TW202019846A - Optical glass, glass preform, optical element, and optical instrument - Google Patents

Abstract

Disclosed is optical glass having a medium refractive index and a low refractive index temperature coefficient, the composition of which comprises optical glasses of SiO2, B2O3, La2O3, RO and Rn2O, wherein RO is one or more of MgO, CaO, SrO and BaO, and Rn2O is one or more of Li2O, K2O and Na2O. The optical glass has a refractive index of 1.65-1.73 and an Abbe number of 47-55, and at the same time also has a lower refractive index temperature coefficient, an excellent crystallization resistance and chemical stability.

Description

Optical glass, glass preforms, optical components and optical instruments

The invention relates to an optical glass, in particular to a lanthanum-containing optical glass with a refractive index of 1.65 to 1.73 and an Abbe number of 47 to 55, as well as glass preforms, optical elements and optical instruments made of the optical glass.

In the prior art, glass with a refractive index of 1.65 to 1.73 and an Abbe number of 47 to 55 is a medium refractive index glass, which is widely used in various types of lenses; in recent years, vehicle lens equipment has been vigorously developed, and general photography Compared with other applications, the quality of the car lens is closely related to safety. Therefore, the car lens emphasizes the reliability of the device, especially when it is exposed outside the car body, it needs to withstand harsh working environments, such as reversing camera, front view camera, and rearview mirror assistance. Camera etc.

The principle of designing a vehicle lens that meets the harsh working environment is that the structure is as simple as possible. The more complex the structure, the worse the reliability; therefore, in order to meet the design requirements of a long-life (up to more than ten years) vehicle lens that can adapt to the harsh working environment In the optical design, the fixed focus lens design is generally used. The number of lenses is less than that of the zoom lens. At the same time, there is no zoom drive structure, so the reliability is greatly improved compared to the zoom lens.

However, although the reliability of the fixed focus lens is very good, it is used in vehicles. Its fatal weakness is that it is very difficult to correct the temperature drift of the lens; the temperature drift of the lens refers to when the temperature changes drastically, such as day and night in a desert area When the temperature difference reaches 60°C, when the car travels from a tropical zone to a cold zone, the focal length of the lens will change, resulting in blurred imaging. For cars, safety is the first priority. Therefore, the car camera needs to be at a temperature Under sharply changing conditions, clear imaging can be maintained.

For optical design, usually more different types of lens combinations and zoom systems can be used to solve the temperature drift problem; however, due to the reliability requirements of the vehicle system, a small number of lenses (even 3 lenses) are required. To solve the problem of temperature drift on the fixed focus imaging system, this requires the development of optical glass with a specific temperature index of refraction. This is also a new topic raised by the development of the times for optical design and optical material research.

At present, the prior art optical glass with a refractive index of 1.65 to 1.73 and an Abbe number of 47 to 55 has a temperature coefficient of refractive index in the range of 20 to 40°C, that is, d-line dn/dt relative(10 ^-6 /°C ) Basically around 1.0～3.0(10 ^-6 /℃) (see Table 1 below). If a lanthanum crown glass with a refractive index temperature coefficient lower than 0 or even lower than -1.0 and above optical properties can be developed, the above temperature drift problem can be effectively solved in the design. Table 1: Refractive index temperature coefficient of glass with partial refractive index of 1.65 to 1.73 and Abbe number of 47 to 55

However, if the above-mentioned lanthanum crown glass with refractive index and Abbe number needs to achieve a refractive index temperature coefficient lower than 0, the composition design needs to be different from conventional, which usually brings poor glass devitrification resistance and fringing to production. Bubbles are not easy to eliminate and other problems.

If the anti-crystallization ability of glass is poor, it will firstly increase the production difficulty of the glass blanks, resulting in a decrease in the yield rate, and even in a serious case, it may not even be able to produce normally; secondly, it is easy to produce crystal precipitation during the secondary molding process, resulting in a decrease in the yield rate. Even secondary molding is not possible. For glass materials used in the automotive field, if the production yield of glass is low and the secondary molding cannot be used instead of cold working, the increase in cost will make it unacceptable.

The technical problem to be solved by the present invention is to provide an optical glass with a medium refractive index and a low refractive index temperature coefficient.

In order to achieve the above object, the present invention provides an optical glass whose composition includes SiO ₂ , B ₂ O ₃ , La ₂ O ₃ , RO, and Rn ₂ O, where RO is one or more of MgO, CaO, SrO, and BaO Rn ₂ O is one or more of Li ₂ O, K ₂ O and Na ₂ O, the refractive index of the glass is 1.65 to 1.73, the Abbe number is 47 to 55, and the temperature coefficient of the refractive index is ≤0.

In one of the embodiments, the composition of the optical glass is expressed as a percentage by weight, including: SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO: 10～ 40%, SrO: 0 to 15%, CaO: 0 to 10%, MgO: 0 to 5%, Li ₂ O: 0 to 5%, K ₂ O: 0 to 6%, Na ₂ O: 0 to 8% , Gd ₂ O ₃ : 0 to 8%, Y ₂ O ₃ : 0 to 5%, ZrO ₂ : 0 to 3%, Al ₂ O ₃ : 0 to 3%, TiO ₂ : 0 to 3%, Nb ₂ O ₅ : 0 to 5%, WO ₃ : 0 to 2%, ZnO: 0 to 5%, clarifying agent: 0 to 2%.

Another embodiment of the present invention provides an optical glass, the composition of which is expressed as a percentage by weight, containing: SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO : 10 to 40%, SrO: 0 to 15%.

In one embodiment, the optical glass further includes: CaO: 0-10%, MgO: 0-5%, Li ₂ O: 0-5%, K ₂ O: 0-6%, Na ₂ O : 0 to 8%, Gd ₂ O ₃ : 0 to 8%, Y ₂ O ₃ : 0 to 5%, ZrO ₂ : 0 to 3%, Al ₂ O ₃ : 0 to 3%, TiO ₂ : 0 to 3 %, Nb ₂ O ₅ : 0 to 5%, WO ₃ : 0 to 2%, ZnO: 0 to 5%, clarifying agent: 0 to 2%.

Yet another embodiment of the present invention provides an optical glass, the composition of which is expressed as a percentage by weight of SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO: 10 ～40%, SrO:0～15%, CaO:0～10%, MgO:0～5%, Rn ₂ 0:0～8%, Gd ₂ O ₃ ：0～8%, Y ₂ O ₃ ：0 ～5%, ZrO ₂ ：0～3%, Al ₂ O ₃ ：0～3%, TiO ₂ ：0～3%, Nb ₂ O ₅ ：0～5%, WO ₃ ：0～2%, ZnO: 0 to 5% composition, in which Rn ₂ O is one or more of Li ₂ O, K ₂ O, and Na ₂ O.

In one of the embodiments, SiO ₂ /B ₂ O ₃ is 0.4 to 1.3, preferably 0.45 to 1.2, more preferably 0.5 to 1.1; and/or BaO/La ₂ O ₃ is 0.6 to 2, preferably 0.65 ~1.9, more preferably 0.7~1.8.

In one of the embodiments, CaO/(BaO+SrO) is 0-0.5, preferably 0.01-0.4, more preferably 0.02-0.3; and/or ZnO/(CaO+SrO+BaO) is 0-0.3, Preferably it is 0-0.2, more preferably 0-0.15; and/or (CaO+SrO+BaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) is 0.7-2.5, preferably 0.8-2.3 , More preferably 0.9-2.1; and/or (CaO+SrO+BaO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) greater than 8, preferably greater than 10, more preferably greater than 12; and/or SrO content ≥CaO Content, preferably BaO content ≥ SrO content ≥ CaO content.

In one of the embodiments, Li ₂ O+Na ₂ O+K ₂ O is 0-8%, preferably 0-6%, more preferably 0-5%; and/or Li ₂ O/(K ₂ O+Na ₂ O) is 0 to 0.5, preferably 0 to 0.4, more preferably 0 to 0.3; and/or Na ₂ O/K ₂ O is 0.2 to 5.0, preferably 0.3 to 4.0, more preferably 0.4 to 3.0; and/or TiO ₂ /Nb ₂ O ₅ is 1 or less, preferably 0.8 or less, and more preferably 0.5 or less.

In one of the embodiments, the composition of the optical glass is expressed as a percentage by weight, including: SiO ₂ : 6-18%, and/or B ₂ O ₃ : 12-25%, and/or La ₂ O ₃ : 12- 30%, and/or BaO: 12 to 35%, and/or SrO: 0.5 to 15%, and/or CaO: 0 to 8%, and/or Gd ₂ O ₃ : 1 to 6%, and/or Y ₂ O ₃ : 0 to 3%, and/or ZrO ₂ : 0.1 to 3%, and/or Al ₂ O ₃ : 0 to 2%, and/or TiO ₂ : 0 to 2%, and/or Nb ₂ O ₅ : 0.1 to 5%, and/or WO ₃ : 0 to 1%, and/or ZnO: 0 to 3%, and/or MgO: 0 to 3%, and/or Li ₂ O: 0 to 3%, And/or K ₂ O: 0.3 to 4%, and/or Na ₂ O: 0.5 to 6%.

In one of the embodiments, the composition of the optical glass is expressed as a percentage by weight, including: SiO ₂ : 8-16%, and/or B ₂ O ₃ : 15-22%, and/or La ₂ O ₃ : 15- 28%, and/or BaO: 15 to 32%, and/or SrO: 1 to 12%, and/or CaO: 0 to 6%, and/or Gd ₂ O ₃ : 1 to 4%, and/or Y ₂ O ₃ : 1 to 3%, and/or ZrO ₂ : 0.1 to 2%, and/or Al ₂ O ₃ : 0.1 to 1%, and/or TiO ₂ : 0 to 1%, and/or Nb ₂ O ₅ : 0.5 to 4%, and/or K ₂ O: 0.5 to 3%, and/or Na ₂ O: 1 to 3%.

In one of the embodiments, the composition of the optical glass is expressed as a percentage by weight, and contains: ZrO ₂ : 0.1 to 1%, and/or Nb ₂ O ₅ : 1 to 3%, and/or SrO: 1.5 to 10%.

In one of the embodiments, the refractive index of the glass is 1.65 to 1.73, preferably 1.67 to 1.72; the Abbe number is 47 to 55, preferably 48 to 52.

In one of the embodiments, the temperature coefficient of refractive index of the glass is ≤0, preferably ≤-0.5, more preferably ≤-1.0, and further preferably ≤-2.0.

In one of the embodiments, the water resistance stability of the glass is Class 4 or above, preferably Class 3 or above, and more preferably Class 2 or above; and/or the degree of bubble is above Class A, preferably A Grade ₀ or more, more preferably grade A ₀₀ ; and/or streak is grade C or more, preferably grade B or more, more preferably grade A; and/or sunlight resistance stability is that the transmittance at 400 nm wavelength does not decrease by more than 10%, It is preferably not more than 8%, further preferably not more than 5%.

Some embodiments of the present invention provide a glass preform made of the aforementioned optical glass.

Some embodiments of the present invention provide an optical element made using the aforementioned optical glass or the aforementioned glass preform.

Some embodiments of the present invention provide an optical instrument made using the aforementioned optical glass or the aforementioned optical element.

Some embodiments of the present invention provide a use of the aforementioned optical glass or the aforementioned optical element, which is applied to a vehicle.

The beneficial effects of the present invention are: through reasonable component design, the optical glass of the present invention has a medium refractive index and a low refractive index temperature coefficient, and the mass production process performance is good.

Next, the composition range of each component of the optical glass of the present invention will be described. In this specification, unless otherwise specified, the content of each component is expressed as a weight percentage relative to the total amount of glass substances converted into oxide compositions. Here, the "composition converted to oxide" refers to the case where the oxide, complex salt, hydroxide, etc. used as the raw material of the optical glass composition of the present invention are decomposed and converted into an oxide when melted , The total amount of the oxide is regarded as 100%.

Unless otherwise specified in specific circumstances, the numerical ranges listed herein include upper and lower limits, "above" and "below" include endpoints, all integers and fractions within the range, not limited to the limited range The specific values listed at the time. The term "about" as used herein refers to formulas, parameters, and other quantities and characteristics that are not, and need not be precise, and can be approximated and/or larger or lower if necessary, which reflects tolerances, conversion factors, and measurement errors, etc. . As used herein, "and/or" is inclusive, such as "A and/or B", meaning that there is only A, or only B, or both.

The optical glass of the present invention is mainly composed of SiO ₂ , B ₂ O ₃ , La ₂ O ₃ , RO (RO is one or more of MgO, CaO, SrO, BaO, the same below), Rn ₂ O (Rn ₂ O is Li One or more than ₂ O, K ₂ O, Na ₂ O, the same below), through a reasonable composition ratio, to form an optical glass with a refractive index of 1.65 to 1.73 and an Abbe number of 47 to 55, and The temperature coefficient of refractive index (d-line dn/dt relative(10 ^-6 /℃)) is low in the temperature range of 20 to 40°C, and it has excellent resistance to devitrification. The transmittance will not drop significantly after long-term use, which is very suitable for vehicle Lens use.

SiO ₂ and B ₂ O ₃ are the network forming bodies constituting the glass of the present invention, and are the basis for forming glass, and their contents are closely related to the key indicators such as glass-forming stability, anti-crystallization property, refractive index and Abbe number. Wherein, when the SiO ₂ content exceeds 20%, it becomes difficult to melt the glass, while the stability of the glass decreases to a sharp decline in the devitrification properties, the refractive index and the Abbe number of the glass design requirements; if the SiO ₂ If the content is less than 4%, the chemical stability of the glass, especially the stability against water, will decrease, and the crystallization resistance of the glass will decrease. Therefore, the content of SiO ₂ is limited to 4 to 20%, preferably 6 to 18%, and more preferably 8 to 16%. In some embodiments, it may comprise about 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17% , 18%, 19%, 20% SiO ₂ .

If the content of B ₂ O ₃ exceeds 30%, the chemical stability of the glass will decrease, and the Abbe number will be higher than the design expectation; if the content of B ₂ O ₃ is less than 10%, the anti-crystallization property of the glass will rapidly decline. And the Abbe number of glass can not meet the design expectations. Therefore, the content of B ₂ O ₃ is limited to 10 to 30%, preferably 12 to 25%, and more preferably 15 to 22%. In some embodiments, it may comprise about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% , 24%, 25%, 26%, 27%, 28%, 29%, 30% of B ₂ O ₃ .

The relative content of SiO ₂ and B ₂ O ₃ will determine the structural state of B ₂ O ₃ in glass to a certain extent, and the structural state of B ₂ O ₃ will have a greater effect on the refractive index temperature coefficient and chemical stability of glass effect, when the ratio of B to SiO ₂ SiO ₂ O ₃ is ₂ / B ₂ O ₃ is greater than 1.3, the refractive index temperature coefficient of the glass will rise quickly reach the design requirements; if SiO ₂ / B ₂ O ₃ is less than At 0.4, the chemical stability of the glass, especially the water resistance, will decrease rapidly, which cannot meet the requirements for use in harsh conditions. Therefore, in the present invention, the value of SiO ₂ /B ₂ O ₃ is preferably limited to 0.4 to 1.3. In addition, in some embodiments, if the value of SiO ₂ /B ₂ O ₃ is less than 0.45, the high-temperature viscosity of the glass during molding is extremely small, and it is easy to produce streaks below the C level in the glass, resulting in the glass can not be used in higher imaging requirements In the system, if the value of SiO ₂ /B ₂ O ₃ is higher than 1.2, bubbles in the glass are difficult to eliminate. Therefore, in some embodiments, the value of SiO ₂ /B ₂ O ₃ is more preferably 0.45 to 1.2, and still more preferably 0.5 to 1.1. In some embodiments, the value of SiO ₂ /B ₂ O ₃ may be 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2 , 1.25, 1.3.

La ₂ O ₃ is an important component of the glass of the present invention. Adding it to the glass can quickly increase the refractive index of the glass, enabling the glass to achieve high refractive index and low dispersion. However, if its content exceeds 35%, the crystallization resistance of the glass will drop sharply. More seriously, the inventors have found that La ₂ O ₃ has a strong aggregation effect. When the content exceeds 35%, the glass will rapidly increase the Refractive index temperature coefficient, which is contrary to the goal of the present invention to reduce the refractive index temperature coefficient of glass; if its content is less than 10%, the refractive index and dispersion of the glass cannot meet the design requirements, and the chemical stability of the glass, especially Water resistance will be reduced. Therefore, the content of La ₂ O ₃ is limited to 10 to 35%, preferably 12 to 30%, and more preferably 15 to 28%. In some embodiments, it may comprise about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% , 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35% La ₂ O ₃ .

In order to maintain good crystallization resistance of glass even when the content of La ₂ O _{3 is} relatively high, the inventors found that adding a certain amount of Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Al ₂ O ₃ can improve the crystallization resistance of glass.

Specifically, the effect of Gd ₂ O ₃ on refractive index and dispersion is similar to La ₂ O ₃ , but if the content is higher than 8%, the temperature coefficient of the refractive index of the glass will rise rapidly, the cost will rise rapidly, and the anti-crystallization performance of the glass Instead, it will decrease, so its content is limited to 0-8%, preferably 1-6%, more preferably 1-4%; in some embodiments, it may contain about 0%, greater than 0%, 1%, 1.5 %, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% of Gd ₂ O ₃ .

A small amount of Y ₂ O ₃ added to the glass instead of La ₂ O ₃ will not cause a large change in the refractive index and dispersion of the glass, but if its content exceeds 5%, the temperature coefficient of the refractive index of the glass will rise rapidly, and the glass’s resistance Crystallization performance will decrease. Therefore, the content is limited to 0 to 5%, preferably 0 to 3%, and more preferably 1 to 3%. In some embodiments, Y ₂ O ₃ may be included at about 0%, greater than 0%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

ZrO ₂ is an optional component in the present invention. Adding a small amount to the glass can improve the crystallization resistance of the glass and significantly improve the chemical stability of the glass. At the same time, adding a small amount of ZrO ₂ can significantly reduce the glass liquid to the refractory during the production process. The erosion on the one hand can improve the furnace life, reduce the cost of furnace maintenance and waste discharge, on the other hand, it can significantly inhibit the impurities in the refractory material from entering the glass, and improve the glass transmittance and anti-crystallization stability. However, ZrO ₂ is harmful to lowering the temperature coefficient of the refractive index of the glass in this system glass. If its content exceeds 3%, the temperature coefficient of the refractive index of the glass will increase rapidly, which cannot meet the design requirements, and the glass becomes very difficult After melting, the devitrification resistance will decrease rapidly. Therefore, the ZrO ₂ content in the present invention is limited to 3% or less. If the content of ZrO ₂ is less than 0.1%, the erosion of refractory materials by glass increases significantly. Therefore, in the present invention, the ZrO ₂ content is preferably 0.1 to 3%, more preferably 0.1 to 2%, and still more preferably 0.1 to 1%. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2 %, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% ZrO ₂ .

A small amount of Al ₂ O ₃ added to the glass can improve the crystallization resistance of the glass, and also reduce the ability of the glass liquid to corrode the crucible material. However, if its added amount is higher than 3%, the temperature coefficient of the refractive index of the glass will increase, and at the same time the melting performance of the glass will decrease, and the refractive index will also decrease rapidly. Therefore, the content is limited to 3% or less, preferably 2% or less, and more preferably 0.1 to 1%. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2 %, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% and 3% Al ₂ O ₃ .

A small amount of TiO ₂ added to the glass will improve the glass's resistance to sunlight, especially for the long-term exposure of the vehicle lens to high ultraviolet environments such as plateau. In addition, a small amount of TiO ₂ will enhance the crystallization resistance of glass. However, TiO ₂ is harmful to the reduction of the refractive index temperature coefficient for the glass of this system; after a large number of experimental studies by the inventors, it has been found that if its content exceeds 3%, the refractive index temperature coefficient of the glass cannot meet the design requirements. Therefore, In the present invention, the TiO ₂ content is 3% or less, preferably 0 to 2%, and more preferably 0 to 1%. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2 %, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% TiO ₂ .

Nb ₂ O ₅ and WO ₃ are high-refractive and high-dispersion oxides. When added to glass, they can adjust the refractive index and dispersion of the glass, and at the same time improve the chemical stability of the glass. The inventors found that in the system glass, the ability of these two oxides to increase the temperature coefficient of the refractive index of the glass is slower than other high-refractive high-dispersion oxides, such as TiO ₂ , Bi ₂ O ₃ , Ta ₂ O ₅ , and PbO. From the perspective of reducing the temperature coefficient of refractive index of the glass of the present invention, these two high-dispersion oxides are ideal oxides to increase the dispersion of glass. If the content of Nb ₂ O ₅ exceeds 5%, the Abbe number of the glass will rapidly decrease and the design requirements will not be met, and the anti-crystallization property of the glass will also decrease rapidly. Therefore, the content of Nb ₂ O ₅ in the present invention is limited to 5 %the following. If the content of Nb ₂ O ₅ is less than 0.1%, it means that more WO ₃ or other high-dispersion oxides mentioned above need to be added, which will cause the transmittance of the glass to drop or the temperature coefficient of the refractive index to rise rapidly, so The content of Nb ₂ O ₅ is preferably 0.1 to 5%, more preferably 0.5 to 4%, and still more preferably 1 to 3%. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2 %, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% Nb ₂ O ₅ .

WO ₃ can be used instead of Nb ₂ O _{5 in} small amounts, but if its content exceeds 2%, the transmittance of glass will be significantly reduced; therefore, its content is limited to 2% or less, preferably 1% or less, and further preferably not introduced. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2 WO _{3 of} %, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%.

Furthermore, the glass involved in the present invention is mainly used in open and harsh environments, such as car lenses, security lenses, etc., and will be exposed to sunlight for a long time, especially in plateau areas. The traditional optical glass is designed for photographic equipment, and usually does not take into account the problem that the transmittance of the glass decreases after long-term exposure; therefore, how to improve the stability of the glass against sunlight is a key issue of the glass of the present invention.

After several experiments by the inventors, it has been found that in some embodiments, the simultaneous use of Nb ₂ O ₅ and TiO ₂ is more effective than the use of TiO ₂ alone to improve the glass's resistance to sunlight; however, when TiO ₂ and Nb ₂ O ₅ When the ratio of TiO ₂ /Nb ₂ O _{5 is} greater than 1, the stability of the glass against sunlight is no longer improved, but the refractive index temperature coefficient rises faster, which is contrary to the goal of obtaining a lower refractive index temperature coefficient. Therefore, in order to obtain a glass with a lower refractive index temperature coefficient and strong resistance to sunlight, the value of TiO ₂ /Nb ₂ O ₅ is 1 or less, preferably 0.8 or less, and more preferably 0.5 or less. In some embodiments, the value of TiO ₂ /Nb ₂ O ₅ may be 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, _0.5 , 0.55, 0.6, 0.65, 0.7, 0.75, 0.8 , 0.85, 0.9, 0.95, 1.

For the glass of the system of the present invention, the addition of ZnO to the glass can improve the chemical stability of the glass, reduce the high-temperature viscosity of the glass, and thus reduce the difficulty of glass production. However, the inventors found that if the content of ZnO exceeds 5%, the temperature coefficient of the refractive index of the glass will rapidly decrease; therefore, the content is limited to 5% or less, preferably 3% or less, and further preferably not introduced. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% of ZnO .

BaO, CaO, SrO, and MgO are all alkaline earth metal oxides. Adding to glass can adjust the refractive index and dispersion of the glass, enhance the stability of the glass, and improve the anti-crystallization performance of the glass. The general technical literature believes that such glass The role of the same family of oxides is basically the same. However, the inventors have found through many experiments that for the temperature coefficient of refractive index, chemical stability, and anti-crystallization performance that the glass of this system is most concerned about, the role of the above alkaline earth metal oxides is very different.

BaO has the strongest ability to reduce the refractive index temperature coefficient of glass, so its content needs to be limited to more than 10% to achieve the desired refractive index temperature coefficient of the invention; but if its content exceeds 40%, the chemical stability of the glass, especially water resistance will Rapid decline, the crystallization resistance of glass will also decline rapidly. Therefore, the content is limited to 10 to 40%, preferably 12 to 35%, and more preferably 15 to 32%. In some embodiments, it may comprise about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% , 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40 % BaO.

The ability of SrO to reduce the temperature coefficient of the refractive index of glass is stronger than CaO but weaker than BaO, and its ability to add glass to destroy the chemical stability of glass is weaker than BaO. If the content of SrO exceeds 15%, the crystallization resistance of glass will deteriorate rapidly At the same time, the temperature coefficient of the refractive index of the glass will rise rapidly, so its content is 15% or less. On the other hand, through a large number of experimental studies, it has been found that when BaO is higher than 15%, the addition of SrO of more than 0.5% can significantly improve the water resistance and devitrification stability of the glass, and the temperature coefficient of the refractive index of the glass will not increase significantly. . Therefore, in the present invention, the SrO content is preferably 0.5 to 15%, more preferably 1 to 12%, and still more preferably 1.5 to 10%. In some embodiments, it may comprise about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5 %, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15% SrO.

Generally speaking, CaO is an indispensable component in lanthanum crown glass. Adding it to glass can increase the refractive index and dispersion of the glass, significantly reduce the density of the glass, make the lens lightweight, reduce the high temperature viscosity and surface tension of the glass To reduce the difficulty of glass production, however, for the system glass of the present invention, CaO has the ability to reduce the refractive index temperature coefficient of glass inferior to BaO and SrO, so from the perspective of reducing the refractive index temperature coefficient, it is preferable not to introduce; Among them, CaO has the weakest ability to destroy water resistance among the above three alkaline earth metal oxides, so from the perspective of improving the water resistance of glass, it can also be added in an appropriate amount. Therefore, the CaO content is limited to 0 to 10%, preferably 0 to 8%, and more preferably 0 to 6%. In some embodiments, it may comprise about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6 %, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% CaO.

For the system glass of the present invention, MgO is harmful to lower the temperature coefficient of the refractive index of the glass, but a small amount of addition can improve the water resistance and stability of the glass. If its content exceeds 5%, the temperature coefficient of the refractive index of the glass does not meet the design requirements, and the anti-crystallization ability of the glass will rapidly decrease. Therefore, its content is limited to 5% or less, preferably 3% or less, and further preferably not introduced; in some embodiments, it may contain about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% MgO.

More importantly, the inventors found that in some embodiments, when BaO, CaO, and SrO are all added to the alkaline earth metal oxides, the glass will have a complex synergistic effect, and the performance does not linear with the addition of a single substance. Change, when the value of CaO/(BaO+SrO) exceeds 0.5, although the chemical stability of the glass will be improved to some extent, the temperature coefficient of the refractive index of the glass will increase rapidly, and the anti-crystallization property of the glass will decrease rapidly. In the invention, the value of CaO/(BaO+SrO) is preferably 0 to 0.5. In some embodiments, it is more preferable that the value of CaO/(BaO+SrO) is 0.01-0.4, and even more preferably 0.02-0.3, the temperature coefficient of refractive index, chemical stability, and anti-crystallization performance of the glass can all meet the design expectations. . In some embodiments, the value of CaO/(BaO+SrO) may be 0, greater than 0, 0.01, 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5.

In some embodiments, if a lower temperature refractive index coefficient is desired, it is preferable to satisfy BaO content ≥ CaO content, further satisfy SrO content ≥ CaO content, and further satisfy BaO content ≥ SrO content ≥ CaO content.

If ZnO is added to the glass system to enhance the chemical stability of the glass, it is necessary to consider the problem of increasing the temperature coefficient of refractive index caused by the addition of ZnO; the inventors found that in some embodiments, ZnO/(CaO+BaO+ The value of SrO) has an effect on the temperature coefficient of refractive index and the chemical stability of the glass; when the value of ZnO/(CaO+BaO+SrO) is greater than 0.3, the chemical stability of the glass hardly increases, but the refractive index of the glass The temperature coefficient rises sharply. Therefore, in order to obtain glass with better chemical stability and a lower refractive index temperature coefficient, the value of ZnO/(CaO+BaO+SrO) should preferably be 0.3 or less, more preferably 0.2 or less, and still more preferably 0.15 or less. In some embodiments, the value of ZnO/(CaO+BaO+SrO) may be 0, greater than 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3.

Li ₂ O, Na ₂ O, and K ₂ O are all alkali metal oxides. The addition of an appropriate amount can reduce the temperature coefficient of the refractive index of the glass, but the chemical stability and anti-crystallization properties of the glass will rapidly decrease. The inventor found through extensive experiments:

1) In the system glass of the present invention, the temperature coefficient of the refractive index of the glass does not decrease linearly with the growth of the alkali metal oxide, but the temperature coefficient of the refractive index does not decrease after reaching an extreme value, but continues at this extreme value With the addition of alkali metal oxides, the crystallization resistance of the glass will deteriorate sharply; in some embodiments, the sum of the contents of Li ₂ O, Na ₂ O and K ₂ O is the value of Li ₂ O+Na ₂ O+K ₂ O If it exceeds 8%, the temperature coefficient of the refractive index of the glass does not decrease any more, and the devitrification resistance and water resistance decrease sharply.

From a production point of view, it is expected that the lower the high-temperature viscosity during clarification, the more favorable it is for the discharge of bubbles. Therefore, if the glass's refractive index temperature coefficient, water resistance and anti-crystallization performance meet the design requirements, it can be added up to 8 % Of the above alkali metal oxides increase the high-temperature viscosity of the glass and the bubble level of the glass during mass production. Therefore, the total amount of Li ₂ O+Na ₂ O+K ₂ O is controlled to 8% or less, preferably 6% or less, and more preferably 5% or less. In some embodiments, the total amount of Li ₂ O+Na ₂ O+K ₂ O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% , 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%.

2) When the above three alkali metal oxides all coexist, there will be a synergistic effect. In some embodiments, if the value of Li ₂ O/(K ₂ O+Na ₂ O) is greater than 0.5, the refractive index temperature of the glass The coefficient is basically unchanged, but the devitrification resistance and chemical stability of the glass decrease sharply. Therefore, the value of Li ₂ O/(K ₂ O+Na ₂ O) is preferably less than 0.5, more preferably less than 0.4, and even more preferably less than 0.3. In some embodiments, the value of Li ₂ O/(K ₂ O+Na ₂ O) may be 0, greater than 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5.

The inventors also found that from the perspective of reducing the temperature coefficient of refractive index, K ₂ O and Na ₂ O are stronger, followed by Li ₂ O; from the perspective of destroying the chemical stability of the glass, K ₂ O and Na ₂ O is stronger, followed by Li ₂ O. In terms of the devitrification resistance of glass, Li ₂ O is the strongest, followed by K ₂ O and Na ₂ O. Therefore, in order to obtain the refractive index temperature coefficient, chemical stability and anti-crystallization performance that meet the design expectations, how to select the appropriate type and the appropriate amount of alkali metal oxide requires a lot of experimental research to determine. For single-component alkali metal oxides, if the Na ₂ O content exceeds 8%, the crystallization resistance and chemical stability of the glass will drop sharply. Therefore, in some embodiments, the content is limited to 0-8 %, preferably 0.5 to 6%, and more preferably 1 to 3%. In some embodiments, if the K ₂ O content is higher than 6%, the devitrification resistance and chemical stability of the glass will rapidly decrease. Therefore, the content is limited to 0 to 6%, preferably 0.3 to 4%, and more preferably 0.5 to 3%. In some embodiments, if the content of Li ₂ O exceeds 5%, the devitrification resistance of the glass will rapidly decrease, so its content is preferably 5% or less, more preferably 3% or less, and further preferably no introduction. In some embodiments, the content of Li ₂ O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% . In some embodiments, the content of Na ₂ O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% , 5.5%, 6%, 6.5%, 7%, 7.5%, 8%. In some embodiments, the content of K ₂ O may be about 0%, greater than 0%, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% , 5%, 5.5%, 6%.

A large number of studies by the inventors have found that in some embodiments, the ratio of Na ₂ O/K ₂ O in the glass has a greater correlation with the bubble degree of the glass and water resistance, when the value of Na ₂ O/K ₂ O is greater than 5.0 , The water resistance of the glass drops sharply; when the value of Na ₂ O/K ₂ O is less than 0.2, the bubble degree of the glass drops rapidly. Therefore, when the value of Na ₂ O/K ₂ O is between 0.2 and 5.0, preferably between 0.3 and 4.0, and more preferably between 0.4 and 3.0, the glass can obtain excellent bubble degree and water resistance. In some embodiments, the value of Na ₂ O/K ₂ O may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4 , 2.5, 2.6, 2.8, 3.0, 3.2, 3.4, 3.5, 3.6, 3.8, 4.0, 4.2, 4.4, 4.5, 4.6, 4.8, 5.0.

For the system glass of the present invention, the ratio of the total content of alkaline earth metal oxides such as BaO, SrO, CaO, and the total content of La ₂ O ₃ , Gd ₂ O ₃ , and Y ₂ O ₃ to the refractive index temperature coefficient of glass, resistance Crystallization performance and water resistance have a greater relationship. In some embodiments, when the value of (BaO+SrO+CaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) is greater than 2.5, the temperature coefficient of the refractive index of the glass no longer decreases, while the Water resistance decreases rapidly; when (BaO+SrO+CaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) is less than 0.7, the water resistance of the glass is improved, but the temperature coefficient of the refractive index of the glass is rapid As it rises, the crystallization resistance of the glass drops rapidly. Therefore, to obtain a glass with a low refractive index temperature coefficient, water resistance that meets the design requirements, and good crystallization resistance, you need to meet (BaO+SrO+CaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ The value of O ₃ ) is 0.7 to 2.5, preferably 0.8 to 2.3, and more preferably 0.9 to 2.1. In some embodiments, the value of (BaO+SrO+CaO)/( La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) may be 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5.

In the system glass of the present invention, BaO and La ₂ O ₃ are the main components. The study found that the ratio has a greater correlation with the temperature coefficient of the refractive index of the glass and the water resistance and crystallization resistance of the glass. In some embodiments, when the ratio of BaO, La ₂ O ₃ content BaO/La ₂ O _{3 is} greater than 2, the temperature coefficient of the refractive index of the glass no longer decreases, but the water resistance of the glass decreases sharply; when BaO/La ₂ O _When the value of ₃ is less than 0.6, although the water resistance of the glass is greatly improved, the temperature coefficient of the refractive index of the glass does not meet the design requirements, and the crystallization resistance of the glass deteriorates sharply, and crystallization occurs even during the smelting process. . Therefore, the value of BaO/La ₂ O ₃ is limited to 0.6 to 2, preferably 0.65 to 1.9, and more preferably 0.7 to 1.8. In some embodiments, the value of BaO/La ₂ O ₃ may be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2.0.

The inventors found that in some embodiments, the value of (CaO+BaO+SrO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) has a greater correlation with the refractive index temperature coefficient of the glass. When the value of (CaO+BaO+SrO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) is less than 8, although the glass’s chemical stability and devitrification performance are slightly improved, the glass’s refractive index temperature coefficient A sharp rise, failing to meet the design requirements; therefore, the value of (CaO+BaO+SrO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) should be greater than 8, preferably greater than 10, and more preferably greater than 12.

One or several components of Sb ₂ O ₃ , SnO ₂ , SnO and CeO ₂ can be added as a clarifying agent. By adding a small amount of Sb ₂ O ₃ , SnO ₂ and CeO ₂ components, the clarifying effect of glass can be improved, but when When the Sb ₂ O ₃ content exceeds 2%, the glass has a tendency to decrease the clarification performance, and at the same time, due to its strong oxidation, the deterioration of the forming mold is promoted. Therefore, the addition amount of Sb ₂ O ₃ of the present invention is 2% or less, preferably 1% Below, more preferably 0.5% or less. SnO ₂ and SnO can also be added as a clarifying agent, but when the content exceeds 2%, the glass will be colored, or when heated, softened glass and molded by reshaping, etc., Sn will become the starting point for the generation of crystal nuclei. Because of the tendency of devitrification, the respective contents of SnO ₂ and SnO of the present invention are 2% or less, preferably 1% or less, more preferably 0.5% or less, and further preferably not introduced. The effect of CeO ₂ and the proportion of the added amount are consistent with SnO ₂ , and its content is 2% or less, preferably 1% or less, more preferably 0.5% or less, and further preferably not introduced. In some embodiments, the content of one or more of the above four clarifiers is about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8 %, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%.

In some embodiments, As ₂ O ₃ , Cl compounds, Br compounds, etc. can also be used as clarifiers, their contents are 2% or less, preferably 1% or less, more preferably 0.5% or less, but from environmental protection Considering other factors, it is preferable not to introduce As ₂ O ₃ . In some embodiments, the content of one or more of the above three clarifiers is about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8 %, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%.

[About ingredients that should not be contained]

As long as the characteristics of the glass of the present invention are not impaired, other components not mentioned above can be added as necessary. However, even if a small amount of transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained alone or in combination, the glass will be colored and absorb at a specific wavelength in the visible light region. As a result, the properties of the present invention for improving the visible light transmittance effect are weakened. Therefore, it is preferred that the optical glass having a transmittance for wavelengths in the visible light region is not actually included.

The cations of Pb, Th, Cd, Tl, Os, Be, and Se have tended to be used as harmful chemicals in recent years, not only in the glass manufacturing process, but also the processing process and the disposal after productization. Measures are required. Therefore, in the case of paying attention to the impact on the environment, it is preferable not to actually contain them except for unavoidable mixing; thereby, the optical glass becomes practically free of substances that pollute the environment, thereby, even if no special Environmental measures, the optical glass of the present invention can also be manufactured, processed, and discarded.

The terms "not introduced", "not included", and "0%" described herein mean that the compound, molecule, or element is not intentionally added as a raw material to the optical glass of the present invention; but as a raw material for producing optical glass and/or There will be some impurities or components that are not intentionally added to the device, and they will be contained in a small amount or trace in the final optical glass. Such a situation is also within the protection scope of the present invention patent.

Next, the performance of the optical glass of the present invention will be described.

[Refractive index and Abbe number]

The refractive index (nd) and Abbe number (ν _d ) of optical glass are tested according to the method specified in GB/T 7962.1-2010.

The refractive index (nd) of the optical glass of the present invention ranges from 1.65 to 1.73, and the preferred range is 1.67 to 1.72; the Abbe number (ν _d ) of the glass of the present invention ranges from 47 to 55, and the preferred range is from 48 to 52.

[Refractive index temperature coefficient]

According to the method stipulated in GB/T 7962.4-2010, the temperature coefficient of refractive index of optical glass in the range of 20～40℃ (d line dn/dt relative(10-6/℃))

The temperature coefficient of refractive index (dn/dt) of the optical glass of the present invention is ≤0, preferably ≤-0.5, more preferably ≤-1.0, further preferably ≤-2.0.

[Water resistance stability]

The optical glass water resistance stability D _w (powder method) is tested according to the method specified in GB/T17129.

The optical glass of the present invention has a water resistance stability _Dw of 4 or more, preferably 3 or more, and more preferably 2 or more.

[Bubble degree]

The bubble degree of optical glass is tested according to the method specified in GB/T7962.8-2010.

The optical glass of the present invention has a bubble degree of A grade or more, preferably A ₀ grade or more, and more preferably A ₀₀ grade.

[Stripe]

The fringe of the glass of the present invention is measured according to the method specified in MLL-G-174B; the method is a fringe instrument composed of a point light source and a lens, which is compared with the standard sample from the direction where the fringe is most easily seen, and is divided into 4 Grades are grades A, B, C, and D respectively. Grade A is no visible stripes under the specified test conditions, Grade B is fine and scattered stripes under the specified test conditions, and Grade C is slight under the specified test conditions. Parallel stripes, class D is rough stripes under the specified detection conditions.

The stripes of the optical glass of the present invention are class C or higher, preferably class B or higher, and more preferably class A.

[Sunlight resistance]

According to JOGIS04-1994 standard conditions, the stability of the optical glass can be irradiated with a 10mm thick sample for 4 hours. By comparing the spectral transmittance curves before and after irradiation, the attenuation of the glass in the 400nm band is determined; the spectral transmittance curve of the glass is used Spectrophotometer measurement.

The stability of the optical glass of the present invention to sunlight resistance is that the transmittance at a wavelength of 400 nm does not decrease by more than 10%, preferably does not exceed 8%, and further preferably does not exceed 5%.

[Anti-crystallization performance]

The test method of the anti-crystallizing performance of optical glass is: cut the sample glass into 20×20×10mm size, put it in a muffle furnace with a temperature of T _g +230℃ for 30 minutes, take it out and put it in insulation cotton to cool it. After cooling, observe the surface crystallization.

The sample glass of the optical glass of the present invention is cut to a size of 20×20×10 mm, placed in a muffle furnace with a temperature of T _g +230° C. and kept warm for 30 minutes. After being taken out, it is placed in a thermal insulation cotton and chilled without obvious crystallizing on the surface. The term "no obvious crystallizing on the surface" in the present invention means that there are no crystallizing spots on the surface or there are crystallizing spots on the surface, but its area accounts for 5% or less of the total area and the crystallizing depth does not exceed 0.5 mm.

Next, the glass preform and optical element of the present invention will be described.

Both the glass preform of the present invention and the optical element are formed of the above-mentioned optical glass of the present invention. The glass preform of the present invention has characteristics of medium refractive index and lower refractive index temperature coefficient; the optical element of the present invention has characteristics of medium refractive index and lower refractive index temperature coefficient, and can provide various optical elements such as various lenses and prisms with high optical value .

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

In addition, since the prism has a relatively high refractive index, it is possible to realize a compact, wide-angle optical system by combining it in an imaging optical system and bending the optical path toward a desired direction.

The optical elements formed by the optical glass of the present invention can be used to make optical instruments such as camera equipment, camera equipment, display devices and monitoring equipment.

Because the optical glass of the present invention has excellent chemical stability, lower refractive index temperature coefficient and other properties, it is particularly suitable for applications in vehicles, monitoring and security, and other fields.

In order to further understand the technical solutions of the present invention, embodiments of the optical glass of the present invention will be described below. It should be noted that these examples do not limit the scope of the present invention.

[Optical glass example]

The optical glasses shown in Tables 2 to 3 (Examples 1 to 20) are obtained by weighing and mixing common raw materials for glass (such as oxides, hydroxides, carbonates, and nitrates) according to the ratios of the examples shown in the table. Etc.), place the mixed raw materials in a platinum crucible, melt at 1300-1350°C for 2.5-4 hours, and after clarification, stirring and homogenization, obtain a homogeneous molten glass without bubbles and without undissolved substances. Molten glass is cast in a mold and annealed.

Examples 1 to 20 show the composition and refractive index (nd) of optical glass; Abbe number (ν _d ); temperature coefficient of refractive index (d line dn/dt relative(10 ^-6 /℃) in the range of 20 to 40℃ ) (Dn/dt); powder method water resistance stability (D _w ); cut the sample glass into 20×20×10mm specifications, put it in a muffle furnace with a temperature of T _g +230℃ for 30 minutes, and take it out Put it in thermal insulation cotton and let it cool. Observe the surface crystallization after cooling. No obvious crystallization is recorded as "A", and there is obvious crystallization as "B"; the degree of bubbles and fringes are expressed according to the standard requirements; stable after sunlight resistance After the sex test, the percentage decrease in transmittance at the wavelength of 400 nm is expressed as "ΔT (%)".

表3

The value of SiO ₂ /B ₂ O ₃ is represented by K1; the value of TiO ₂ /Nb ₂ O ₅ is represented by K2; the value of CaO/(BaO+SrO) is represented by K3; the value of ZnO/(CaO+BaO+SrO) Represented by K4; the total amount of Li ₂ O+Na ₂ O+K ₂ O is represented by K5; the value of Li ₂ O/(K ₂ O+Na ₂ O) is represented by K6; the value of Na ₂ O/K ₂ O is represented by K7 represents; (BaO+SrO+CaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) value is represented by K8; BaO/La ₂ O ₃ value is represented by K9; (CaO+BaO+ The value of SrO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) is represented by K10. Table 2

table 3

[Example of glass preform]

The optical glass obtained in Examples 1 to 10 in Table 2 was cut to a predetermined size, and then a release agent was evenly coated on the surface, and then heated and softened, and subjected to pressure molding to produce concave meniscus lenses and convex Preforms for various lenses and prisms such as meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, etc.

[Example of optical element]

Annealing these preforms obtained in the above examples of glass preforms, and fine-tuning while reducing the internal deformation of the glass, so that the optical properties such as refractive index reach the desired values.

Next, each preform is ground and ground 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-reflection film can also be coated on the surface of the obtained optical element.

no

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Claims (18)

An optical glass, characterized in that its composition includes SiO ₂ , B ₂ O ₃ , La ₂ O ₃ , RO and Rn ₂ O, wherein RO is one or more of MgO, CaO, SrO and BaO, Rn ₂ O It is one or more of Li ₂ O, K ₂ O, and Na ₂ O. The refractive index of the glass is 1.65 to 1.73, the Abbe number is 47 to 55, and the temperature coefficient of the refractive index is ≤0. The optical glass according to claim 1, wherein the composition is expressed as a percentage by weight and includes: SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO: 10 to 40%, SrO: 0 to 15%, CaO: 0 to 10%, MgO: 0 to 5%, Li ₂ O: 0 to 5%, K ₂ O: 0 to 6%, Na ₂ O: 0 to 8%, Gd ₂ O ₃ : 0 to 8%, Y ₂ O ₃ : 0 to 5%, ZrO ₂ : 0 to 3%, Al ₂ O ₃ : 0 to 3%, TiO ₂ : 0 to 3% , Nb ₂ O ₅ : 0 to 5%, WO ₃ : 0 to 2%, ZnO: 0 to 5%, clarifying agent: 0 to 2%. An optical glass, characterized in that its composition is expressed as a percentage by weight, including: SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO: 10～ 40%, SrO: 0 to 15%. The optical glass according to claim 3, further comprising: CaO: 0-10%, MgO: 0-5%, Li ₂ O: 0-5%, K ₂ O: 0-6%, Na ₂ O: 0 to 8%, Gd ₂ O ₃ : 0 to 8%, Y ₂ O ₃ : 0 to 5%, ZrO ₂ : 0 to 3%, Al ₂ O ₃ : 0 to 3%, TiO ₂ : 0 to 3%, Nb ₂ O ₅ : 0 to 5%, WO ₃ : 0 to 2%, ZnO: 0 to 5%, clarifying agent: 0 to 2%. An optical glass, characterized in that its composition is expressed as a percentage by weight of SiO ₂ : 4-20%, B ₂ O ₃ : 10-30%, La ₂ O ₃ : 10-35%, BaO: 10-40%, SrO: 0 to 15%, CaO: 0 to 10%, MgO: 0 to 5%, Rn ₂ 0: 0 to 8%, Gd ₂ O ₃ : 0 to 8%, Y ₂ O ₃ : 0 to 5%, ZrO ₂ : 0 to 3%, Al ₂ O ₃ : 0 to 3%, TiO ₂ : 0 to 3%, Nb ₂ O ₅ : 0 to 5%, WO ₃ : 0 to 2%, ZnO: 0 to 5% Composition, wherein Rn ₂ O is one or more of Li ₂ O, K ₂ O, and Na ₂ O. The optical glass according to any one of claims 1 to 5, wherein SiO ₂ /B ₂ O ₃ is 0.4 to 1.3, preferably 0.45 to 1.2, and more preferably 0.5 to 1.1; and/or BaO/La ₂ O ₃ is 0.6 to 2, preferably 0.65 to 1.9, and more preferably 0.7 to 1.8. The optical glass according to any one of claims 1 to 5, wherein CaO/(BaO+SrO) is 0 to 0.5, preferably 0.01 to 0.4, more preferably 0.02 to 0.3; and/or ZnO/(CaO +SrO+BaO) is 0-0.3, preferably 0-0.2, more preferably 0-0.15; and/or (CaO+SrO+BaO)/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) 0.7-2.5, preferably 0.8-2.3, more preferably 0.9-2.1; and/or (CaO+SrO+BaO)/(Al ₂ O ₃ +ZrO ₂ +TiO ₂ ) greater than 8, preferably greater than 10, more preferably Greater than 12; and/or SrO content ≥ CaO content, preferably BaO content ≥ SrO content ≥ CaO content. The optical glass according to any one of claims 1 to 5, wherein Li ₂ O+Na ₂ O+K ₂ O is 0 to 8%, preferably 0 to 6%, and more preferably 0 to 5%; And/or Li ₂ O/(K ₂ O+Na ₂ O) is 0 to 0.5, preferably 0 to 0.4, more preferably 0 to 0.3; and/or Na ₂ O/K ₂ O is 0.2 to 5.0, preferably 0.3 to 4.0, more preferably 0.4 to 3.0; and/or TiO ₂ /Nb ₂ O ₅ is 1 or less, preferably 0.8 or less, and more preferably 0.5 or less. The optical glass according to any one of claims 1 to 5, wherein the composition is expressed as a percentage by weight and contains: SiO ₂ : 6-18%, and/or B ₂ O ₃ : 12-25%, and/ Or La ₂ O ₃ : 12-30%, and/or BaO: 12-35%, and/or SrO: 0.5-15%, and/or CaO: 0-8%, and/or Gd ₂ O ₃ : 1 ～6%, and/or Y ₂ O ₃ : 0～3%, and/or ZrO ₂ :0.1～3%, and/or Al ₂ O ₃ ：0～2%, and/or TiO ₂ ：0～2 %, and/or Nb ₂ O ₅ : 0.1 to 5%, and/or WO ₃ : 0 to 1%, and/or ZnO: 0 to 3%, and/or MgO: 0 to 3%, and/or Li ₂ O: 0 to 3%, and/or K ₂ O: 0.3 to 4%, and/or Na ₂ O: 0.5 to 6%. The optical glass according to any one of claims 1 to 5, wherein the composition is expressed as a percentage by weight and contains: SiO ₂ : 8-16%, and/or B ₂ O ₃ : 15-22%, and/ Or La ₂ O ₃ : 15 to 28%, and/or BaO: 15 to 32%, and/or SrO: 1 to 12%, and/or CaO: 0 to 6%, and/or Gd ₂ O ₃ : 1 ～4%, and/or Y ₂ O ₃ :1～3%, and/or ZrO ₂ :0.1～2%, and/or Al ₂ O ₃ :0.1～1%, and/or TiO ₂ :0～1 %, and/or Nb ₂ O ₅ : 0.5 to 4%, and/or K ₂ O: 0.5 to 3%, and/or Na ₂ O: 1 to 3%. The optical glass according to any one of claims 1 to 5, wherein the composition is expressed as a percentage by weight and contains: ZrO ₂ : 0.1 to 1%, and/or Nb ₂ O ₅ : 1 to 3%, and/ Or SrO: 1.5～10%. The optical glass according to any one of claims 1 to 5, wherein the refractive index of the glass is 1.65 to 1.73, preferably 1.67 to 1.72; and the Abbe number is 47 to 55, preferably 48 to 52. The optical glass according to any one of claims 1 to 5, wherein the refractive index temperature coefficient of the glass is ≤0, preferably ≤-0.5, more preferably ≤-1.0, and further preferably ≤-2.0. The optical glass according to any one of claims 1 to 5, wherein the water resistance stability of the glass is Class 4 or higher, preferably Class 3 or higher, and more preferably Class 2 or higher; and/or The degree of porosity is A grade or more, preferably A ₀ grade or more, and more preferably A ₀₀ grade; and/or the streak is C grade or more, preferably B grade or more, more preferably A grade; and/or the sunlight resistance is 400 nm The transmittance at the wavelength does not decrease by more than 10%, preferably does not exceed 8%, and further preferably does not exceed 5%. A glass preform made of the optical glass according to any one of claims 1 to 14. An optical element made of the optical glass according to any one of claims 1 to 14 or the glass preform according to claim 15. An optical instrument made of the optical glass according to any one of claims 1 to 14 or the optical element according to claim 16. Use of the optical glass according to any one of claims 1 to 14 or the optical element according to claim 16, wherein the optical glass or the optical element is applied to a vehicle.