CN110835229B

CN110835229B - Optical glass, glass preform, optical element and optical instrument having the same

Info

Publication number: CN110835229B
Application number: CN201810943109.7A
Authority: CN
Inventors: 孙伟
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2022-05-27
Anticipated expiration: 2038-08-17
Also published as: CN110835229A

Abstract

The invention discloses optical glass, a glass prefabricated member, an optical element and an optical instrument with the optical element. Wherein the optical glass comprises: 5 to 25 wt.% of B₂O₃25 to 45% by weight of La₂O₃0 to 10% by weight of Y₂O₃10 to 35% by weight of Gd₂O₃0.5 to 15% by weight of SiO₂1 to 15% by weight of ZrO₂0 to 5% by weight of TiO₂0 to 7% by weight of WO₃0 to 15% by weight of Ta₂O₅0 to 10 wt% of ZnO and 0 to 8.5 wt% of Nb₂O₅Wherein m is_{(ZrO2+TiO2+La2O3)/}m_{(Nb2O5+SiO2+WO3+Gd2O3)}1.0 to 1.6. The refractive index nd of the optical glass is more than 1.86, and the Abbe number vd is more than 38.8, so that the technical problems of high-refractive-index low-dispersion optical glass, high volatile transmittance, high difficulty in production and high cost in the prior art are solved.

Description

Optical glass, glass preform, optical element and optical instrument having the same

Technical Field

The invention belongs to the technical field of optical glass, and particularly relates to optical glass, a glass prefabricated member, an optical element and an optical instrument with the optical element.

Background

The high-refraction low-dispersion optical glass can simplify an optical system, eliminate spherical aberration, chromatic aberration and image quality distortion, enlarge the view field of the lens, has important significance for improving the imaging quality of an optical instrument, enables the lens to be miniaturized and lightened, can better meet the requirements of novel photoelectric products on the imaging quality and quality, and has larger market demand particularly for the high-refraction low-dispersion optical glass with the refractive index nd larger than 1.86 and the Abbe number vd larger than 38.8.

Generally, more rare earth oxides are required to be introduced into a high-refraction low-dispersion glass formulation system to improve the refractive index of the glass, but in different formulation systems, more lanthanide oxides are introduced to influence the glass forming property, so that the difficulty is brought to mass production process manufacturing. Therefore, the existing optical glass composition is yet to be further explored.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, an object of the present invention is to provide an optical glass, a glass preform, an optical element and an optical instrument having the same, in which the refractive index nd of the optical glass is greater than 1.86, and the abbe number vd of the optical glass is greater than 38.8, so as to solve the technical problems of high-refractive-index low-dispersion optical glass, such as high difficulty in mass production and high cost in the prior art.

In one aspect of the invention, an optical glass is provided. According to an embodiment of the present invention, the optical glass includes: 5 to 25 wt.% of B₂O₃25 to 45% by weight of La₂O₃0 to 10% by weight of Y₂O₃10 to 35% by weight of Gd₂O₃0.5 to 15% by weight of SiO₂1 to 15% by weight of ZrO₂0 to 5% by weight of TiO₂0 to 7% by weight of WO₃0 to 15% by weight of Ta₂O₅0 to 10 wt% of ZnO and 0 to 8.5 wt% of Nb₂O₅Wherein m is_{(ZrO2+TiO2+La2O3)/}m_{(Nb2O5+SiO2+WO3+Gd2O3)}＝1.0～1.6。

The inventors have found that the optical glass of the present invention can be used with little or no Ta by controlling the components, the contents and the ratio of the amounts of the specific components₂O₅In the case of (2), a high-refractive-index low-dispersion optical glass (an optical glass having a refractive index nd of more than 1.86 and an Abbe number vd of more than 38.8) which is resistant to devitrification and excellent in performance can be obtained, and the optical glass of the present invention is low in production cost and easy to mass-produce.

In addition, the optical glass according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the present invention, the above optical glass comprises: 8 to 20% by weight of B₂O₃And/or 30 to 42 wt% of La₂O₃And/or 0 to 8% by weight of Y₂O₃And/or 15 to 28 wt% of Gd₂O₃And/or 2 to 13% by weight of SiO₂And/or 1 to 10 wt% of ZrO₂And/or 0.1 to 5 wt% of TiO₂And/or 0.1 to 5% by weight of WO₃And/or 0.5 to 10% by weight of Ta₂O₅And/or 0 to 5 wt% of ZnO and/or 0 to 8.5 wt% of Nb₂O₅. Thereby, the optical glass can be ensured to have excellent performance.

In some embodiments of the present invention, the above optical glass comprises: 10 to 16% by weight of B₂O₃And/or 33 to 39 wt% of La₂O₃And/or 1 to 5% by weight of Y₂O₃And/or 17 to 25% by weight of Gd₂O₃And/or 4 to 10Weight% SiO₂And/or 3 to 8 wt% of ZrO₂And/or 0.5 to 3 wt% of TiO₂And/or 0.5 to 4% by weight of WO₃And/or 3 to 10% by weight of Ta₂O₅And/or 1 to 3 wt% of ZnO and/or 0 to 8.5 wt% of Nb₂O₅. Thereby, the optical glass can be ensured to have excellent performance.

In some embodiments of the present invention, in the above optical glass composition, m_{(ZrO2+TiO2+La2O3)/}m_{(Nb2O5+SiO2+WO3+Gd2O3)}The content is 1.1 to 1.45, and more preferably 1.35 to 1.42. Thereby, the optical glass can be further ensured to have excellent performance.

In some embodiments of the present invention, the above optical glass further comprises: 0 to 1% by weight of Sb₂O₃And/or 0 to 1 wt.% of SnO₂And/or 0 to 1% by weight of CeO₂And/or 0 to 10 wt% of Yb₂O₃And/or 0 to 10 wt% of Lu₂O₃And/or 0 to 10% by weight of Al₂O₃And/or 0 to 10% by weight of Bi₂O₃And/or 0 to 10% by weight of GeO₂And/or 0 to 10% by weight of Li₂O、Na₂O and K₂O and/or 0-10 wt% of CaO, SrO, BaO and MgO. Thereby, the optical glass can be further ensured to have excellent performance.

In some embodiments of the present invention, the refractive index of the optical glass is greater than 1.86, preferably 1.87 to 1.89, and the Abbe number is greater than 38.8, preferably 39.0 to 41.0.

In some embodiments of the present invention, λ of the above optical glass₇₀Not more than 420nm, preferably not more than 390nm, lambda₅Not more than 360nm, preferably not more than 350 nm.

In some embodiments of the present invention, the optical glass has a water-resistance stability of not less than grade 3, preferably not less than grade 2, and the optical glass has an acid-resistance stability of not less than grade 3, preferably not less than grade 2.

In some embodiments of the present invention, the optical glass has a bubble size of not less than class A, preferably not less than class AAt A is₀Stage, more preferably A₀₀And (4) stages.

In some embodiments of the invention, the optical glass has a density of not greater than 5.6g/cm³Preferably not higher than 5.5g/cm³。

In a second aspect of the present invention, a glass preform is provided. According to an embodiment of the present invention, the glass preform is made of the above optical glass. Therefore, the glass preform prepared by adopting the optical glass with high refraction and low dispersion has excellent performance, thereby meeting the market demand.

In a third aspect of the invention, an optical element is presented. According to an embodiment of the present invention, the optical element is made of the above optical glass or glass preform. Therefore, the optical element prepared by adopting the optical glass or the glass prefabricated member with high refraction and low dispersion has excellent performance, thereby meeting the market demand.

In a fourth aspect of the invention, an optical instrument is presented. According to an embodiment of the present invention, the optical instrument has the optical element described above. Therefore, the optical device can improve the customer experience of the optical device by using the optical element with excellent performance.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Detailed Description

The following detailed description of embodiments of the invention is intended to be illustrative, and is not to be construed as limiting the invention.

Glass composition:

B₂O₃the glass is a skeleton component of the glass, and has the effects of improving the meltability of the glass, resisting devitrification and reducing the dispersion of the glass. However, when the amount of incorporation exceeds 25% by weight, the glass stability is lowered and the refractive index is lowered, and when the amount of incorporation is less than 5% by weight, the glass meltability is lowered and the optical constants required in the present invention are not obtained. Thus, B of the present invention₂O₃Is 5 to 25 wt%, preferably B₂O₃The content is 8 to 20% by weight, more preferably 10 to 16% by weight.

La₂O₃Is an essential component for obtaining the desired optical properties of the present invention when La₂O₃When the content of (b) is less than 25% by weight, it is difficult to achieve desired optical characteristics, but when the content exceeds 45% by weight, both devitrification resistance and melting property of the glass are deteriorated. Thus, the La of the present invention₂O₃The content of (A) is 25 to 45 wt%, preferably La₂O₃The content is 30 to 42 wt%, more preferably 33 to 39 wt%.

Y₂O₃The melting property and devitrification resistance of the glass can be improved and the upper limit crystallization temperature of the glass can be lowered, but if the content exceeds 10 wt%, the stability and devitrification resistance of the glass are lowered. Thus, Y of the present invention₂O₃The content is 0-10 wt%, preferably Y₂O₃The content is in the range of 0 to 8% by weight, more preferably 1 to 5% by weight.

In the present invention, Gd is used₂O₃And La₂O₃Coexisting, the stability of the glass formed can be improved, but when Gd is used₂O₃When the content is less than 10% by weight, the above effects are not significant, if the content is excessiveIf the amount is more than 35% by weight, the devitrification resistance of the glass is lowered, and the stability of the formed glass is deteriorated. Thus, Gd of the present invention₂O₃Is 10 to 35 wt%, preferably Gd₂O₃The content of (B) is 15 to 28 wt%, more preferably 17 to 25 wt%.

SiO₂The glass skeleton is a component constituting the glass skeleton, and has the effects of improving resistance to devitrification, improving the weather resistance of glass, improving the thermal stability of glass, and the like. But when SiO₂When the content is less than 0.5% by weight, the effect of improving the devitrification resistance is insignificant, and when the content exceeds 15% by weight, the glass is deteriorated in meltability and the refractive index required in the present invention cannot be obtained. Accordingly, in the present invention, the content of SiO2 is 0.5 to 15% by weight, and SiO is preferable₂The content is 2 to 13% by weight, more preferably 4 to 10% by weight.

ZrO₂The glass is formed as an intermediate oxide to improve the refractive index and stability, and therefore, it also has the effect of improving the resistance to devitrification and chemical durability. ZrO (ZrO)₂When the content of (A) is less than 1% by weight, the above-mentioned intended effects cannot be obtained, and when ZrO is contained in the composition₂When the content of (b) exceeds 15% by weight, devitrification tendency becomes strong and vitrification tends to become difficult. Therefore, ZrO in the present invention₂The content is 1 to 15 wt%, preferably ZrO₂The content is 1 to 10% by weight, more preferably 3 to 8% by weight.

TiO₂Also has the function of improving the refractive index of the glass, can participate in the formation of a glass network, and leads the glass to be more stable by introducing a proper amount. However, if the content is more than 5% by weight, the glass dispersion is remarkably increased, and the transmittance of the glass in a short wavelength region in a visible light region is lowered, so that the glass tends to be colored. Therefore, TiO in the present invention₂The content is 0 to 5 wt%, preferably TiO₂The content is 0.1 to 5% by weight, more preferably 0.5 to 3% by weight.

WO₃The effect of increasing the refractive index is exhibited, but when the content exceeds 7 wt%, the dispersion is significantly increased, and the transmittance on the short wavelength side of the visible light region of the glass is decreased, and the tendency of coloring is increased. Therefore, in the present invention, WO₃The content of (A) is 0-7 wt%Preferably WO₃The content of (B) is 0.1 to 5% by weight, more preferably 0.5 to 4% by weight.

Ta₂O₅Has the effect of increasing the refractive index, has the effect of maintaining the low dispersion of the glass, and if the content thereof is more than 15% by weight, the cost of the optical glass is increased because the price thereof is more expensive than other components, and therefore, the present invention reduces the amount thereof used from the viewpoint of practicality and cost. Ta of the invention₂O₅The content is 0 to 15 wt%, preferably Ta₂O₅The content is 0.5 to 10% by weight, more preferably 3 to 10% by weight.

While ZnO can adjust the refractive index and dispersion of the glass, and a suitable amount of ZnO can improve the stability or melting property of the glass and press formability, when the content is more than 10% by weight, the refractive index decreases, which does not meet the requirements of the present invention, and the devitrification resistance of the glass decreases and the upper limit temperature of devitrification increases. Accordingly, the ZnO content of the present invention is 0 to 10% by weight, preferably 0 to 5% by weight, more preferably 1 to 3% by weight.

Nb₂O₅The glass is a high-refraction high-dispersion component, can improve the refractive index while not obviously improving the dispersion, and also has the functions of improving the crystallization resistance and the chemical stability of the glass. If the content exceeds 8.5% by weight, the optical characteristics of the glass of the present invention cannot be achieved and the devitrification resistance of the glass is deteriorated. Therefore, Nb in the present invention₂O₅The content is 0 to 8.5 wt%, and preferably no introduction.

The inventors found that the optical glass of the present application is required to have excellent devitrification resistance, transmittance, chemical stability and optical properties and lightweight property, and the present application controls ZrO₂、TiO₂And La₂O₃Total weight of (2) and Nb₂O₅、SiO₂、WO₃And Gd₂O₃The total weight ratio of the components is 1.0-1.6, so that the components play a synergistic effect, the gas dissolution rate in the melting process is effectively controlled, the transmittance of the glass is improved, the stability of the glass is improved, the light weight of the glass is realized, and the refractive index of the obtained optical glass isGreater than 1.86, Abbe number greater than 38.8, lambda₇₀Not more than 420nm, lambda₅No more than 360nm, water-resistant stability no less than 3, acid-resistant stability no less than 3, and density no more than 5.6g/cm³The degree of blistering is not less than class A, and the obtained optical glass has excellent devitrification resistance, and ZrO is further preferably controlled₂、TiO₂And La₂O₃Total weight of (2) and Nb₂O₅、SiO₂、WO₃And Gd₂O₃The total weight ratio of (A) to (B) is 1.1 to 1.45, more preferably 1.35 to 1.42, and the refractive index of the obtained optical glass is 1.87 to 1.89, Abbe number is 39.0 to 41.0, and lambda is₇₀No more than 390nm, lambda₅No more than 350nm, water-resistant stability of no less than 2 grade, acid-resistant stability of no less than 2 grade, and density of no more than 5.5g/cm³The bubble degree is not less than A₀Stage, preferably A₀₀And (4) stages.

According to still another embodiment of the present invention, the above optical glass further comprises: 0 to 1% by weight of Sb₂O₃And/or 0 to 1 wt.% of SnO₂And/or 0 to 1% by weight of CeO₂And/or 0 to 10 wt% of Yb₂O₃And/or 0 to 10 wt% of Lu₂O₃And/or 0 to 10% by weight of Al₂O₃And/or 0 to 10% by weight of Bi₂O₃And/or 0 to 10% by weight of GeO₂And/or 0 to 10% by weight of Li₂O、Na₂O and K₂O and/or 0-10 wt% of CaO, SrO, BaO and MgO. The inventors found that Sb was added in a small amount₂O₃And/or SnO₂And/or CeO₂The component can improve the fining effect of the glass, but when Sb is used₂O₃When the content exceeds 1% by weight, the glass tends to have a reduced fining property and the deterioration of a forming mold is promoted by its strong oxidizing action, so Sb is preferable in the present invention₂O₃The amount of (B) is 0 to 1% by weight, more preferably 0 to 0.5% by weight, and further preferably not added. SnO₂It can also be added as a fining agent, but when the content exceeds 1% by weight, the glass is colored, or when heatedWhen the glass is softened and subjected to secondary forming such as press forming, Sn becomes a starting point of nucleation and tends to devitrify. Thus the SnO of the invention₂The content of (b) is preferably 0 to 1% by weight, more preferably 0 to 0.5% by weight, and further preferably not added. CeO (CeO)₂Action and addition amount ratio of (B) and SnO₂The content is preferably 0 to 1% by weight, more preferably 0 to 0.5% by weight, and further preferably no addition. Yb of₂O₃Also in the glass of the present invention, when the content of the high-refractivity low-dispersion component exceeds 10% by weight, the stability and devitrification resistance of the glass are lowered, and Yb is preferable₂O₃The content ranges from 0 to 10% by weight, more preferably from 0 to 8% by weight, and further preferably is not incorporated. Lu (Lu)₂O₃The refractive index of the glass can be increased and the dispersion can be reduced, but when the content exceeds 10% by weight, the glass is deteriorated in both devitrification resistance and melting property, and the cost of the optical glass is increased because it is expensive compared with other components. Thus, Lu of the present invention₂O₃0-10% of (A), Lu₂O₃The content is preferably in the range of 0 to 8% by weight, more preferably not incorporated. Introducing small amount of Al₂O₃Although the stability and chemical stability of the formed glass can be improved, when the content exceeds 10% by weight, the glass tends to be deteriorated in meltability and devitrification resistance is lowered, so that Al is preferable in the present invention₂O₃The content of (B) is 0 to 10% by weight, more preferably 0 to 8% by weight. Bi₂O₃Although the refractive index of the glass can be increased, when added in an excessive amount, the transmittance at the short wavelength side of the visible light region is lowered, and the glass tends to be colored, so Bi is preferred in the present invention₂O₃The content is 0 to 10% by weight, more preferably 0 to 5% by weight, and further preferably not incorporated. GeO₂The glass forming stability and devitrification resistance can also be effectively improved, but due to GeO₂Is a very expensive component, GeO is therefore preferred₂The content is 0 to 10% by weight, more preferably 0 to 5% by weight, and further preferably not incorporated. Li₂O、Na₂O and K₂O is a component for suppressing phase separation and improving the stability of the glass. When the total content thereof exceeds 10% by weight, the resistance is presentSince the weatherability is remarkably reduced or the refractive index is lowered, Li is preferable in the present invention₂O、Na₂O and K₂The total content of O is 0 to 10% by weight, more preferably 0 to 5% by weight, and still more preferably not incorporated. Alkaline earth metal oxides such as CaO, SrO, BaO and MgO can significantly reduce the weather resistance of the glass and raise the crystallization upper limit temperature, but when the total content thereof exceeds 10% by weight, the devitrification resistance of the glass is reduced, so that the total weight of CaO, SrO, BaO and MgO is preferably 0 to 10% by weight, more preferably in the range of 0 to 5% by weight, and further preferably not incorporated.

The properties and the test method of the optical glass of the present invention will be explained below.

1. Degree of coloration (. lamda.)₇₀/λ₅)

Coloring degree (. lamda.) for short-wave transmission spectral characteristics of the glass of the present invention₇₀/λ₅) And (4) showing. Lambda₇₀Refers to the wavelength, lambda, corresponding to a glass having a transmittance of 70%₅Refers to the wavelength corresponding to the glass transmittance of 5%, wherein₇₀Is measured by measuring the spectral transmittance in a wavelength region from 280nm to 700nm using a glass having a thickness of 10. + -. 0.1mm with two opposing planes parallel to each other and optically polished and exhibiting a wavelength of 70% transmittance. The spectral transmittance or transmittance is the intensity I of light incident perpendicularly to the surface of the glass_inLight transmitted through the glass and having an intensity I emitted from a plane_outIn the case of light of (1) through (I)_out/I_inThe quantity expressed and also the transmission of the surface reflection losses on the above-mentioned surface of the glass. The higher the refractive index of the glass, the greater the surface reflection loss. Thus, in high refractive index glasses, λ₇₀A small value of (b) means that the glass itself is less colored. The optical glass of the present invention has a wavelength (lambda) corresponding to a transmittance of 70%₇₀) Not more than 420nm, preferably not more than 390nm, and a wavelength (lambda) corresponding to a glass transmittance of 5%₅) Not more than 360nm, preferably not more than 350 nm.

The spectral transmittance was measured using a glass sample having a thickness of 10. + -. 0.1mm with two optically polished planes opposed to each other, and calculated from the result thereof.

2. Density of

The density of the optical glass is the weight per unit volume at a temperature of 20 ℃ in g/cm³Shows that the density of the optical glass of the present invention is not higher than 5.6g/cm³Preferably not higher than 5.5g/cm³。

The measurement was carried out according to the method specified in GB/T7962.20-2010.

3. Chemical stability (stability to Water action DW, stability to acid action DA)

The ability of the polished surface of the optical glass element to resist the action of various erosion media such as water, acid and the like during the manufacturing and use process is called the chemical stability of the optical glass, which mainly depends on the chemical components of the glass, and the stability Dw (powder method) of the optical glass of the present invention to water action is not less than 3 grades, preferably not less than 2 grades, and more preferably 1 grade; acid resistance stability DA (powder method) is not less than grade 3, preferably not less than grade 2, more preferably grade 1.

The stability to water action Dw and the stability to acid action DA were tested according to the test method of GB/T17129.

4. Air bubble

The bubble content is a level of an allowable bubble content in the glass, and the bubbles affect not only the appearance quality of the glass product but also the optical properties, transparency, mechanical strength and the like of the glass, and cause many adverse effects on the glass, so it is important to control the bubble content of the glass, and the optical glass of the present invention has a bubble content of not less than class A, preferably not less than class A₀Stage, more preferably A₀₀And (4) stages.

The bubble quality of the optical glass is measured according to the test method specified in GB/T7962.8-2010.

5. Refractive index and Abbe number

The optical glass of the present invention is a high refractive index low dispersion glass, and a lens made of the high refractive index low dispersion glass is often used for chromatic aberration correction in combination with a lens made of the high refractive index high dispersion glass, and when the optical glass is used as a lens, the lens can be thinned as the refractive index is increased, and it is advantageous for miniaturization of an optical device that the refractive index nd of the optical glass of the present invention is > 1.86, preferably nd is 1.87 to 1.89, Abbe number vd is > 38.8, preferably vd is 39.0 to 41.0.

The refractive index and Abbe number were measured according to the method specified in GB/T7962.1-2010.

In a second aspect of the present invention, a glass preform is provided. According to an embodiment of the present invention, the glass preform is made of the above optical glass. Therefore, the optical prefabricated member has the characteristics of high refractive index, low dispersion and the like, thereby meeting the market demand for high-performance glass. Specifically, the obtained optical glass is cut into a predetermined size, and a mold release agent made of boron nitride powder is uniformly applied to the surface of the optical glass, and then heated, softened, and pressure-molded to produce preforms for various lenses and prisms such as a concave meniscus lens, a convex meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens, and a plano-concave lens. It should be noted that the features and advantages described above for optical glasses apply equally to the glass preform and are not described in detail here.

In a third aspect of the invention, an optical element is presented. According to an embodiment of the present invention, the optical element is made of the above optical glass or glass preform. Thus, the optical element of the present invention has high refractive index and low dispersion characteristics, and can provide various optical elements such as lenses and prisms having excellent performance at low cost. For example, the lens may be a convex meniscus lens, a concave meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, or the like, whose lens surface is spherical or aspherical. The lens can correct chromatic aberration by combining with a lens made of high-refractivity high-dispersion glass, and is suitable as a lens for chromatic aberration correction. Further, the lens is also effective for the compactness of an optical system. Further, since the prism has a high refractive index, by combining the prism with an imaging optical system and bending the optical path to direct the prism in a desired direction, a compact and wide-angle optical system can be realized. Specifically, the glass preform is annealed to reduce the deformation in the glass and fine-tune the glass so that the optical characteristics such as refractive index and the like reach a desired value, and then each preform is ground and polished to produce various lenses such as a concave meniscus lens, a convex meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens, and a plano-concave lens, or optical elements such as prisms, and the surfaces of the optical elements obtained may be coated with an antireflection film. It should be noted that the features and advantages described above for the glass preform apply equally to the optical element and are not described in further detail here.

In a fourth aspect of the invention, an optical instrument is presented. According to an embodiment of the invention, the optical instrument has the optical element described above. Therefore, the optical device can improve the customer experience of the optical device by using the optical element with excellent performance. Specifically, the optical instrument of the present invention may be a digital camera, a video camera, or the like. It should be noted that the features and advantages described above for the optical element apply equally to the optical instrument and are not described in detail here.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.

In order to obtain glasses having compositions shown in tables 1 to 5, carbonates, nitrates, hydroxides, oxides, boric acid and the like are used as raw materials, the raw materials corresponding to the optical glass components are weighed in proportion, the raw materials are fully mixed to form a blended raw material, the blended raw material is put into a platinum crucible, the crucible is heated to 1200 to 1450 ℃, the blended raw material is melted, stirred and clarified to form uniform molten glass, the molten glass is appropriately cooled, poured into a preheated mold, kept at 650 to 700 ℃ for 2 to 4 hours and then slowly cooled, and the optical glass is obtained. The characteristics of each glass were measured by the methods described above, and the measurement results are shown in tables 1 to 5.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

Note: the total of 100% in the above table is data with measurement errors, equipment accuracy and inevitable impurities subtracted.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. An optical glass, comprising:

5 to 25 wt.% of B₂O₃；

33-42 wt% of La₂O₃；

0 to 10% by weight of Y₂O₃；

10-35% by weight of Gd₂O₃；

0.5 to 15% by weight of SiO₂；

1 to 15% by weight of ZrO₂；

0.5 to 3% by weight of TiO₂；

0 to 7% by weight of WO₃；

0 to 15% by weight of Ta₂O₅；

0 to 10% by weight of ZnO;

0% by weight of Nb₂O₅，

Wherein m is_{（ZrO2+TiO2+La2O3）/}m_{（Nb2O5+SiO2+WO3+Gd2O3）}=1.35~1.6。

2. The optical glass according to claim 1, comprising:

8 to 20% by weight of B₂O₃(ii) a And/or

33-42 wt% of La₂O₃(ii) a And/or

0 to 8% by weight of Y₂O₃(ii) a And/or

15-28 wt% of Gd₂O₃(ii) a And/or

2-13% by weight of SiO₂(ii) a And/or

1 to 10% by weight of ZrO₂(ii) a And/or

0.5 to 3% by weight of TiO₂(ii) a And/or

0.1 to 5% by weight of WO₃(ii) a And/or

0.5 to 10% by weight of Ta₂O₅(ii) a And/or

0 to 5% by weight of ZnO; and/or

0% by weight of Nb₂O₅。

3. The optical glass according to claim 2, comprising:

10 to 16% by weight of B₂O₃(ii) a And/or

33-39 wt% of La₂O₃(ii) a And/or

1 to 5% by weight of Y₂O₃(ii) a And/or

17-25 wt% Gd₂O₃(ii) a And/or

4 to 10% by weight of SiO₂(ii) a And/or

3 to 8% by weight of ZrO₂(ii) a And/or

0.5 to 3% by weight of TiO₂(ii) a And/or

0.5 to 4% by weight of WO₃(ii) a And/or

3 to 10% by weight of Ta₂O₅(ii) a And/or

1 to 3% by weight of ZnO; and/or

0% by weight of Nb₂O₅。

4. The optical glass according to any of claims 1 to 3, wherein m is_{（ZrO2+TiO2+La2O3）/}m_{（Nb2O5+SiO2+WO3+Gd2O3）}=1.35~1.45。

5. The optical glass according to any one of claims 1 to 3, further comprising:

0 to 1% by weight of Sb₂O₃(ii) a And/or

0 to 1% by weight of SnO₂(ii) a And/or

0 to 1% by weight of CeO₂(ii) a And/or

0 to 10% by weight of Yb₂O₃(ii) a And/or

0 to 10% by weight of Lu₂O₃(ii) a And/or

0 to 10% by weight of Al₂O₃(ii) a And/or

0 to 10% by weight of Bi₂O₃(ii) a And/or

0 to 10% by weight of GeO₂(ii) a And/or

0 to 10% by weight of Li₂O、Na₂O and K₂The sum of O; and/or

0 to 10% by weight of the sum of CaO, SrO, BaO and MgO.

6. An optical glass according to any of claims 1 to 3, wherein the optical glass has a refractive index of more than 1.86 and an Abbe number of more than 38.8.

7. The optical glass according to claim 6, wherein the optical glass has a refractive index of 1.87 to 1.89 and an Abbe number of 39.0 to 41.0.

8. An optical glass according to any of claims 1 to 3, characterised in that the optical glass has a lambda₇₀Not more than 420nm, lambda₅Not greater than 360 nm.

9. An optical glass according to claim 8, characterized in that the optical glass has a lambda₇₀No more than 390nm, lambda₅Not greater than 350 nm.

10. The optical glass according to any one of claims 1 to 3, wherein the stability against water action of the optical glass is not less than grade 3, and the stability against acid action of the optical glass is not less than grade 3.

11. The optical glass according to claim 10, wherein the stability against water action of the optical glass is not less than grade 2, and the stability against acid action of the optical glass is not less than grade 2.

12. The optical glass according to any one of claims 1 to 3, wherein the optical glass has a bubble degree of not less than class A.

13. The optical glass according to claim 12, wherein the optical glass has a bubble degree of not less than A₀And (4) stages.

14. The optical glass according to claim 13, wherein the optical glass has a bubble degree of not less than A₀₀And (4) stages.

15. An optical glass according to any one of claims 1 to 3, wherein the optical glass has a density of not higher than 5.6g/cm³。

16. The optical glass according to claim 15, wherein the optical glass has a density of not higher than 5.5g/cm³。

17. A glass preform, characterized in that it is made of an optical glass according to any one of claims 1 to 16.

18. An optical element, characterized in that it is made of the optical glass according to any one of claims 1 to 16 or the glass preform according to claim 17.

19. An optical instrument having the optical element of claim 18.