the latent scratch resistance was grade 4. . The A4 of the glass of Example 6 of the same publication was 0.717, the weight loss D STPP was 0.50 mg / (cm 2 · hr), and the latent scratch resistance was grade 4. A4 of the glass of Example 8 of the publication was 0.702, the mass reduction D STPP was 0.26 mg / (cm 2 · hr), and the latent scratch resistance was grade 3. The A4 of the glass of Example 9 of the publication was 0.596, the weight loss D STPP was 0.25 mg / (cm 2 · hr), and the latent scratch resistance was grade 3.
（比較例４）
　特開２０１０－０７６９８７号公報に記載の実施例２のＡ４は０．６７９、質量減ＤSTPPが０．３７ｍｇ／（ｃｍ2・時）であり、耐潜傷性は３級であった。同公報の実施例７のＡ４は０.７６４、質量減ＤSTPPが０．２５ｍｇ／（ｃｍ2・時）であり、耐潜傷性は３級であった。 (Comparative Example 4)
The A4 of Example 2 described in JP-A-2010-076987 was 0.679, the weight loss D STPP was 0.37 mg / (cm 2 · hr), and the latent resistance was grade 3. A4 of Example 7 of the publication was 0.764, the mass loss D STPP was 0.25 mg / (cm 2 · hr), and the latent scratch resistance was grade 3.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005

Claims (5)

  1. 　酸化物基準において、質量％表示によるガラス成分ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の含有量をそれぞれＣ（ＳｉＯ2）、Ｃ（Ｂ2Ｏ3）、Ｃ（Ａｌ2Ｏ3）、Ｃ（Ｌｉ2Ｏ）、Ｃ（Ｎａ2Ｏ）、Ｃ（Ｋ2Ｏ）、Ｃ（ＭｇＯ）、Ｃ（ＣａＯ）、Ｃ（ＳｒＯ）、Ｃ（ＢａＯ）、Ｃ（ＺｎＯ）、Ｃ（Ｌａ2Ｏ3）、Ｃ（Ｇｄ2Ｏ3）、Ｃ（Ｙ2Ｏ3）、Ｃ（ＺｒＯ2）、Ｃ（Ｎｂ2Ｏ5）、Ｃ（ＷＯ3）およびＣ（Ｔａ2Ｏ5）、
    　ＳｉＯ2、Ｂ2Ｏ3、Ａｌ2Ｏ3、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ、ＺｎＯ、Ｌａ2Ｏ3、Ｇｄ2Ｏ3、Ｙ2Ｏ3、ＺｒＯ2、Ｎｂ2Ｏ5、ＷＯ3およびＴａ2Ｏ5の各化学式量をそれぞれＭ（ＳｉＯ2）、Ｍ（Ｂ2Ｏ3）、Ｍ（Ａｌ2Ｏ3）、Ｍ（Ｌｉ2Ｏ）、Ｍ（Ｎａ2Ｏ）、Ｍ（Ｋ2Ｏ）、Ｍ（ＭｇＯ）、Ｍ（ＣａＯ）、Ｍ（ＳｒＯ）、Ｍ（ＢａＯ）、Ｍ（ＺｎＯ）、Ｍ（Ｌａ2Ｏ3）、Ｍ（Ｇｄ2Ｏ3）、Ｍ（Ｙ2Ｏ3）、Ｍ（ＺｒＯ2）、Ｍ（Ｎｂ2Ｏ5）、Ｍ（ＷＯ3）およびＭ（Ｔａ2Ｏ5）とし、
    　Ａ１＝－５５０Ｃ（ＳｉＯ2）－５００Ｃ（Ｂ2Ｏ3）－４５０Ｃ（Ａｌ2Ｏ3）＋１００Ｃ（Ｌｉ2Ｏ）－２８０Ｃ（Ｎａ2Ｏ）－３００Ｃ（Ｋ2Ｏ）－３００Ｃ（ＭｇＯ）－１００Ｃ（ＳｒＯ）＋５０Ｃ（ＺｎＯ）＋２００Ｃ（Ｌａ2Ｏ3）＋１５０Ｃ（Ｇｄ2Ｏ3）＋２５０Ｃ（Ｙ2Ｏ3）＋２５０Ｃ（ＺｒＯ2）＋４００Ｃ（Ｎｂ2Ｏ5）＋３００Ｃ（ＷＯ3）、
    　Ａ２＝０．４Ｃ（ＳｉＯ2）＋０．８Ｃ（Ｂ2Ｏ3）＋０．１Ｃ（Ａｌ2Ｏ3）－０．３Ｃ（Ｌｉ2Ｏ）－０．５Ｃ（Ｎａ2Ｏ）－０．５Ｃ（Ｋ2Ｏ）－０．３Ｃ（ＭｇＯ）－０．２Ｃ（ＣａＯ）－０．３Ｃ（ＳｒＯ）－０．０５Ｃ（ＢａＯ）－０．６Ｃ（ＺｎＯ）－０．２Ｃ（Ｌａ2Ｏ3）－０．２Ｃ（Ｇｄ2Ｏ3）－０．２Ｃ（Ｙ2Ｏ3）－Ｃ（ＺｒＯ2）－２Ｃ（Ｎｂ2Ｏ5）－２Ｃ（ＷＯ3）、
    　Ａ３＝２０Ｃ（Ｌｉ2Ｏ）＋１２Ｃ（Ｎａ2Ｏ）＋１０Ｃ（Ｋ2Ｏ）＋２Ｃ（ＺｎＯ）－２Ｃ（ＢａＯ）－３Ｃ（ＳｉＯ2）－３Ｃ（Ｂ2Ｏ3）－３Ｃ（ＺｒＯ2）－Ｃ（Ｔａ2Ｏ5）－２Ｃ（Ａｌ2Ｏ3）、
    　Ａ４＝２×｛Ｃ（Ｂ2Ｏ3）／Ｍ（Ｂ2Ｏ3）｝×［｛Ｃ（ＭｇＯ）／Ｍ（ＭｇＯ）｝＋｛Ｃ（ＣａＯ）／Ｍ（ＣａＯ）｝＋｛Ｃ（ＳｒＯ）／Ｍ（ＳｒＯ）｝＋｛Ｃ（ＢａＯ）／Ｍ（ＢａＯ）｝＋２×｛Ｃ（Ｌｉ2Ｏ）／Ｍ（Ｌｉ2Ｏ）｝＋２×｛Ｃ（Ｎａ2Ｏ）／Ｍ（Ｎａ2Ｏ）｝＋２×｛Ｃ（Ｋ2Ｏ）／Ｍ（Ｋ2Ｏ）｝］／［｛Ｃ（ＳｉＯ2）／Ｍ（ＳｉＯ2）｝＋２×｛Ｃ（Ａｌ2Ｏ3）／Ｍ（Ａｌ2Ｏ3）｝＋２×｛Ｃ（Ｌａ2Ｏ3）／Ｍ（Ｌａ2Ｏ3）｝＋２×｛Ｃ（Ｇｄ2Ｏ3）／Ｍ（Ｇｄ2Ｏ3）｝＋２×｛Ｃ（Ｙ2Ｏ3）／Ｍ（Ｙ2Ｏ3）｝＋｛Ｃ（ＺｒＯ2）／Ｍ（ＺｒＯ2）｝＋｛Ｃ（ＺｎＯ）／Ｍ（ＺｎＯ）｝＋２×｛Ｃ（Ｎｂ2Ｏ5）／Ｍ（Ｎｂ2Ｏ5）｝］、
    としたとき、
    　Ａ１が－１８０００以上かつ－７０００以下、
    　Ａ２が－１以上１５以下、
    　Ａ３が－６４以上、
    　Ａ４が０．５８以下、
    　Ｃ（ＢａＯ）が１０以下、
    　Ｃ（Ｇｄ2Ｏ3）が４以下、
    　Ｃ（Ｔａ2Ｏ5）が３未満、
    である光学ガラス。     In the oxide basis, the glass component SiO 2, B 2 O 3 by mass percentage, Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3 , Gd 2 O 3 , Y 2 O 3 , ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 , the contents of C (SiO 2 ), C (B 2 O 3 ), C (Al 2 O, respectively) 3 ), C (Li 2 O), C (Na 2 O), C (K 2 O), C (MgO), C (CaO), C (SrO), C (BaO), C (ZnO), C (La 2 O 3 ), C (Gd 2 O 3 ), C (Y 2 O 3 ), C (ZrO 2 ), C (Nb 2 O 5 ), C (WO 3 ) and C (Ta 2 O 5 ) ,
    SiO 2, B 2 O 3, Al 2 O 3, Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO, BaO, ZnO, La 2 O 3, Gd 2 O 3, Y 2 O 3, The chemical formula amounts of ZrO 2 , Nb 2 O 5 , WO 3 and Ta 2 O 5 are respectively M (SiO 2 ), M (B 2 O 3 ), M (Al 2 O 3 ), M (Li 2 O), M (Na 2 O), M (K 2 O), M (MgO), M (CaO), M (SrO), M (BaO), M (ZnO), M (La 2 O 3 ), M (Gd 2 O 3 ), M (Y 2 O 3 ), M (ZrO 2 ), M (Nb 2 O 5 ), M (WO 3 ) and M (Ta 2 O 5 ),
    A1 = −550C (SiO 2 ) −500C (B 2 O 3 ) −450C (Al 2 O 3 ) + 100C (Li 2 O) −280C (Na 2 O) −300C (K 2 O) −300C (MgO) — 100C (SrO) + 50C (ZnO ) + 200C (La 2 O 3) + 150C (Gd 2 O 3) + 250C (Y 2 O 3) + 250C (ZrO 2) + 400C (Nb 2 O 5) + 300C (WO 3),
    A2 = 0.4C (SiO 2) + 0.8C (B 2 O 3) + 0.1C (Al 2 O 3) -0.3C (Li 2 O) -0.5C (Na 2 O) -0.5C ( K 2 O) -0.3C (MgO) -0.2C (CaO) -0.3C (SrO) -0.05C (BaO) -0.6C (ZnO) -0.2C (La 2 O 3 )- 0.2C (Gd 2 O 3) -0.2C (Y 2 O 3) -C (ZrO 2) -2C (Nb 2 O 5) -2C (WO 3),
    A3 = 20C (Li 2 O) + 12C (Na 2 O) + 10C (K 2 O) + 2C (ZnO) -2C (BaO) -3C (SiO 2) -3C (B 2 O 3) -3C (ZrO 2) - C (Ta 2 O 5 ) -2C (Al 2 O 3 ),
    A4 = 2 × {C (B 2 O 3 ) / M (B 2 O 3 )} × [{C (MgO) / M (MgO)} + {C (CaO) / M (CaO)} + {C ( SrO) / M (SrO)} + {C (BaO) / M (BaO)} + 2 × {C (Li 2 O) / M (Li 2 O)} + 2 × {C (Na 2 O) / M (Na 2 O)} + 2 × {C (K 2 O) / M (K 2 O)}] / [{C (SiO 2 ) / M (SiO 2 )} + 2 × {C (Al 2 O 3 ) / M ( Al 2 O 3 )} + 2 × {C (La 2 O 3 ) / M (La 2 O 3 )} + 2 × {C (Gd 2 O 3 ) / M (Gd 2 O 3 )} + 2 × {C (Y 2 O 3 ) / M (Y 2 O 3 )} + {C (ZrO 2 ) / M (ZrO 2 )} + {C (ZnO) / M (ZnO)} + 2 × {C (Nb 2 O 5 ) / M (Nb 2 O 5)} ],
    When
    A1 is -18000 or more and -7000 or less,
    A2 is -1 or more and 15 or less,
    A3 is -64 or more,
    A4 is 0.58 or less,
    C (BaO) is 10 or less,
    C (Gd 2 O 3 ) is 4 or less,
    C (Ta 2 O 5 ) is less than 3,
    Optical glass that is.
  2. 　屈折率ｎｄが１．６５～１．７２、アッベ数νｄが５０～５７である請求項１に記載の光学ガラス。 The optical glass according to claim 1, wherein the refractive index nd is 1.65 to 1.72, and the Abbe number νd is 50 to 57.
  3. 　ガラス転移温度が５４０℃以下である請求項１または２に記載の光学ガラス。 The optical glass according to claim 1 or 2, wherein the glass transition temperature is 540 ° C or lower.
  4. 　請求項１～３のいずれかに記載の光学ガラスによりなるプレス成形用プリフォーム。 A press-molding preform made of the optical glass according to any one of claims 1 to 3.
  5. 　請求項１～３のいずれかに記載の光学ガラスよりなる光学素子。 An optical element made of the optical glass according to any one of claims 1 to 3.
PCT/JP2016/069603 2015-07-02 2016-07-01 Optical glass and optical element WO2017002956A1 (en)

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JP2007137701A (en) * 2005-11-16 2007-06-07 Nippon Electric Glass Co Ltd Optical glass for mold press molding
JP2010168224A (en) * 2009-01-20 2010-08-05 Nippon Electric Glass Co Ltd Method for producing glass molded article
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CN115072993A (en) * 2019-06-27 2022-09-20 成都光明光电股份有限公司 Optical glass, glass preform, optical element and optical instrument

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