JP7612003B2 - Optical Glass and Optical Elements - Google Patents

Description

The present invention relates to optical glass, and in particular to optical glass with a low thermal expansion coefficient and a high refractive index suitable for precision pressing, as well as glass preforms and optical elements made from the same.

Optical glass is a glass material used to manufacture lenses, prisms, mirrors, windows, etc. in optical instruments and mechanical systems. At present, the main method of manufacturing optical glass as optical elements is precision press molding (including direct pressing and secondary pressing). Lenses manufactured using precision pressing technology do not need to be ground and polished, which can reduce raw material consumption, reduce human and material costs, and reduce environmental pollution. Therefore, this technology can be used to mass-produce optical elements at low cost. Precision pressing is the press molding of a glass preform with a high-precision mold having a predetermined product shape at a certain temperature and pressure to obtain a glass product with the shape and optical function of the finished product. Precision pressing technology can be used to manufacture a variety of optical glass products, such as spherical lenses, aspherical lenses, prisms, and diffraction gratings.

When performing precision press molding, it is necessary to press mold a glass preform at high temperatures (usually above the glass transition temperature of 20 to 60°C) in order to transfer the highly precise mold surface to the glass product. In this case, the molding mold is subjected to high temperature and pressure shocks, and even if there is a protective gas, the surface of the mold is easily oxidized or eroded. In order to extend the life of the mold and suppress damage to the mold due to the high temperature environment, it is necessary to lower the press temperature. Therefore, the transition temperature (T _g ) of the glass material used in press molding must be as low as possible.

With the progress of science and technology, the renewal of optoelectronic information products is continuing, the demand for optical glass is getting bigger and bigger, and the performance requirements for optical glass are becoming more stringent. For example, if the thermal expansion coefficient of optical glass is too large, it is easy to burst during the thermal processing process, which reduces the yield rate of glass elements and also deteriorates the thermal shock resistance of optical glass.
For the same radius of curvature, the higher the refractive index of a glass, the larger the imaging field that can be obtained, and as optical devices become increasingly smaller, the demand for high refractive index glass tends to increase.

The technical problem that this invention aims to solve is to provide a high refractive index optical glass that has a low thermal expansion coefficient and is suitable for precision pressing.

The technical solutions adopted in the present invention to solve the technical problems are as follows:
(1) Optical glass containing the following components by weight: _{B2O3 :} 8-20%, _La2O3 : 21-40%, _Gd2O3 : _6-20 %, _ZrO2 : 1-10%, ZnO: 7-20%, _WO3 : 8-20%, _TiO2 : more than 0 and less than 10%, ( _{WO3 +ZnO)/(La2O3 + TiO2 + ZrO2} ) is 0.3-1.5.
(2) The optical glass according to (1), further comprising the following components in weight percent: _SiO2 : 0-9%, and/or _Y2O3 : 0-10%, and/or _Yb2O3 : 0-10%, and/or _Nb2O5 : 0-8 _% , and/or _Rn2O : 0-10%, and/or _RO : 0-10%, and/or _Al2O3 : 0-5%, and _/ or _Ta2O5 : 0-5%, and/or fining agent: 0-1%, wherein _Rn2O is one or more of _Li2O , _Na2O , and _K2O , RO is one or more of MgO _, CaO, SrO, _and BaO, and the fining _agent is one or more of _Sb2O3 , _SnO2 , SnO, and _CeO2 .
(3) An optical glass containing the necessary components _B2O3 , _La2O3 , _Gd2O3 , _ZrO2 , ZnO _{, WO3} , and _TiO2 , expressed in weight percent: ( _WO3 +ZnO)/( _La2O3 + _TiO2 + _ZrO2 ) is 0.3 to _1.5 , the refractive index _nd of the optical glass is 1.85 to 1.91, the Abbe number _vd is 32 to 38.5, and the thermal expansion coefficient α100 _/300°C is ₁₀₀ × ^10-7 /K or _less .
(4) The optical glass according to (3), containing the following components by weight: B ₂ O ₃ : 8-20%, and/or La ₂ O ₃ : 21-40%, and/or Gd ₂ O ₃ : 6-20%, and/or ZrO ₂ : 1-10%, and/or ZnO: 7-20%, and/or WO ₃ : 8-20%, and/or TiO ₂ : more than 0 and 10% or less, and/or SiO ₂ : 0-9%, and/or Y ₂ O ₃ : 0-10%, and/or Yb ₂ O ₃ : 0-10%, and/or Nb ₂ O ₅ : 0-8%, and/or Rn ₂ O: 0-10%, and/or RO: 0-10%, and/or Al ₂ O ₃ : 0-5%, and/or Ta ₂ O ₅ : 0-5%, and/or fining agent: 0-1%, wherein Rn ₂ O is one or more of Li ₂ O, Na ₂ O, K ₂ O, RO is one or more of MgO, CaO, SrO, BaO, and the fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , SnO, CeO ₂ .
(5) An optical glass consisting of the following components by weight: B ₂ O ₃ : 8-20%, La ₂ O ₃ : 21-40%, Gd ₂ O ₃ : 6-20%, ZrO ₂ : 1-10%, ZnO: 7-20%, WO ₃ : 8-20%, TiO ₂ : 0-10%, SiO ₂ : 0-9%, Y ₂ O ₃ : 0-10%, Yb ₂ O ₃ : 0-10%, Nb ₂ O ₅ : 0-8%, Rn ₂ O: 0-10%, RO: 0-10%, Al ₂ O ₃ : 0-5%, Ta ₂ O ₅ : 0-5%, fining agent: 0-1%, and the ratio of (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.3-1.5, _Rn2O is one or more of _Li2O , _Na2O , _K2O , RO is one or more of MgO, CaO, _SrO , BaO, and the fining agent is one or more of _Sb2O3 , _SnO2 , SnO, _CeO2 .
(6) An optical glass according to any one of (1) to (5), comprising the following components in weight percent and satisfying one or more of the following nine conditions:
1) _Nb2O5 / _{Y2O3 is 0.1-2.5} ;
2) _{Y2O3 / WO3} is 0.05-1.0;
3) _{Y2O3 /} TiO2 _is 0.2-3.5;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.05 to 1.5;
5) ZnO/La ₂ O ₃ is 0.2-0.8;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.2 to 0.8;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.5 to 1.0;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.05 to 5.0;
9) _Nb2O5 / _WO3 is _0.03-0.7 .
(7) An optical glass according to any one of (1) to (5), comprising the following components by weight: B ₂ O ₃ : 10-18%, and/or La ₂ O ₃ : 25-38%, and/or Gd ₂ O ₃ : 8-18%, and/or ZrO ₂ : 1-8%, and/or ZnO: 8-18%, and/or WO ₃ : 10-18%, and/or TiO ₂ : 0.5-7%, and/or SiO ₂ : 0.5-9%, and/or Y ₂ O ₃ : more than 0 to 6%, and/or Yb ₂ O ₃ : 0-5%, and/or Nb ₂ O ₅ : 0.5-6%, and/or Rn ₂ O: 0-5%, and/or RO: 0-5%, and/or Al ₂ O ₃ : 0-2%, and/or Ta. _2O5 : 0-2%, and/or fining agent: 0-0.5 _% , where _Rn2O is one or more of _Li2O , _Na2O , _K2O , RO is one or more of MgO, CaO, SrO, BaO, and the fining agent is one or more of _Sb2O3 , _{SnO2 ,} SnO, _CeO2 .
(8) An optical glass according to any one of (1) to (5), comprising the following components in weight percent and satisfying one or more of the following nine conditions:
1) _Nb2O5 / _{Y2O3 is 0.25-1.5} ;
2) _{Y2O3 / WO3} is 0.1-0.6;
3) _{Y2O3 /} TiO2 _is 0.5-2.0;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.1 to 1.0;
5) ZnO/La ₂ O ₃ is 0.3-0.7;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.25 to 0.65;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.6 to 0.9;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.1 to 2.0;
9) _Nb2O5 / _WO3 is _0.05-0.5 .
(9) An optical glass according to any one of (1) to (5), comprising the _following components in weight _percent : _B2O3 : 11-17%, and/or _La2O3 : 28-35%, and/or _Gd2O3 : 9.5-16%, preferably _Gd2O3 : _11-16 %, and/or _ZrO2 : 2-6%, and/or ZnO: 10-16%, preferably ZnO _: 11-16%, and/or _WO3 : 12-17%, and/or _TiO2 : 1-5%, and/or _SiO2 : 1-8%, preferably _SiO2 : _2-6 %, and/or _Y2O3 : 1-5%, and/or _Yb2O3 : _{0-2%, and/or Nb2O5 :} 1-5%, and/or _Rn2O5 : 1-5% _. O: 0.5-3%, and/or RO: 0-2%, and/or Al ₂ O ₃ : 0-1%, and/or Ta ₂ O ₅ : 0-1%, and/or fining agent: 0-0.1%, where Rn ₂ O is one or more of Li ₂ O, Na ₂ O, K ₂ O, RO is one or more of MgO, CaO, SrO, BaO, and the fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , SnO, CeO ₂ .
(10) An optical glass according to any one of (1) to (5), comprising the following components in weight percent and satisfying one or more of the following nine conditions:
1) Nb ₂ O ₅ /Y ₂ O ₃ is 0.3-0.8;
2) _{Y2O3 / WO3} is 0.1-0.4;
3) _{Y2O3 /} TiO2 _is 0.8-1.3;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.15 to 0.5;
5) ZnO/La ₂ O ₃ is 0.35-0.65;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.35 to 0.55;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.7 to 0.85;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.2 to 1.0;
9) _Nb2O5 / _WO3 is _0.06-0.4 .
(11) An optical glass according to any one of (1) to (5), comprising the following components in weight percent and satisfying one or more of the following five conditions:
1) Nb ₂ O ₅ /Y ₂ O ₃ is 0.4-0.7;
2) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.2-0.4;
3) ZnO/La ₂ O ₃ is 0.4-0.55;
4) 5 × Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.3 to 0.8;
5) _{Nb2O5 / WO3} is 0.08-0.3.
(12) An optical glass according to any one of (1) to (5) containing the following components in weight percent: _Li2O : 0-6%, preferably more than 0 and 4% or less _Li2O , more preferably _0.1-3 %, even more preferably 0.5-2% _Li2O , and/or _Na2O : 0-5%, preferably 0-3% _Na2O , more preferably 0-2% _Na2O , and/or _K2O : 0-5%, preferably 0-3% _K2O , more preferably 0-2% _K2O .
(13) An optical glass according to any one of (1) to (5), comprising, as its components, no _Ta2O5 , and/or no _GeO2 , and/or no _{F ,} and/or no _Al2O3 , and/or no RO _, and/or no _P2O5 , and/or _{no Bi2O3} .
(14) An optical glass according to any one of (1) to (5), wherein the optical glass has a refractive index n _d of 1.85 to 1.91, preferably 1.86 to 1.90, more preferably 1.88 to 1.90, and an Abbe number v _d of 32 to 38.5, preferably 33 to 37.5, more preferably 34 to 37.
(15) An optical glass according to any one of (1) to (5), wherein the acid resistance stability D _A of the optical glass is class 3 or more, preferably class 2 or more, more preferably class 1, and/or the water resistance stability D _W of the optical glass is class 2 or more, preferably class 1, and/or the density ρ is 5.50 g/cm ³ or less, preferably 5.40 g/cm ³ or less, more preferably 5.30 g/cm ³ or less, even more preferably 5.20 g/cm ³ or less, and/or λ ₇₀ is 410 nm or less, preferably λ 70 is 405 nm or less, more preferably λ ₇₀ is 400 nm or less, even more preferably λ ₇₀ is 395 nm or less, and/or λ ₅ is 375 _nm or less, preferably λ ₅ is 370 nm or less, more preferably λ ₅ is 365 nm or less, even more preferably λ ₅ is 360 nm or less.
(16) An optical glass according to any one of (1) to (5), wherein the optical glass has a thermal expansion coefficient α _100/300°C of 100×10 ^-7 /K or less, preferably 95×10 ^-7 /K or less, more preferably 90×10 ^-7 /K or less, and/or a transition temperature T _g of 620°C or less, preferably 610°C or less, more preferably 600°C or less, and/or an upper crystallization temperature of 1250°C or less, preferably 1200°C or less, more preferably 1180°C or less, even more preferably 1160°C or less.
(17) A glass preform produced from the optical glass according to any one of (1) to (16).
(18) An optical element produced from the optical glass according to any one of (1) to (16) or the glass preform according to (17).
(19) An optical instrument comprising the optical glass according to any one of (1) to (16) and/or the optical element according to (18).

The beneficial effects of the present invention are as follows: Due to the rational component design, the optical glass obtained by the present invention has a relatively low transition temperature and thermal expansion coefficient, and is suitable for precision press molding.

The following describes in detail the embodiments of the optical glass according to the present invention, but the present invention is not limited to the embodiments described below, and can be modified as appropriate within the scope of the object of the present invention. Furthermore, although some details are omitted, the gist of the present invention is not limited by the repetition of the description, and hereinafter the optical glass of the present invention may be referred to simply as glass.

[Optical glass]
The range of the components of the optical glass of the present invention will be described below. In this description, the content and total content of each component will be expressed in weight percent (wt%) unless otherwise specified. In other words, the content and total content of each component will be expressed in weight percent relative to the total weight of the glass material converted into an oxide composition. "Converted into an oxide composition" here refers to the case where the total weight of the oxide material when the oxide, complex salt, hydroxide, etc. used as the raw material of the optical glass composition of the present invention is decomposed and converted into an oxide during melting is taken as 100%.
Specifically, the numerical ranges described herein include upper and lower limits, and the terms "greater than or equal to" and "less than or equal to" include the endpoints, and all integers and fractions subsumed within the range, but are not limited to the specific values set forth when the range is limited. As used herein, "and/or" is inclusive, e.g., "A and/or B" means A only, B only, or both A and B.

<Required and optional ingredients>
In the present invention, _B2O3 is a network forming component, which improves the thermal stability of glass, improves the melting property of glass, and furthermore, can obtain glass without molten residue of glass raw material. In the present invention, 8 _% or more of _B2O3 is added to obtain the above-mentioned _effect , preferably the content of _B2O3 is ₁₀ % or more, more preferably the content of _B2O3 is 11 _% or more. However, if the content of _B2O3 is too high, the refractive index of glass decreases and the chemical stability deteriorates, so in the present invention, _the upper limit of the content of _B2O3 is 20%, preferably 18 _% , more preferably 17%.

_SiO2 plays a role in improving the chemical stability of glass, maintaining a viscosity suitable for forming molten glass, and reducing erosion of refractories, but if its content is too high, it becomes difficult to melt glass and is disadvantageous in lowering the glass transition temperature. Therefore, in the present invention, the content of _SiO2 is 9% or less, preferably 0.5-9%, more preferably 1-8%, and even more preferably 2-6%.

_La2O3 is _a component with a high refractive index and low light dispersion, which can be added to glass to increase the refractive index of glass, adjust the light dispersion, and reduce the high-temperature viscosity of glass. In the present invention, the content of _La2O3 is 21% or more, preferably _the content of _La2O3 is 25% or more, and more preferably the content of _La2O3 is 28% or more. On the other hand, by limiting the content of _La2O3 to 40% or less, _the stability of the glass _can be improved, the devitrification of _the glass can be reduced _, and the increase in the refractive index temperature coefficient and Abbe number can be suppressed from exceeding the design requirements. Therefore, the content of _La2O3 is 40% or less, preferably 38% or less, and more preferably 35% or less.

In the present invention, the addition of 6% or _more of _Gd2O3 improves the chemical stability of the optical _glass and adjusts the thermal expansion coefficient and refractive index of the glass. Therefore, the content of _Gd2O3 is preferably 8% or more, more preferably 9.5% or _{more, and even more preferably 11% or more. However, if the content of Gd2O3 exceeds} 20 _% , the devitrification resistance of the _glass deteriorates and the transition temperature _of the glass increases. Therefore, in the present invention, the content of _Gd2O3 is 20% or less, preferably 18 _% or less, and more preferably 16 _% or less.

In the present invention, it is preferable to further include 10% or less of Y ₂ O ₃ , and by adding Y ₂ O ₃ and La ₂ O ₃ at the same time, the melting property and devitrification resistance of the glass are improved while maintaining a high refractive index and low dispersion. However, if the content of Y ₂ O ₃ exceeds 10 _% , the stability and devitrification resistance of the glass are reduced, and the transition temperature is increased. Therefore, the content of Y ₂ O ₃ is 0 to 10%, preferably more than 0 and 6% or less. In some embodiments, the upper crystallization temperature and density of the glass can also be reduced by adding 1% or more of Y 2 O _3. Therefore, in the present invention, the content of Y ₂ O ₃ is more preferably 1 to 5%.

In some embodiments, when _Gd2O3 /( _La2O3 + _{Y2O3 )} is less than 0.2, the stability of the glass is reduced, _the temperature coefficient of refractive index is increased, and the glass is subject to temperature changes during use, whereas when _{Gd2O3 /} ( _La2O3 + _Y2O3 ) is more than 0.8, the wear resistance of the glass is poor and _the density is _increased . Therefore, it is preferred _{that Gd2O3/(La2O3+Y2O3) is 0.2-0.8, more preferably Gd2O3/(La2O3+Y2O3 ) is 0.25-0.65 , and even more preferably Gd2O3 / ( La2O3 + Y2O3 ) is 0.35-0.55 .}

_Yb2O3 is _also a component that imparts a high refractive index and low dispersion to the glass, and is an optional component in the present invention, and if its content exceeds 10%, the crystallization resistance and chemical stability of the _glass will decrease. Therefore, the content of _Yb2O3 is limited to 0-10%, preferably 0-5%, more preferably 0-2%, and even more preferably, _{no Yb2O3} is contained.

In the glass of the present invention, ZnO can adjust the refractive index and dispersion of the glass, lower the transition temperature, improve the crystallinity of the glass, and increase the stability of the glass. At the same time, ZnO can lower the high-temperature viscosity of the glass, make the glass melt at a relatively low temperature, and increase the transmittance of the glass. In the present invention, 7% or more of ZnO is added to obtain the above effect, and the ZnO content is preferably 8% or more, more preferably 10% or more, and even more preferably 11% or more. On the other hand, if the ZnO content exceeds 20%, the wear resistance of the glass is deteriorated, the molding becomes difficult, and the crystallinity of the glass is deteriorated. Therefore, the ZnO content is limited to 20% or less, preferably 18% or less, and more preferably 16% or less.

In some embodiments of the present invention, the ratio of the ZnO content to the _La2O3 content, ZnO/ _{La2O3 ,} is set to 0.2 or more to improve the chemical stability and the refractive index temperature _coefficient of the _glass , but if the ZnO/ _La2O3 exceeds 0.8, the crystallinity resistance of the _glass decreases. Therefore, the ZnO/ _La2O3 content is preferably _0.2-0.8 , more _preferably 0.3-0.7, even more preferably _{0.35-0.65 , and} even more preferably _0.4-0.55 .

_WO3 can increase the refractive index and mechanical strength of glass and lower the transition temperature of glass. In the present invention, 8% or more of _WO3 is added to obtain the above effects, and the lower limit of the _WO3 content is preferably 10%, more preferably 12%. If _{the WO3 content} exceeds 20%, the thermal stability of the glass decreases and the devitrification resistance decreases. Therefore, the upper limit of the _WO3 content is 20%, preferably 18%, more preferably 17%.

In some embodiments of the present invention, when _{Y2O3 / WO3} is less than 0.05, the density of the glass increases, which is _{disadvantageous} for reducing the weight of the glass, and when _Y2O3 / _WO3 exceeds 1.0, the thermal stability of the glass decreases. Therefore, _Y2O3 / _WO3 is preferably 0.05 to 1.0 _, more _preferably 0.1 to 0.6, _and even _{more preferably} 0.1 _to 0.4 _.

_Nb2O5 is a component with high refractive index and high light dispersion _{, which can increase the refractive index and devitrification resistance of glass and reduce the thermal expansion coefficient of glass. If the content of Nb2O5 is too} high, the thermal stability and chemical stability of glass will decrease, and the light transmittance will decrease. Therefore, in the present invention, the content of _Nb2O5 is 0-8 _% , preferably 0.5-6%, more preferably 1-5%.

The inventors have found through a large amount of experimental research that in some embodiments of the present invention, _Nb2O5 , _{WO3 and Gd2O3} generate a complex synergistic effect in the glass, and in particular, by controlling 5× _Nb2O5 /( _WO3 + _Gd2O3 ) within the range of _0.05-1.5 , the glass can obtain good hot pressing stability and at the same time have a suitable degree of wear. Preferably _, 5× _Nb2O5 /( _{WO3 + Gd2O3} ) is _0.1-1.0 . Furthermore _{, by controlling 5×Nb2O5/(WO3+Gd2O3 ) within the range} of 0.15-0.5, the thermal expansion coefficient of the glass can be further optimized _. Therefore, it is more preferable that 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.15 to 0.5, and further more preferable that 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.2 to 0.4.

In some embodiments of the present invention, making Nb ₂ O ₅ /Y ₂ O ₃ 0.1 or more helps improve the crystallization resistance of the glass, but if Nb _{2 O 5} /Y ₂ O ₃ exceeds 2.5, the glass becomes more prone to coloration _{and the light transmittance decreases. Therefore, Nb 2 O 5 /Y 2 O 3 is preferably 0.1} to 2.5, more preferably 0.25 to _{1.5 ,} even more _{preferably 0.3} to _0.8 , and _{even more} preferably _0.4 to _0.7 .

In some embodiments of the present invention, controlling _Nb2O5 / _WO3 within the range of 0.03-0.7 helps improve the thermal stability of the glass and optimize the chemical stability of _the glass, preferably _Nb2O5 / _WO3 is 0.05-0.5 _{, more preferably Nb2O5} / _WO3 is 0.06-0.4, and even more preferably _Nb2O5 / _WO3 is 0.08-0.3.

_TiO2 can increase the refractive index and dispersion of glass, and adding an appropriate amount of TiO2 can make glass more stable and reduce the viscosity of glass. However, if the _TiO2 content exceeds 10%, the crystallization tendency of glass increases, the transition temperature of glass increases, and the glass is easily colored during press molding. Therefore, in the present invention, the _TiO2 content is more than 0 and 10% or less, preferably the _TiO2 content is 0.5-7%, more preferably 1-5%.

In some embodiments of the present invention, the weather resistance of the glass can be improved by controlling the ratio _{Y2O3 / TiO2} of the _Y2O3 content to _{the TiO2} content to be 0.2 or more, but if _Y2O3 / _TiO2 exceeds 3.5 _, the degree of bubbles in the glass will deteriorate and the hardness will decrease. Therefore, _Y2O3 / _{TiO2 is preferably} 0.2-3.5 _{, more preferably} 0.5-2.0, _and even more preferably _0.8-1.3 .

_ZrO2 is a component with a high refractive index and low light dispersion, and adding it to glass can increase the refractive index of glass, adjust the dispersion, and improve the crystallinity of glass. In the present invention, the above effect is obtained by adding _ZrO2 at 1% or more, and the content of _ZrO2 is preferably 2% or more. If the content of _ZrO2 exceeds 10%, it becomes difficult to melt the glass, the melting temperature increases, and further, inclusions may occur inside the glass, causing a decrease in transmittance. Therefore, the content of _ZrO2 is 10% or less, preferably 8% or less, and more preferably 6% or less.

In some embodiments of the present invention, the ratio ( _WO3 +ZnO)/ _{(La2O3 + TiO2} +ZrO2 ₎ of the total content of _WO3 and ZnO _{( WO3} + _ZnO ) to the total content of _La2O3 , _TiO2 , and _ZrO2 ( _La2O3 + _TiO2 + _ZrO2 ) is controlled within the range of 0.3-1.5, so that the glass can have _a lower transition temperature and a lower thermal expansion coefficient at the same time. Therefore, in _the present invention, the ratio ( _WO3 +ZnO)/( _La2O3 + _TiO2 + _{ZrO2 )} is _{preferably 0.3-1.5} , and more preferably _0.5-1.0 . Furthermore, by controlling ( _WO3 +ZnO)/( _La2O3 + _TiO2 + _ZrO2 ) within the range of 0.6 to _0.9 , the degree of voids and wear of the glass can be optimized; therefore, more preferably, ( _WO3 +ZnO)/( _La2O3 + _TiO2 + _ZrO2 ) is _0.6 to 0.9, and even more preferably, ( _WO3 +ZnO)/( _La2O3 + _{TiO2 + ZrO2} ) is 0.7 to 0.85.

Rn ₂ O is an _alkali metal oxide, which is one or more of Li ₂ O, Na ₂ O, and K ₂ O, and can improve the melting property of glass and lower the glass transition temperature, but if the content of Rn ₂ O exceeds 10%, the devitrification resistance of the glass deteriorates and the refractive index drops significantly. Therefore, in the present invention, the content of Rn ₂ O is 0 to 10%, preferably 0 to 5%, and more preferably 0.5 to 3%.

Although Li ₂ O can lower the glass transition temperature, a high Li _{2 O content is detrimental to the acid resistance stability and thermal expansion coefficient of the glass. Therefore, in the present invention, the Li 2} O content is 6% or less, preferably more than 0 and 4% or less, more preferably 0.1 to 3%, and further preferably 0.5 to 2%.

In some embodiments of the present invention, the value of 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is controlled within the range of 0.05 to 5.0, thereby optimizing the viscosity of the glass and improving the degree of stripes and bubbles. Therefore, 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is preferably 0.1 to 2.0. Furthermore, the value of 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is controlled within the range of 0.2 to 1.0, thereby obviously improving the pressability of the glass and reducing the probability of clouding of the glass during press processing. Therefore, more preferably, 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.2 to 1.0, and even more preferably, 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.3 to 0.8.

Na ₂ O can improve the melting property of glass, enhance the melting effect of glass, and lower the transition temperature of glass, but if the content of Na ₂ O exceeds 5%, the chemical stability and weather resistance of glass will be reduced. Therefore, the content of Na ₂ O is 0-5%, preferably the content of Na ₂ O is 0-3%, and more preferably the content of Na ₂ O is 0-2%.

Although K ₂ O can improve the thermal stability and meltability of glass, if its content exceeds 5%, the devitrification resistance of the glass decreases and the chemical stability of the glass deteriorates. Therefore, in the present invention, the K ₂ O content is 5% or less, preferably the K ₂ O content is 0 to 3%, and more preferably the K 2 O content is 0 to 2%.

RO is an alkaline earth metal oxide, and RO is one or more of MgO, CaO, SrO, and BaO. Adding RO to glass can improve the meltability of glass and lower the glass transition temperature, but if the RO content exceeds 10%, the devitrification resistance of the glass decreases. Therefore, in the present invention, the RO content is 0-10%, preferably 0-5%, more preferably 0-2%, and even more preferably no RO.

Although _Al2O3 can improve the chemical stability of glass, if its content exceeds 5%, the melting property and transmittance of glass will be deteriorated. Therefore, in the present _{invention, the content of Al2O3 is} 0-5%, preferably _0-2 %, more preferably 0-1%, and further preferably no _{Al2O3 is} contained.

_Ta2O5 can increase the refractive index and improve the devitrification resistance of glass, but if its content is too high, the _chemical stability of glass decreases and it is difficult to control the optical constants within the desired range. On the other hand, _Ta2O5 is very expensive compared to other components, and from the practical and cost perspective _{, its usage amount should be reduced as much as possible. Therefore, in the present invention, the content of Ta2O5 is} limited to _{0-5 %} , preferably 0-2%, more preferably 0-1%, and further preferably does not contain _Ta2O5 .

In the present invention, the clarification effect of glass can be improved by adding one or more of Sb ₂ O ₃ , SnO, SnO ₂ and CeO ₂ components in an amount of 0-1% as a clarifier, and the content of the clarifier is preferably 0-0.5%, more preferably 0-0.1%. If the content of Sb ₂ O ₃ exceeds 1%, the clarification effect of glass tends to decrease, and at the same time, due to its strong oxidizing action, the corrosion of the platinum or platinum alloy container used for melting the glass and the deterioration of the molding die are accelerated. Therefore, in the present invention, the addition amount of Sb ₂ O ₃ is preferably 0-1%, more preferably 0-0.5%, and even more preferably 0-0.1%. SnO and SnO ₂ may be added as clarifiers, but if the content exceeds 1%, the glass tends to be colored more, and when the glass is heated and softened to be reshaped by press molding or the like, Sn becomes the starting point of nucleation, and devitrification tends to occur. Therefore, in the present invention, the content of _SnO2 is preferably 0-1%, more preferably 0-0.5%, even more preferably 0-0.1%, and even more preferably not included. The content of SnO is preferably 0-1%, more preferably 0-0.5%, even more preferably 0-0.1%, and even more preferably not included. The function and the ratio of the added amount of _CeO2 are the same as _those of SnO2, and the content is preferably 0-1%, more preferably 0-0.5%, even more preferably 0-0.1%, and even more preferably not included.

The glass of the present invention may contain an appropriate amount of F (fluorine), but in some embodiments, the addition of F reduces the stability of the glass, lowering its resistance to devitrification, and its volatility causes instability in the optical constants of the glass and worsens stripes, so it is preferable not to contain F.

Although a suitable amount of _GeO2 can be added to the glass of the present invention, in some embodiments, the addition of _GeO2 reduces the transmittance of the glass. In addition, _GeO2 is an expensive raw material, and the economical efficiency of the glass is also reduced, so it is preferable not to include _GeO2 .

An appropriate amount _{of P2O5} can be added to the glass of the present invention. However, in some embodiments, the addition _{of P2O5} to the glass makes it difficult to obtain the desired high refractive index and reduces the devitrification resistance of the glass, so it is preferable that _the glass does not contain _P2O5 .

The glass of the present invention may contain a suitable amount of _Bi2O3 . However, in some embodiments, it is preferred not to contain _Bi2O3 , since _the addition of _Bi2O3 reduces _the light transmittance of the glass, deteriorates the abrasion resistance and _chemical stability, and significantly increases the density.

<Ingredients that should not be included>
In the glass of the present invention, even when oxides of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained alone or in combination in small amounts, the glass is colored and specific wavelengths in the visible light region are absorbed, weakening the visible light transmission effect of the present invention. Therefore, it is preferable that optical glasses which require wavelength transmittance in the visible light region in particular not actually contain such oxides.

In recent years, there has been a trend to restrict the use of oxides of Th, Cd, Tl, Os, Be, and Se as harmful chemicals, and environmental protection efforts are required not only in the glass manufacturing process, but also in the processing process and disposal of the finished product. Therefore, when the impact on the environment is important, it is preferable not to contain them except for unavoidable contamination. This means that the optical glass does not actually contain substances that pollute the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and disposed of without taking special environmental measures.

In consideration of the environment, the optical glass of the present invention is preferably free of _As2O3 and _PbO . _As2O3 has the effect of removing bubbles and preventing coloring of the glass, but the addition of _As2O3 increases platinum erosion in the glass melting _furnace , especially the platinum melting furnace, _so that more platinum ions enter the glass, adversely affecting the service life of the platinum melting furnace.

The terms "not added," "not included," and "0%" used in this specification mean that the component was not intentionally added as a raw material for the glass of the present invention. However, impurities or components that are not intentionally added as raw materials and/or equipment for manufacturing the glass may be present in small or trace amounts in the final glass, and these are also covered by the patent of this invention.

The characteristics of the optical glass of the present invention will be described below.
<Refractive index and Abbe number>
The refractive index (n _d ) and Abbe number (ν _d ) of optical glasses are tested according to the method specified in GB/T 7962.1-2010.
In some embodiments, the lower limit of the refractive index (n _d ) of the optical glass of the present invention is 1.85, preferably 1.86, more preferably 1.88, and the upper limit of the refractive index (n _d ) is 1.91, preferably 1.90.
In some embodiments, the lower limit of the Abbe number (ν _d ) of the optical glass of the present invention is 32, preferably 33, more preferably 34, and the upper limit of the Abbe number (ν _d ) is 38.5, preferably 37.5, more preferably 37.

<Density>
The density (ρ) of optical glass is tested according to the method specified in GB/T7962.20-2010.
In some embodiments, the density (ρ) of the optical glass of the present invention is 5.50 g/cm ³ or less, preferably 5.40 g/cm ³ or less, more preferably 5.30 g/cm ³ or less, and even more preferably 5.20 g/cm ³ or less.

<Thermal expansion coefficient>
The thermal expansion coefficient (α _100/300℃ ) of optical glass is measured from 100 to 300℃ according to the method specified in GB/T7962.16-2010.
In some embodiments, the thermal expansion coefficient (α _{100/300° C.} ) of the optical glasses of the present invention is 100×10 ⁻⁷ /K or less, preferably 95×10 ⁻⁷ /K or less, and more preferably 90×10 ⁻⁷ /K or less.

<Transition Temperature>
The transition temperature (T _g ) of optical glasses is tested according to the method specified in GB/T7962.16-2010.
In some embodiments, the transition temperature (T _g ) of the optical glasses of the present invention is 620° C. or less, preferably 610° C. or less, and more preferably 600° C. or less.

<Coloring level>
The short-wave transmission spectrum characteristics of the glass of the present invention are expressed by the coloring degree (λ ₇₀ and λ ₅ ). λ ₇₀ refers to the wavelength corresponding to when the glass transmittance reaches 70%. λ ₇₀ is measured by measuring the spectral transmittance in the wavelength range from 280 nm to 700 nm using a glass with a thickness of 10±0.1 mm having two parallel relative flat surfaces that have been optically polished, and indicates the wavelength at which the transmittance reaches 70%. The spectral transmittance or transmittance is a quantity expressed as Iout/Iin when light with intensity I _in is incident perpendicularly to the surface of the glass, passes through the glass, and exits from one flat surface with intensity I _out , and also includes the transmittance of the surface reflection loss on the surface of the glass. The higher the refractive index of the glass, the greater the surface reflection loss. Therefore, in high refractive index glass, the smaller the value of λ ₇₀ , the less coloring the glass itself is and the higher the light transmittance is.

In some embodiments, the optical glass of the present invention has a λ ₇₀ of 410 nm or less, preferably a λ ₇₀ of 405 nm or less, more preferably a λ ₇₀ of 400 nm or less, and even more preferably a λ ₇₀ of 395 nm or less.
In some embodiments, the optical glass of the present invention has a λ ₅ of 375 nm or less, preferably a λ ₅ of 370 nm or less, more preferably a λ ₅ of 365 nm or less, and even more preferably a λ ₅ of 360 nm or less.

<Acid resistance>
The acid resistance (D _A ) of optical glass (powder method) is tested according to the method specified in GB/T 17129.
In some embodiments, the acid resistance stability (D _A ) of the optical glass of the present invention is class 3 or higher, preferably class 2 or higher, and more preferably class 1.

<Water resistance stability>
The water stability (D _W ) of optical glass (powder method) is tested according to the method specified in GB/T 17129.
In some embodiments, the water resistance stability (D _W ) of the optical glass of the present invention is Class 2 or higher, and preferably Class 1.

<Upper crystallization temperature limit>
The temperature gradient furnace method is used to measure the crystallinity of glass. A glass sample of 180 x 10 x 10 mm is prepared, the sides are polished, and the sample is heated to 1300°C in a temperature gradient (10°C/cm) furnace and kept at that temperature for 4 hours. It is then removed and allowed to cool naturally to room temperature. The crystal state of the glass is observed under a microscope, and the maximum temperature at which crystals appear is the upper limit of the crystallization temperature of the glass.
In some embodiments, the upper crystallization temperature of the optical glass of the present invention is 1250° C. or less, preferably 1200° C. or less, more preferably 1180° C. or less, and even more preferably 1160° C. or less.

[Method of manufacturing optical glass]
The method for producing the optical glass of the present invention is as follows: the glass of the present invention is produced by conventional raw materials, including but not limited to carbonates, nitrates, sulfates, hydroxides, and oxides, and is prepared by conventional processes and blended in a conventional manner. The prepared furnace materials are then put into a melting furnace (such as platinum crucibles or aluminum oxide crucibles) at 1200 to 1400°C to melt. Then, the glass is clarified, stirred, and homogenized to obtain a homogeneous molten glass without bubbles or unmelted materials, and the molten glass is cast into a mold and annealed. Those skilled in the art can appropriately select the raw materials, manufacturing methods, and process parameters according to the actual needs.

[Glass preform and optical element]
A glass preform can be produced from the produced optical glass using press molding means such as polishing, hot press molding, precision press molding, etc. That is, an optical preform can be produced from the optical glass by mechanical processing such as grinding or polishing, or a blank for press molding can be produced from the optical glass, and this blank can be hot press molded and then polished to produce an optical preform, or the blank produced by polishing can be precision press molded to produce an optical preform.
The manufacturing method of the optical preform is not limited to the above. As described above, the optical glass of the present invention is useful for various optical elements and optical designs. In particular, it is preferable to form a blank from the optical glass of the present invention, and use this blank to carry out hot press molding, precision press molding, etc. to manufacture optical elements such as lenses and prisms.

The optical preform and optical element of the present invention are both formed from the optical glass of the present invention. The optical preform of the present invention has the excellent properties of optical glass, and the optical element of the present invention has the excellent properties of optical glass, making it possible to provide optical elements such as various lenses and prisms with high optical value.

Examples of lenses include various lenses with spherical or aspherical lens surfaces, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses.

[Optical equipment]
Optical elements formed from the optical glass of the present invention can be used to fabricate optical instruments such as photographic devices, imaging devices, display devices, and monitoring devices.

<Optical Glass Examples>
In order to further clearly illustrate the technical solutions of the present invention, the following non-limiting examples are provided.
In this example, the above-mentioned method for producing optical glass was used to obtain optical glasses having the compositions shown in Tables 1 and 2. The properties of each glass were measured by the test methods described in the present invention, and the results are shown in Tables 1 and 2.

<Glass Preform Example>
The glasses obtained in the optical glass Examples 1 to 20 are subjected to polishing, hot press molding, precision press molding, or other press molding means to produce various lenses, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses, as well as preforms such as prisms.

Optical Element Examples
The preform obtained in the above optical preform example is tempered to fine-tune the refractive index while reducing distortion within the glass so that the optical properties, such as the refractive index, reach the desired values.
Each preform is then ground and polished to produce various lenses and prisms, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. An anti-reflective coating can also be applied to the surfaces of the obtained optical elements.

Optical Instrument Examples
The optical elements manufactured according to the above optical element embodiments can be used in imaging devices, sensors, microscopes, medical technology, digital projection, communication, optical communication technology/information transmission, optics/illumination in the automotive field, photolithography technology, excimer lasers, wafers, computer chips and integrated circuits and electronic devices containing such circuits and chips, or imaging equipment and devices in the automotive field by forming optical parts or components using one or more optical elements according to optical design.

Claims (22)

An optical glass containing the following components by weight: B ₂ O ₃ : 8-20%, La ₂ O ₃ : 21-40%, Gd ₂ O ₃ : 6-20%, ZrO ₂ : 1-10%, ZnO: 7-20%, WO ₃ : 8-20%, TiO ₂ : over 0 and up to 10%, Y ₂ O ₃ : over 0 and up to 10%, Nb ₂ O ₅ : 0.5-8%, (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.3-1.5, and Nb ₂ O ₅ /Y ₂ O ₃ is 0.1-2.5. The optical glass of claim 1 further comprising, in weight percentages: _SiO2 : 0-9%, and/or _Yb2O3 : 0-10%, and/or _Rn2O : 0-10%, and/or _RO : 0-10%, and/or _Al2O3 : 0-5%, and/or _Ta2O5 : 0-5%, and/or fining agent: 0-1%, wherein _Rn2O is one or more of _Li2O , _Na2O , _K2O , _RO is one or more of MgO _, CaO, SrO, BaO, and the fining agent is one or more of _Sb2O3 , _SnO2 , _SnO , _CeO2 . _{An optical glass} containing _B2O3 , _La2O3 , _Gd2O3 , _ZrO2 , ZnO, _WO3 , _TiO2 , _{Y2O3 ,} and _Nb2O5 as necessary components: B2O3 : 8-20%, La2O3: 21-40%, Gd2O3 : _{6-20 %} , ZrO2 _: 1-10%, _{ZnO :} 7-20%, WO3 _: 8-20%, TiO2 _{: over 0} and 10% or less, _{Y2O3 :} over 0 and 10% or less, _Nb2O5 : _0.5-8 % _,
In terms of weight percentage, ( _WO3 +ZnO)/( _La2O3 + _TiO2 + _ZrO2 ) is 0.3-1.5, _Nb2O5 / _Y2O3 is 0.1-2.5, the refractive index _nd of the optical glass is 1.85-1.91, _the Abbe _{number νd is} 32-38.5, and the thermal expansion coefficient α100 _/300°C is 100 _× ^10-7 /K or less. 4. The optical glass according to claim 3, comprising the following components in weight percent : SiO2 _: 0-9%, and/or _Yb2O3 : 0-10%, and/or _Rn2O : 0-10%, and/or _RO : _0-10 %, and/or _Al2O3 : 0-5%, and/or _Ta2O5 : _0-5 %, and/or fining agent: 0-1%,
The _Rn2O is one or more of _Li2O , _Na2O , _K2O , the RO is one or more of MgO, CaO, SrO, _BaO , and the fining agent is one or more of _Sb2O3 , _SnO2 , SnO, _CeO2 . An optical glass consisting of the following components by weight: B ₂ O ₃ : 8-20%, La ₂ O ₃ : 21-40%, Gd ₂ O ₃ : 6-20%, ZrO ₂ : 1-10%, ZnO: 7-20%, WO ₃ : 8-20%, TiO ₂ : 0-10%, SiO ₂ : 0-9%, Y ₂ O ₃ : 0-10 %, Yb ₂ O ₃ : 0-10% , Nb ₂ O ₅ : 0.5-8% , Rn ₂ O: 0-10%, RO: 0-10%, Al ₂ O ₃ : 0-5%, Ta ₂ O ₅ : 0-5% , fining agent : 0-1%, and the ratio of (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.3-1.5, _Nb2O5 / _Y2O3 is 0.1-2.5, the _Rn2O is one or more of _Li2O , _Na2O , _K2O , the RO is one or more of _MgO , CaO, SrO, BaO, and the fining agent is one or more of _{Sb2O3 , SnO2} , _SnO , _CeO2 . The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent and satisfying one or more of the following eight conditions:
2) _{Y2O3 / WO3} is 0.05-1.0;
3) _{Y2O3 /} TiO2 _is 0.2-3.5;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.05 to 1.5;
5) ZnO/La ₂ O ₃ is 0.2-0.8;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.2 to 0.8;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.5 to 1.0;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.05 to 5.0;
9) _Nb2O5 / _WO3 is _0.03-0.7 . 6. The optical glass according to claim 1, comprising the following components in % by weight _{: B2O3} : 10-18%, and/or _La2O3 : 25-38%, and/or _Gd2O3 : 8-18%, and/or _ZrO2 : 1-8%, and/or _ZnO : 8-18%, and/or _WO3 : 10-18%, and/or _TiO2 : 0.5-7%, and/or _SiO2 : 0.5-9%, and/or _Y2O3 : >0 to 6%, and/or _Yb2O3 : 0-5%, and/or _Nb2O5 : 0.5-6%, and/or _Rn2O : 0-5%, and _/ or _{RO :} 0-5%, and/ _{or Al2O3} : 0-2%, and _/ or _{Ta2O5 .} : 0-2%, and/or fining agent: 0-0.5%,
The _Rn2O is one or more of _Li2O , _Na2O , _K2O , the RO is one or more of MgO, CaO, SrO, _BaO , and the fining agent is one or more of _Sb2O3 , _SnO2 , SnO, _CeO2 . The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent and satisfying one or more of the following nine conditions:
1) _Nb2O5 / _{Y2O3 is 0.25-1.5} ;
2) _{Y2O3 / WO3} is 0.1-0.6;
3) _{Y2O3 /} TiO2 _is 0.5-2.0;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.1 to 1.0;
5) ZnO/La ₂ O ₃ is 0.3-0.7;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.25 to 0.65;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.6 to 0.9;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.1 to 2.0;
9) _Nb2O5 / _WO3 is _0.05-0.5 . 6. The optical glass according to claim 1, comprising the following components in % by _weight : _B2O3 : 11-17%, and/or _La2O3 : 28-35%, and _/ or _Gd2O3 : 9.5-16%, and/or _ZrO2 : 2-6%, and/or _ZnO : 10-16%, and/or _WO3 : 12-17%, and/or _TiO2 : 1-5%, and/or _SiO2 : 1-8%, and/or _Y2O3 : 1-5%, and/or _Yb2O3 : 0-2%, and/or _Nb2O5 : 1-5%, and/or _Rn2O : _0.5-3 % _, and/or _RO : 0-2%, and/or _{Al2O3 :} 0-1%, and/or _{Ta2O5 .} : 0-1%, and/or fining agent: 0-0.1%,
The _Rn2O is one or more of _Li2O , _Na2O , _K2O , the RO is one or more of MgO, CaO, SrO, _BaO , and the fining agent is one or more of _Sb2O3 , _SnO2 , SnO, _CeO2 . The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent:
Gd ₂ O ₃ : 11-16%, and/or ZnO: 11-16%, and/or SiO ₂ : 2-6%. The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent and satisfying one or more of the following nine conditions:
1) Nb ₂ O ₅ /Y ₂ O ₃ is 0.3-0.8;
2) _{Y2O3 / WO3} is 0.1-0.4;
3) _{Y2O3 /} TiO2 _is 0.8-1.3;
4) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.15-0.5;
5) ZnO/La ₂ O ₃ is 0.35-0.65;
6) Gd ₂ O ₃ /(La ₂ O ₃ +Y ₂ O ₃ ) is 0.35 to 0.55;
7) (WO ₃ +ZnO)/(La ₂ O ₃ +TiO ₂ +ZrO ₂ ) is 0.7 to 0.85;
8) 5×Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.2 to 1.0;
9) _Nb2O5 / _WO3 is _0.06-0.4 . The optical glass according to any one of claims 1 to 5, which comprises the following components in weight percent and which satisfies one or more of the following five conditions:
1) Nb ₂ O ₅ /Y ₂ O ₃ is 0.4-0.7;
2) 5 × Nb ₂ O ₅ / (WO ₃ + Gd ₂ O ₃ ) is 0.2-0.4;
3) ZnO/La ₂ O ₃ is 0.4-0.55;
4) 5 × Li ₂ O/(TiO ₂ +SiO ₂ ) is 0.3 to 0.8;
5) _{Nb2O5 / WO3} is 0.08-0.3. The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent:
Li ₂ O: 0-6%, and/or Na ₂ O: 0-5%, and/or K ₂ O: 0-5%. The optical glass according to any one of claims 1 to 5, comprising the following components in weight percent:
Li ₂ O: 0.1-3%, and/or Na ₂ O: 0-2%, and/or K ₂ O: 0-2%. The optical glass according to any one of claims 1 to 5:
The components are: _{Ta2O5 -} free, and/or _GeO2 -free, and/or F-free, and/or _Al2O3 -free, and/ _or RO-free, and _/ or _P2O5 -free, and/or _{Bi2O3 -} free. The optical glass according to any one of claims 1 to 5:
The optical glass has a refractive index n _d of 1.85 to 1.91 and an Abbe number v _d of 32 to 38.5. The optical glass according to any one of claims 1 to 5:
The optical glass has a refractive index n _d of 1.86-1.90 and an Abbe number v _d of 34-37. The optical glass according to any one of claims 1 to 5:
The optical glass has an acid resistance stability D _A of class 2 or higher, and/or a water resistance stability D _W of class 2 or higher, and/or a density ρ of 5.50 g/cm ³ or lower, and/or a λ ₇₀ of 410 nm or lower, and/or a λ ₅ of 375 nm or lower, and/or a thermal expansion coefficient α _100/300°C of 100×10 ^-7 /K or lower, and/or a transition temperature T _g of 620°C or lower, and/or an upper crystallization temperature of 1250°C or lower. The optical glass according to any one of claims 1 to 5:
The optical glass has an acid resistance stability D _A of Class 1, and/or a water resistance stability D _W of Class 1, and/or a density ρ of 5.20 g/cm ³ or less, and/or a λ ₇₀ of 400 nm or less, and/or a λ ₅ of 365 nm or less, and/or a thermal expansion coefficient α _{100/300° C.} of 90×10 ^-7 /K or less, and/or a transition temperature T _g of 600° C. or less, and/or an upper crystallization temperature of 1160° C. or less. A glass preform manufactured from the optical glass according to any one of claims 1 to 19. An optical element manufactured from the optical glass according to any one of claims 1 to 19 or the glass preform according to claim 20. An optical device comprising the optical glass according to any one of claims 1 to 19 and/or the optical element according to claim 21.