JPWO2010126097A1 - Optical glass, optical element and precision press molding preform - Google Patents

Abstract

An optical glass having a low Abbe number (νd) while having a refractive index (nd) within a desired range, high transparency to visible light, easy to soften at a low temperature, and easy to polish. The optical element used and the precision press molding preform are obtained. The optical glass is selected from the group consisting of 40.0% or more and less than 75.0% of TeO2 component, Bi2O3 component, Nb2O5 component, WO3 component and TiO2 component in mol% with respect to the total amount of glass of oxide conversion composition. One or more kinds of components are contained in an amount of 1.0% to 40.0% and have an Abbe number (νd) of 30 or less. The optical element and the precision press-molding preform are made of this optical glass.

Description

  The present invention relates to an optical glass, an optical element, and a precision press-molding preform.

  In recent years, the digitization and high definition of devices that use optical systems have been rapidly progressing, and the precision of optical elements such as lenses used in various optical devices, including photography devices such as digital cameras and video cameras, The demand for light weight and downsizing is increasing.

For this reason, among optical glasses for producing optical elements, in particular, it has a high refractive index ( _nd ) of 1.70 or more and 2.20 or less, which can reduce the weight and size of optical elements and optical systems. However, the demand for high refractive index and high dispersion glass having an Abbe number (ν _d ) of 30 or less is greatly increasing. As such a high refractive index and high dispersion glass, for example, Patent Documents 1 to 5 describe optical glasses having a refractive index (n _d ) of 1.8 or more and an Abbe number (ν _d ) of around 20. The tellurite glass as represented is known.

JP 2001-180971 A JP 2008-273750 A JP 2002-241144 A JP 2006-182577 A JP 2008-105869 A

  When producing an optical element using such glass, a method of grinding and polishing a glass molded product obtained by softening and molding glass (reheat press molding), or cutting and polishing a gob or a glass block There is used a method (precise press molding) in which a preform material or a preform material formed by known flotation molding is heat-softened and pressure-molded with a mold having a highly accurate molding surface.

  However, since the glass disclosed in Patent Document 1 and Patent Document 2 has a high glass transition point (Tg), these glasses were difficult to soften even when heated. Therefore, when a preform material is prepared from the glass of Patent Document 1 and Patent Document 2, and an optical element is manufactured by heat softening and press molding the preform material, it is necessary to increase the temperature at which the preform material is heat softened. For this reason, the die used for press molding and the preform material are fused, and the optical characteristics of the optical element are affected.

On the other hand, as the glass disclosed in Patent Document 3 is a glass having a lower Abbe number (ν _d ), it is more difficult to vitrify due to devitrification, and the transmittance for visible light is colored by reduction of the Te component. Was low. For this reason, it was difficult for the glass disclosed in Patent Document 3 to achieve both a low Abbe number (ν _d ) of glass and the productivity of the glass itself.

The glass disclosed in Patent Document 4 has a low Abbe number (ν _d ) because it contains a large amount of TiO ₂ and WO _3, but these glasses are all colored. The transmittance for visible light was low. For this reason, it was difficult for the glass disclosed in Patent Document 4 to achieve both a low Abbe number (ν _d ) of glass and high transparency to visible light.

  Moreover, when the inventor produced the glass disclosed by patent document 5, although all had a low glass transition point (Tg), they were glasses with high abrasion degree (Aa). For this reason, since all the glasses disclosed in Patent Document 3 are easily scratched on the surface and difficult to polish, it is difficult to improve press formability and polishing processability.

The present invention has been made in view of the above problems, and its object is to have a low Abbe number (ν _d ) while the refractive index (n _d ) is within a desired range and is low. An object is to obtain an optical glass that is easily softened at a temperature and is easily polished, an optical element using the optical glass, and a preform for precision press molding. Another object of the present invention is to obtain an optical glass having high transparency to visible light and high resistance to devitrification during glass formation, an optical element using the optical glass, and a precision press-molding preform.

In order to solve the above-mentioned problems, the present inventors have conducted intensive test studies, and as a result, they have a TeO ₂ component, a Bi ₂ O ₃ component, a Nb ₂ O ₅ component, a WO ₃ component, and a TiO ₂ component. One or more selected components are used in combination, and by suppressing the content of these components within a predetermined range, the glass has a high refractive index, but the dispersion is increased and a low Abbe number is obtained. As a result, the inventors have found that the glass transition point (Tg) is low and the wear degree of the glass is low, and the present invention has been completed. Also, it found in combination of TeO ₂ component and _Bi 2 _{O 3} component, by suppressing the content of TeO ₂ component and _Bi 2 _{O 3} component in the predetermined range, also the transmittance of the glass to visible light is enhanced It was. Also, a combination of TeO ₂ component and WO ₃ components, by suppressing the content of TeO ₂ component and WO ₃ components within a predetermined range, the transmittance of the glass to visible light is enhanced, and resistance at the time of glass formation It has also been found that devitrification is improved. Specifically, the present invention provides the following.

(1) 40.0% or more and less than 75.0% of TeO ₂ component, Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component, An optical glass containing 1.0% or more and 40.0% or less of one or more components selected from the group consisting of TiO ₂ components and having an Abbe number (ν _d ) of 30 or less.

(2) The optical glass according to (1), which contains Bi ₂ O ₃ component in an amount of 1.0% to 40.0% by mol% with respect to the total amount of the glass having an oxide equivalent composition.

(3) The optical glass according to (2), wherein the content of the TeO ₂ component is less than 70.0% with respect to the total amount of glass having an oxide equivalent composition.

(4) The optical glass according to (1), which contains 1.0% or more and 25.0% or less of Nb ₂ O ₅ component in mol% with respect to the total amount of glass having an oxide equivalent composition.

(5) The optical glass according to (1), containing 1.0% or more and 30.0% or less of a TiO ₂ component in mol% with respect to the total amount of the glass having an oxide conversion composition.

(6) The optical glass according to (1), which contains 1.0% or more and 40.0% or less of the WO ₃ component in mol% with respect to the total amount of glass having an oxide equivalent composition.

(7) The optical glass according to any one of (1) to (6), wherein the wavelength (λ ₇₀ ) at which the spectral transmittance is 70% is 500 nm or less.

(8) the glass the total amount of substance of the oxide composition in terms of, 0~25.0% Li ₂ O component in mol% and / or Na ₂ O component from 0 to 30.0% and / or _{K 2} O ingredient 0 30.0% and / or Cs ₂ O component from 0 to 30.0%
The optical glass according to any one of (1) to (7), further containing each component of:

(9) The optical glass according to (8), wherein the substance amount sum Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O is 30.0% or less with respect to the total amount of the glass having an oxide conversion composition.

(10) The optical glass according to (9), wherein a substance amount sum Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O is less than 20.0% with respect to the total amount of the glass having an oxide conversion composition.

(11) The optical glass according to any one of (1) to (10), wherein the content of the Ga ₂ O ₃ component is 20.0% or less in terms of mol% with respect to the total amount of the glass having an oxide equivalent composition.

(12) The optical glass according to (11), wherein the content of the Ga ₂ O ₃ component is less than 5.0% in terms of mol% with respect to the total amount of glass having an oxide equivalent composition.

(13) ZnO component 0 to 30.0% and / or La ₂ O ₃ component 0 to 25.0% in mol% with respect to the total amount of glass in the oxide equivalent composition
The optical glass according to any one of (1) to (12), further comprising:

(14) The optical glass according to (13), wherein the content of the La ₂ O ₃ component is 9.5% or less in terms of mol% with respect to the total amount of the glass having an oxide equivalent composition.

(15) The optical glass according to (14), wherein the content of the La ₂ O ₃ component is less than 8.0% in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.

  (16) The optical glass according to any one of (1) to (15), which contains substantially no lead compound.

(17) The optical glass according to any one of (1) to (16), in which the content of the B ₂ O ₃ component is 40.0% or less in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.

(18) The optical glass according to (17), wherein the content of the B ₂ O ₃ component is less than 20.0% in terms of mol% with respect to the total amount of the glass having an oxide conversion composition.

(19) 0 to 15.0% of MgO component and / or 0 to 20.0% of CaO component and / or 0 to 20.0% of SrO component and in mol% with respect to the total amount of glass in the oxide conversion composition / Or BaO component 0 to 20.0%
The optical glass according to any one of (1) to (18), further comprising:

  (20) The optical glass according to (19), wherein the total amount of MgO + CaO + SrO + BaO is 20.0% or less with respect to the total amount of glass having an oxide equivalent composition.

(21) SiO ₂ component 0 to 30.0% and / or GeO ₂ component 0 to 30.0% and / or P ₂ O ₅ component in mol% with respect to the total amount of glass in the oxide conversion composition 0 30.0% and / or Al ₂ O ₃ component 0 to 30.0% and / or In ₂ O ₃ component 0 to 15.0% and / or ZrO ₂ component 0 to 20.0% and / or Ta ₂ O ₅ components 0 to 20.0% and / or Gd ₂ O ₃ components 0 to 25.0% and / or Y ₂ O ₃ components 0 to 20.0% and / or Yb ₂ O ₃ components 0 to 20.0% And / or Sb ₂ O ₃ component 0-1.0% and / or CeO ₂ component 0-1.0%
The optical glass according to any one of (1) to (20), further comprising:

(22) The optical glass according to any one of (1) to (21), which has a refractive index (n _d ) of 1.70 or more and 2.20 or less.

  (23) The optical glass according to any one of (1) to (22), which has a glass transition point (Tg) of 200 ° C. or higher and 550 ° C. or lower.

  (24) The optical glass according to any one of (1) to (23), wherein the degree of wear (Aa) is 100 or more and 1000 or less.

(25) (−0.00160 × ν _d +0.63460) ≦ (θg, F) ≦ () in the range of the partial dispersion ratio (θg, F) to the Abbe number (ν _d ) and v _d ≦ 25. −0.00563 × ν _d +0.75873), and (−0.00250 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.00340 × in the range of ν _d > 25. The optical glass according to any one of (1) to (24), which satisfies a relationship of ν _d +0.70300.

  (26) An optical element made of the optical glass according to any one of (1) to (25).

  (27) A precision press-molding preform comprising the optical glass according to any one of (1) to (25).

  (28) An optical element obtained by precision press-molding the precision press-molding preform according to (27).

According to the present invention, a combination of TeO ₂ component and one or more components selected from the group consisting of Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component and TiO ₂ component are used together. By suppressing the content within a predetermined range, the glass has a high refractive index, but the dispersion is increased to obtain a low Abbe number, the transmittance of the glass to visible light is increased, and the glass Abrasion degree decreases. For this reason, it has a low Abbe number (ν _d ) while its refractive index (n _d ) is within a desired range, is highly transparent to visible light, is easily softened at a low temperature, and is easy to polish. Glass, an optical element using the glass, and a precision press-molding preform can be obtained.

It is a figure which shows the normal line in the orthogonal coordinate whose vertical axis is a partial dispersion ratio ((theta) g, F) and whose horizontal axis is Abbe number ((nu) d). It is a figure which shows the relationship between the partial dispersion ratio ((theta) g, F) and the Abbe number ((nu) _d ) about the glass of the Example (No.A1-No.A25) of this application. It is a figure which shows the relationship between the partial dispersion ratio ((theta) g, F) and the Abbe number ((nu) _d ) about the glass of the Example (No.B1-No.B22) of this application. It is a figure which shows the relationship between the partial dispersion ratio ((theta) g, F) and the Abbe number ((nu) _d ) about the glass of the Example (No.C1-No.C10) of this application. It is a figure which shows the relationship between the partial dispersion ratio ((theta) g, F) and the Abbe number ((nu) _d ) about the glass of the Example (No.D1-No.D7) of this application.

In the optical glass of the present invention, the TeO ₂ component is 40.0% or more and less than 75.0% in mol% with respect to the total amount of glass in the oxide conversion composition, Bi ₂ O ₃ component, Nb ₂ O ₅ component, It contains 1.0% or more and 40.0% or less of one or more components selected from the group consisting of WO ₃ component and TiO ₂ component, and has an Abbe number (ν _d ) of 30 or less. TeO ₂ component and one or more components selected from the group consisting of Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component and TiO ₂ component are used in combination, and the content of these components is within a predetermined range. While keeping the refractive index within the range, the refractive index of the glass is increased, but the dispersion is increased to obtain a low Abbe number, the transmittance of the glass to visible light is increased, and the glass transition point (Tg) is lowered. In addition, the glass is provided with an appropriate degree of wear. Accordingly, an optical glass having a low Abbe number (ν _d ) while having a refractive index (n _d ) within a desired range, high transparency to visible light, easy softening at a low temperature, and easy polishing. And an optical element using this and a precision press-molding preform can be obtained.

In particular, the first optical glass has a TeO ₂ component of 40.0% or more and less than 75.0% and a Bi ₂ O ₃ component of 1.0% in terms of mol% with respect to the total amount of the glass having an oxide conversion composition. The content is 40.0% or less and has an Abbe number (ν _d ) of 30 or less. Here, a combination of TeO ₂ component and _Bi 2 _{O 3} component, by suppressing the content of TeO ₂ component and _Bi 2 _{O 3} component in the predetermined range, the transmittance of the glass to visible light is enhanced. Therefore, an optical glass that can be preferably used for applications that transmit visible light, an optical element using the glass, and a precision press-molding preform can be obtained.

In addition, the second optical glass has a TeO ₂ component of 40.0% or more and less than 75.0% and an Nb ₂ O ₅ component of 1.0% in mol% with respect to the total amount of the glass in an oxide conversion composition. The content is 25.0% or less and has an Abbe number (ν _d ) of 30 or less.

The third optical glass has a TeO ₂ component of 40.0% or more and less than 75.0% and a TiO ₂ component of 1.0% or more and 30% by mol% with respect to the total amount of glass in the oxide equivalent composition. 0.0% or less and an Abbe number (ν _d ) of 30 or less.

Further, the fourth optical glass has a TeO ₂ component of 40.0% or more and less than 75.0% and a WO ₃ component of 1.0% or more and 40% by mol% with respect to the total amount of the glass having an oxide conversion composition. 0.0% or less and an Abbe number (ν _d ) of 30 or less. Here, the TeO ₂ component and the WO ₃ component are used in combination, and the transmittance of the TeO ₂ component and the WO ₃ component is suppressed within a predetermined range, whereby the transmittance for visible light of the glass is increased, and at the time of glass formation Devitrification resistance is improved. Therefore, an optical glass that can be preferably used for applications that transmit visible light, an optical element using the glass, and a precision press-molding preform can be obtained.

  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. In the present specification, unless otherwise specified, the content of each component is all expressed in mol% with respect to the total amount of glass having an oxide equivalent composition. Here, the “equivalent oxide 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 amount of substances of a production | generation oxide into 100 mol%.

<About essential and optional components>
The TeO ₂ component is a glass forming component, and is a component that increases the refractive index of the glass while increasing the dispersion of the glass. In particular, by setting the TeO ₂ component content to 40.0% or more, the dispersion and refractive index of the glass can be increased, so that a desired Abbe number (ν _d ) and refractive index can be obtained. On the other hand, by setting the content of TeO ₂ component to less than 75.0%, it is possible to improve the devitrification resistance when forming glass by lowering the liquidus temperature of the glass. Therefore, the content ratio of the TeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 40.0%, more preferably 43.0%, and most preferably 45.0%. The TeO ₂ content is preferably less than 75.0%, more preferably 70.0%, more preferably less than 70.0%, and most preferably 65.0%. And The TeO ₂ component can be contained in the glass using, for example, TeO ₂ as a raw material.

In the optical glass of the present invention, the sum of the content ratios of one or more components selected from the group consisting of Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component and TiO ₂ component is 1.0% or more and 40 0.0% or less. In particular, by making the sum of the content ratios 1.0% or more, it is easy to vitrify the TeO ₂ component while increasing the refractive index and dispersion of the glass. While obtained, the coloration of the glass can be reduced. On the other hand, by setting the sum of the contents to 40.0% or less, the liquidus temperature and the glass transition point (Tg) of the glass are lowered. Molding can be facilitated. Therefore, the sum of the content ratios of one or more components selected from the group consisting of Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component and TiO ₂ component with respect to the total amount of glass in oxide equivalent composition is The lower limit is preferably 1.0%, more preferably 3.0%, and most preferably 5.0%, preferably 40.0%, more preferably 35.0%, most preferably 30.0%. The upper limit.

Among, Bi ₂ O ₃ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the Bi ₂ O ₃ component content to 40.0% or less, the liquidus temperature of the glass and the glass transition point (Tg) are lowered, while increasing the devitrification resistance during glass formation, It is possible to facilitate press molding. On the other hand, in the first optical glass, by making the content of the Bi ₂ O ₃ component 1.0% or more, it is easy to vitrify the TeO ₂ component while increasing the dispersion of the glass. Low Abbe number (ν _d ) and coloring of the glass can be reduced.

Therefore, the upper limit of the content ratio of the Bi ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 40.0%, more preferably 30.0%, and most preferably 20.0%. Among these, in the first optical glass, the content of the Bi ₂ O ₃ component with respect to the total amount of the glass having an oxide conversion composition is preferably 40.0%, more preferably 35.0%, and most preferably 30. The upper limit is 0%. In the second and third optical glasses, the content ratio of the Bi ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 25.0%, more preferably 23.0%, most preferably The upper limit is 20.0%. In the fourth optical glass, the content ratio of the Bi ₂ O ₃ component with respect to the total amount of the glass having an oxide conversion composition is preferably 25.0%, more preferably 20.0%, and most preferably 15.0. % Is the upper limit. On the other hand, in the first optical glass, the content of the Bi ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 1.0%, more preferably 3.0%, and most preferably 5.0. % Is the lower limit. The Bi ₂ O ₃ component can be contained in the glass using, for example, Bi ₂ O ₃ as a raw material.

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 setting the content of the Nb ₂ O ₅ component to 25.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the devitrification resistance of the glass. On the other hand, in the second optical glass, by setting the content of the Nb ₂ O ₅ component to 1.0% or more, the degree of abrasion of the glass is lowered while the dispersion of the glass is increased. (Ν _d ) and workability during glass polishing can both be achieved.

Therefore, the content of the Nb ₂ O ₅ component is preferably 25.0%, more preferably 22.0%, still more preferably 20.0%, and most preferably 15.5% with respect to the total amount of glass having an oxide equivalent composition. The upper limit is 0%. On the other hand, in the second optical glass, the content of the Nb ₂ O ₅ component is preferably 1.0%, more preferably 2.0%, and most preferably 3.0 with respect to the total amount of glass in the oxide equivalent composition. % Is the lower limit. The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ as a raw material.

Further, TiO ₂ component, while increasing the refractive index and dispersion of the glass is a component to 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 TiO ₂ component to 30.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the devitrification resistance of the glass. On the other hand, in the third optical glass, by setting the content of the TiO ₂ component to 1.0% or more, the degree of abrasion of the glass is lowered while the dispersion of the glass is increased. Therefore, a desired low Abbe number ( ν _d ) and workability during glass polishing can both be achieved.

Therefore, the content of the TiO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. In particular, in the first optical glass, the content of the TiO ₂ component is preferably 30.0%, more preferably 15.0%, and most preferably 10.0% with respect to the total amount of glass in the oxide equivalent composition. The upper limit. In the second to fourth optical glasses, the content of the TiO ₂ component with respect to the total amount of the glass having an oxide conversion composition is preferably 30.0%, more preferably 25.0%, most preferably 20. The upper limit is 0%. On the other hand, in the third optical glass, the content of the TiO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 1.0%, more preferably 1.5%, and most preferably 2.0%. The lower limit. TiO ₂ component may be contained in the glass by using as the starting material for example TiO ₂ or the like.

Further, WO ₃ 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, when the content of the WO ₃ component is set to 40.0% or less, the glass transition point (Tg) and the liquidus temperature are prevented from rising, so that while maintaining good devitrification resistance, it is good. Press characteristics can be obtained. On the other hand, in the fourth optical glass, by setting the content of the WO ₃ component to 1.0% or more, the glass liquid phase temperature is lowered while the dispersion of the glass is increased. The number (ν _d ) can be compatible with the devitrification resistance during glass formation.

Accordingly, the content of the WO ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 40.0%, more preferably 30.0%, and most preferably 20.0%. Among these, in the first to third optical glasses, the content of the WO ₃ component with respect to the total amount of glass having an oxide conversion composition is preferably 25.0%, more preferably 20.0%, and most preferably 15. 0.0% is the upper limit. In the fourth optical glass, the content of the WO ₃ component is preferably 40.0%, more preferably 30.0%, and most preferably 20.0% with respect to the total amount of glass in the oxide equivalent composition. The upper limit. On the other hand, in the fourth optical glass, the content of the WO ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 1.0%, more preferably 1.5%, and most preferably 1.7%. The lower limit. The WO ₃ component can be contained in the glass using, for example, WO ₃ as a raw material.

Li 2 _O component is a component that lowers the melting temperature and the glass transition point of the glass (Tg), which is an optional component of the optical glass of the present invention. In particular, by reducing the Li ₂ O component content to 25.0% or less, it is possible to reduce the refractive index of the glass while facilitating accurate transfer of the lens surface during press molding by reducing the glass expansion coefficient. And the chemical durability of the glass can be increased. Therefore, the upper limit of the content ratio of the Li ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably 25.0%, more preferably 22.0%, and most preferably 20.0%. The Li ₂ O component can be contained in the glass using, for example, Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

The Na ₂ O component is a component that lowers the melting temperature and glass transition point (Tg) of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Na ₂ O component to 30.0% or less, it is possible to improve the chemical durability of the glass while suppressing a decrease in the refractive index of the glass. Therefore, the content of the Na ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%. The Na ₂ O component can be contained in the glass using, for example, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like as a raw material.

K 2 _O component is a component that lowers the melting temperature and the glass transition point of the glass (Tg), which is an optional component of the optical glass of the present invention. In particular, by setting the content of the K ₂ O component to 30.0% or less, the chemical durability of the glass can be enhanced while suppressing a decrease in the refractive index of the glass. Therefore, the upper limit of the content of the K ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. The K ₂ O component can be contained in the glass using, for example, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material.

Cs 2 _O component is a component that lowers the melting temperature of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Cs ₂ O component to 30.0% or less, it is possible to increase the chemical durability of the glass while suppressing a decrease in the refractive index of the glass. Therefore, the upper limit of the content of the Cs ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. Cs ₂ O component may be contained in the glass by using as the starting material for example _Cs 2 _{CO 3,} CsNO 3, and the like.

In the optical glass of the present invention, the content amount of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) is 30.0% or less. Preferably there is. By setting the amount of this substance to 30.0% or less, it is possible to reduce the coloration of the glass and increase the chemical durability of the glass while suppressing a decrease in the refractive index of the glass. Therefore, the total amount of the Rn ₂ O component content relative to the total glass material amount in oxide equivalent composition is preferably 30.0%, more preferably 28.0%, even more preferably 25.0%, most preferably Has an upper limit of 20.0%. In particular, the sum of the content of the Rn ₂ O component with respect to the total amount of glass in the oxide conversion composition is preferably less than 20.0% in that the abrasion degree of the optical glass can be reduced to facilitate polishing. More preferably, it is less than 15.0%, more preferably 12.0%, and most preferably 10.0%.

Ga ₂ O ₃ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Ga ₂ O ₃ component to 20.0% or less, it is possible to increase the abrasion degree of the glass and facilitate the polishing while enhancing the devitrification resistance of the glass. Therefore, the content of the Ga ₂ O ₃ component with respect to the total glass substance amount of the oxide conversion composition is preferably 20.0%, more preferably 10.0% as an upper limit, further preferably less than 5.0%, Most preferably, it is less than 4.0%. The Ga ₂ O ₃ component can be contained in the glass using, for example, Ga ₂ O ₃ , GaF ₃ or the like as a raw material.

The ZnO component is a component that increases the devitrification resistance during glass formation, reduces the coloration of the glass, and improves the solubility of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the ZnO component to 30.0% or less, an increase in the liquidus temperature of the glass due to excessive inclusion of the ZnO component can be suppressed. Therefore, the content of the ZnO component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 29.0%, still more preferably 28.0%, and most preferably 25.0%. The upper limit. In particular, in terms of being able to lower the glass transition point (Tg), the content of the ZnO component with respect to the total amount of glass in the oxide conversion composition is preferably less than 15.0%, more preferably 12.0%, most preferably Has an upper limit of 10.0%. In addition, even if it does not contain a ZnO component, it is possible to obtain an optical glass having a desired high dispersion and high polishing workability and press workability, but by containing 1.0% or more of the ZnO component, Since the transparency with respect to visible light of glass is improved, coloring of glass can be reduced. Therefore, in this case, the content of the ZnO component with respect to the total amount of glass in the oxide conversion composition is preferably 1.0%, more preferably 2.0%, and most preferably 5.0%. The ZnO component can be contained in the glass using, for example, ZnO, ZnF ₂ or the like as a raw material.

La ₂ O ₃ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the La ₂ O ₃ component to 25.0% or less, it is possible to easily maintain good devitrification resistance while suppressing an increase in the glass transition point (Tg). Therefore, the content of the La ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 25.0%, more preferably 20.0%, and most preferably 15.0%. In particular, in terms of increasing the dispersion and reducing the Abbe number, the content of the La ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably less than 10.0%, more preferably less than 8.0%. And most preferably less than 7.0%. Further, in terms of being able to obtain a glass having a low liquidus temperature and high devitrification resistance, the content of the La ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 9.5%, The upper limit is more preferably 8.0%, and most preferably 6.0%. 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 B ₂ O ₃ component is a component that constitutes the network of the glass, and is a component that increases the devitrification resistance of the glass to homogenize the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content ratio of the B ₂ O ₃ component to 40.0% or less, devitrification resistance can be increased by increasing the liquidus temperature of the glass while easily obtaining a desired refractive index. . Therefore, the content of the B ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 40.0%, more preferably 35.0%, and most preferably 30.0%. In particular, when paying attention to the point that the increase in the glass transition point (Tg) can be suppressed, the content ratio of the B ₂ O ₃ component in the first optical glass with respect to the total amount of the glass having the oxide conversion composition is preferably 20. The upper limit is less than 0%, more preferably less than 17.0%, and most preferably 15.0%. In the second optical glass, the content ratio of the B ₂ O ₃ component with respect to the total amount of the glass having an oxide conversion composition is preferably less than 20.0%, more preferably 17.0%, and most preferably 15%. 0.0% is the upper limit. In the third optical glass, the content ratio of the B ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably less than 25.0%, more preferably less than 23.0%, most preferably The upper limit is 20.0%. In the fourth optical glass, the content ratio of the B ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably less than 25.0%, more preferably less than 20.0%, and most preferably The upper limit is 17.0%. 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 MgO component is a component that increases the transmittance in the visible region of the glass and improves the solubility and stability of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the MgO component to 15.0% or less, an increase in the liquidus temperature of the glass can be suppressed while suppressing a decrease in the refractive index of the glass. Therefore, the upper limit of the content of the MgO component with respect to the total amount of glass in the oxide conversion composition is preferably 15.0%, more preferably 10.0%, and most preferably 5.0%. The MgO component can be contained in the glass using, for example, MgCO ₃ or MgF ₂ as a raw material.

A CaO component is a component which improves the transmittance | permeability in the visible region of glass, and improves the solubility and stability of glass, and is an arbitrary component in the optical glass of this invention. In particular, by setting the content of the CaO component to 20.0% or less, it is possible to suppress an increase in the liquidus temperature of the glass while suppressing a decrease in the refractive index of the glass. Accordingly, the content of the CaO component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The CaO component can be contained in the glass using, for example, CaCO ₃ , CaF ₂ or the like as a raw material.

The SrO component is a component that increases the transmittance in the visible region of the glass and improves the solubility and stability of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the SrO component to 20.0% or less, it is possible to suppress an increase in the liquidus temperature of the glass while suppressing a decrease in the refractive index of the glass. Therefore, the upper limit of the content of the SrO component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The SrO component can be contained in the glass using, for example, Sr (NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

The BaO component is a component that improves the solubility and stability of the glass, and is an optional component in the optical glass of the present invention. In particular, by controlling the content of the BaO component to 20.0% or less, an increase in the liquidus temperature of the glass can be suppressed while suppressing a decrease in the refractive index of the glass. Therefore, the upper limit of the content of the BaO component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The BaO component can be contained in the glass using, for example, BaCO ₃ , Ba (NO ₃ ) ₂ or the like as a raw material.

  In the optical glass of the present invention, the content amount of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr and Ba) is 20.0% or less. Is preferred. By setting the total amount of substances to 20.0% or less, the degree of wear of the glass is lowered, so that the glass can be easily polished. Therefore, the sum of the content ratio of the RO component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%, and most preferably 8.0. % Is the upper limit.

The SiO ₂ component is a component that reduces devitrification of the glass by promoting stable glass formation, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the SiO ₂ component to 30.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the refractive index of the glass. Accordingly, the content of the SiO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 15.0%. 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 GeO ₂ component is a component that reduces devitrification of the glass by promoting stable glass formation, and is an optional component in the optical glass of the present invention. In particular, an increase in the glass transition point (Tg) can be suppressed by setting the content of the GeO ₂ component to 30.0% or less. Accordingly, the content of the GeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. In particular, in the first, third, and fourth optical glasses, the content of the GeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably The upper limit is 15.0%. On the other hand, in the second optical glass, the content of the GeO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, still more preferably 10.0%, Most preferably, the upper limit is 4.5%. The GeO ₂ component can be contained in the glass using, for example, GeO ₂ as a raw material.

The P ₂ O ₅ component is a component that reduces devitrification of the glass by promoting stable glass formation, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the P ₂ O ₅ component to 30.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the refractive index of the glass. Therefore, the content of the P ₂ O ₅ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%. 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 Al ₂ O ₃ component is a component that increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content ratio of the Al ₂ O ₃ component is 30.0% or less, a decrease in the refractive index of the glass can be suppressed. Therefore, the upper limit of the content of the Al ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 15.0%. The Al ₂ O ₃ component can be contained in the glass using, for example, Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ or the like as a raw material.

The In ₂ O ₃ component is a component that increases the refractive index of the glass and is an optional component in the optical glass of the present invention. In particular, by setting the content of the In ₂ O ₃ component to 15.0% or less, it is possible to facilitate polishing by increasing the degree of wear of the glass while increasing the devitrification resistance of the glass. Therefore, the content ratio of the In ₂ O ₃ component with respect to the total amount of glass in the oxide-converted composition is preferably 15.0%, more preferably 10.0%, and even more preferably less than 5.0%. Most preferably, it is less than 4.0%. The In ₂ O ₃ component can be contained in the glass using, for example, In ₂ O ₃ , InF ₃ or the like as a raw material.

The ZrO ₂ component is a component that suppresses devitrification in the process of cooling the glass from the molten state while increasing the refractive index of the glass, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the ZrO ₂ component to 20.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the devitrification resistance of the glass. Therefore, the content of the ZrO ₂ component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The ZrO ₂ component can be contained in the glass using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

Ta ₂ O ₅ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Ta ₂ O ₅ component to 20.0% or less, it is possible to suppress an increase in the glass transition point (Tg) while suppressing a decrease in the devitrification resistance of the glass. Accordingly, the content of the Ta ₂ O ₅ component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Ta ₂ O ₅ component can be contained in the glass using, for example, Ta ₂ O ₅ as a raw material.

Gd ₂ O ₃ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Gd ₂ O ₃ component to 25.0% or less, an increase in the glass transition point (Tg) can be suppressed while suppressing a decrease in the devitrification resistance of the glass. Therefore, the content of the Gd ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 25.0%, more preferably 20.0%, and most preferably 15.0%. 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.

Y ₂ O ₃ component, while increasing the refractive index of the glass, or to enhance the chemical durability of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Y ₂ O ₃ component to 20.0% or less, it is possible to suppress an increase in the glass transition point (Tg) while suppressing a decrease in the devitrification resistance of the glass. Therefore, the content of the Y ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Y ₂ O ₃ component can be contained in the glass using, for example, Y ₂ O ₃ , YF ₃ or the like as a raw material.

Yb ₂ O ₃ component is a component that raises the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, by setting the content of the Yb ₂ O ₃ component to 20.0% or less, it is possible to easily maintain good devitrification resistance while maintaining a desired optical constant. Therefore, the upper limit of the content of the Yb ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 20.0%, more preferably 15.0%, and most preferably 10.0%. The Yb ₂ O ₃ component can be contained in the glass using, for example, Yb ₂ O ₃ as a raw material.

The Sb ₂ O ₃ component is a component that promotes defoaming of the glass, and is an optional component in the optical glass of the present invention. In particular, by making the content of the Sb ₂ O ₃ component 1.0% or less, excessive foaming at the time of melting the glass is less likely to occur, so a melting facility for the Sb ₂ O ₃ component (especially a noble metal such as Pt) and Can be reduced. Therefore, the upper limit of the content of the Sb ₂ O ₃ component with respect to the total amount of glass in the oxide conversion composition is preferably 1.0%, more preferably 0.9%, and most preferably 0.8%. 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.

The CeO ₂ component is a component effective for clarifying the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the CeO ₂ component is 1.0% or less, an optical glass with good internal quality can be obtained. Accordingly, the CeO ₂ component content relative to the total amount of glass in the oxide equivalent composition is preferably 1.0%, more preferably 0.9%, and most preferably 0.8%. The CeO ₂ component can be contained in the glass using, for example, CeO ₂ as a raw material.

In addition, the component which clarifies and defoams glass is not limited to the above Sb ₂ O ₃ component or CeO ₂ component, but a known clarifier or defoamer in the field of glass production, or a combination thereof. Can be used.

<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, excluding Ti, Nb, W, Zr, Ta, La, Gd, Y, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Mo, Eu, Nd, Sm, Tb, Dy, Er, etc. These transition metal components are used especially for wavelengths in the visible region because they have the property that the glass is colored and absorbs at a specific wavelength in the visible region even when contained in a small amount by combining them individually or in combination. In optical glass, it is preferable that it does not contain substantially. Here, “substantially does not contain” means that it does not contain unless it is mixed as an impurity.

Furthermore, lead compounds such as PbO, arsenic compounds such as As ₂ O ₃ , and components of Th, Cd, Tl, Os, Be, and Se are components that tend to refrain from being used as harmful chemical substances in recent years. . When at least one of these is contained, not only the glass manufacturing process but also the processing steps and measures for environmental measures are required until the disposal after commercialization. Therefore, when importance is placed on the environmental impact, it is preferable not to substantially contain them except for inevitable mixing. As a result, the optical glass is substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking any special environmental measures.

The glass composition of the present invention is not expressed directly in terms of mass% because the composition is expressed in terms of mol% with respect to the total amount of glass in the oxide-converted composition, but is required in the present invention. The composition represented by mass% of each component present in the glass composition satisfying the characteristics generally takes the following values in terms of oxide conversion.
TeO ₂ component 40.0-75.0 mass%
And Bi ₂ O ₃ component 0 to 55.0 mass% and / or Nb ₂ O ₅ component 0 to 35.0 mass% and / or TiO ₂ component 0 to 15.0 mass% and / or WO ₃ component 0 to 55 0.0 mass% and / or Li ₂ O component 0-7.0 mass% and / or Na ₂ O component 0-12.0 mass% and / or K ₂ O component 0-18.0 mass% and / or Cs ₂ O component from 0 to 40.0% by weight and / or _Ga 2 _{O 3} component from 0 to 25.0% by weight and / or ZnO component from 0 to 25.0% by weight and / or _La 2 _{O 3} component from 0 to 40.0 wt% and / or _B 2 _{O 3} component from 0 to 30.0% by weight and / or MgO component from 0 to 8.0 wt% and / or CaO component from 0 to 8.0 wt% and / or SrO component 0-15. 0% by mass and / or BaO component 0-20.0% by mass and / or Si ₂ components from 0 to 13.0% by weight and / or GeO ₂ component 0 to 20.0% by weight and / or _P 2 _{O 5} component from 0 to 30.0% by weight and / or _Al 2 _{O 3} component 0 to 20.0 Mass% and / or In ₂ O ₃ component 0 to 25.0 mass% and / or ZrO ₂ component 0 to 15.0 mass% and / or Ta ₂ O ₅ component 0 to 40.0 mass% and / or Gd ₂ O ₃ component 0 to 40.0 mass% and / or Y ₂ O ₃ component 0 to 30.0 mass% and / or Yb ₂ O ₃ component 0 to 35.0 mass% and / or Sb ₂ O ₃ component 0 1.0 mass% and / or CeO ₂ component 0-1.0 mass%

In particular, the composition expressed by mass% of each component contained in the first optical glass generally takes the following values in terms of oxide.
TeO ₂ component 40.0-75.0 mass% and Bi ₂ O ₃ component 1.0-55.0 mass%,
And Li ₂ O component 0 to 7.0 mass% and / or Na ₂ O component 0 to 12.0 mass% and / or K ₂ O component 0 to 18.0 mass% and / or Cs ₂ O component 0 to 40 0.0% by mass and / or La ₂ O ₃ component 0-40.0% by mass and / or MgO component 0-8.0% by mass and / or CaO component 0-8.0% by mass and / or SrO component 0 15.0% by mass and / or BaO component 0-20.0% by mass and / or SiO ₂ component 0-13.0% by mass and / or B ₂ O ₃ component 0-30.0% by mass and / or GeO ₂ component 0 to 20.0% by weight and / or _P 2 _{O 5} component from 0 to 30.0% by weight and / or _Al 2 _{O 3} component 0 to 20.0% by weight and / or _Ga 2 _{O 3} component 0-25. 0% by weight and / or _In 2 _{O 3} component from 0 to 25.0% by weight and / or ZnO component from 0 to 25.0% by weight and / or ZrO ₂ component from 0 to 15.0% by weight and / or WO ₃ components from 0 to 35.0% by weight and / or _Ta 2 _{O 5} component from 0 to 40.0% by weight And / or TiO ₂ component 0 to 15.0 mass% and / or Nb ₂ O ₅ component 0 to 35.0 mass% and / or Gd ₂ O ₃ component 0 to 40.0 mass% and / or Y ₂ O ₃ components from 0 to 30.0% by weight and / or _Yb 2 _{O 3} component from 0 to 35.0% by weight and / or _Sb 2 _{O 3} component 0-1.0% by weight and / or CeO ₂ component 0-1.0 mass %

Moreover, the composition by the mass% display of each component contained in 2nd optical glass takes the following values in an oxide conversion composition in general.
TeO ₂ component 40.0-75.0 mass% and Nb ₂ O ₅ component 1.0-35.0 mass%,
And Li ₂ O component 0 to 7.0 mass% and / or Na ₂ O component 0 to 12.0 mass% and / or K ₂ O component 0 to 18.0 mass% and / or Cs ₂ O component 0 to 40 0.0% by mass and / or ZnO component 0-25.0% by mass and / or La ₂ O ₃ component 0-40.0% by mass and / or WO ₃ component 0-35.0% by mass and / or B ₂ O ₃ components 0 to 30.0 mass% and / or MgO component 0 to 8.0 mass% and / or CaO component 0 to 8.0 mass% and / or SrO component 0 to 15.0 mass% and / or BaO component 0-20.0% by mass and / or SiO ₂ component 0-13.0% by mass and / or GeO ₂ component 0-20.0% by mass and / or P ₂ O ₅ component 0-30.0% by mass and / or or _Al 2 _{O 3} component 0 to 20.0% by weight and / or _Ga 2 O Components from 0 to 25.0% by weight and / or _In 2 _{O 3} component from 0 to 25.0% by weight and / or ZrO ₂ component from 0 to 15.0% by weight and / or _Ta 2 _{O 5} component from 0 to 40.0 mass % And / or TiO ₂ component 0 to 15.0 mass% and / or Bi ₂ O ₃ component 0 to 45.0 mass% and / or Gd ₂ O ₃ component 0 to 40.0 mass% and / or Y ₂ O ₃ components 0 to 30.0 mass% and / or Yb ₂ O ₃ components 0 to 35.0 mass% and / or Sb ₂ O ₃ components 0 to 1.0 mass% and / or CeO ₂ components 0 to 1.0 mass%

Moreover, the composition by the mass% display of each component contained in 3rd optical glass takes the following values in an oxide conversion composition in general.
TeO ₂ component 40.0-75.0 mass% and TiO ₂ component 1.0-15.0 mass%,
And Li ₂ O component 0 to 7.0 mass% and / or Na ₂ O component 0 to 12.0 mass% and / or K ₂ O component 0 to 18.0 mass% and / or Cs ₂ O component 0 to 40 0.0% by mass and / or ZnO component 0-25.0% by mass and / or La ₂ O ₃ component 0-40.0% by mass and / or WO ₃ component 0-35.0% by mass and / or B ₂ O ₃ components 0 to 30.0 mass% and / or MgO component 0 to 8.0 mass% and / or CaO component 0 to 8.0 mass% and / or SrO component 0 to 15.0 mass% and / or BaO component 0-20.0% by mass and / or SiO ₂ component 0-13.0% by mass and / or GeO ₂ component 0-20.0% by mass and / or P ₂ O ₅ component 0-30.0% by mass and / or or _Al 2 _{O 3} component 0 to 20.0% by weight and / or _Ga 2 O Components from 0 to 25.0% by weight and / or _In 2 _{O 3} component from 0 to 25.0% by weight and / or ZrO ₂ component from 0 to 15.0% by weight and / or _Ta 2 _{O 5} component from 0 to 40.0 mass % And / or Nb ₂ O ₅ component 0 to 35.0 mass% and / or Bi ₂ O ₃ component 0 to 45.0 mass% and / or Gd ₂ O ₃ component 0 to 40.0 mass% and / or Y ₂ O ₃ component 0 to 30.0 mass% and / or Yb ₂ O ₃ component 0 to 35.0 mass% and / or Sb ₂ O ₃ component 0 to 1.0 mass% and / or CeO ₂ component 0 to 1 .0 mass%

Moreover, the composition by the mass% display of each component contained in 4th optical glass takes the following values in an oxide conversion composition in general.
TeO ₂ component 40.0-75.0 mass% and WO ₃ component 1.0-55.0 mass%,
And Li ₂ O component 0 to 7.0 mass% and / or Na ₂ O component 0 to 12.0 mass% and / or K ₂ O component 0 to 18.0 mass% and / or Cs ₂ O component 0 to 40 0.0% by mass and / or ZnO component 0-25.0% by mass and / or La ₂ O ₃ component 0-40.0% by mass and / or B ₂ O ₃ component 0-30.0% by mass and / or MgO Component 0-8.0 mass% and / or CaO component 0-8.0 mass% and / or SrO component 0-15.0 mass% and / or BaO component 0-20.0 mass% and / or SiO ₂ component 0 to 13.0% by mass and / or GeO ₂ component 0 to 20.0% by mass and / or P ₂ O ₅ component 0 to 30.0% by mass and / or Al ₂ O ₃ component 0 to 20.0% by mass and / or _Ga 2 _{O 3} component from 0 to 25.0% by weight and / or In O ₃ component from 0 to 25.0% by weight and / or ZrO ₂ component from 0 to 15.0% by weight and / or _Ta 2 _{O 5} component from 0 to 40.0% by weight and / or TiO ₂ component from 0 to 15.0 mass % And / or Nb ₂ O ₅ component 0 to 35.0 mass% and / or Bi ₂ O ₃ component 0 to 45.0 mass% and / or Gd ₂ O ₃ component 0 to 40.0 mass% and / or Y ₂ O ₃ component 0 to 30.0 mass% and / or Yb ₂ O ₃ component 0 to 35.0 mass% and / or Sb ₂ O ₃ component 0 to 1.0 mass% and / or CeO ₂ component 0 to 1 .0 mass%

[Production method]
The optical glass of the present invention is produced, for example, as follows. That is, the above raw materials are uniformly mixed so that each component is within a predetermined content range, and the prepared mixture is put into a quartz crucible or an alumina crucible and roughly melted, and then a gold crucible, a platinum crucible, a platinum alloy It is prepared by putting in a crucible or iridium crucible, melting in a temperature range of 500 to 1200 ° C., stirring and homogenizing, blowing out bubbles, etc., then 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 predetermined high refractive index (n _d ) and high dispersion. In particular, the refractive index of the optical glass of the present invention _{(n d)} is preferably 1.70, more preferably 1.75, and most preferably with a lower limit on 1.80, preferably 2.20, more preferably 2. 18, most preferably 2.15. Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 30, more preferably 25, still more preferably 24, and most preferably 23. As a result, the degree of freedom in optical design is widened, so that a large amount of light refraction can be obtained even if the device is made thinner. The lower limit of the Abbe number (ν _d ) of the optical glass of the present invention is not particularly limited, but the Abbe number (ν _d ) of the glass obtained by the present invention is generally 10 or more, specifically 12 or more, more specifically. In many cases, it is 14 or more.

In the optical glass of the present invention, the partial dispersion ratio (θg, F) is preferably close to the normal line. More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is (−0.00160 × ν _d +0...) In the range of ν _d ≦ 25 with respect to the Abbe number (ν _d ). 63460) ≦ (θg, F) ≦ (−0.00563 × ν _d +0.75873) and in the range of ν _d > 25, (−0.00250 × ν _d +0.65710) ≦ (θg , F) ≦ (−0.00340 × ν _d +0.70300). Thereby, the position of the plot of the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) is brought close to the normal line shown in FIGS. Therefore, it can be inferred that chromatic aberration due to an optical element using this optical glass is reduced. Here, the partial dispersion ratio (θg, F) of the optical glass at ν _d ≦ 25 is preferably (−0.00160 × ν _d +0.63460), more preferably (−0.00160 × ν _d +0.63660). ), Most preferably (−0.00160 × ν _d +0.63860) as the lower limit, preferably (−0.00563 × ν _d +0.75873), more preferably (−0.00563 × ν _d +0.755673). ), More preferably (−0.00563 × ν _d +0.75473), and most preferably (−0.00563 × ν _d +0.75273). The partial dispersion ratio (θg, F) of the optical glass at ν _d > 25 is preferably (−0.00250 × ν _d +0.65710), more preferably (−0.00250 × ν _d +0.65910). Most preferably, (−0.00250 × ν _d +0.66110) is the lower limit, preferably (−0.00340 × ν _d +0.70300), more preferably (−0.00340 × ν _d +0.70100). The upper limit is more preferably (−0.00340 × ν _d +0.69900), and most preferably (−0.00340 × ν _d +0.69700).

Note that the normal line (Normal Line, see FIG. 1) in the present application is based on the orthogonal coordinate system in which the partial dispersion ratio (θg, F) is used on the vertical axis and the Abbe number (ν _d ) is used on the horizontal axis. Is a straight line representing a linear relationship found between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) for general glass including low-dispersion glass. Here, the normal line in FIG. 1 is defined by a straight line connecting two points plotting the partial dispersion ratio and Abbe number of NSL7 and PBM2 (both manufactured by OHARA) (PBM2 Abbe number (ν _d ) is 36.3, the partial dispersion ratio (θg, F) is 0.5828, the Abbe number (ν _d ) of NSL7 is 60.5, and the partial dispersion ratio (θg, F) is 0.5436. Is).

As in the optical glass of the present invention, particularly in the region where the Abbe number (ν _d ) is small, the partial dispersion ratio (θg, F) of the general glass is higher than that of the normal line, and the general glass portion. The relationship between the dispersion ratio (θg, F) and the Abbe number (ν _d ) is represented by a curve (upward curve in FIG. 2). However, since it is difficult to approximate this curve, the present invention uses a straight line having a different slope from ν _d = 25 as a partial dispersion ratio (θg, F) lower than that of general glass. Expressed.

Further, the optical glass of the present invention needs to be less colored. 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 500 nm or less, more preferably 485 nm or less, and most preferably. Is 470 nm or less. In the optical glass of the present invention, a wavelength (λ ₅ ) showing a spectral transmittance of 5% in a sample having a thickness of 10 mm is 450 nm or less, more preferably 435 nm or less, and most preferably 420 nm or less. Thereby, since the absorption edge of the glass is positioned in the vicinity of the ultraviolet region, the transparency of the glass in the visible region is enhanced, so that this optical glass can be used as a material for an optical element such as a lens.

  Moreover, it is preferable that the optical glass of this invention has a glass transition point (Tg) of 200 degreeC or more and 550 degrees C or less. When the glass transition point (Tg) is 200 ° C. or higher, particularly when polishing is performed on glass, adverse effects due to frictional heat generated by the polishing can be reduced. On the other hand, when the glass transition point (Tg) is 550 ° C. or lower, softening occurs at a lower temperature. Therefore, by enabling press molding at a low temperature, it is possible to reduce the oxidation of the mold used for press molding and extend the life of the mold. Accordingly, the glass transition point (Tg) of the optical glass of the present invention is preferably 200 ° C., more preferably 220 ° C., and most preferably 250 ° C., preferably 550 ° C., more preferably 530 ° C., most preferably The upper limit is 500 ° C.

  The optical glass of the present invention preferably has a predetermined degree of wear. In particular, the abrasion degree (Aa) in the measurement method according to “Measurement method of abrasion degree of JOGIS10-1994 optical glass” of optical glass preferably has an abrasion degree of 100 or more and 1000 or less. By setting the degree of wear to 100 or more, the glass is easily polished when polishing is performed. Therefore, it is possible to facilitate the polishing process by increasing the processing efficiency of the polishing process. On the other hand, by setting the degree of wear to 1000 or less, unnecessary wear and scratches of the optical glass are reduced, so that it is possible to facilitate the polishing process while facilitating the handling of the optical glass in the polishing process. Therefore, the abrasion degree of the optical glass of the present invention is preferably 100, more preferably 120, most preferably 150, and the upper limit is preferably 1000, more preferably 950, and most preferably 900.

[Preforms and optical elements]
The optical glass of the present invention is useful for various optical elements and optical designs. Among them, in particular, it is used for applications of optical elements that transmit visible light into glass, such as lenses, prisms, and mirrors. Is preferred. As a result, chromatic aberration due to the optical element using this optical glass is reduced. Therefore, when used in an optical device such as a camera or a projector, the optical element and the optical system are miniaturized, and high definition and high accuracy are achieved. Imaging characteristics can be realized. Here, in order to produce an optical element made of the optical glass of the present invention, it is possible to omit cutting and polishing, so that glass in a molten state is dropped from an outlet of an outflow pipe of platinum or the like to form a spherical shape. It is preferable to prepare a precision press-molding preform such as, and perform precision press-molding on the precision press-molding preform.

Examples of the present invention (No. A1 to No. A25, No. B1 to No. B22, No. C1 to No. C10, No. D1 to No. D7), Reference Examples (No. A1, No. B1) and Comparative examples (No.A1~No.A2, No.B1~No.B2, No.C1~No.C2, No.D1~No.D3 ) composition, and the refractive index of these glasses _{(n d} ), Abbe number (ν _d ), partial dispersion ratio (θg, F), glass transition point (Tg), abrasion degree (Aa), and wavelengths at which the spectral transmittances are 70% and 5% (λ ₇₀ , λ ₅ ). Tables 1 to 10 show the results and the results of the presence or absence of devitrification in the formed glass. In addition, Abbe number (ν _d ) and partial dispersion ratio (θg) in the glasses of Examples (No. A1 to No. A25), Reference Examples (No. A1), and Comparative Examples (No. A1 to No. A2). , F) is shown in FIG. Moreover, the Abbe number ((nu) _d ) and partial dispersion ratio ((theta) g) in the glass of an Example (No.B1-No.B22), a reference example (No.B1), and a comparative example (No.B1-No.B2). , F) is shown in FIG. FIG. 4 shows the relationship between the Abbe number (ν _d ) and the partial dispersion ratio (θg, F) in the glasses of the examples (No. C1 to No. C10) and the comparative examples (No. C1 to No. C2). Show. FIG. 5 shows the relationship between the Abbe number (ν _d ) and the partial dispersion ratio (θg, F) in the glasses of Examples (No. D1 to No. D7) and Comparative Examples (No. D1 to No. D3). Show. The following examples are merely for illustrative purposes, and are not limited to these examples.

  The optical glass of the example of the present invention, and the glass of the reference example and the comparative example are all equivalent oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric acids as raw materials of the respective components. A high-purity raw material used for ordinary optical glass such as a compound is selected, weighed so as to have a composition ratio of each example shown in Table 1 to Table 10, and mixed uniformly, and then a quartz crucible or platinum The glass was put into a crucible, melted in a temperature range of 500 to 1200 ° C. in an electric furnace according to the melting difficulty of the glass composition, homogenized with stirring, cast into a mold, and slowly cooled to produce glass. At this time, among Examples (No. D1 to No. D7) and Comparative Examples (No. D1 to No. D3), Examples and Comparative Examples in which the glass was not devitrified are shown in Table 3. "None" in the "Presence / absence" column. On the other hand, about the Example and comparative example in which the glass devitrified, it described as "devitrification" in the "presence / absence of devitrification" column of Table 3.

Here, regarding the refractive index (n _d ), Abbe number (ν _d ) and partial dispersion ratio (θg, F) of the optical glass of the example of the present invention and the glass of the reference example and the comparative example, Nippon Optical Glass Industry Measured based on the association standard JOGIS01-2003. Then, with respect to the obtained Abbe number (ν _d ) and partial dispersion ratio (θg, F), the slope a in the relational expression (θg, F) = − a × ν _d + b is 0.00160 and 0.00563. The intercept b at that time was determined. The glass used in this measurement was annealed under a slow cooling furnace with a slow cooling rate of −25 ° C./hr.

  Moreover, the glass transition point (Tg) of the optical glass of the Example of this invention, and the glass of a reference example and a comparative example was measured using the differential-thermal-measurement apparatus (STAC409CD by a Netchgeretebau company). The sample particle size at this time was set to 425-600 micrometers, and the temperature increase rate was 10 degrees C / min.

Moreover, the abrasion degree of the optical glass of the Example of this invention, and the glass of a reference example and a comparative example was measured according to "the measuring method of the abrasion degree of JOGIS10-1994 optical glass". That is, a sample of a glass square plate having a size of 30 × 30 × 10 mm is placed on a fixed position of 80 mm from the center of a flat plate made of cast iron (250 mmφ) horizontally rotating 60 times per minute, and a load of 9.8 N (1 kgf) is applied. While applying vertically, a polishing solution obtained by adding 10 g of lapping material (alumina A abrasive grains) of # 800 (average particle size 20 μm) to 20 mL of water is uniformly fed and rubbed for 5 minutes to measure the sample mass before and after the lapping. Then, the wear mass was obtained. Similarly, the wear mass of the standard sample specified by the Japan Optical Glass Industry Association was obtained,
Abrasion degree = {(wear mass / specific gravity of sample) / (wear mass / specific gravity of standard sample)} × 100
Calculated by

Moreover, the transmittance of the optical glass of the example of the present invention, and the glass of the reference example and the comparative example was measured according to Japan Optical Glass Industry Association Standard JOGIS02. In the present invention, the presence / absence and degree of coloration of the glass were determined by measuring the transmittance of the glass. Specifically, a face parallel polished product having a thickness of 10 ± 0.1 mm is measured in accordance with JISZ8722 to measure the spectral transmittance with respect to light having a wavelength of 200 to 800 nm, and λ ₇₀ (wavelength at 70% transmittance) and λ ₅ (wavelength at 5% transmittance) was determined.

As shown in Tables 1 to 10, all of the optical glasses of the examples of the present invention had an Abbe number (ν _d ) of 30 or less, more specifically 25 or less. In particular, in the optical glasses of Examples (No. B1 to No. B22, No. D1 to No. D7) corresponding to the second and fourth optical glasses, the Abbe number (ν _d ) was 24 or less. In particular, the optical glass of Examples (No. C1 to No. C10) corresponding to the third optical glass had an Abbe number (ν _d ) of 23 or less. For this reason, it became clear that the optical glass of the Example of this invention has a desired low Abbe number ((nu) _d ).

The optical glasses of the examples of the present invention all have a refractive index (n _d ) of 1.70 or more, more specifically 1.91 or more, and this refractive index (n _d ) is 2.20 or less. More specifically, it was 2.11 or less, and was within the desired range. In particular, the optical glass of Examples (No. A1 to No. A25) corresponding to the first optical glass had a refractive index (n _d ) of 2.07 or less. The optical glass of Embodiment (No.C1~No.C10) corresponding to the third optical glass, refractive index _{(n d)} was 2.05 or less. The optical glass of Embodiment (No.D1~No.D7) corresponding to the fourth optical glass, refractive index _{(n d)} was 2.08 or less.

The optical glasses of the examples of the present invention all have an Abbe number (ν _d ) of 25 or less, and as shown in FIGS. 2 to 5, the partial dispersion ratio (θg, F) has an Abbe number ( In relation to ν _d ), all were (−0.00160 × ν _d +0.63460) or more, and more specifically, (−0.00160 × ν _d +0.65000) or more. Further, the partial dispersion ratio (θg, F) is (−0.00563 × ν _d +0.75873) or less, more specifically, (−0.00563 × ν _d +0.75200) or less, and a desired range. It was in. For this reason, it became clear that the optical glass of the example of the present invention has a partial dispersion ratio (θg, F) close to the normal line and small chromatic aberration.

  Further, the optical glass of the example of the present invention had a glass transition point (Tg) of 550 ° C. or lower, more specifically 500 ° C. or lower. In particular, the optical glass of Examples (No. A1 to No. A25) had a glass transition point (Tg) of 460 ° C. or lower. Moreover, as for the optical glass of an Example (No.B1-No.B22, No.C1-No.C10), the glass transition point (Tg) was 450 degrees C or less. Further, the optical glass of the example of the present invention had a glass transition point (Tg) of 200 ° C. or higher, more specifically 250 ° C. or higher. In particular, the optical glass of Examples (No. B1 to No. B22, No. C1 to No. C10, No. D1 to No. D7) had a glass transition point (Tg) of 270 ° C. or higher. For this reason, since the optical glass of the Example of this invention has a low glass transition point (Tg), it became clear that it was easy to soften at low temperature.

  On the other hand, the optical glass of the comparative example (No. A1 to No. A2) of the present invention had a glass transition point (Tg) higher than 460 ° C. For this reason, it became clear that the optical glass of the Example (No.A1-No.A25) of this invention is easy to soften at low temperature compared with the glass of a comparative example (No.A1-No.A2). .

  Moreover, the glass of the comparative example (No. B2, No. C2) had a glass transition point (Tg) higher than 450 ° C. For this reason, the optical glass of the Example (No.B1-No.B22, No.C1-No.C10) of this invention is softened at low temperature compared with the glass of a comparative example (No.B2, No.C2). It became clear that it was easy to do.

  Moreover, the glass of the comparative example (No. D1) had a glass transition point (Tg) higher than 500 ° C. For this reason, it became clear that the optical glass of the Example (No.D1-No.D7) of this invention tends to soften at low temperature compared with the glass of a comparative example (No.D1).

Further, in all of the optical glasses of the examples of the present invention, λ ₇₀ (wavelength at 70% transmittance) was 500 nm or less, more specifically, 484 nm or less. In particular, in the optical glass of Examples (No. A1 to No. A25), λ ₇₀ was 450 nm or less. Further, in the optical glass of Examples (No. B1 to No. B22), λ ₇₀ was 474 nm or less. Moreover, (lambda) ₇₀ was 475 nm or less in all the optical glass of an Example (No.D1-No.D7). On the other hand, in the optical glass of the example of the present invention, λ ₅ (wavelength at a transmittance of 5%) was 450 nm or less, more specifically, 424 nm or less. In particular, in the optical glass of Examples (No. A1 to No. A25) of the present invention, λ ₅ was 400 nm or less. Moreover, as for the optical glass of an Example (No.B1-No.B22), (lambda) ₅ was 410 nm or less in any case. Moreover, as for the optical glass of the Example (No.D1-No.D7), all (lambda) ₅ was 411 nm or less. For this reason, it became clear that the optical glass of the Example of this invention was difficult to color, and its transparency with respect to visible light was high.

On the other hand, in the glass of the comparative example (No. A2), λ ₇₀ was larger than 450 nm. For this reason, it becomes clear that the optical glass of the Example (No.A1-No.A25) of this invention is hard to color compared with the glass of a comparative example (No.A2), and its transparency with respect to visible light is high. It was.

In the glass of the comparative example (No. D1), λ ₇₀ was larger than 475 nm. The glass of Comparative Example (No.D3), the transmittance of light can not be measured is poor lambda _70. For this reason, the optical glass of the Example (No.D1-No.D7) of this invention is hard to be colored compared with the glass of a comparative example (No.D1 and No.D3), and has high transparency with respect to visible light. Became clear.

  Further, the optical glasses of the examples of the present invention all had an abrasion degree of 1000 or less, and this abrasion degree was 100 or more, more specifically 200 or more. In particular, the fourth optical glass had an abrasion degree of 600 or more. On the other hand, the glass of the reference examples (No. A1, No. B1) and the comparative examples (No. B1, No. C1, No. D2) had a degree of wear larger than 1000. For this reason, the optical glass of the Example of this invention has a low abrasion degree compared with the glass of a reference example (No. A1) and a comparative example (No. B1, No. C1, No. D2), and the time of glass polishing It became clear that the workability was good.

Therefore, the optical glass of the example of the present invention is easily softened at a low temperature while having a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range, and has high transparency in the visible range, In addition, it has become clear that polishing is easy during glass polishing.

  Furthermore, using the optical glass of the example of the present invention, after forming a preform for polishing, grinding and polishing were performed to form lenses and prisms. In addition, a precision press-molding preform was formed using the optical glass of the example of the present invention, and the precision press-molding preform was precision press-molded into a lens and a prism. In either case, it could be processed 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 (20)

40.0% or more and less than 75.0% of TeO ₂ component, Bi ₂ O ₃ component, Nb ₂ O ₅ component, WO ₃ component, and TiO ₂ component in mol% with respect to the total amount of glass in oxide conversion composition An optical glass containing 1.0% or more and 40.0% or less of one or more components selected from the group consisting of and having an Abbe number (ν _d ) of 30 or less. _2. The optical glass according to claim 1, wherein the Bi ₂ O ₃ component is contained in an amount of 1.0% to 40.0% in terms of mol% with respect to the total amount of the glass having an oxide equivalent composition. The optical glass according to claim 1, comprising 1.0% or more and 25.0% or less of the Nb ₂ O ₅ component in mol% with respect to the total amount of the glass having an oxide conversion composition. The optical glass according to claim 1, comprising 1.0% or more and 30.0% or less of a TiO ₂ component in mol% with respect to the total amount of the glass having an oxide conversion composition. 2. The optical glass according to claim 1, comprising 1.0% to 40.0% of WO ₃ component in mol% with respect to the total amount of the glass having an oxide equivalent composition. The optical glass according to any one of claims 1 to 5, wherein the wavelength (λ ₇₀ ) at which the spectral transmittance shows 70% is 500 nm or less. Li ₂ O component 0-25.0% and / or Na ₂ O component 0-30.0% and / or K ₂ O component 0-30. 0% and / or Cs ₂ O component from 0 to 30.0%
The optical glass according to claim 1, further comprising: The optical glass according to claim 7, wherein a substance amount sum Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O is 30.0% or less with respect to the total glass substance amount of an oxide conversion composition. The glass the total amount of substance of the oxide composition in terms, _Ga 2 _{O 3} component from 0 to 20.0% and / or ZnO component from 0 to 30.0% and / or _La 2 _{O 3} component 0-25 by mol%. 0% and / or B ₂ O ₃ component 0-40.0%
The optical glass according to claim 1, further comprising:   The optical glass according to any one of claims 1 to 9, which contains substantially no lead compound. MgO component 0 to 15.0% and / or CaO component 0 to 20.0% and / or SrO component 0 to 20.0% and / or BaO in mol% with respect to the total amount of glass in oxide conversion composition Ingredient 0-20.0%
The optical glass according to claim 1, further comprising:   The optical glass according to claim 11, wherein a substance amount sum MgO + CaO + SrO + BaO is 20.0% or less with respect to a total glass substance amount of an oxide conversion composition. SiO ₂ component 0 to 30.0% and / or GeO ₂ component 0 to 30.0% and / or P ₂ O ₅ component 0 to 30.0 in mol% with respect to the total amount of glass in the oxide conversion composition % And / or Al ₂ O ₃ component 0 to 30.0% and / or In ₂ O ₃ component 0 to 15.0% and / or ZrO ₂ component 0 to 20.0% and / or Ta ₂ O ₅ component 0 20.0% and / or _Gd 2 _{O 3} component from 0 to 25.0% and / or _Y 2 _{O 3} component from 0 to 20.0% and / or _Yb 2 _{O 3} component from 0 to 20.0% and / or Sb ₂ O ₃ component 0-1.0% and / or CeO ₂ component 0-1.0%
The optical glass according to claim 1, further comprising: The optical glass according to claim 1, which has a refractive index (n _d ) of 1.70 or more and 2.20 or less.   The optical glass according to any one of claims 1 to 14, which has a glass transition point (Tg) of 200 ° C or higher and 550 ° C or lower.   The optical glass according to any one of claims 1 to 15, which has an abrasion degree (Aa) of 100 or more and 1000 or less. (−0.00160 × ν _d +0.63460) ≦ (θg, F) ≦ (−0...) In the range where the partial dispersion ratio (θg, F) is Abbe number (ν _d ) and ν _d ≦ 25. 00563 × ν _d +0.757873) and (−0.00250 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.00340 × ν _d +0) in the range of ν _d > 25. .70300), the optical glass according to any one of claims 1 to 16.   An optical element made of the optical glass according to claim 1.   A precision press-molding preform comprising the optical glass according to claim 1.   An optical element obtained by precision press-molding the precision press-molding preform according to claim 19.

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