JP7642018B2 - Optical Glass and Optical Elements - Google Patents

Description

The present invention relates to optical glass, and in particular to optical glass that is suitable for precision press processing and has excellent intrinsic quality, as well as glass preforms, optical elements, and optical devices manufactured from the optical glass.

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 process of press-molding 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.

With the rapid development of technologies such as smart driving and face recognition, the demand for optical aspherical lenses with a refractive index of 1.57-1.61 and an Abbe number in the range of 58-64 has rapidly increased. In addition, the inherent quality of optical glass is extremely important for its application, and excellent optical glass products are required to have a low bubble content or even to be bubble-free. Optical glass aspherical precision pressing technology can produce aspherical lenses at low cost, so the development of optical glass with a refractive index of 1.57-1.61, an Abbe number of 58-64, excellent inherent quality, and suitable for precision pressing is of great significance to the development of the optoelectronics industry.

The technical problem that this invention aims to solve is to provide optical glass that has excellent intrinsic quality and is suitable for precision press processing.

The technical solutions adopted by the present invention to solve the technical problems are as follows:

(1) An optical glass containing the following in weight percent: _SiO2 : 17-47%, _B2O3 : 20-50%, _Al2O3 : 0.5-8%, ZnO: 0.5-8%, _{RO : 6-45%, La2O3 + Y2O3 + Gd2O3: 0.5-15%, Li2O + Na2O + K2O : less than 15 % ,} ZnO/ _{( La2O3 + Y2O3 + Gd2O3 ) is 0.2-4.0 , and the} RO is the total content of BaO, SrO, CaO, and MgO.

(2) The optical glass according to (1), further comprising the following components in weight percent: P ₂ O ₅ : 0-3%, and/or ZrO ₂ : 0-3%, and/or a fining agent: 0-1%, and the fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , Na ₂ SiF ₆ , and K ₂ SiF ₆ .

(3) An optical glass containing _SiO2 , _B2O3 , _Al2O3 , _ZnO and alkaline earth _metal oxides, and further containing the following components by weight: 0.5-15% _La2O3 + _Y2O3 + _Gd2O3 , ZnO/( _{La2O3 + Y2O3} + _Gd2O3 ) is _0.2-4.0 , and the refractive index n _d of _{the optical} glass is 1.57-1.61, the Abbe number v _d is 58-64, _and the bubble level is Class A or _higher .

(4) The optical glass according to (3), containing the following components by weight: _SiO2 : 17-47%, and/or _B2O3 : 20-50%, and/or _Al2O3 : 0.5-8%, and/or _ZnO : _0.5-8 %, and/or RO: 6-45%, and/or _Li2O + _Na2O + _K2O : less than 15%, and/ _{or P2O5 :} 0-3%, and/or _ZrO2 : 0-3%, and/or fining agent: 0-1%, wherein the RO is the total content of BaO, SrO, CaO, and _MgO , and the fining agent is one or more _{of Sb2O3} , _SnO2 , _Na2SiF6 , and _{K2SiF6 .}

(5) An optical glass according to any one of (1) to (4), comprising the following components in weight percent and satisfying one or more of the following seven conditions:
1) B ₂ O ₃ /SiO ₂ is 0.55 to 2.3, preferably B ₂ O ₃ /SiO ₂ is 0.7 to 2.0, more preferably B ₂ O ₃ /SiO ₂ is 0.8 to 1.8, and even more preferably B ₂ O ₃ /SiO ₂ is 1.0 to 1.5;
2) (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.4, preferably (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.3, more preferably (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.25, and even more preferably (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.2;
3) BaO/RO is 0.4 to 0.95, preferably BaO/RO is 0.5 to 0.95, more preferably BaO/RO is 0.65 to 0.95, and even more preferably BaO/RO is 0.7 to 0.9;
4) RO/B ₂ O ₃ is 0.3 to 1.3, preferably RO/B ₂ O ₃ is 0.4 to 1.2, more preferably RO/B ₂ O ₃ is 0.5 to 1.0, and even more preferably RO/B ₂ O ₃ is 0.6 to 0.9;
5) (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.05 to 0.9, preferably (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.6, more preferably (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.4, and even more preferably (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.35;
6) ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is 0.3 to 3.0, preferably ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is 0.5 to 2.0, more preferably ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is 0.6 to 1.6;
7) (Na ₂ O+K ₂ O)/Li ₂ O is 0.1 to 1.5, preferably (Na ₂ O+K ₂ O)/Li ₂ O is 0.1 to 1.0, more preferably (Na ₂ O+K ₂ O)/Li ₂ O is 0.2 to 0.8, and even more preferably (Na ₂ O+K ₂ O)/Li ₂ O is 0.25 to 0.65;
The RO is the total content of BaO, SrO, CaO and MgO.

(6) The optical glass according to any one of (1) to (4), comprising the following components in weight percent: SiO ₂ : 22 to 40%, preferably SiO ₂ : 25 to 38%, and/or B ₂ O ₃ : 22 to 38%, preferably B ₂ O ₃ : 23 to 35%, and/or Al ₂ O ₃ : 1 to 7%, preferably Al ₂ O ₃ : 1 to 6.5%, and/or ZnO: 1 to 7%, preferably ZnO: 1 to 6%, and/or RO: 8 to 40%, preferably RO: 10 to 35%, and/or La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ : 1 to 12%, preferably La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ : 2 to 10%, and/or Li _2O +Na ₂ O+K ₂ O: less than 12%, preferably Li ₂ O+Na ₂ O+K ₂ O: less than 10%, more preferably Li ₂ O+Na ₂ O+K ₂ O: less than 8%, and/or P ₂ O ₅ : 0-1.5%, and/or ZrO ₂ : 0-2%, preferably ZrO ₂ : 0-1%, and/or fining agent: 0-0.8%, preferably fining agent: 0-0.5%, wherein RO is the total content of BaO, SrO, CaO, and MgO, and the fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , Na ₂ SiF ₆ , and K ₂ SiF ₆ .

(7) An optical glass according to any one of (1) to (4), comprising the following components in weight percent: BaO: 5 to 30%, preferably BaO: 6 to 28%, more preferably BaO: 8 to 25%, and/or SrO: 0.5 to 15%, preferably SrO: 0.5 to 13%, more preferably SrO: 0.5 to 12%, and/or CaO: 0 to 10%, preferably CaO: 0 to 9%, more preferably CaO: 0 to 8%, and/or MgO: 0 to 5%, preferably MgO: 0 to 3%, and/or La ₂ O ₃ : 0.5 to 10%, preferably La ₂ O ₃ : 1 to 9%, more preferably La ₂ O ₃ : 1.5 to 8%, and/or Y ₂ O ₃ : 0 to 8%, preferably Y ₂ O ₃ : 0 to 5%, more preferably Y ₂ O ₃ : 0-3%, and/or Gd ₂ O ₃ : 0-5%, preferably Gd ₂ O ₃ : 0-3%, and/or Li ₂ O: 1-7%, preferably Li ₂ O: 2-6.5%, more preferably Li ₂ O: 3-5.5%, and/or Na ₂ O: 0.1-7%, preferably Na ₂ O: 0.1-6%, more preferably Na ₂ O: 0.5-5%, and/or K ₂ O: 0-5%, preferably K ₂ O: 0-2%, more preferably K ₂ O: 0-1%.

(8) An optical glass according to any one of (1) to (4), further comprising the following components in weight percent: F: 0-10%, preferably F: 0-5%, more preferably F: 0-3%.

(9) An optical glass according to any one of (1) to (4), the components of which are free of P ₂ O ₅ and/or free of MgO and/or free of Gd ₂ O ₃ and/or free of F.

(10) An optical glass according to any one of (1) to (4), having a refractive index n _d of 1.57 to 1.61, preferably 1.575 to 1.605, more preferably 1.575 to 1.60, and an Abbe number v _d of 58 to 64, preferably 58.5 to 63.5, more preferably 59 to 63.

(11) The _optical glass according to any one of (1) to (4), having an _Nd consistency within ±50×10 ⁻⁵ , preferably within ±30×10 ⁻⁵ , and/or _{a Ts} stability within ±5° C., preferably within ±3° C.

(12) A yield point temperature _Ts is 610°C or lower, preferably 600°C or lower, more preferably 595°C or lower, and/or a thermal expansion coefficient α20-300 _°C is 85× ^10-7 or lower, preferably 83× ^10-7 or lower, more preferably 81× ^10-7 or lower, and/or an acid resistance stability D _A is Class 5 or higher, preferably Class 4 or higher, and/or a water resistance stability D _W is Class 4 or higher, preferably Class 3 or higher, and/or a bubble degree is Class A or higher, preferably Class _A0 or higher, more preferably Class A The optical glass according to any one of (1) to (4), which has a grade of ₀₀ or higher, and/or a stripe grade of C or higher, preferably grade of B or higher, and/or a high temperature viscosity at 1200°C of 25 dPaS or lower, preferably 23 dPaS or lower, more preferably 20 dPaS or lower, and/or a high temperature viscosity at 900°C of 35 dPaS or higher, preferably 40 dPaS or higher, more preferably 50 dPaS or higher, and/or a crystallization upper limit temperature of 1100°C or lower, preferably 1050°C or lower, more preferably 1020°C or ^{lower, and/or a thermoplastic crystallization resistance stability of grade B or higher, preferably grade A, and/or a refractive index temperature coefficient dn/dt of 6.0×10 -6 /} °C or lower, preferably 5.5×10 ^-6 /°C or lower, more preferably 5.0×10 -6 /°C or lower.

(13) A glass preform manufactured from the optical glass described in any one of (1) to (12).

(14) An optical element manufactured from the optical glass described in any one of (1) to (12) or the glass preform described in (13).

(15) An optical device comprising the optical glass according to any one of (1) to (12) and/or the optical element according to (14).

The beneficial effects of the present invention are as follows: Through rational component design, the optical glass obtained by the present invention has the desired refractive index and Abbe number, as well as a low yield temperature and excellent inherent quality.

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. Hereinafter, the optical glass of the present invention may be simply referred to 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. That is, 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 "greater than or equal to" and "less than or equal to" include the endpoints, and all integers and fractions within the range, but are not limited to the specific values described when the range is limited. References to "and/or" herein are inclusive, e.g., "A and/or B" means A only, B only, or both A and B.

<Required and optional ingredients>
SiO ₂ is a necessary component of the glass of the present invention, and if its content exceeds 47%, the refractive index and Abbe number of the glass will be lower than the design requirements. On the other hand, the melting temperature of the glass will rise rapidly, and the melting difficulty will increase, especially when a large amount of alkali metal oxide components are included, the corrosion ability of the glass to the melting furnace will rise rapidly, reducing the service life of the furnace body, and at the same time, the difficulty of controlling the _Nd consistency and _Ts stability will increase, and there is a risk of increasing the content of bubbles and inclusions in the glass, which may not meet the quality requirements. If the content of SiO ₂ is less than 17%, the chemical stability of the glass will rapidly decrease, the water resistance will not meet the design requirements, and the surface will be prone to mist-like defects when polishing the aspherical preform, and the yield rate of the aspherical preform will decrease. Therefore, the content of SiO ₂ is 17-47%, preferably 22-40%, more preferably 25-38%.

_B2O3 can improve the refractive index and Abbe number of glass and reduce _{the Ts} of glass. By adding an appropriate amount _{of B2O3} , when _SiO2 is simultaneously used to form a glass network, the strength of the glass network _can be further improved, and the chemical stability of glass, especially the acid resistance of glass, can be further improved. When the content of _B2O3 exceeds 50%, _B2O3 will loosen _the glass network and the water resistance will rapidly decrease. During production, _B2O3 is usually introduced _in the form of boric acid, and after a large amount of research by the inventors, it was found that a high content of boric acid will accelerate the erosion of the melting furnace during dissolution, while in dissolution, excessive boric acid will intensify volatilization, causing the glass components to change significantly, and the _Nd consistency and _Ts stability will rapidly decrease. In addition, boric acid is decomposed into _H2O during dissolution, and _H2O usually exists in the high-temperature glass liquid in the form of bubbles, and excess boric acid will bring great challenges to the next clarification process. If the content of B ₂ O ₃ is less than 20%, the Abbe number and T _s of the glass are difficult to meet the design requirements, so the content of B ₂ O ₃ is 20-50%, preferably 22-38%, more preferably 23-35%.

After extensive research, the inventors have found that in the glass system of the present invention, when the value of B ₂ O ₃ /SiO ₂ is greater than 2.3, the time required for the glass liquid to cool from liquid to solid at the forming temperature is greatly increased, and the surface is cooled and hardened first during forming, but the temperature of the middle part is still high, and the difference in time between the surface and the middle part is very large, making it easy to form stripes inside the glass, which is particularly serious for thick products. The glass system of the present invention generally has a forming temperature of 900-1000°C, and if its viscosity is less than 35 dPas within this temperature range, the glass is prone to the above problem, and the stripes do not meet the requirements. Therefore, the value of B ₂ O ₃ /SiO ₂ is preferably less than 2.3, more preferably less than 2.0, even more preferably less than 1.8, and even more preferably less than 1.5. If the value of _{B 2} O ₃ /SiO ₂ is less than 0.55, the T _s of the glass rises rapidly, making it difficult to achieve the design goal, and at the same time, the high temperature viscosity of the glass at 1200°C makes it difficult to achieve the design goal. In some embodiments, if the viscosity of the glass at high temperature of 1200° C. is too large, it is very difficult to eliminate bubbles inside the glass, and the temperature needs to be increased to effectively eliminate the bubbles, but the corrosion ability of the glass liquid to the furnace body at 1200° C. or higher increases rapidly. Therefore, the value of B ₂ O ₃ /SiO ₂ is preferably 0.55 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and even more preferably 1.0 or more.

A suitable amount of Al ₂ O ₃ can reinforce the glass network, improve the chemical stability of the glass, and increase the high-temperature viscosity of the glass. However, in the glass of the present invention, if more than 8% Al ₂ O ₃ is added, the network structure in the glass will rapidly loosen, and in particular when the B ₂ O ₃ content is relatively high, corrosion points will easily occur on the element surface during the polishing process of manufacturing an aspheric preform, and the yield rate will rapidly decrease. In addition, since Al ₂ O ₃ has a large dispersion, if it is contained in excess, the Abbe number may be lower than the design requirement. If the content is less than 0.5%, the corrosiveness to the furnace body will rapidly increase during the melting process of the glass raw material, and at the same time, the chemical stability, especially the water resistance, will rapidly decrease. Therefore, the content of Al ₂ O ₃ is limited to 0.5-8%, preferably 1-7%, and more preferably 1-6.5%.

Adding _ZrO2 to glass can reduce the corrosion ability of glass liquid to furnace body, extend the service life of melting furnace, and improve the crystallization resistance of glass. If the content of _ZrO2 exceeds 3%, insoluble matter is likely to appear in glass, the inherent quality of glass is deteriorated, and the crystallization resistance of glass is rapidly deteriorated. Therefore, the content of _ZrO2 is 3% or less, preferably 2% or less, more preferably 1% or less.

In some embodiments, the use _{of ZrO2} and _Al2O3 in combination has a significant effect on _the structure state of _B2O3 , especially when the content of alkaline earth metal oxides is high, which affects the thermoplastic crystallization resistance stability of glass. When the value of ( _{ZrO2 + Al2O3} )/ _B2O3 is less than 0.05, the improvement of thermoplastic crystallization resistance stability is not significant, and when the value of ( _ZrO2 + _Al2O3 )/ _B2O3 is _greater than 0.4, _the thermoplastic crystallization resistance stability _{of glass} is rather rapidly reduced. Therefore, the value of ( _{ZrO2 + Al2O3} )/ _B2O3 is preferably 0.05-0.4, more preferably 0.05-0.3, even more preferably 0.05-0.25, and even more preferably 0.05-0.2.

A suitable amount of ZnO can significantly improve the refractive index and chemical stability of glass, and reduce the thermal expansion coefficient and Ts of _glass . If the content is less than 0.5%, the above effects are not significant. If the content of ZnO exceeds 8%, especially if the _B2O3 content is relatively high, the Abbe number of glass _is difficult to meet the design requirements, and the bubble elimination ability of glass is reduced. Therefore, the content of ZnO is 0.5-8%, preferably 1-7%, more preferably 1-6%.

BaO, SrO, CaO, and MgO are alkaline earth metal oxides. An appropriate amount of alkaline earth metal oxides can increase the refractive index of glass and strengthen the crystallization resistance of glass. However, if the total content RO exceeds 45%, the crystallization resistance of glass will rapidly decrease and the glass may even emulsify. Therefore, the total content RO of BaO, SrO, CaO, and MgO is 6-45%, preferably 8-40%, and more preferably 10-35%.

After a large amount of experimental research, the inventors found that the order of the elements in terms of the ability to improve the crystallization resistance of glass is BaO>SrO>CaO>MgO. Therefore, the glass of the present invention preferably uses BaO to improve the refractive index and crystallization resistance of glass, but if the content exceeds 30%, the water resistance of glass will rapidly decrease, and bubbles are easily accumulated during the melting of glass and are difficult to eliminate, which will seriously affect the stability of the production process, and will further affect the _Nd consistency and _Ts stability of glass. If the content of BaO is less than 5%, the refractive index of glass will be difficult to meet the design requirements, and the crystallization resistance of glass will rapidly decrease. Therefore, the content of BaO is 5-30%, preferably 6-28%, more preferably 8-25%.

SrO forms a synergistic effect with BaO in glass, which more effectively improves the crystallization resistance stability of glass and is also advantageous in increasing the refractive index of glass. However, if the SrO content is less than 0.5%, the above-mentioned effect is not significant, and if the SrO content exceeds 15%, the synergistic effect of crystallization resistance weakens and the cost of glass rises rapidly. Therefore, the SrO content is 0.5-15%, preferably 0.5-13%, and more preferably 0.5-12%.

CaO can improve the crystallization resistance of glass, increase the refractive index of glass, rapidly reduce the high-temperature viscosity of glass, and make it relatively easy to remove bubbles, and the effect is relatively prominent, especially when the relative content of BaO is low. If the CaO content exceeds 10%, the crystallization resistance of glass will rapidly decrease and the Abbe number will be lower than the design requirement. Therefore, the CaO content is 0-10%, preferably 0-9%, and more preferably 0-8%.

Although MgO can increase the stability of glass, if its content exceeds 5%, the crystallization resistance of the glass will rapidly decrease and the Abbe number will be lower than the design requirements. Therefore, the MgO content is limited to 5% or less, preferably 3% or less, and more preferably, no MgO is contained.

In some embodiments, the alkaline earth metal oxide in the glass of the present invention is mainly BaO, and when the value of BaO/RO is preferably 0.4 to 0.95, more preferably 0.5 to 0.95, even more preferably 0.65 to 0.95, and even more preferably 0.7 to 0.9, the reduction in the upper crystallization temperature of the glass due to the synergistic effect between the alkaline earth metal oxides is most significant.

In some embodiments, the free oxygen provided by the alkaline earth metal oxides can strengthen the B ₂ O ₃ network, increase its density, and further improve the water resistance and weather resistance of the glass, but when the value of RO/B ₂ O ₃ is less than 0.3, the above-mentioned effect is not significant and the thermal expansion coefficient increases. When the value of RO/B ₂ O ₃ is more than 1.3, the excess alkaline earth metal components will destroy the glass network, and the water resistance and weather resistance of the glass will rapidly decrease. Therefore, the value of RO/B ₂ O ₃ is preferably 0.3 to 1.3, more preferably 0.4 to 1.2, even more preferably 0.5 to 1.0, and even more preferably 0.6 to 0.9.

_La2O3 can increase the refractive index of glass and reduce the high-temperature viscosity of glass, but if its content is less than 0.5%, the above effects are not significant. If the content of _La2O3 exceeds _{10 %} , the acid resistance of glass will rapidly decrease, the _{thermoplastic} crystallization resistance of glass will rapidly decrease, and the _Ts of glass will increase. Therefore, the content of _La2O3 is 0.5-10%, preferably 1-9%, more preferably 1.5-8%.

Although _Y2O3 can be added to glass to increase the refractive index and thermal shock resistance, if _its content exceeds 8%, the chemical stability of the glass will rapidly decrease. Therefore, the content of _Y2O3 is limited to ₈ % or less, preferably 5% or less, and more preferably 3% or less.

_Gd2O3 can increase the refractive index, water resistance and weather resistance of glass, but if its content exceeds 5%, the cost of glass will rise rapidly and the _{crystallization} resistance will drop rapidly. Therefore, the content of _Gd2O3 is limited to 5% or less, preferably 3% or less, _and more preferably, _{no Gd2O3} is contained.

The glass of the present invention requires a longer cooling time from a high-temperature solution to a solid state than general optical glasses, and then requires two more high-temperature moldings, so adding excessive La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ will rapidly reduce the thermoplastic crystallization resistance of the glass, generate crystals during thermoplastic processing, and further emulsify, causing a rapid decrease in acid resistance. Therefore, the total content of La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ , La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O _3, is preferably 0.5-15%, more preferably 1-12%, and even more preferably 2-10%.

In some embodiments, the appropriate amount _{of La2O3} , _Y2O3 , _Gd2O3 and RO can increase the refractive index and Abbe number of glass, _and more importantly, it can reduce the problem of glass water resistance caused by a large amount _of RO, while controlling the acid resistance within the design range, reducing the high-temperature viscosity _of glass, and further _reducing the melting temperature _of glass. When the value of ( _La2O3 + _Y2O3 + _Gd2O3 )/RO is less than 0.05, the above effects are not significant. When the value of ( _La2O3 + _Y2O3 + _Gd2O3 )/RO is more than 0.9, the corrosion of _the glass liquid to _the furnace body increases, the stability _of glass decreases rapidly, and _Ts increases, making it difficult to meet the design requirements. Therefore, the value of (La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ )/RO is preferably from 0.05 to 0.9, more preferably from 0.1 to 0.6, even more preferably from 0.1 to 0.4, and even more preferably from 0.1 to 0.35.

In some embodiments, when components such as La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ are present in the glass, the stability of the glass may decrease, and fine bubbles may easily occur during cooling, which may lead to the disposal of the product. As a result of extensive experimental research, the inventors have found that when ZnO coexists with La ₂ O ₃ , Y ₂ O ₃ , and Gd ₂ O ₃ , and the value of ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is within the range of 0.2 to 4.0, the decrease in stability and bubble content of the glass can be prevented. Therefore, the value of ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is preferably 0.2 to 4.0, more preferably 0.3 to 3.0, even more preferably 0.5 to 2.0, and even more preferably 0.6 to 1.6.

Alkali metal oxides ( _Li2O , _Na2O , _K2O , etc.) are one of the main components of the glasses of the present invention, and their content and relative content have a significant effect on important indexes such as _Ts , refractive index, Abbe number, thermal expansion coefficient, chemical stability and crystallization resistance of the glass.

From the viewpoint of the function of single alkali metal oxide, Li ₂ O has the strongest ability to reduce the T _s of glass, and when its content is less than 1%, the T _s of glass is higher than the design requirement, the chemical stability of glass is rapidly reduced, and the high-temperature viscosity of glass is rapidly increased. When the Li ₂ O content exceeds 7%, not only the corrosion of glass liquid to furnace body is rapidly increased, but also the platinum products are corroded during melting, platinum inclusions are generated in glass, and the _Nd consistency and T _s stability of glass are relatively difficult to control. Therefore, the Li ₂ O content is 1-7%, preferably 2-6.5%, more preferably 3-5.5%.

A suitable amount of Na ₂ O can improve the melting performance of glass, reduce the T _s of glass, and reduce the high-temperature viscosity of glass, but if the content is less than 0.1%, the above effects are not significant. If the content of Na ₂ O exceeds 7%, the corrosiveness of glass to the furnace body increases, the chemical stability of glass decreases, and the thermal expansion coefficient increases rapidly. Therefore, the content of Na ₂ O is 0.1-7%, preferably 0.1-6%, and more preferably 0.5-5%.

If the content of _K2O exceeds 5%, the destruction of the glass network structure is severe, and the water resistance and weather resistance of the glass are difficult to meet the design requirements. Therefore, the content of _K2O is limited to 5% or less, preferably 2% or less, more preferably 1% or less.

As a result of the inventors' research, they found that when three kinds of alkali metal oxides, Li ₂ O, Na ₂ O, and K ₂ O, are mixed and present, a complex synergistic effect occurs, which further affects the corrosiveness to the furnace body, high temperature viscosity, and refractive index temperature coefficient. By using an aspheric lens, it is possible to achieve high-definition imaging while greatly reducing the number of lenses used. However, for lenses used in environments with relatively large temperature differences (such as vehicle-mounted and safety lenses), if the refractive index temperature coefficient of the glass is too large and the number of lenses is small, the "temperature drift" of the lens becomes extremely difficult to control, resulting in serious problems of different imaging quality at different temperatures. In some embodiments, the inventors found that when the value of Li ₂ O + Na ₂ O + K ₂ O is preferably less than 15%, more preferably less than 12%, even more preferably less than 10%, and even more preferably less than 8%, the corrosiveness of the glass liquid to the furnace body is reduced, the _Ts stability meets the design requirements, and the refractive index temperature coefficient of the glass does not exceed the design requirements.

In some embodiments, when the value of (Na ₂ O+K ₂ O)/Li ₂ O is preferably 0.1-1.5, more preferably 0.1-1.0, even more preferably 0.2-0.8, and even more preferably 0.25-0.65, the corrosion of the glass liquid to the furnace body is reduced, the _Ts stability meets the design requirements, and the refractive index temperature coefficient of the glass does not exceed the design requirements. More importantly, when the above three kinds of alkali metal oxides are within the above ranges, a lower thermal expansion coefficient can also be achieved, which is very important for reducing lens bursting in aspherical pressing, and greatly improves the freedom and stability of aspherical pressing.

_P2O5 can adjust the refractive index and dispersion of glass. _However , in the glass system of the present invention, if its content exceeds 3%, the crystallization resistance of the glass will rapidly decrease, causing a devastating impact on important processes such as glass melting production, blank secondary pressing, and aspherical precision pressing _. Therefore, its content is limited to 3% or less, preferably 1.5% or less, and more preferably does not contain _P2O5 .

A suitable amount of F (fluorine) can significantly reduce the _Ts of glass, increase the Abbe number of glass, and reduce the use of alkali metal oxides in glass. If its content exceeds 10%, F is very easy to volatilize during high-temperature melting, and its unit content has a particularly large effect on the refractive index and Abbe number, making it very difficult to control the _Nd consistency and _Ts stability during the melting process, which will have a devastating effect on the subsequent aspheric pressing process. Therefore, the F content is limited to 10% or less, preferably 5% or less, more preferably 3% or less. If the composition design can meet the design requirements for _Ts , it is even more preferable to not contain F.

_Sb2O3 , _SnO2 , _Na2SiF6 , _{K2SiF6 ,} etc. can be used as fining agents and are advantageous in increasing the foaming rate of the glass, and when present alone or in combination _, their content is not more than 1%, preferably not _more than 0.8%, more preferably not more than 0.5%.

In addition to optimizing the melting property of glass and improving the bubble degree of glass by component design, similar high viscosity silicate glasses usually optimize the melting property and bubble degree of glass by introducing oxide components in the form of nitrates. Nitrates emit most of the nitrogen element into the atmosphere as _NOX gas during the melting process, and nitrogen oxides cause great damage to human health, and long-term inhalation has the risk of causing lung cancer. Therefore, the inventors are engaged in research to reduce the emission of nitrogen oxides while ensuring the melting performance of glass. After a large amount of experimental research, the inventors have found that when nitrates are introduced in the form of _KNO3 and Ba( _NO3 ) ₂ and mixed with _the above-mentioned fining agents ( _Sb2O3 , _SnO2 , _Na2SiF6 , _{K2SiF6 ,} etc.), the bubble degree of glass meets the quality requirements and the emission _of nitrogen oxides can be reduced to a lower level. By conversion, the N (nitrogen) element content in the glass raw material (N element introduction amount when 100 kg of theoretical glass is melted/100 kg glass weight×100%) is less than 2.0%, preferably less than 1.5%, and more preferably less than 1.0%.

<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 transmitting 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 chemical substances, and it is necessary to take measures to protect the environment not only in the manufacturing process of the glass, but also in the processing process and the treatment of the finished product. Therefore, when the impact on the environment is important, it is preferable that they are not included except for unavoidable contamination. This makes the optical glass actually free of 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 order to be environmentally friendly, it is preferable that the optical glass of the present invention does not include _As2O3 and PbO.

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 were 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 performance 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 (v _d ) of the optical glasses are tested according to the methods specified in GB/T7962.1-2010. In some embodiments, the refractive index (n _d ) of the optical glasses of the present invention is from 1.57 to 1.61, preferably the refractive index (n _d ) is from 1.575 to 1.605, and more preferably the refractive index (n _d ) is from 1.575 to 1.60. In some embodiments, the Abbe number (v _d ) of the optical glasses of the present invention is from 58 to 64, preferably the Abbe number (v _d ) is from 58.5 to 63.5, and more preferably the Abbe number (v _d ) is from 59 to 63.

< _Nd Consistency>
During production, a total of five glass samples are extracted every 24 hours, annealed, and then the refractive index (N _d ) is measured using the method specified in GB/T7962.1-2010, and the difference from the standard value is the N _d consistency. In some embodiments, the N _d consistency of the optical glass of the present invention is within ±50×10 ⁻⁵ , and preferably the N _d consistency is within ±30×10 ⁻⁵ .

<Yield point temperature>
The yield point temperature ( _Ts ) of the optical glass is measured according to the method specified in GB/T7962.16-2010. In some embodiments, the optical glass of the present invention has a yield point temperature ( _Ts ) of 610°C or less, preferably a yield point temperature ( _Ts ) of 600°C or less, and more preferably a yield point temperature (Ts ₎ of 595°C or less.

< _Ts Stability>
During production, a total of five glass samples are extracted every 24 hours, annealed, and then _Ts is measured according to the method specified in GB/T7962.16-2010, and the difference from the standard value is the _Ts stability. In some embodiments, the _Ts stability of the optical glass of the present invention is within ±5°C, and preferably the _Ts stability is within ±3°C.

<Thermal expansion coefficient>
The thermal expansion coefficient (α _{20-300° C.} ) of optical glass is data measured at 20 to 300° C. according to the method specified in GB/T7962.16-2010. In some embodiments, the thermal expansion coefficient (α _{20-300° C.} ) of the optical glass of the present invention is 85×10 ⁻⁷ or less, preferably the thermal expansion coefficient (α _{20-300° C.} ) is 83×10 ⁻⁷ or less, and more preferably (α _{20-300° C.} ) is 81×10 ⁻⁷ or less.

<Acid resistance>
The acid resistance stability (D _A ) (powder method) of optical glass is tested by the method specified in GB/T17129. In this specification, acid resistance stability may be referred to as acid resistance. In some embodiments, the acid resistance stability (D _A ) of the optical glass of the present invention is class 5 or higher, and preferably _class 4 or higher.

<Water resistance stability>
The water resistance stability (D _W ) (powder method) of optical glass is tested by the method specified in GB/T17129. In this specification, water resistance stability may be referred to as water resistance. In some embodiments, the water resistance stability (D _W ) of the optical glass of the present invention is Class 4 or higher, and preferably Class ₃ or higher.

<Bubble level>
The porosity of the optical glass is tested according to the method specified in GB/T7962.8-2010. In some embodiments, the porosity of the optical glass of the present invention is Class A or higher, preferably Class _A0 or higher, and more preferably Class _A00 .

＜Stripe＞
The stripes of the optical glass are confirmed by comparing a standard sample with a stripe meter consisting of a point light source and a lens from the direction in which the stripes are most visible. Grades are divided into four stages. For details, see Table 1. In some embodiments, the stripes of the optical glass of the present invention are Class C or higher, preferably Class B or higher.

<High temperature viscosity>
The high temperature viscosity of optical glasses is tested according to the following method: using a THETA Rheotronic II high temperature viscometer in a rotational method, the numerical unit is dPaS (poise), and the smaller the numerical value, the smaller the viscosity. In some embodiments, the high temperature viscosity of the optical glasses of the present invention at 1200° C. is 25 dPaS or less, preferably 23 dPaS or less, and more preferably 20 dPaS or less at 1200° C. In some embodiments, the high temperature viscosity of the optical glasses of the present invention at 900° C. is 35 dPaS or more, preferably 40 dPaS or more, and more preferably 50 dPaS or more at 900° C.

<Crystallization resistance>
For glass applied to aspheric precision press processing, three stages of high-temperature processing are required, including high-temperature molding, high-temperature secondary press processing, and high-temperature precision press processing, so the crystallization resistance stability of glass is very important. There are two types of crystallization resistance stability: one is the crystallization resistance during the process of cooling the glass liquid from liquid to solid state, which is represented by the upper crystallization temperature limit, and the crystallization resistance during high-temperature secondary press processing and high-temperature precision press processing can be represented by a thermoplastic crystallization resistance test. The crystallization resistance (or glass stability) described in this specification generally refers to the above two types of crystallization resistance.

Crystallization resistance stability can be divided into two types. One is the crystallization resistance during the process of cooling the glass liquid from a high-temperature (1000-1200°C) liquid to a solid state, which is represented by the upper crystallization temperature limit. The crystallization resistance during high-temperature secondary pressing and high-temperature precision pressing can be represented by the thermoplastic crystallization resistance test.

The test method for the upper crystallization temperature limit is as follows: the temperature gradient furnace method is used to measure the crystallization performance of glass. A glass sample of 180 x 10 x 10 mm is polished on the side and placed in a gradient temperature (10°C/cm) furnace to heat up to a maximum temperature range of 1400°C. After keeping the temperature for 4 hours, it is taken out and naturally cooled to room temperature. The crystal state of the glass is observed under a microscope. The maximum temperature at which devitrification of the glass occurs is the upper crystallization temperature limit of the glass. In some embodiments, the upper crystallization temperature limit of the optical glass of the present invention is 1100°C or less, preferably 1050°C or less, and more preferably 1020°C or less.

The thermoplastic crystallization resistance test method is as follows: a sample processed to 20x20x10 mm is polished on both sides, the sample is placed in a crystallization furnace at _Ts +200°C for 30 minutes, taken out and cooled, and then the two large surfaces are polished, and the crystallization resistance performance of the glass is judged according to Table 2, with Grade A being the best and Grade E being the worst. In some embodiments, the thermoplastic crystallization resistance of the optical glass of the present invention is Grade B or higher, preferably Grade A, and has excellent crystallization resistance.

<Refractive index temperature coefficient>
The refractive index temperature coefficient (dn/dt) of glass is measured in accordance with the method specified in GB/T7962.4-2010, within the range of 40 to 60° C. (d-line dn/dt relative (10 ⁻⁶ /° C.)). In some embodiments, the refractive index temperature coefficient (dn/dt) of the optical glass of the present invention is 6.0×10 ⁻⁶ /° C. or less, preferably 5.5×10 ⁻⁶ /° C. or less, and more preferably 5.0×10 ⁻⁶ /° C. or less.

[Production method]
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 and conventional processes, including but not limited to oxides, hydroxides, fluorides, various salts (carbonates, nitrates, sulfates, phosphates, metaphosphates), boric acid, etc., and is mixed in a conventional manner. The prepared furnace material is then put into a melting furnace (such as a platinum, gold or platinum alloy crucible) at 1400 to 1550°C to melt. The glass is then clarified 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 manufactured from the optical glass prepared by using a press molding method such as direct drop molding, polishing, or hot press molding. That is, a precision glass preform can be manufactured from molten optical glass by direct precision drop molding, a glass preform can be manufactured by mechanical processing such as grinding or polishing, or a preform blank for press molding can be manufactured using optical glass, and the preform blank can be hot pressed and polished to manufacture a glass preform. It should be noted that the manufacturing means of the optical preform is not limited to the above means.

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 for hot press molding, precision press molding, etc. to produce 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, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses, with spherical or aspheric lens surfaces. Lenses described in the present invention further include lenses for automotive lamps.

[Optical equipment]
The optical elements made of the optical glass of the present invention can be used in the manufacture of optical instruments, including, but not limited to, photographic devices, imaging devices, projection devices, display devices, vehicle-mounted devices (including lamps), and surveillance 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 the present examples, the above-mentioned method for producing optical glass was used to obtain optical glasses having the compositions shown in Tables 3 to 5. The properties of each glass were measured by the test methods described in the present invention, and the results are shown in Tables 3 to 5.

<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 a variety of lenses and prisms, including 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 resulting 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 (20)

The composition contains, in weight percent, _SiO2 : 17-47%, _B2O3 : _20-50 %, _Al2O3 : 0.5-8%, _ZnO : 0.5-8%, RO: 6-45%, _La2O3 + _{Y2O3 + Gd2O3} : 0.5-15%, _Li2O + Na2O + _K2O : less than 15%, ZnO/ _{( La2O3 + Y2O3} + _Gd2O3 ): 0.2-4.0, BaO _/ RO: 0.65-0.95, _{( Na2O} + _K2O )/ _{Li2O : 0.1-0.68} ,
The optical glass, wherein RO is the total content of BaO, SrO, CaO, and MgO. Further comprising, in weight percent, P ₂ O ₅ : 0-3%, and/or ZrO ₂ : 0-3%, and/or a fining agent: 0-1%,
2. The optical glass according to claim 1, _{wherein the} fining agent is one or more of _Sb2O3 , _SnO2 , _Na2SiF6 , _{and K2SiF6} . An optical glass comprising SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , ZnO and an alkaline earth metal oxide,
The composition _further contains , in weight percent, the following components: SiO2 : 17-47%, _B2O3 : _20-50 %, _Al2O3 : 0.5-8%, ZnO: 0.5-8%, RO: 6-45%, _{La2O3 + Y2O3 + Gd2O3} : 0.5-15%, Li2O +Na2O +K2O _: less than 15%, _ZnO / _{( La2O3} + _Y2O3 + _Gd2O3 ): 0.2-4.0 _, BaO/ _{RO :} 0.65-0.95, _{( Na2O} + _K2O )/ _{Li2O :} 0.1-0.68,
The RO is the total content of BaO, SrO, CaO, and MgO,
The optical glass has a refractive index n _d of 1.57 to 1.61, an Abbe number v _d of 58 to 64, and a bubble level of A class or higher. The composition contains , in weight percent, P ₂ O ₅ : 0-3%, and/or ZrO ₂ : 0-3%, and/or a fining agent: 0-1%,
The RO is the total content of BaO, SrO, CaO, and MgO,
4. The optical glass according to claim 3, _{wherein the} fining agent is one or more of _Sb2O3 , _SnO2 , _Na2SiF6 , _{and K2SiF6} . The components expressed in weight percent are:
1) _B2O3 / _{SiO2 is} 0.55-2.3;
2) (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.4;
3) RO/B ₂ O ₃ is 0.3 to 1.3;
4) (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.05 to 0.9;
5) ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is 0.3 to 3.0;
The optical glass according to any one of claims 1 to 4, wherein said RO is a total content of BaO, SrO, CaO and MgO. The components expressed in weight percent are:
1) _B2O3 / _{SiO2 is} 0.7-2.0;
2) (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.3;
3) RO/B ₂ O ₃ is 0.4 to 1.2;
4) (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.6;
5) ZnO/(La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ ) is 0.5 to 2.0;
The optical glass according to any one of claims 1 to 4, wherein said RO is a total content of BaO, SrO, CaO and MgO. The components expressed in weight percent are:
1) _B2O3 / _{SiO2 is} 0.8-1.8;
2) (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.25;
3) BaO/RO is 0.65 to 0.9;
4) RO/B ₂ O ₃ is 0.5 to 1.0;
5) (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.4;
6) ZnO/(La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ ) is 0.6 to 1.6;
7) (Na ₂ O + K ₂ O) / Li ₂ O is 0.2 to 0.68, and one or more of the following is satisfied;
The optical glass according to any one of claims 1 to 4, wherein said RO is a total content of BaO, SrO, CaO and MgO. The components expressed in weight percent are:
1) _B2O3 / _{SiO2 is} 1.0-1.5;
2) (ZrO ₂ +Al ₂ O ₃ )/B ₂ O ₃ is 0.05 to 0.2;
3) BaO/RO is 0.7-0.9;
4) RO/B ₂ O ₃ is 0.6 to 0.9;
5) (La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ )/RO is 0.1 to 0.35;
6) (Na ₂ O + K ₂ O) / Li ₂ O is 0.25 to 0.65, and one or more of the following is satisfied;
The optical glass according to any one of claims 1 to 4, wherein said RO is a total content of BaO, SrO, CaO and MgO. The composition contains, in weight percent, SiO ₂ : 22-40%, and/or B ₂ O ₃ : 22-38%, and/or Al ₂ O ₃ : 1-7%, and/or ZnO: 1-7%, and/or RO: 8-40%, and/or La ₂ O ₃ +Y ₂ O ₃ +Gd ₂ O ₃ : 1-12%, and/or Li ₂ O + Na ₂ O + K ₂ O: less than 12%, and/or P ₂ O ₅ : 0-1.5%, and/or ZrO ₂ : 0-2%, and/or fining agent: 0-0.8%,
5. The optical glass according to claim 1, wherein said RO is the total content of BaO, SrO, CaO and MgO, and said fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , Na ₂ SiF ₆ and K ₂ SiF ₆ . The composition contains, in weight percent, SiO ₂ : 25-38%, and/or B ₂ O ₃ : 23-35%, and/or Al ₂ O ₃ : 1-6.5%, and/or ZnO: 1-6%, and/or RO: 10-35%, and/or La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O ₃ : 2-10%, and/or Li ₂ O + Na ₂ O + K ₂ O: less than 8%, and/or ZrO ₂ : 0-1%, and/or fining agent: 0-0.5%;
5. The optical glass according to claim 1, wherein said RO is the total content of BaO, SrO, CaO and MgO, and said fining agent is one or more of Sb ₂ O ₃ , SnO ₂ , Na ₂ SiF ₆ and K ₂ SiF ₆ . 5. The optical glass according to claim 1, containing, by weight, the following components: BaO: 5-30%, and/or SrO: 0.5-15%, and/or CaO: 0-10%, and/or MgO: 0-5%, and/or La ₂ O ₃ : 0.5-10%, and/or Y ₂ O ₃ : 0-8%, and/or Gd _{2 O 3} : 0-5%, and/or Li ₂ O: 1-7%, and/or Na ₂ O: 0.1-7%, and/or K 2 O: 0-5%. 5. The optical glass according to claim 1, containing, by weight, the following components: BaO: 8-25%, and _/ or SrO: 0.5-12%, and/or CaO: 0-8%, and/or MgO: 0-3%, and/or La _{2 O 3} : 1.5-8%, and/or Y ₂ O ₃ : 0-3%, and/or Gd ₂ O 3: 0-3%, and/or Li ₂ O: 3-5.5%, and/or Na ₂ O: 0.5-5%, and/or K 2 O: 0-1%. 5. The optical glass according to claim 1, further comprising, by weight, 0 to 5% of F. The optical glass according to any one of claims 1 to 4, wherein the optical glass has a refractive index n _d of 1.57 to 1.61 and an Abbe number v _d of 58 to 64. The optical glass according to any one of claims 1 to 4, wherein the optical glass has a refractive index n _d of 1.575 to 1.60 and an Abbe number v _d of 59 to 63. 5. The optical glass according to any one of claims 1 to 4, wherein the optical glass has an _Nd conformity within ±50×10 ^-5 , and/or a _Ts stability within ±5°C, and/or a yield point temperature _Ts of 610°C or less, and/or a thermal expansion coefficient α _20-300°C of 85×10 ^-7 or less, and/or an acid resistance stability D _A of Class 5 or more, and/or a water resistance stability D _W of Class 4 or more, and/or a cellularity of Class A or more, and/or a stripe of Class C or more, and/or a high temperature viscosity at 1200°C of 25 dPaS or less, and/or a high temperature viscosity at 900°C of 35 dPaS or more, and/or an upper crystallization temperature of 1100°C or less, and/or a thermoplastic crystallization resistance stability of Class B or more, and/or a refractive index temperature coefficient dn/dt of 6.0×10 ^-6 /°C or less. 5. The optical glass according to any one of claims 1 to 4, wherein the optical glass has an _Nd consistency within ± ^30x10-5 , and/or a _Ts stability within ±3°C, and/or a yield point temperature _Ts of 595°C or less, and/or a thermal expansion coefficient α20-300 _°C of ^81x10-7 or less, and/or an acid resistance stability D _A of Class 4 or more, and/or a water resistance stability D _W of Class ₃ or more, and/or a cellularity of Class A00, and/or a stripe of Class B or more, and/or a high temperature viscosity at 1200°C of 20 dPaS or less, and/or a high temperature viscosity at 900°C of 50 dPaS or more, and/or an upper crystallization temperature of 1020°C or less, and/or a thermoplastic crystallization resistance stability of Class A, and/or a refractive index temperature coefficient dn/dt of ^5.0x10-6 /°C or less. A glass preform manufactured from the optical glass according to any one of claims 1 to 4. An optical element manufactured from the optical glass according to any one of claims 1 to 4. An optical device comprising the optical glass according to any one of claims 1 to 4.