JP5827067B2 - Optical glass and optical element - Google Patents

Description

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

  In recent years, digitization and high definition of devices using optical systems have been rapidly progressing, and various optical devices such as photographing devices such as digital cameras and video cameras, and image reproduction (projection) devices such as projectors and projection televisions. In this field, there is an increasing demand to reduce the number of optical elements such as lenses and prisms used in the optical system, and to reduce the weight and size of the entire optical system.

Among optical glasses for producing optical elements, in particular, it has a refractive index (n _d ) of 1.80 or more and an Abbe number of 35 or more and 50 or less (which can reduce the weight and size of the entire optical system). There is a great demand for high refractive index, low dispersion glass with ν _d ). As such a high refractive index and low dispersion glass, glass compositions represented by Patent Documents 1 to 4 are known.

JP 2001-348244 A JP 2006-016293 A JP 2009-102215 A JP 2009-203083 A

  As a method for producing an optical element from optical glass, for example, a gob or glass block formed from optical glass is ground and polished to obtain the shape of the optical element, or a gob or glass formed from optical glass. A method of grinding and polishing a glass molded product obtained by reheating and molding a block (reheat press molding), and molding a preform material obtained from a gob or glass block with an ultra-precision machined mold A method of obtaining the shape of an optical element by (precise mold press molding) is known. In any method, when forming a gob or a glass block from a molten glass raw material, it is required to reduce devitrification of the formed glass. Here, when devitrification occurs due to generation of crystals in the obtained gob or glass block, it is no longer possible to obtain glass suitable as an optical element.

  In addition, in order to reduce the material cost of the optical glass, it is desirable that the raw material costs of the components constituting the optical glass be as low as possible. Moreover, in order to reduce the manufacturing cost of optical glass, it is desired that the raw material has high meltability, that is, it is melted at a lower temperature. However, it is difficult to say that the glass compositions described in Patent Documents 1 to 4 sufficiently satisfy these various requirements.

The present invention has been made in view of the above problems, and its object is to provide resistance to devitrification while the refractive index (n _d ) and Abbe number (ν _d ) are within the desired ranges. It is to obtain a glass having a high price at a lower cost.

In order to solve the above-mentioned problems, the present inventors have conducted extensive test studies, and as a result, the content of the Ta ₂ O ₅ component is reduced with respect to the glass containing the B ₂ O ₃ component and the La ₂ O ₃ component. As a result, it was found that the material cost of the glass was reduced while having the desired refractive index and Abbe number, and the liquidus temperature of the glass was lowered, and the present invention was completed. Specifically, the present invention provides the following.

(1) 1.0 to 30.0% of B ₂ O ₃ component and 10.0 to 55.0% of La ₂ O ₃ component are contained in mass% with respect to the total glass mass of the oxide equivalent composition, An optical glass having a Ta ₂ O ₅ component content of 20.0% or less.

(2) The optical glass according to (1), which contains at least one selected from the group consisting of a TiO ₂ component, an Nb ₂ O ₅ component, and a WO ₃ component in an oxide equivalent composition.

(3) The sum of at least one content selected from the group consisting of TiO ₂ component, Nb ₂ O ₅ component and WO ₃ component is 0.5% or more and 40. The optical glass according to (2), which is 0% or less.

(4) TiO ₂ component 0 to 20.0% and / or Nb ₂ O ₅ component 0 to 20.0% and / or WO ₃ component 0 to 25% by mass with respect to the total glass mass of the oxide equivalent composition .0%
The optical glass according to (2) or (3).

(5) SiO ₂ component 0 to 20.0% and / or ZrO ₂ component 0 to 12.0% in mass% with respect to the total glass mass of the oxide equivalent composition
The optical glass according to any one of (1) to (4), further comprising:

(6) The optical glass according to any one of the sum of the content of _B 2 _{O 3} component and SiO ₂ component to the glass the total weight of the oxide basis the composition is not more than 25.0% (1) (5).

(7) The mass ratio (ZrO ₂ + Ta ₂ O ₅ + Nb ₂ O ₅ ) / (B ₂ O ₃ + SiO ₂ ) of the oxide equivalent composition is 2.00 or less, and any one of (1) to (6) Optical glass.

(8) Gd ₂ O ₃ component 0 to 45.0% and / or Y ₂ O ₃ component 0 to 30.0% and / or Yb ₂ O _{3 in} mass% with respect to the total glass mass of the oxide equivalent composition. Ingredient 0-20.0%
The optical glass according to any one of (1) to (7), further containing each component of:

(9) The mass sum of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) with respect to the total glass mass of the oxide equivalent composition is 30.0% or more. The optical glass according to any one of (1) to (8), which is 75.0% or less.

(10) The mass sum of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) with respect to the total glass mass of the oxide equivalent composition is from 40.0%. Optical glass as described in (9) in large quantities.

(11) The optical component according to any one of (1) to (10), wherein the mass ratio Ta ₂ O ₅ / (Ln ₂ O ₃ + ZrO ₂ + Nb ₂ O ₅ + WO ₃ ) of the oxide equivalent composition is 0.300 or less. Glass (wherein Ln is at least one selected from the group consisting of La, Gd, Y, Yb).

(12) MgO component 0 to 20.0% and / or CaO component 0 to 20.0% and / or SrO component 0 to 20.0% and / Or BaO component 0-25.0%
The optical glass according to any one of (1) to (11), further comprising:

  (13) The mass sum of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) with respect to the total glass mass of the oxide equivalent composition is 25.0% or less ( 12) Optical glass as described.

(14) the entire mass of the glass in terms of oxide composition, from 0 to 10.0% Li ₂ O component in% by weight and / or Na ₂ O component from 0 to 10.0% and / or _{K 2} O ingredient 0 10.0% and / or Cs ₂ O component from 0 to 10.0%
The optical glass according to any one of (1) to (13), further containing each component of:

(15) The mass sum of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) with respect to the total glass mass of the oxide equivalent composition is 15.0% or less. An optical glass according to (14).

(16) The mass ratio (B ₂ O ₃ + SiO ₂ + WO ₃ ) / (Ln ₂ O ₃ + ZrO ₂ + Li ₂ O) of the oxide equivalent composition is 0.20 or more and 2.00 or less (1) to (15) The optical glass according to any one of the above.

(17) as oxide entire mass of the glass composition, _P 2 _{O 5} component from 0 to 10.0% and / or GeO ₂ component from 0 to 10.0% and / or ZnO ingredient 0-25 mass%. 0% and / or Al ₂ O ₃ component 0 to 10.0% and / or Ga ₂ O ₃ component 0 to 10.0% and / or Bi ₂ O ₃ component 0 to 20.0% and / or TeO ₂ component 0 to 20.0% and / or SnO ₂ component 0 to 1.0% and / or Sb ₂ O ₃ component 0 to 1.0%
The optical glass according to any one of (1) to (16), further containing each component of

(18) The optical glass according to any one of (1) to (17), which has a refractive index (n _d ) of 1.75 or more and an Abbe number (ν _d ) of 30 to 50.

  (19) The optical glass according to any one of (1) to (18), which has a liquidus temperature of 1300 ° C. or lower.

  (20) An optical element having the optical glass according to any one of (1) to (19) as a base material.

  (21) An optical device comprising the optical element according to (20).

According to the present invention, while reducing the content of Ta ₂ O ₅ component to glass containing B ₂ O ₃ component and La ₂ O ₃ component, while having a desired refractive index and Abbe number. The glass transition point is lowered, and the material cost of the glass is reduced. For this reason, an optical glass with high devitrification resistance can be obtained at a lower cost while the refractive index (n _d ) and Abbe number (ν _d ) are within the desired ranges.

The optical glass of the present invention, the entire mass of the glass in terms of oxide composition, 1.0 to 30.0% of _B 2 _{O 3} component in mass% and _La 2 _{O 3} component from 10.0 to 50.0 %, And the content of the Ta ₂ O ₅ component is 20.0% or less. By reducing the content of Ta ₂ O ₅ component, the amount of Ta ₂ O ₅ component requiring melting for expensive and high temperature to reduce the raw material cost and manufacturing cost of the optical glass is reduced. At the same time, based on the B ₂ O ₃ component and the La ₂ O ₃ component, while having a refractive index (n _d ) of 1.80 or more and an Abbe number (ν _d ) of 35 to 50, The liquidus temperature tends to be low. Therefore, an optical glass having high devitrification resistance and an optical element using the same can be obtained at a lower cost while the refractive index (n _d ) and Abbe number (ν _d ) are within the desired ranges.

  Hereinafter, embodiments of the optical glass of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. be able to. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the meaning of invention is not limited.

[Glass component]
The composition range of each component constituting the optical glass of the present invention is described below. Unless otherwise specified in the present specification, the contents of the respective components are all expressed in mass% with respect to the total mass of the glass in terms of oxide. Here, the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as a raw material of the glass component of the present invention are all decomposed and changed into an oxide when melted. It is the composition which described each component contained in glass by making the total mass of the said production | generation oxide into 100 mass%.

<About essential and optional components>
The B ₂ O ₃ component is an essential component that is indispensable as a glass-forming oxide in the optical glass of the present invention containing a large amount of rare earth oxides. In particular, by setting the content of the B ₂ O ₃ component to 1.0% or more, the devitrification resistance of the glass can be increased and the dispersion of the glass can be reduced. Therefore, the content of the B ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 1.0%, more preferably 5.0%, further preferably 8.5%, and most preferably 10.0. % Is the lower limit. On the other hand, by setting the content of the B ₂ O ₃ component to 30.0% or less, it is possible to easily obtain a larger refractive index and suppress deterioration of chemical durability. Therefore, the content of the B ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 30.0%, more preferably 20.0%, still more preferably 18.0%, most preferably 15.0. % Is the upper limit. The B ₂ O ₃ component can be contained in the glass using, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ .10H ₂ O, BPO ₄ or the like as a raw material.

The La ₂ O ₃ component is a component that increases the refractive index of the glass and increases the Abbe number of the glass by reducing the dispersion of the glass. In particular, by setting the content of _La 2 _{O 3} component in more than 10.0%, it is possible to increase the refractive index of the glass. Therefore, the content of the La ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 20.0%, further preferably 25.0%, and most preferably 30.0. % Is the lower limit. On the other hand, by setting the content of the La ₂ O ₃ component to 55.0% or less, more preferably 50.0% or less, it is possible to increase the stability of the glass and reduce the devitrification of the glass. Therefore, the content of the La ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 55.0%, more preferably 50.0%, still more preferably 49.0%, and most preferably 48.0. % Is the upper limit. The La ₂ O ₃ component can be contained in the glass using, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer) or the like as a raw material.

The Ta ₂ O ₅ component is a component that increases devitrification resistance by increasing the refractive index of the glass and lowering the liquidus temperature of the glass, and is an optional component in the optical glass of the present invention. In particular, by making the content of the Ta ₂ O ₅ component 20.0% or less, the content of the expensive Ta ₂ O ₅ component is reduced, so that an optical glass having a desired optical constant can be obtained at a lower material cost. Can be produced. On the other hand, when the content of the Ta ₂ O ₅ component exceeds 20.0%, it becomes difficult to obtain a stable glass. Therefore, the content of the Ta ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0% as an upper limit, more preferably less than 17.5%, and most preferably 13.9% as an upper limit. And Here, in particular, by setting the content of the Ta ₂ O ₅ component to 9.5% or less, the temperature at which the raw material is melted can be lowered, and the energy required for melting the raw material is reduced. The manufacturing cost can be reduced. Therefore, the content of the Ta ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition in this viewpoint is preferably 9.5%, more preferably 7.0%, and most preferably 5.0%. To do. On the other hand, when the content of the Ta ₂ O ₅ component is more than 9.5%, the refractive index of the glass can be increased while suppressing the coloring of the glass, and the devitrification resistance of the glass can be increased. . Therefore, the content of the Ta ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition in this viewpoint is preferably more than 9.5%, more preferably 11.0%, and most preferably 12.8%. Is the lower limit. The Ta ₂ O ₅ component can be contained in the glass using, for example, Ta ₂ O ₅ as a raw material.

The optical glass of the present invention preferably contains one or more selected from the group consisting of a TiO ₂ component, a WO ₃ component, and an Nb ₂ O ₅ component. Thus, even if reducing the content of Ta ₂ O ₅ component in order to reduce the material cost of the glass, it is possible to increase the refractive index of the glass, and it is possible to improve the devitrification resistance of the glass. Therefore, the sum of the content of one or more selected from the group consisting of TiO ₂ component, Nb ₂ O ₅ component and WO ₃ component with respect to the total glass mass of the oxide conversion composition is preferably more than 0%, More preferably, the lower limit is 0.5%, and most preferably 1.0%. On the other hand, by setting the sum of the contents to 40.0% or less, coloring due to these components can be reduced, and deterioration of devitrification resistance due to excessive inclusion of these components can be suppressed. Therefore, the sum of the content of one or more selected from the group consisting of TiO ₂ component, Nb ₂ O ₅ component and WO ₃ component with respect to the total glass mass of oxide conversion composition is preferably 40.0%, more The upper limit is preferably 30.0%, more preferably 20.0%, and most preferably 8.0%.

TiO ₂ component adjusts the refractive index of the glass and the Abbe number is a component that improves the devitrification resistance, which is an optional component of the optical glass of the present invention. However, when there is too much TiO ₂ , the devitrification resistance is adversely affected, and the transmittance of the glass at a visible short wavelength (500 nm or less) is also deteriorated. Therefore, the content of the TiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 10.0%, still more preferably 8.0%, and most preferably 5.0%. The upper limit. TiO ₂ component may be contained in the glass by using as the starting material for example TiO ₂ or the like.

Nb ₂ O ₅ component is a component that raises the refractive index and dispersion of the glass, an optional component of the optical glass of the present invention. In particular, by reducing the content of the Nb ₂ O ₅ component to 20.0% or less, deterioration of the devitrification resistance of the glass due to the excessive content of the Nb ₂ O ₅ component is suppressed, and the glass transmits visible light. Reduction in rate can be suppressed. Therefore, the content of the Nb ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 12.0%. The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ as a raw material.

The WO ₃ component is a component that increases the refractive index and dispersion of the glass and improves the devitrification resistance of the glass. In particular, by reducing the content of the WO ₃ component to 25.0%, more preferably 20.0% or less, the coloring of the glass is reduced, and in particular, the transmittance in the visible-short wavelength region (less than 500 nm) is reduced. Can be difficult. Accordingly, the content of the WO ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 25.0%, more preferably 20.0%, further preferably 15.0%, and most preferably 12.0%. The upper limit. Although the optical glass of the present invention it is possible to obtain a glass having desired optical constants and devitrification resistance even without containing WO ₃ components, by containing a WO ₃ components, glass of the liquid phase Since temperature falls further, the devitrification resistance of glass can further be improved. Accordingly, the content of the WO ₃ component with respect to the total glass mass of the oxide conversion composition is preferably more than 0%, more preferably 0.1%, and most preferably 1.0%. The WO ₃ component can be contained in the glass using, for example, WO ₃ as a raw material.

The SiO ₂ component is a component that increases the viscosity of the molten glass, promotes stable glass formation, and reduces devitrification (generation of crystal) that is not desirable as an optical glass, and is an optional component in the optical glass of the present invention. . In particular, when the content of the SiO ₂ component is 20.0% or less, an increase in the glass transition point (Tg) can be suppressed, and a decrease in the refractive index can be suppressed. Therefore, the content of the SiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. Incidentally, the SiO ₂ component is not detrimental technically without containing, by containing a SiO ₂ component, since the liquidus temperature of the glass is lowered, it hardly more devitrified glass. Therefore, the content of the SiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 0.1%, more preferably 1.0%, and still more preferably 2.0%. In particular, the content of the SiO ₂ component is most preferably 4.0% or more from the viewpoint of making it difficult to color the glass even if it contains a TiO ₂ component or a WO ₃ component. SiO ₂ component may be contained in the glass by using as a raw material such as _{SiO 2, K 2 SiF 6,} Na 2 SiF 6 or the like.

The ZrO ₂ component is a component that contributes to the high refractive index and low dispersion of the glass, and is an optional component in the optical glass of the present invention. However, if the amount of ZrO ₂ is too large, the devitrification resistance is deteriorated. Therefore, the content of the ZrO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 12.0%, more preferably 10.0%, and most preferably 8.0%. Although ZrO ₂ component is possible to obtain a desired glass without containing, by containing a ZrO ₂ component, it can easily obtain a performance of the high refractive index and low dispersion, and enhance resistance to devitrification The effect can be easily obtained. Therefore, the content of the ZrO ₂ component with respect to the total glass mass of the oxide equivalent composition is preferably more than 0%, more preferably 0.5%, and most preferably 1.0%. The ZrO ₂ component can be contained in the glass using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

In the optical glass of the present invention, the mass sum of the B ₂ O ₃ component and the SiO ₂ component is preferably 25.0% or less, and more preferably 23.0% or less. Thus, the decrease in B ₂ O ₃ component and SiO ₂ component refractive index due to the inclusion of is suppressed, it is possible to easily obtain the desired high refractive index. Therefore, the mass sum of the B ₂ O ₃ component and the SiO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 25.0%, more preferably 23.0%, and even more preferably 21.0%. Most preferably, the content is less than 20.0%.

In the optical glass of the present invention, the ratio of the mass sum (ZrO ₂ + Ta ₂ O ₅ + Nb ₂ O ₅ ) to the mass sum (B ₂ O ₃ + SiO ₂ ) is preferably 2.00 or less. Thus, since a high ZrO ₂ component of the material cost, the content of _Ta 2 _{O 5} component and _Nb 2 _{O 5} component reduced, the optical glass having a desired low liquidus temperature, can be more inexpensively manufactured. Therefore, the mass ratio (ZrO ₂ + Ta ₂ O ₅ + Nb ₂ O ₅ ) / (B ₂ O ₃ + SiO ₂ ) of the oxide equivalent composition is preferably 2.00, more preferably 1.80, and most preferably 1. 50 is the upper limit.

The Gd ₂ O ₃ component is a component that increases the refractive index of the glass and increases the Abbe number, and is an optional component in the optical glass of the present invention. In particular, when the content of the Gd ₂ O ₃ component is 45.0% or less, more preferably 40.0% or less, it becomes easy to obtain a desired optical constant of the glass, and an excess of the Gd ₂ O ₃ component. An increase in the glass transition point (Tg) due to such inclusion can be suppressed, and the devitrification resistance of the glass can be enhanced. Moreover, by reducing the Gd ₂ O ₃ component can be reduced material cost of the optical glass. Therefore, the content of the Gd ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 45.0%, more preferably 40.0%, still more preferably 30.0%, most preferably 25.0. % Is the upper limit. Although there is no technical disadvantage even if the Gd ₂ O ₃ component is not contained, devitrification resistance can be further improved by lowering the liquidus temperature of the glass by containing more than 0%. . Therefore, the content of the Gd ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably more than 0%, more preferably 1.0%, and even more preferably 2.0%. Here, from the viewpoint of easily obtaining a desired optical constant by increasing the refractive index and Abbe number of the glass, the content of the Gd ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 5.0. %, More preferably 5.5%, and most preferably 6.0%. Further, from the viewpoint of further improving the devitrification resistance of the glass, the ratio of the content of the Gd ₂ O ₃ component to the content of the La ₂ O ₃ component (Gd ₂ O ₃ / La ₂ O ₃ ) is 0.01 It is preferably 2.00 or less, more preferably 0.03 or more and 1.70 or less, and most preferably 0.05 or more and 1.50 or less. The Gd ₂ O ₃ component can be contained in the glass using, for example, Gd ₂ O ₃ , GdF ₃ or the like as a raw material.

The Y ₂ O ₃ component and the Yb ₂ O ₃ component are components that increase the refractive index of the glass and reduce the dispersion, and are optional components in the optical glass of the present invention. In particular, by making the content of the Y ₂ O ₃ component 30.0% or less and / or making the content of the Yb ₂ O ₃ component 20.0% or less, the desired optical constant of the glass Can be easily obtained, and the devitrification resistance of the glass can be improved. Therefore, the content of the Y ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%, and most preferably 15. The upper limit is 0%. Accordingly, the content of the Yb ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Y ₂ O ₃ component and the Yb ₂ O ₃ component can be contained in the glass using, for example, Y ₂ O ₃ , YF ₃ , Yb ₂ O ₃ or the like as a raw material.

In the optical glass of the present invention, the mass sum of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is 30.0% or more and 75.0% or less. Preferably, it is 30.0% or more and 70.0% or less. In particular, by setting the mass sum of the Ln ₂ O ₃ component to 30.0% or more, both the refractive index and the Abbe number of the glass can be increased, so that it is easy to obtain a glass having a desired refractive index and Abbe number. Can do. Therefore, the mass sum of the Ln ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 30.0%, more preferably 33.0% as the lower limit, and even more preferably more than 40.0%, Most preferably, it is more than 55.0%. On the other hand, by the mass sum of Ln ₂ O ₃ component below 75.0%, because the liquidus temperature of the glass is lowered, thereby reducing the devitrification of the glass. Therefore, the mass sum of the Ln ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 75.0%, more preferably 70.0%, still more preferably 65.0%, and even more preferably 60.0. %, Most preferably 55.0%.

In the optical glass of the present invention, the content ratio of the Ta ₂ O ₅ component to the mass sum (Ln ₂ O ₃ + ZrO ₂ + Nb ₂ O ₅ + WO ₃ ) is preferably 0.300 or less. Accordingly, since the content of high Ta ₂ O ₅ component of the material cost of the component that raises the refractive index is reduced, can be manufactured at a lower cost optical glass having a high refractive index. Therefore, the mass ratio Ta ₂ O ₅ / (Ln ₂ O ₃ + ZrO ₂ + Nb ₂ O ₅ + WO ₃ ) with respect to the total glass mass of the oxide equivalent composition is preferably 0.300, more preferably 0.280, and most preferably The upper limit is 0.250.

The MgO component, CaO component, SrO component, and BaO component are components that adjust the refractive index, meltability, and devitrification of the glass, and are optional components in the optical glass of the present invention. In particular, the content of each of the MgO component, the CaO component, the SrO component, and the BaO component is made 20.0% or less, and / or the content of the BaO component is made 25.0% or less. By suppressing the lowering of the refractive index due to the components, it is possible to easily obtain a desired refractive index, and it is possible to reduce the occurrence of devitrification of the glass due to excessive inclusion of these components. Therefore, the content of each of the MgO component, CaO component and SrO component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 10.0%, and most preferably 5.0%. And Further, the content of the BaO component with respect to the total glass mass of the oxide conversion composition is preferably 25.0%, more preferably 15.0%, and most preferably 10.0%. The MgO component, CaO component, SrO component and BaO component are raw materials such as MgCO ₃ , MgF ₂ , CaCO ₃ , CaF ₂ , Sr (NO ₃ ) ₂ , SrF ₂ , BaCO ₃ , Ba (NO ₃ ) ₂ , BaF _2. Etc. can be contained in the glass.

  In the optical glass of the present invention, the total content of RO components (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 25.0% or less. Thereby, it is possible to easily obtain a desired refractive index by suppressing a decrease in the refractive index due to the RO component. Therefore, the mass sum of the RO component with respect to the total glass mass of the oxide conversion composition is preferably 25.0%, more preferably 15.0%, more preferably less than 12.0%, most preferably 10. Less than 0%.

The Li ₂ O component, the Na ₂ O component, the K ₂ O component, and the Cs ₂ O component are components that improve the meltability of the glass and lower the glass transition point, and are optional components in the optical glass of the present invention. . Among these, the Na ₂ O component, the K ₂ O component, and the Cs ₂ O component are components that increase the devitrification resistance of the glass. In particular, by making each content of the Li ₂ O component, the Na ₂ O component, the K ₂ O component, and the Cs ₂ O component 10.0% or less, it is difficult to lower the refractive index of the glass, and the glass Therefore, it is possible to reduce the occurrence of devitrification and the like. Therefore, the content of each of the Li ₂ O component, Na ₂ O component, K ₂ O component, and Cs ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0. %, Most preferably 5.0%. For example, Li ₂ CO ₃ , LiNO ₃ , Li ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO are used as raw materials for the Li ₂ O component, Na ₂ O component, K ₂ O component, and Cs ₂ O component. ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ , Cs ₂ CO ₃ , CsNO _{3, and the} like can be contained in the glass.

The Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) is a component that improves glass meltability and reduces glass devitrification. Here, by making the total content of the Rn ₂ O components 15.0% or less, it is difficult to lower the refractive index of the glass, and the stability of the glass is increased to reduce the occurrence of devitrification and the like. it can. Therefore, the upper limit of the mass sum of the Rn ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%.

In the optical glass of the present invention, the ratio of the mass sum (B ₂ O ₃ + SiO ₂ + WO ₃ ) to the mass sum (Ln ₂ O ₃ + ZrO ₂ + Li ₂ O) is preferably 0.20 or more and 2.00 or less. More preferably, it is 0.27 or more and 2.00 or less. In particular, when the ratio is 0.27 or more, the devitrification resistance is reduced with respect to the content of the components (Ln ₂ O ₃ component, ZrO ₂ component, and Li ₂ O component) that lower the devitrification resistance. Since the content of the components to be increased (B ₂ O ₃ component, SiO ₂ component and WO ₃ ) increases, an optical glass having a lower liquidus temperature and less devitrification can be obtained. On the other hand, by setting this ratio to 2.00 or less, the Ln ₂ O ₃ component, which is a component that increases the refractive index and the Abbe number, is likely to be contained in the glass, so that the desired refractive index and Abbe number can be easily obtained. . Therefore, the mass ratio (B ₂ O ₃ + SiO ₂ + WO ₃ ) / (Ln ₂ O ₃ + ZrO ₂ + Li ₂ O) of the oxide equivalent composition is preferably 0.20, more preferably 0.27, and even more preferably 0. .28, most preferably 0.29. The mass ratio is preferably 2.00, more preferably 1.50, and most preferably 1.00.

P ₂ O ₅ component is a component having an effect of improving resistance to devitrification and lower the liquidus temperature of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the P ₂ O ₅ component to 10.0% or less, it is possible to suppress a decrease in chemical durability, particularly water resistance, of the glass. Therefore, the content of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0%. The P ₂ O ₅ component can be contained in the glass using, for example, Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ or the like as a raw material. .

The GeO ₂ component is a component having an effect of increasing the refractive index of the glass and improving the devitrification resistance, and is an optional component in the optical glass of the present invention. However, since the raw material price of GeO ₂ is high, the production cost increases when the amount of GeO ₂ is large, thereby reducing the effect of reducing the Ta ₂ O ₅ component. Accordingly, the content of the GeO ₂ component with respect to the total glass mass of the oxide-converted composition is preferably 10.0%, more preferably 5.0%, and most preferably 1.0%. The GeO ₂ component can be contained in the glass using, for example, GeO ₂ as a raw material.

The ZnO component is a component that lowers the glass transition temperature (Tg) and improves the chemical durability, and is an optional component in the optical glass of the present invention. However, when there is too much content of a ZnO component, the devitrification resistance of glass will deteriorate easily. Accordingly, the content of the ZnO component with respect to the total glass mass of the oxide conversion composition is preferably 25.0%, more preferably 20.0%, further preferably 15.0%, and most preferably 10.0%. And Although it is possible to obtain a glass having desired characteristics even if it does not contain a ZnO component, the glass transition point is lowered by containing a ZnO component, so that an optical glass that is easy to press-mold is obtained. Easy to do. Therefore, the content of the ZnO component with respect to the total glass mass of the oxide conversion composition is preferably more than 0%, more preferably 0.1%, and most preferably 1.0%. The ZnO component can be contained in the glass using, for example, ZnO, ZnF ₂ or the like as a raw material.

The Al ₂ O ₃ component and the Ga ₂ O ₃ component are components that improve the chemical durability of the glass and improve the devitrification resistance of the molten glass, and are optional components in the optical glass of the present invention. In particular, by setting the content of each of the Al ₂ O ₃ component and the Ga ₂ O ₃ component to 10.0% or less, the devitrification tendency of the glass can be weakened and the stability of the glass can be improved. Therefore, the content of each of the Al ₂ O ₃ component and the Ga ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 10.0%, more preferably 8.0%, and most preferably 5.0. % Is the upper limit. The Al ₂ O ₃ component and the Ga ₂ O ₃ component should be contained in the glass using, for example, Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ , Ga ₂ O ₃ , Ga (OH) _3, etc. as raw materials. Can do.

The Bi ₂ O ₃ component is a component that increases the refractive index and decreases the glass transition point (Tg), and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Bi ₂ O ₃ component to 20.0% or less, an increase in the liquidus temperature can be suppressed, so that a decrease in the devitrification resistance of the glass can be suppressed. Further, by setting the content of _Bi 2 _{O 3} component below 20.0%, it is possible to reduce the coloration of the glass. Therefore, the content of the Bi ₂ O ₃ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Bi ₂ O ₃ component can be contained in the glass using, for example, Bi ₂ O ₃ as a raw material.

The TeO ₂ component is a component that raises the refractive index and lowers the glass transition point (Tg), and is an optional component in the optical glass of the present invention. However, TeO ₂ has a problem that it can be alloyed with platinum when melting a glass raw material in a crucible made of platinum or a melting tank in which a portion in contact with molten glass is formed of platinum. Therefore, the content of the TeO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The TeO ₂ component can be contained in the glass using, for example, TeO ₂ as a raw material.

The SnO ₂ component is a component that reduces the oxidation of the molten glass to clarify the molten glass and makes it difficult to deteriorate the transmittance of the glass against light irradiation, and is an optional component in the optical glass of the present invention. In particular, when the content of the SnO ₂ component is 1.0% or less, it is possible to make it difficult to cause coloration of the glass due to the reduction of the molten glass and glass devitrification. Further, since the alloying of the SnO ₂ component and the melting equipment (especially a noble metal such as Pt) is reduced, the life of the melting equipment can be extended. Therefore, the content of the SnO ₂ component with respect to the total glass mass of the oxide conversion composition is preferably 1.0%, more preferably 0.7%, and most preferably 0.5%. The SnO ₂ component can be contained in the glass using, for example, SnO, SnO ₂ , SnF ₂ , SnF ₄ or the like as a raw material.

The Sb ₂ O ₃ component is a component that defoams the molten glass and is an optional component in the optical glass of the present invention. When the amount of Sb ₂ O ₃ is too large, the transmittance in the short wavelength region of the visible light region is deteriorated. Therefore, the content of the Sb ₂ O ₃ component with respect to the total glass mass of the oxide-converted composition is preferably 1.0%, more preferably 0.7%, and most preferably 0.5%. The Sb ₂ O ₃ component can be contained in the glass using, for example, Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ · 5H ₂ O, or the like as a raw material.

Incidentally, components defoamed fining glass is not limited to the above Sb ₂ O ₃ component, a known refining agents in the field of glass production, it is possible to use a defoamer or a combination thereof.

<About ingredients that should not be included>
Next, components that should not be contained in the optical glass of the present invention and components that are not preferably contained will be described.

  Other components can be added as necessary within the range not impairing the properties of the glass of the present invention. However, each transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Mo, excluding Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, is independent of each other. Or, even when it is contained in a small amount in combination, the glass is colored and has the property of causing absorption at a specific wavelength in the visible range. .

Moreover, since lead compounds such as PbO and arsenic compounds such as As ₂ O ₃ are components with high environmental loads, it is desirable that they are not substantially contained, that is, not contained at all except for inevitable mixing.

  Furthermore, each component of Th, Cd, Tl, Os, Be, and Se has tended to be refrained from being used as a harmful chemical material in recent years, and not only in the glass manufacturing process, but also in the processing process and disposal after commercialization. Until then, environmental measures are required. Therefore, when importance is placed on the environmental impact, it is preferable that these are not substantially contained.

The glass composition of the present invention cannot be expressed directly in the description of mol% because the composition is expressed by mass% with respect to the total mass of the glass of oxide conversion composition, but various properties required in the present invention. The composition expressed by mol% of each component present in the glass composition satisfying the above conditions generally takes the following values in terms of oxide conversion.
B ₂ O ₃ component 2.0 to 55.0 mol%,
La ₂ O ₃ component from 5.0 to 35.0 mol%, and _Ta 2 _{O 5} component 0 to 10.0 mol%,
TiO ₂ component 0 to 30.0 mol% and / or Nb ₂ O ₅ component 0 to 15.0 mol% and / or WO ₃ component 0 to 30.0 mol% and / or SiO ₂ component 0 to 50.0 mol % And / or ZrO ₂ component 0 to 18.0 mol% and / or Gd ₂ O ₃ component 0 to 25.0 mol% and / or Y ₂ O ₃ component 0 to 20.0 mol% and / or Yb ₂ O ₃ components 0 to 10.0 mol% and / or MgO component 0 to 50.0 mol% and / or CaO component 0 to 40.0 mol% and / or SrO component 0 to 30.0 mol% and / or BaO component 0 to 35.0 mol% and / or Li ₂ O component from 0 to 30.0 mol% and / or Na ₂ O component from 0 to 25.0 mol% and / or _{K 2} O ingredient 0 to 20.0 mol% and / or Cs ₂ O component 0 to 10.0 mol% and / or _{P 2 5} components from 0 to 15.0 mol% and / or GeO ₂ component 0 to 10.0 mol% and / or ZnO component from 0 to 50.0 mol% and / or _Al 2 _{O 3} component from 0 to 15.0 mol% and // Ga ₂ O ₃ component 0-5.0 mol% and / or Bi ₂ O ₃ component 0-10.0 mol% and / or TeO ₂ component 0-25.0 mol% and / or Sb ₂ O ₃ component 0-0.5 mol%

[Production method]
The optical glass of the present invention is produced, for example, as follows. That is, the above raw materials are uniformly mixed so that each component is within a predetermined content range, the prepared mixture is put into a platinum crucible, and 1100-1500 ° C. in an electric furnace depending on the difficulty of melting the glass composition. It is produced by melting in the temperature range of 2 to 5 hours, stirring and homogenizing, lowering to an appropriate temperature, casting into a mold, and slow cooling.

[Physical properties]
The optical glass of the present invention needs to have a high refractive index (n _d ) and low dispersion. In particular, the refractive index (n _d ) of the optical glass of the present invention is preferably 1.75, more preferably 1.80, still more preferably 1.82, and most preferably 1.85. Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 30, more preferably 35, still more preferably 37, and most preferably 39, preferably 50, more preferably 47, most preferably 45 is the upper limit. As a result, the degree of freedom in optical design is increased, and a large amount of light refraction can be obtained even if the device is made thinner. The upper limit of the refractive index (n _d ) of the optical glass of the present invention is, for example, 2.00 or less, more specifically 1.98 or less, and more specifically 1.95 or less in many cases.

Further, the optical glass of the present invention needs to have high devitrification resistance even if the content of the Ta ₂ O ₅ component is small. In particular, the optical glass of the present invention preferably has a low liquidus temperature of 1300 ° C. or lower. More specifically, the liquidus temperature of the optical glass of the present invention is preferably 1300 ° C., more preferably 1280 ° C., and most preferably 1250 ° C. As a result, even if the molten glass flows out at a lower temperature, the crystallization of the produced glass is reduced, so that the devitrification resistance when the glass is formed from the molten state can be increased. The influence on the optical characteristics of the optical element can be reduced. Moreover, since the range of the temperature which can form glass stably becomes wide, even if glass melting temperature is made low, glass can be shape | molded and the energy consumed at the time of glass shaping | molding can be suppressed. On the other hand, the lower limit of the liquidus temperature of the optical glass of the present invention is not particularly limited, but the liquidus temperature of the glass obtained by the present invention is approximately 500 ° C. or higher, specifically 550 ° C. or higher, more specifically 600. Often above ℃. In this specification, “liquid phase temperature” means that a 30 cc cullet-like glass sample is placed in a platinum crucible in a platinum crucible having a capacity of 50 ml and completely melted at 1350 ° C., and the temperature is lowered to a predetermined temperature. Then, the glass surface and the presence or absence of crystals in the glass are observed immediately after taking out of the furnace and cooling to indicate the lowest temperature at which no crystals are observed. Here, the predetermined temperature represents a temperature set in increments of 20 ° C. from 1300 ° C. to 1160 ° C.

Moreover, it is preferable that the optical glass of this invention has little coloring. In particular, when the optical glass of the present invention is represented by the transmittance of the glass, the wavelength (λ ₇₀ ) showing a spectral transmittance of 70% in a sample having a thickness of 10 mm is 450 nm or less, more preferably 430 nm or less, and most preferably. Is 400 nm or less. Further, the wavelength (λ ₅ ) exhibiting a spectral transmittance of 5% is 400 nm or less, more preferably 380 nm or less, and most preferably 360 nm or less. Thereby, the absorption edge of the glass is positioned in the vicinity of the ultraviolet region, and the transparency of the glass in the visible region is enhanced. Therefore, this optical glass can be preferably used as a material for an optical element such as a lens.

The optical glass of the present invention preferably has a low partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is (−2.50 × 10 ⁻³ × ν _d +0.6571) ≦ with respect to the Abbe number (ν _d ) ≦ The relationship (θg, F) ≦ (−2.50 × 10 ⁻³ × ν _d +0.6971) is satisfied. Thereby, since an optical glass having a small partial dispersion ratio (θg, F) is obtained, chromatic aberration of an optical element formed from the optical glass can be reduced. The partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably (−2.50 × 10 ⁻³ × ν _d +0.6571), more preferably (−2.50 × 10 ⁻³ × ν _d). +0.6591), and most preferably, (-2.50 × 10 ⁻³ × ν _d +0.6611) is the lower limit. On the other hand, the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably (−2.50 × 10 ⁻³ × ν _d +0.6971), more preferably (−2.50 × 10 ^−3). × ν _d +0.6921), most preferably (−2.50 × 10 ⁻³ × ν _d +0.6871) is set as the upper limit.

[Glass molding and optical element]
A glass molded body can be produced from the produced optical glass by means of, for example, polishing or molding press molding such as reheat press molding or precision press molding. That is, a glass molded body is manufactured by performing mechanical processing such as grinding and polishing on optical glass, or glass molding is performed by performing a polishing process after performing reheat press molding on a preform manufactured from optical glass. A glass molded body can be produced by producing a body, or by performing precision press molding on a preform produced by polishing or a preform formed by known float forming or the like. In addition, the means for producing the glass molded body is not limited to these means.

  As described above, the glass molded body formed from the optical glass of the present invention is useful for various optical elements and optical designs, and among them, it is particularly preferable to use them for optical elements such as lenses and prisms. This makes it possible to form a glass molded body with a large diameter, so that the optical elements can be enlarged, but with high definition and high precision imaging characteristics and projection when used in optical equipment such as cameras and projectors. The characteristics can be realized.

Composition of Examples (No. 1 to No. 285), Reference Examples (No. A to No. B) and Comparative Examples (No. A to No. B) of the present invention, and refractive indexes of these glasses ( Tables 1 to 37 show the results of nd), Abbe number (νd), partial dispersion ratio (θg, F), liquidus temperature, and wavelengths (λ5 and λ70) at which the spectral transmittance is 5% and 70%. Among these, Examples (No. 1 to No. 64, No. 68, No. 69, No. 74 to No. 79, No. 201 to No. 236) are reference examples of the present invention. The following examples are merely for illustrative purposes, and are not limited to these examples.

  Each of the glass of Examples (No. 1 to No. 285), Reference Examples (No. A to No. B) and Comparative Examples (No. A to No. B) of the present invention is used as a raw material for each component. High purity raw materials used for ordinary optical glass such as corresponding oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric acid compounds, etc. were selected and shown in Tables 1 to 37. After weighing and mixing uniformly so as to have the composition ratio of the example, it is put into a platinum crucible and melted in a temperature range of 1100 to 1500 ° C. for 2 to 5 hours in an electric furnace depending on the melting difficulty of the glass composition. Then, after homogenizing with stirring, it was cast into a mold or the like and slowly cooled to produce a glass.

Here, Example (No.1~No.285), Reference Example (No.A~No.B) and the glass of Comparative Example (No.A~No.B), refractive index _(n d), Abbe The number (ν _d ) and the partial dispersion ratio (θg, F) were measured based on Japan Optical Glass Industry Association Standard JOGIS01-2003. Then, with respect to the obtained Abbe number (ν _d ) and partial dispersion ratio (θg, F), the intercept when the slope a is 0.0025 in the relational expression (θg, F) = − a × ν _d + b b was determined. Here, the refractive index (n _d ), Abbe number (ν _d ), and partial dispersion ratio (θg, F) are measured by measuring the glass obtained at a slow cooling rate of -25 ° C./hr. Asked.

Moreover, the transmittance | permeability of the glass of an Example (No.1-No.285), a reference example (No.A-No.B), and a comparative example (No.A-No.B) is Japan Optical Glass Industry Association standard. It measured according to JOGIS02. In the present invention, the presence / absence and degree of coloration of the glass were determined by measuring the transmittance of the glass. More specifically, a face parallel polished product having a thickness of 10 ± 0.1 mm is measured for a spectral transmittance of 200 to 800 nm in accordance with JISZ8722, and λ ₅ (wavelength when the transmittance is 5%) and λ ₇₀ (transmittance). Wavelength at 70%).

Moreover, the liquidus temperature of the glass of an Example (No.1-No.285), a reference example (No.A-No.B), and a comparative example (No.A-No.B) is platinum with a capacity | capacitance of 50 ml. A 30 cc cullet-shaped glass sample is put in a platinum crucible in a crucible made into a completely melted state at 1350 ° C., lowered to any temperature set in increments of 20 ° C. from 1300 ° C. to 1160 ° C. and held for 12 hours, Immediately after taking it out of the furnace and cooling, the glass surface and the presence or absence of crystals in the glass were observed, and the lowest temperature at which no crystals were observed was determined.

  As shown in Tables 1 to 37, all of the optical glasses of Examples (No. 1 to No. 285) of the present invention have a liquidus temperature of 1300 ° C. or lower, more specifically 1260 ° C. or lower. Was within the desired range. For this reason, it became clear that the optical glass of the Example of this invention has low liquidus temperature. In addition, since all of the reference examples (No. A to No. B) and the comparative examples (No. A to No. B) have been devitrified, it is assumed that the liquidus temperature is high.

In addition, the optical glasses of the examples of the present invention each had a λ ₇₀ (wavelength at a transmittance of 70%) of 420 nm or less, more specifically 405 nm or less. In addition, in the optical glasses of the examples of the present invention, each of λ ₅ (wavelength when the transmittance was 5%) was 400 nm or less, more specifically 360 nm or less. For this reason, it became clear that the optical glass of the Example of this invention was hard to color.

The optical glasses of the examples of the present invention all have a refractive index (n _d ) of 1.75 or more, more specifically 1.86 or more, and this refractive index (n _d ) is 2.00 or less. More specifically, it was 1.97 or less, and was within the desired range.

The optical glasses of the examples of the present invention all have an Abbe number (ν _d ) of 30 or more, and the Abbe number (ν _d ) is 50 or less, more specifically 42 or less, and the desired range. It was in.

Further, the optical glasses of the examples of the present invention all have a partial dispersion ratio (θg, F) of (−2.50 × 10 ⁻³ × ν _d +0.6571) or more, more specifically (−2.50). × 10 ⁻³ × ν _d +0.6665) or more. On the other hand, the partial dispersion ratio (-2.50 × 10 ⁻³ × ν _d +0.6971) or less of the optical glass of the embodiment of the present invention, more specifically (−2.50 × 10 ⁻³ × ν _d). +0.6813) or less. Therefore, it was found that these partial dispersion ratios (θg, F) are within a desired range.

Therefore, the optical glass of the embodiment of the present invention can be manufactured at low cost while having a refractive index (n _d ) and an Abbe number (ν _d ) within desired ranges, has high resistance to devitrification, and has little coloration. It became clear.

  Furthermore, a glass block was formed using the optical glass of the example of the present invention, and this glass block was ground and polished to be processed into the shape of a lens and a prism. As a result, it was possible to stably process into various lens and prism shapes.

  Although the present invention has been described in detail for the purpose of illustration, this embodiment is only for the purpose of illustration, and many modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. Will be understood.

Claims (16)

The B ₂ O ₃ component is 5.0 to 30.0% by mass% relative to the total glass mass of the oxide equivalent composition ,
La ₂ O ₃ component 10.0-55.0% ,
0.1 to 15.0% of SiO ₂ component,
ZrO ₂ component more than 0 to 12.0% and
WO ₃ component 1.0 to 15.0% ( excluding those in which the content of WO ₃ component is 2% or less)
Contains,
Ta ₂ O ₅ content of 9.5% or less,
The content of GeO ₂ component is 5.0% or less (excluding those containing GeO ₂ component of 5.0% or more) ,
The ZnO component content is 10.0% or less,
The sum of the content of one or more selected from the group consisting of TiO ₂ component, Nb ₂ O ₅ component and WO ₃ component is 17.03% or less,
The mass sum of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, Yb) is more than 55.0% to 75.0%,
An optical glass having a refractive index (n _d ) of 1.82 or more. The entire mass of the glass in terms of oxide composition, TiO ₂ component from 0 to 20.0% by mass%及beauty <br/> Nb ₂ O ₅ component from 0 to 20.0%
The optical glass according to claim 1 containing. The optical glass according to claim 1 or 2, wherein the sum of the content of the B ₂ O ₃ component and the SiO ₂ component with respect to the total glass mass of the oxide equivalent composition is 25.0% or less. The optical glass according to any one of claims 1 to 3 , wherein a mass ratio (ZrO ₂ + Ta ₂ O ₅ + Nb ₂ O ₅ ) / (B ₂ O ₃ + SiO ₂ ) of an oxide conversion composition is 2.00 or less. Gd ₂ O ₃ component 0 to 45.0% in mass% with respect to the total glass mass of oxide conversion composition,
Y ₂ O ₃ component from 0 to 30.0% and _Yb 2 _{O 3} component from 0 to 20.0%
The optical glass according to any one of claims 1 to 4 , further comprising: The optical glass according to any one of claims 1 to 5 , wherein the mass ratio of oxide equivalent composition Ta ₂ O ₅ / (Ln ₂ O ₃ + ZrO ₂ + Nb ₂ O ₅ + WO ₃ ) is 0.139 or less. Ln is at least one selected from the group consisting of La, Gd, Y, and Yb). MgO component 0 to 20.0% in mass% with respect to the total glass mass of oxide conversion composition,
CaO component 0 to 20.0%,
SrO component 0 to 20.0% and BaO component 0 to 25.0%
The optical glass according to any one of claims 1 to 6 which further contains each component of. RO component (wherein, R Mg, Ca, Sr, 1 or more selected from the group consisting of Ba) the glass the total weight of the oxide basis composition according to claim 7, wherein the mass sum is less than 25.0% Optical glass. Li ₂ O component 0 to 10.0% in mass% with respect to the total glass mass of oxide conversion composition,
Na ₂ O component 0 to 10.0%,
K ₂ O component from 0 to 10.0% and Cs ₂ O component from 0 to 10.0%
The optical glass according to any one of claims 1 to 8 which further comprises the components of. The mass sum of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) with respect to the total glass mass of the oxide equivalent composition is 15.0% or less. 9. The optical glass according to 9 . The weight ratio of oxide composition in terms of _{(B 2 O 3 + SiO 2} + WO 3) / (Ln 2 O 3 + ZrO 2 + Li 2 O) is the optical glass according to any one of claims 1 to 10 which is the 0.20 or more. The entire mass of the glass in terms of oxide composition, _P 2 _{O 5} component from 0 to 10.0% by mass%,
Al ₂ O ₃ component 0 to 10.0%,
Ga ₂ O ₃ component 0 to 10.0%,
Bi ₂ O ₃ component 0 to 20.0%,
TeO ₂ component 0 to 20.0%,
SnO ₂ component 0-1.0% and Sb ₂ O ₃ component 0-1.0%
Any description of the optical glass of claims 1 to 11 containing further components of. 30 to 50. Abbe number ([nu _d) The optical glass according to any one of claims 1 to 12 having a. The optical glass according to any one of claims 1 to 13 having a 1300 ° C. below the liquidus temperature. The optical element which uses the optical glass in any one of Claim 1 to 14 as a base material. An optical apparatus comprising the optical element according to claim 15 .