JP7331092B2 - Optical glass, preforms, optical elements and their optical equipment - Google Patents

Description

The present invention belongs to the field of optical glasses, and more particularly to optical glasses, preforms, optical elements and optical instruments thereof.

Optical glasses can be used to make lenses, prisms, and reflectors for optical instruments, and all parts made from optical glasses are important components of optical instruments. Optical glass with a refractive index (nd) of 1.84-1.87 and an Abbe number (vd) of 38-41 is widely used in cameras, telescopes, microscopes and other precision optics due to its excellent transmittance and high refractive index. Widely applied in the manufacture of instrument lenses. In recent years, there has been a trend towards achieving smaller and lighter optical instruments, and aspherical lenses have been utilized to reduce the number of optical elements. On the other hand, the market demand is also increasing more and more.

However, aspheric lenses are costly and complex to operate using conventional methods of hot press molding followed by polishing, grinding, and remanufacturing of molten glass. Precision molding is a method of making optical elements made from optical glass that is simple to operate and low cost. However, the aspherical lenses produced by this method have high requirements on the properties of the glass material, i.e., accurate molding, high resistance to devitrification, low melting point, and excellent bubble degree can be easily achieved. is required. In order to ensure the service quality and life of the lens when the optical elements are used in digital cameras, vidicon, and other outdoor long-term photographic equipment, the optical glass material is further protected against water and acid in the outdoor environment. must have excellent chemical stability to withstand corrosion such as Also, for optics operating at particular temperatures, the glass material should have a better coefficient of thermal expansion to reduce the degree of expansion and contraction of the glass when the temperature changes.

Patents CN104803600A, CN104098267A, and CN105819682A respectively provide optical glasses with the same or similar refractive index (nd) and Abbe number (vd) as the present invention, but fail to meet other requirements.

In view of the deficiencies of the prior art, the present invention aims to provide an optical glass with a refractive index (nd) of 1.84-1.87 and an Abbe number (vd) of 38-41. Optical glass is easy to precision press mold, has high devitrification resistance, high degree of bubble, high chemical stability, and low cost.

The invention further provides preforms, optical elements, and optical instruments made from the optical glass.

The technical solutions applied to achieve the purpose are as follows.

The optical glass is 0-10% _SiO2 , 5-25% _B2O3 , 0-15% _ZrO2 , 10-25% ZnO _, 2-30% TiO in weight percentage. ₂ +Nb ₂ O ₅ +WO ₃ and 30-55% Ln ₂ O ₃ where Ln ₂ O ₃ is La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ is the total content of B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.8, Y ₂ O ₃ /B ₂ O ₃ is 0.15 to 2, and Y ₂ O ₃ / Gd ₂ O ₃ is 1.100 to 3, and the upper limit of the crystallization temperature of the optical glass is 1,250° C. or less .

Further, the optical glass contains 0 to 10% RO, 0 to 10% Rn ₂ O, and 0 to 1% fining agent in weight percentage, and RO is MgO, CaO, SrO. , or one or more of BaO, Rn ₂ O is one or more of Li ₂ O, Na ₂ O and K ₂ O, and the refining agent is one or more of Sb ₂ O ₃ , SnO _{2 and} CeO ₂ is.

The optical glass is composed of 0-10% _{SiO2 ,} 5-25% _B2O3 , 0-15% _ZrO2 , 10-25% ZnO _, and 2-30% TiO ₂ +Nb ₂ O ₅ +WO ₃ , 30-55% Ln ₂ O ₃ , 0-10% RO, 0-10% Rn ₂ O, 0-1% clarifier Ln ₂ O ₃ is the total content of La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ , and RO is one or more of MgO, CaO, SrO, or BaO. wherein Rn ₂ O is one or more of Li ₂ O, Na ₂ O and K ₂ O, the clarifier is one or more of Sb ₂ O ₃ , SnO _{2 and} CeO ₂ , and B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.8, Y ₂ O ₃ /B ₂ O ₃ is 0.15 to 2, Y ₂ O ₃ /Gd ₂ O ₃ is 1.100 to 3, optical glass The upper limit of the crystallization temperature of is 1,250° C. or less .

Furthermore, according to the optical glass, the content of all constituent elements satisfies one or more of the following four conditions.

1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0 to 0.25;

2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.08 to 0.45;

3) Y ₂ O ₃ /Gd ₂ O ₃ is 1.155 to 2.5 ;

4) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.16 to 0.8;

Further, according to the optical glass, 1-8% SiO ₂ and/or 10-23% B ₂ O ₃ and/or 1-10% gZrO ₂ and/or 10-20% ZnO, and/or TiO ₂ +Nb ₂ O ₅ +WO ₃ 4-22% and/or Ln ₂ O ₃ 35-52% and/or RO 0-5% and/or R ₂ O 0-5 %, and/or 0-0.5% fining agent.

Furthermore, according to the optical glass, the content of all constituent elements satisfies one or more of the following six conditions.

1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0.05 to 0.23;

2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.1 to 0.4;

3) Y ₂ O ₃ /Gd ₂ O ₃ is 1.165-2 .

4) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.2 to 0.7;

5) B ₂ O ₃ /Ln ₂ O ₃ 0.3 to 0.6.

6) Y ₂ O ₃ /B ₂ O ₃ is 0.2 to 1.5;

Further, according to said optical glass, 1-4% SiO ₂ and/or 15-20% B ₂ O ₃ and/or 2-6% ZrO ₂ and/or 13-17% ZnO, and/or 10-18% TiO ₂ +Nb ₂ O ₅ +WO ₃ and/or 40-50% Ln ₂ O ₃ .

Furthermore, according to the optical glass, the content of all constituent elements satisfies one or more of the following six conditions.

1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0.08 to 0.2.

2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.1 to 0.3;

3 ) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.3 to 0.6.

4 ) B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.5.

5 ) Y ₂ O ₃ /B ₂ O ₃ is 0.3-1.

Further, according to said optical glass, 1-15% Nb ₂ O ₅ and/or 1-15% WO ₃ and/or 0-10% TiO ₂ and/or 20% La ₂ O ₃ 45%, and/or 0-15% Gd ₂ O ₃ , and/or 1-15% Y ₂ O ₃ , and/or 0-5% Yb ₂ O ₃ .

Further, according to said optical glass, 2-10% Nb ₂ O ₅ and/or 2-12% WO ₃ and/or 0-5% TiO ₂ and/or 25% La ₂ O ₃ ˜40%, and/or 1-10% Gd ₂ O ₃ and/or 3-15% Y ₂ O ₃ .

Further, according to said optical glass, 4-8% Nb ₂ O ₅ and/or 6-10% WO ₃ and/or 30-35% La ₂ O ₃ and/or Gd ₂ O ₃ is 3-7%, and/or Y ₂ O ₃ is 6-10%, and/or TiO ₂ is absent.

Furthermore, the optical glass has a refractive index (nd) of 1.84 to 1.87 and an Abbe number (vd) of 38.0 to 41.0. property (D _W ) is grade 2 or higher, powder method acid resistance (D _A ) is grade 3 or higher, and the thermal expansion coefficient (α _{−30° C. to 70° C.} ) of the optical glass is 75×10. ⁻⁷ /K or less, the bubble level of the optical glass is grade A or more, the conversion temperature (Tg) of the optical glass is 640° C. or less, and the upper limit of the crystallization temperature of the optical glass is 1,200. ℃ or less .

Further, the optical glass has a refractive index (nd) of 1.85 to 1.86, an Abbe number (vd) of 38.5 to 40.0, and is water resistant to the powder method of the optical glass. property (D _W ) is grade 1, powder method acid resistance (D _A ) is grade 2, and the thermal expansion coefficient (α _{−30° C. to 70° C.} ) of the optical glass is 70×10 ^{−7 .} /K or less, the bubble degree of the optical glass is grade A ₀ or more, the conversion temperature (Tg) of the optical glass is 625 ° C. or less, and the upper limit of the crystallization temperature of the optical glass is 1,180 ° C. It is below .

A glass preform is made of the optical glass.

An optical element is made from the optical glass or the glass preform.

An optical instrument is made from the optical element.

The high refractive index and low dispersion glass material provided by the present invention has excellent devitrification resistance, is easy to be precision press-molded, suppresses the content of expensive raw materials such as rare earth oxides, and is cost effective. lower the Therefore, it is suitable for acceleration and application in precision press molding processes. On the other hand, in order to improve the yield of the product, the chemical stability of the glass and the degree of foaming are improved by the reasonable ratio of constituents in the present invention. Some preferred technical solutions are to further optimize the ratio of constituent elements, reduce the coefficient of thermal expansion, optimize the anti-crystallization performance, and enhance the chemical stability of the glass. A cost-effective glass material is provided for producing optical elements and optical instruments with better production quality and longer service life.

optical glass

The following paragraphs detail the compositions of optical glasses provided by the present invention. Unless otherwise indicated, all glass composition contents and total contents refer to weight contents expressed in weight percent. A weight percent is the percentage of the total weight of a particular component or of several compositions that make up the total weight of the optical glass. A proportion of all glass compositions or a sum of several compositions is a proportion of the corresponding weight content or sum of the weight contents.

The optical glass provided by the present invention has the optical properties necessary for lens materials for the manufacture of precision instruments, a refractive index (nd) of 1.84 to 1.87, and an Abbe number (vd) of 38-41. It is easy to precision press mold and has excellent chemical stability and degree of foaming. The optical glass is composed of 0-10% SiO ₂ , 5-25% B ₂ O ₃ , 0-15% ZrO ₂ , 10-25% ZnO, and 2-30% by weight. TiO ₂ +Nb ₂ O ₅ +WO ₃ and 30-55% Ln ₂ O ₃ , where Ln ₂ O ₃ is La ₂ O ₃ , Gd ₂ O _{3 ,} Y ₂ O ₃ and Yb ₂ O ₃ , B ₂ O ₃ /Ln ₂ O ₃ is 0.3-0.8, and Y ₂ O ₃ /B ₂ O ₃ is 0.15-2.

B ₂ O ₃ is a network-shaped component of glass that can improve the meltability and devitrification resistance of the glass. To achieve the above effect, 5% or more B ₂ O ₃ , preferably 10% or more B ₂ O ₃ , more preferably 15% or more B ₂ O ₃ is introduced. If the amount of incorporation is higher than 25%, the stability of glass molding is lowered and the refractive index is lowered. Therefore, the upper limit of the B ₂ O ₃ content is set to 25%, preferably 23%, more preferably 20%.

SiO ₂ is an optional constituent of the present invention and constitutes a constituent of the glass former. _SiO2 forms a three-dimensional network of very compact and rigid silica tetrahedra within the glass. This network is added to the glass and strengthens and densifies the loose boron oxide triangular network bodies, thereby increasing the high temperature viscosity of the glass. Moreover, the higher the content of _SiO2 , the lower the coefficient of thermal expansion of the glass. The lower limit of the _SiO2 content in the optical glass provided by the present invention is 0%, preferably 1%. If the _SiO2 content is too high, the conversion temperature of the glass will increase, the meltability of the glass will decrease, and the processing difficulty will increase. Therefore, the upper limit of its content is 10%, preferably 8%, more preferably 4%.

Both SiO ₂ and B ₂ O ₃ are network-shaped constituents of glass. The inventors have discovered through research results that _SiO2 /( _SiO2 + _B2O3 ) affects the anti-crystallization performance and thermal expansion coefficient of the glass under the formulation of the present invention _. The higher the SiO ₂ /(SiO ₂ +B ₂ O ₃ ) value, the lower the coefficient of thermal expansion of the glass, further helping to reduce the sensitivity of the glass to temperature. However, on the other hand, the crystallization resistance of the glass is lowered. Through research, in the formulations of the present invention, the thermal expansion coefficient of the glass is lower than 75×10 ⁻⁷ /K when the SiO ₂ /(SiO ₂ +B ₂ O ₃ ) value ranges from 0 to 0.25. Furthermore, it was discovered that the crystallization resistance performance was excellent. Further, the ratio is preferably in the range of 0.05 to 0.23, more preferably 0.08 to 0.2.

_ZrO2 as an optional component of the present invention is an oxide with high reflection and low dispersion and may be added to the glass to improve the refractive index and adjust the dispersion of the glass. On the other hand, an approximate amount of _ZrO2 may be added to the glass to improve its anti-crystallization performance and chemical stability. However, if the content of the optical glass of the present invention is higher than 15%, it becomes difficult to melt, the melting temperature rises, foreign substances are likely to be mixed in the glass, and the transmittance decreases. Therefore, its content is set to 0-15%, preferably 1-10%, more preferably 2-6%.

ZnO can adjust the refractive index and dispersion of the glass, improve the anti-crystallization performance of the glass, lower the conversion temperature of the glass, and improve the chemical stability of the glass. Also, ZnO can reduce the high-temperature viscosity of the glass, so that the glass can be melted at a lower temperature and the transmittance of the glass can be increased. However, when excessive ZnO is added, the anti-crystallization performance of the glass deteriorates, and the relatively low high-temperature viscosity makes molding difficult. Therefore, in the glass system provided by the present invention, the lower limit of ZnO content is set at 10%, preferably 13%. The upper limit of the ZnO content is set at 25%, preferably 20%, more preferably 17%.

As an optional component, _TiO2 , which can improve the refractive index of the glass, may be added to the glass provided by the present invention in order to enhance the anti-crystallization stability of the glass. Also, to some extent Nb ₂ O ₅ and WO ₃ may be substituted. However, its excessive content causes a decrease in the transmittance of the glass. In the optical glass provided by the present invention, the TiO ₂ content is 0-10%, preferably 0-5%, more preferably 0%.

Nb ₂ O ₅ is a component that can improve the chemical stability and refractive index of glass. If the Nb ₂ O ₅ content is lower than 1%, the optical constants do not reach the design requirements. When the content is higher than 15%, the devitrification resistance of the glass is lowered. Therefore, the Nb ₂ O ₅ content is defined as 1-15%, preferably 2-10%, more preferably 4-8%.

_WO3 is mainly used to maintain the optical constant of the glass and improve the crystallization properties of the glass, but if its content is too high, the transmittance of the glass will decrease, the degree of staining will increase, Crystallization properties deteriorate. Therefore, the WO ₃ content is preferably 1-15%, more preferably 2-12%, more preferably 6-10%.

TiO ₂ , Nb ₂ O ₅ and WO ₃ are effective in improving refractive index and dispersion. Therefore, based on the requirement that the optical glass provided by the _present invention has high reflection, low dispersion and high transmittance, the upper limit of _TiO2 + _Nb2O5 + _WO3 is 30%, preferably It is set to 22%, more preferably 18%. However, if TiO ₂ +Nb ₂ O ₅ +WO ₃ is too low, the thermal stability and formability of the glass will deteriorate. Therefore, the lower limit is set at 2%, preferably 4%, more preferably 10%.

The rare earth oxides Ln ₂ O ₃ (La ₂ O _{3 ,} Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ ) are added because they are beneficial in improving the refractive index of the glass. If the total content is lower than 30%, the expected optical constants cannot be obtained. However, when the total content is higher than 55%, the chemical stability and resistance to devitrification of the glass are lowered, and the raw material cost of the glass is also increased. Therefore, the total content of La ₂ O _{3 ,} Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ , Ln ₂ O ₃ is 30-55%, preferably 35-52%, more preferably 40-55%. Set to 50%.

Rare earth oxides Ln ₂ O ₃ are dispersed in the glass network and are mainly used to improve the refractive index. However, the inventors of the present application have discovered in their studies that the ratio of the glass network constituents B ₂ O ₃ and Ln ₂ O ₃ has a great effect on the chemical stability of the glass. If B ₂ O ₃ /Ln ₂ O ₃ is less than 0.3, chemical stability, especially acid resistance, cannot meet the requirements. When _B2O3 / _{Ln2O3 is} higher than _0.8 , the refractive index decreases. According to the invention, the range is set between 0.3 and 0.8, preferably between 0.3 and 0.6, more preferably between 0.3 and 0.5.

La ₂ O ₃ in the rare earth oxide is a component capable of improving the optical properties of the glass, but if its content exceeds 45%, the devitrification resistance and meltability of the glass may deteriorate. Therefore, the La ₂ O ₃ content provided by the present invention is preferably 20-45%, more preferably 25-40%, more preferably 30-35%.

Gd ₂ O ₃ as an optional component can increase the refractive index of the glass, but does not obviously improve the dispersion of the glass. According to the present invention, the Gd ₂ O ₃ provided by the present invention improves the stability of the glass, significantly enhances the chemical stability of the glass, and prevents excessive increases in dispersion while maintaining the refractive index. can be introduced to control However, when the content is higher than 15%, the devitrification resistance of the glass decreases, but the glass density increases. Therefore, the Gd ₂ O ₃ content provided by the present invention is 0-15%, preferably 1-10%, more preferably 3-7%.

Y ₂ O ₃ can maintain a high refractive index and Abbe number, suppress the increase in the cost of glass materials, improve the meltability and devitrification resistance of the glass, and increase the upper limit of the crystallization temperature and specific gravity of the glass. It is a component that can reduce the However, if its content is higher than 15% in the formulation of the present invention, the chemical stability and resistance to devitrification of the glass are reduced. Therefore, the Y ₂ O ₃ content ranges from 1% to 15%, more preferably from 3% to 15%, more preferably from 6% to 10%.

Y ₂ O ₃ and other rare earth oxides can improve the refractive index of glass. Also, its cost is lower than Gd ₂ O ₃ and its components benefit from weight savings. That component is therefore introduced into the prior art. However, in the formulation system of the present invention, the Y ₂ O ₃ content not only affects the glass independently, but synergistically adjusts the properties of the glass together with other components, including:

If the optical glass provided by the present _invention contains both _Y2O3 and _La2O3 , the devitrification resistance of the glass can be effectively improved, and a glass element _is made from the glass material. In some cases, precision press molding becomes easier, and the difficulty in manufacturing the glass element can be reduced.

If the Y ₂ O ₃ /B ₂ O ₃ ratio is too low, it becomes difficult to release gas during the melting process, which worsens the degree of bubbles in the glass. Therefore, the lower limit of Y ₂ O ₃ /B ₂ O ₃ is 0.15, preferably 0.2, more preferably 0.3. However, if Y ₂ O ₃ /B ₂ O ₃ is too high, the chemical stability of the glass tends to decrease. Therefore, the upper limit of Y ₂ O ₃ /B ₂ O ₃ is 2, preferably 1.8, more preferably 1.5, more preferably 1.3, and even more preferably 1.

Gd ₂ O ₃ and Y ₂ O ₃ can be substituted to some extent in terms of refractive index. Higher Y ₂ O ₃ /Gd ₂ O ₃ values are beneficial in reducing raw material costs. Furthermore, the inventors discovered that when Y ₂ O ₃ /Gd ₂ O ₃ is lower than 0.3 or higher than 3, the crystallization resistance performance of the glass deteriorates. Therefore, Y ₂ O ₃ /Gd ₂ O ₃ is set to 0.3 to 3, preferably 0.5 to 2.5, more preferably higher than 1 but 2 or less.

The proportion of Y ₂ O ₃ in the total rare earth oxide Y ₂ O ₃ /Ln ₂ O ₃ has obvious effect of adjusting anti-crystallization performance. When the value of Y ₂ O ₃ /Ln ₂ O ₃ is 0.08 to 0.45, the anti-crystallization performance is excellent. Its value is more preferably 0.1 to 0.4, more preferably 0.1 to 0.3.

Furthermore, Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) influences the chemical stability of the glass. When the value is between 0.16 and 0.8, the chemical stability of the glass is excellent, the corrosion resistance is strong, and the service life of the optical equipment can be effectively extended. The Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) value is more preferably 0.2-0.7, more preferably 0.3-0.6.

Yb ₂ O ₃ is a component with high refractive index and low dispersion. When its content is higher than 5%, the stability and devitrification resistance of the glass are reduced. Therefore, the range of the content of Yb ₂ O ₃ is defined as 0-5%. On the other hand, when comparing Gd ₂ O ₃ and Y ₂ O ₃ , Yb ₂ O ₃ is expensive and has little effect on improving the meltability of the glass, so it is preferable not to introduce it.

RO belonging to alkaline earth metal oxides is one or more of CaO, MgO, SrO and BaO and is an optional component of the present invention. Estimated amounts of alkaline earth metal oxides are added to the glass to improve the Young's modulus of the glass and reduce the high temperature viscosity of the glass, while balancing the glass composition and improving the meltability of the glass. may However, when the total content of RO is higher than 10%, excessive alkaline earth metal oxides reduce the anti-crystallization performance. Therefore, according to the invention, the RO value is set between 0 and 10%, preferably between 0 and 5%.

Rn ₂ O belonging to alkali metal oxides is one or more of Li ₂ O, Na ₂ O, K ₂ O and is an optional constituent of the present invention. In the glass systems provided by the present invention, approximate amounts of alkali metal oxides may be added to obtain the expected high temperature viscosities. On the other hand, when an approximate amount of alkali metal oxide coexists with B ₂ O ₃ , the compactness of the B ₂ O ₃ network is improved and better light transmittance can be obtained. If the amount of alkali metal oxide is too small, the viscosity of the glass cannot be adjusted to an appropriate range, but if the amount of alkali metal oxide is too large, the resistance to crystallization of the _glass is greatly impaired. It is set to 10%, preferably 0-5%.

The glass provided by the present invention can also incorporate 0-1%, preferably 0-0.5% of a fining agent. The fining agent may be selected from _Sb2O3 , _or /and CeO2 _, or/and _SnO2 .

P ₂ O ₅ , Bi ₂ O ₃ , TeO ₂ , Ga ₂ O ₃ , GeO ₂ , Ta ₂ O ₅ and Lu ₂ O ₃ are included as necessary within a range that does not impair the properties of the glass of the present invention. Minor amounts of other ingredients not listed above can be added. However, transition metal constituents such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo, even when contained in the form of elements or compounds, color the glass and produce May absorb certain wavelengths. Since it weakens the property of the present invention for improving the visible light transmittance, it is preferable that it is not actually contained in an optical glass that requires a wavelength transmittance particularly in the visible region.

Pb, Th, Cd, Tl, Os, Be, and Se compounds have been controlled and used as hazardous chemicals in recent years, not only in the glass manufacturing process, but also in processing procedures and environmental protection measures. It is also necessary for post-manufacturing disposal. Therefore, if environmental impact is a concern, it is preferred that they are not actually included, except for inevitable incorporation. As a result, optical glasses are practically 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.

Characteristics of optical glass

Optical properties

The refractive index (nd) is analyzed according to the method of GB/T7962.1-2010.

The coefficient of dispersion (ie Abbe number, vd) is analyzed according to the method of GB/T7962.1-2010.

[Thermal characteristics]

The coefficient of thermal expansion (α _{−30° C. to 70° C.} ) is analyzed in units of 10 ⁻⁷ /K according to the method of GB/T7962.16-2010.

The conversion temperature (T _g ) is analyzed in °C according to the method specified in GB/T7962.16-2010.

The method of analyzing the upper limit of the crystallization temperature is to use the process of temperature gradient furnace to analyze the crystallization properties of the glass, prepare the glass into a sample of 180 × 10 × 10 mm, polish it laterally, and adjust the temperature Place in a furnace with a gradient (5°C/cm), heat to 1,400°C, keep warm for 4 hours, take out, allow to cool naturally to room temperature, observe crystallization of the glass with a microscope, and respond to crystals. Obtaining an upper bound on the crystallization temperature of the glass when the highest temperature of the glass is found. The lower the upper limit of the crystallization temperature of the glass, the stronger the stability of the glass at high temperatures and the better the performance of the manufacturing process.

[Chemical stability]

Water resistance ( _Dw ) is analyzed according to the method of GB/T17129.

Acid resistance (D _A ) is analyzed according to the method of GB/T17129.

[Degree of bubbles]

The degree of foam is analyzed according to the method of GB/T7962.8-2010.

After analysis, the glass provided by the present invention has the following properties. The refractive index (nd) is 1.84-1.87, preferably 1.85-1.86. Abbe number (vd) is 38-41, preferably 38.5-40. The coefficient of thermal expansion (α _{−30° C. to 70° C.} ) is 75×10 ⁻⁷ /K or less, preferably 70×10 ⁻⁷ /K or less. Water resistance (D _W ) is grade 2 or better, preferably grade 1. The acid resistance is preferably grade 3 or higher, preferably grade 2 or higher. The upper limit of the crystallization temperature is 1,250° C. or lower, more preferably 1,200° C. or lower, and more preferably 1,180° C. or lower. The degree of foaming is grade A or higher, preferably grade _A0 or higher, more preferably grade _A00 . The conversion temperature (Tg) of the glass is 640°C or less, preferably 630°C or less, more preferably less than 625°C.

Optical glass embodiment

The following non-limiting embodiments are provided for the purpose of more clearly describing and illustrating the technical solutions of the present invention.

Weighing according to the corresponding content of all embodiments or comparative examples, mixing the usual raw materials of optical glass (including oxides, hydroxides, carbonates and nitrates), and placing the mixed raw materials into a platinum crucible and melted at 1,200-1,500°C for 2-6 hours, then fined, stirred, and homogenized to obtain a homogeneous molten glass, and then cast the molten glass in the mold. and annealing, optical glasses of Embodiments 1 to 48 in Tables 1 to 6 and Comparative Examples 1 to 5 in Table 7 are obtained.

The optical glass according to the embodiment of the present invention is easy to be precisely press-molded and has excellent devitrification resistance. The Ln ₂ O ₃ content is lower than 55% and the cost is also low. With good chemical stability, the water resistance (D _W ) is grade 2 or higher, and grade 1 in the preferred technical solution. The acid resistance is grade 3 or above, and grade 2 or above in the preferred technical solution. The degree of foam is grade A or above, grade A ₀ or above in the preferred technical solution, and grade A ₀₀ or above in the more preferred technical solution. Thus the degree of foaming is excellent. In addition, the coefficient of thermal expansion (α _{−30° C. to 70° C.} ) is 75×10 ⁻⁷ /K or less, more preferably α _{−30° C. to 70° C.} is 70×10 ⁻⁷ /K or less, Small degree of temperature-affected expansion or contraction. On the other hand, optical glass has even better resistance to crystallization.

Embodiment of Glass Preform The optical glass obtained in Embodiments 1 to 48 is cut into a predetermined size, and a release agent is uniformly applied to the surface. The mold is then heated and softened and press molded 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. Alternatively, the optical glass obtained in Embodiments 1 to 48 is used to form a pre-molded product for precision press molding, which is then precision press-molded into a lens and prism shape by precision press molding and processing to produce a preform. do.

Optical Element Embodiments The preforms obtained in the glass preform embodiments are annealed for fine tuning while reducing deformation inside the glass so that optical properties such as refractive index are at desired values. Become.

Each preform is then ground and polished to form various lenses and prisms, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. An antireflection coating may be coated on the surface of the resulting optical element.

Optical Device Embodiments Optical components or optical members are formed by optical elements obtained in optical element embodiments, either through optical design or through one or more optical elements. Optical components or optical members are used in imaging devices, sensors, microscopes, medical technology, digital projection, telecommunications, optical communication technology/information transmission, optics/illumination in the automotive sector, photolithography, excimer lasers, wafers, computer chips, integrated circuits, and electronic equipment containing such circuits and chips, in particular camera equipment and equipment in the vehicle field.

Claims (16)

In weight percentage, 0-10% SiO ₂ , 5-25% B ₂ O ₃ , 0-15% ZrO ₂ , 10-25% ZnO, 2-30% TiO ₂ +Nb ₂ O ₅ +WO ₃ and 30-55% Ln ₂ O ₃ , said Ln ₂ O ₃ being the sum of La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ content, B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.8, Y ₂ O ₃ /B ₂ O ₃ is 0.15 to 2, Y ₂ O ₃ /Gd ₂ O ₃ is 1.100 to 3, the upper limit of the crystallization temperature of the optical glass is 1,250 ° C. or less,
Nb ₂ O ₅ 4-8%, WO 3 6-10%, La _{2 O} 3 _30-35 %, Gd ₂ O ₃ 3-7%, Y ₂ O ₃ 6-10% An optical glass characterized by: 0-10% RO, 0-10% Rn ₂ O, and 0-1% clarifier, wherein the RO is one or more of MgO, CaO, SrO, or BaO; _{2. Rn2O} is one or more of _Li2O , _Na2O , _K2O , and said fining agent is one or more of _Sb2O3 , _{SnO2 , CeO2} . The optical glass described in . In weight percentage, 0-10% SiO _{2 ,} 5-25% B ₂ O ₃ , 0-15% ZrO ₂ , 10-25% ZnO, 2-30% TiO ₂ +Nb ₂ O ₅ +WO ₃ , 30-55% Ln ₂ O ₃ , 0-10% RO, 0-10% Rn ₂ O, 0-1% refining agent, Ln ₂ O ₃ is the total content of La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ , and the RO is one or more of MgO, CaO, SrO, or BaO; The Rn ₂ O is one or more of Li ₂ O, Na ₂ O, K ₂ O, the fining agent is one or more of Sb ₂ O ₃ , SnO _{2 ,} CeO ₂ and B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.8, Y ₂ O ₃ /B ₂ O ₃ is 0.15 to 2, Y ₂ O ₃ /Gd ₂ O ₃ is 1.100 to 3, optical glass The upper limit of the crystallization temperature of is 1,250 ° C. or less,
Nb ₂ O ₅ 4-8%, WO 3 6-10%, La _{2 O} 3 _30-35 %, Gd ₂ O ₃ 3-7%, Y ₂ O ₃ 6-10% An optical glass characterized by: The optical glass according to any one of claims 1 to 3, wherein the content of all the constituent elements satisfies one or more of the following four conditions:
1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0 to 0.25;
2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.08 to 0.45;
3) Y ₂ O ₃ /Gd ₂ O ₃ is 1.155 to 2.5;
4) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.16 to 0.8; 1-8% SiO ₂ and/or 10-23% B ₂ O ₃ and/or 1-10% ZrO ₂ and/or 10-20% ZnO and/or TiO ₂ +Nb ₂ O ₅ +WO ₃ 4-22%, and/or Ln ₂ O ₃ 35-52%, and/or RO 0-5%, and/or R ₂ O 0-5%, and/or refining agent 4. The optical glass according to any one of claims 1 to 3, which is 0 to 0.5%. The optical glass according to any one of claims 1 to 3, wherein the content of all constituent elements satisfies one or more of the following six conditions:
1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0.05 to 0.23;
2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.1 to 0.4;
3) Y ₂ O ₃ /Gd ₂ O ₃ is 1.165 to 2;
4) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.2 to 0.7;
5) B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.6;
6) Y ₂ O ₃ /B ₂ O ₃ is 0.2 to 1.5; 1-4% SiO ₂ and/or 15-20% B ₂ O ₃ and/or 2-6% ZrO ₂ and/or 13-17% ZnO and/or TiO ₂ +Nb ₂ O _{4. The} optical glass according to any one of claims 1 to 3, characterized in that 5+ _WO3 is 10-18% and/or _Ln2O3 is 40-50%. The optical glass according to any one of claims 1 to 3, wherein the content of all constituent elements satisfies one or more of the following six conditions:
1) SiO ₂ /(SiO ₂ +B ₂ O ₃ ) is 0.08 to 0.2;
2) Y ₂ O ₃ /Ln ₂ O ₃ is 0.1 to 0.3;
3) Y ₂ O ₃ /(SiO ₂ +B ₂ O ₃ ) is 0.3 to 0.6;
4) B ₂ O ₃ /Ln ₂ O ₃ is 0.3 to 0.5;
5) Y ₂ O ₃ /B ₂ O ₃ is 0.3-1. The optical glass according to any one of claims 1 to 3, characterized in that TiO ₂ is 0-10% and Yb ₂ O ₃ is 0-5%. The optical glass according to any one of claims 1 to 3, characterized in that TiO ₂ is 0-5% . The optical glass according to any one of claims 1 to 3, characterized in that it does not contain TiO ₂ . The refractive index (nd) of the optical glass is 1.84 to 1.87, the Abbe number (vd) is 38.0 to 41.0, and the powder method water resistance (DW) of the optical glass is grade 2 or more, the acid resistance (DA) of the powder method is grade 3 or more, the thermal expansion coefficient (α _{−30° C to 70° C} ) of the optical glass is 75×10 −7 /K or less, The degree of bubbles of the optical glass is grade A or higher, the conversion temperature (Tg) of the optical glass is 640° C. or lower, and the upper limit of the crystallization temperature of the optical glass is 1,200° C. or lower. The optical glass according to any one of claims 1 to 3. The refractive index (nd) of the optical glass is 1.85 to 1.86, the Abbe number (vd) is 38.5 to 40.0, and the water resistance (D _W ) of the optical glass by the powder method is It is grade 1, the acid resistance (D _A ) of the powder method is grade 2, the thermal expansion coefficient (α _{−30 ° C to 70 ° C} ) of the optical glass is 70 × 10 ^-7 /K or less, The degree of bubbles of the optical glass is grade _A0 or higher, the conversion temperature (Tg) of the optical glass is 625°C or lower, and the upper limit of the crystallization temperature of the optical glass is 1,180°C or lower. The optical glass according to any one of claims 1 to 3. A glass preform made from the optical glass according to any one of claims 1-13. An optical element made from the optical glass according to any one of claims 1 to 13 or the glass preform according to claim 14. An optical instrument made from the optical element according to claim 15 .