CN108341593B

CN108341593B - Optical glass

Info

Publication number: CN108341593B
Application number: CN201711295096.9A
Authority: CN
Inventors: 李丹
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2017-12-08
Filing date: 2017-12-08
Publication date: 2021-08-24
Anticipated expiration: 2037-12-08
Also published as: CN108341593A

Abstract

The invention provides the optical glass which has the advantages of low cost, favorable glass bubble stripe and easy and stable production, and even does not contain tantalum. The optical glass comprises the following components in percentage by weight: SiO 2₂10‑30％、B₂O₃20‑45％、La₂O₃10‑35％、BaO 12‑30％、ZrO₂0-10% of ZnO and 0-10% of ZnO. The invention makes the refractive index of the optical glass 1.62-1.70 and Abbe number 55-62 through reasonable formula design, the optical glass has low cost, good chemical stability, excellent anti-devitrification performance and good transmittance, simultaneously the glass has good bubbles and stripes, is easy to produce stably, and can be widely applied to equipment such as digital cameras, digital video cameras, camera phones and the like.

Description

Optical glass

Technical Field

The invention relates to an optical glass with a refractive index of 1.62-1.70 and an Abbe number of 55-62, and a glass preform and an optical element which are composed of the optical glass.

Background

In recent years, with the development of optoelectronic systems, optical glass with a refractive index of 1.62-1.70 and an Abbe number of 55-62 is widely used. Along with the rapid development of the smart phone capable of photographing, the goods output quantity of the digital camera market is continuously reduced, and the market competition of the optical glass is increasingly severe. Meanwhile, the price of the optical glass raw material is obviously increased, so that the manufacturing cost of the glass is further increased. Only products with low raw material cost and excellent comprehensive performance have stronger competitiveness.

CN1323281A discloses an optical glass with a refractive index of 1.65-1.73 and an Abbe number of 50-60, the glass component contains a certain amount of Ta₂O₅Due to Ta₂O₅The price is high, the production cost of the glass can be greatly improved, and the competitiveness of the glass is reduced.

Optical glass must satisfy not only the characteristic optical properties but also excellent internal qualities such as striae, bubbles, inclusions and the like. Chinese patent application 200780006271.6 discloses glass B₂O₃In an amount of 46-70%, B₂O₃High content of (B), easy melting, but too low glass viscosity, unfavorable for molding, and B₂O₃The volatilization is serious, which is unfavorable for the stable control of the refractive index and the dispersion in the production process, and the stripe is easy to generate in the batch production to influence the inherent quality of the glass. At the same time, too much B₂O₃Is not beneficial to improving the chemical stability of the glass.

Disclosure of Invention

The invention aims to solve the technical problem of providing the optical glass which has the advantages of reduced or even no tantalum content, low cost, good glass bubble stripe and easy and stable production.

The present invention also provides a glass preform and an optical element formed of the above optical glass.

The technical scheme adopted by the invention for solving the technical problem is as follows: the optical glass comprises the following components in percentage by weight: SiO 2₂ 10-30％、B₂O₃ 20-45％、La₂O₃ 10-35％、BaO 12-30％、ZrO₂ 0-10％、ZnO 0-10％。

Further, it contains Gd₂O₃ 0-10％、Y₂O₃ 0-10％、Yb₂O₃ 0-10％、Li₂O 0-10％、Na₂O 0-10％、K₂O 0-10％、CaO 0-13％、SrO 0-10％、MgO 0-10％、Al₂O₃ 0-10％、TiO₂ 0-10％、Nb₂O₅0-10％、WO₃ 0-10％、Sb₂O₃ 0-1％。

The optical glass comprises the following components in percentage by weight: SiO 2₂ 10-30％、B₂O₃ 20-45％、La₂O₃10-35％、BaO 12-30％、ZrO₂ 0-10％、ZnO 0-10％、Gd₂O₃ 0-10％、Y₂O₃ 0-10％、Yb₂O₃ 0-10％、Li₂O 0-10％、Na₂O 0-10％、K₂O 0-10％、CaO 0-13％、SrO 0-10％、MgO 0-10％、Al₂O₃ 0-10％、TiO₂0-10％、Nb₂O₅ 0-10％、WO₃ 0-10％、Sb₂O₃ 0-1％。

Further, SiO₂12 to 28 percent; and/or B₂O₃25 to 40 percent; and/or La₂O₃15 to 30 percent; and/or BaO 15-28%; and/or ZrO₂0.5-9%; and/or ZnO 0.5-9.5%; and \ or Gd₂O₃0 to 5 percent; and/or Y₂O₃0 to 5 percent; and/or Yb₂O₃0 to 5 percent; and/or Li₂0-5% of O; and/or Na₂0-5% of O; and/or K₂0-5% of O; and/or CaO 0-10%; and/or SrO 0-5%; and/or MgO 0-5%; and/or Al₂O₃0 to 5 percent; and/or TiO₂0 to 5 percent; and/or Nb₂O₅0 to 5 percent; and/or WO₃0 to 5 percent; and/or Sb₂O₃ 0-0.5％。

Further, Li₂O+Na₂O+K₂O is 0 to 10 percent; and/or SiO₂/La₂O₃0.7-2.7; and/or BaO/SiO₂Is 0.26-2; and/or BaO + SrO + CaO + MgO is 18-36%; and/or

(La₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.4-1.45.

Further, SiO₂15 to 25 percent; and/or B₂O₃28 to 38 percent; and/or La₂O₃18 to 28 percent; and/or ZrO₂1.1-4%; and/or ZnO 1-7%; and/or Li₂0-3% of O; and/or CaO 0-5%; and/or SrO 0-3.5%; and/or Al₂O₃0 to 2 percent; and/or does not contain Y₂O₃、Yb₂O₃、MgO、TiO₂、Nb₂O₅、WO₃。

Further, Li₂O+Na₂O+K₂O is 0 to 5 percent; and/or SiO₂/La₂O₃0.75-2.5; and/or BaO/SiO₂0.6 to 1.8; and/or BaO + SrO + CaO + MgO is 22-30%; and/or (La)₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.6 to 1.3.

Further, Li₂O+Na₂O+K₂O is 0 to 4 percent; and/or SiO₂/La₂O₃0.85-2.3; and/or BaO/SiO₂0.8 to 1.5; and/or (La)₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.7 to 1.1.

Further, the refractive index of the optical glass is 1.62 to 1.70, preferably 1.64 to 1.68; the Abbe number of the optical glass is 55 to 62, preferably 56 to 60.

Further, the optical glass λ₈₀Less than or equal to 370nm, preferably lambda₈₀Less than or equal to 360 nm; stability of acid resistance of optical glass D_AAre of class 4 or more.

Further, the glass is cut into the specification of 20 multiplied by 10mm, put into a muffle furnace with the temperature of 700 and 900 ℃ for 30 minutes, taken out and put into heat preservation cotton for slow cooling, the surface is polished after cooling, and the surface is observed to have no obvious crystallization under a microscope.

Glass preform made of the optical glass according to claim.

The optical element is made of the optical glass.

The invention has the beneficial effects that: the invention makes the refractive index of the optical glass 1.62-1.70 and Abbe number 55-62 through reasonable formula design, the optical glass has low cost, good chemical stability, excellent anti-devitrification performance and good transmittance, simultaneously the glass has good bubbles and stripes, is easy to produce stably, and can be widely applied to equipment such as digital cameras, digital video cameras, camera phones and the like.

Detailed Description

I, optical glass

The composition of the optical glass of the present invention will be described in detail below, and the content and the total content of each glass component are expressed in% by weight unless otherwise specified, and the ratio of the content to the total content of the glass component is expressed in terms of a weight ratio.

SiO₂Is a framework of optical glass, and has the functions of maintaining the chemical stability of the glass and improving the devitrification resistance of the glass as a glass network forming body. When SiO is present₂When the content is less than 10%, the above effects are difficult to achieve; but when SiO₂Above 30%, the glass becomes very refractory and the desired refractive index of the invention cannot be achieved. Thus, SiO₂The content of (B) is 10 to 30%, preferably 12 to 28%, more preferably 15 to 25%.

B₂O₃The glass of the present invention is also an essential component for forming glass as a glass network forming body. When B is present₂O₃When the content is less than 20%, the crystallization stability of the glass is not ideal enough; but when B is₂O₃When the content is more than 45%, the viscosity of the glass becomes small, and the volatilization increases, which is not favorable for the stable control of the refractive index and dispersion. Thus, B₂O₃The content is limited to 20 to 45%, preferably 25 to 40%, and more preferably 28 to 38%.

La₂O₃Is an essential component for obtaining the glass required by the invention, if the content is insufficient, the optical constant is difficult to reach the design requirement; and when the content is too large, of the glassThe devitrification resistance is remarkably deteriorated. Thus, the La of the present invention₂O₃The content of (B) is 10 to 35%, preferably 15 to 30%, and more preferably 18 to 28%.

SiO₂Substituted moiety B₂O₃Beneficial for improving the chemical stability of the glass, but limits La₂O₃And dissolved in the glass to destroy the structure of the glass, resulting in deterioration of devitrification resistance. The inventors have found through research that La₂O₃With SiO₂When a certain proportion exists between the components, the glass with good chemical stability and crystallization performance can be obtained. When SiO is present₂And La₂O₃Ratio of (A) to (B) SiO₂/La₂O₃When the refractive index is more than 2.7, the chemical stability of the glass is improved, but the refractive index of the glass is reduced, and the crystallization performance is poor; when SiO is present₂/La₂O₃When the amount is less than 0.7, the glass stability is poor. Thus, the invention defines SiO₂/La₂O₃Is 0.7 to 2.7, preferably 0.75 to 2.5, and more preferably 0.85 to 2.3.

Gd₂O₃Can be used for improving refractive index and reducing dispersion to partially replace La₂O₃Can improve the devitrification resistance and the chemical stability of the glass, but the expensive raw material price limits Gd₂O₃Use in glass. Thus, Gd is present in the invention₂O₃The content of (B) is 0 to 10%, preferably 0 to 5%.

Y may also be incorporated into the glass composition of the present invention₂O₃In order to improve the melting property and devitrification resistance of the glass, the upper limit temperature of devitrification of the glass can be lowered to improve the chemical stability of the glass, but if the content exceeds 15%, the stability and devitrification resistance of the glass are lowered. Thus, Y₂O₃The content is in the range of 0 to 10%, preferably 0 to 5%, and further preferably not contained.

Yb₂O₃Also, a glass may be added with a component, and when the content exceeds 10%, the stability and devitrification resistance of the glass are lowered. Thus, Yb₂O₃The content range is defined to be 0 to 10%, and is preferably0 to 5%, and further preferably not incorporated.

Li as alkali metal oxide₂O、Na₂O and K₂And O, the optical data of the glass can be adjusted, the glass melting effect is improved, and the glass has low transition temperature. When Li is present₂O、Na₂O and K₂Total content of O Li₂O+Na₂O+K₂When O exceeds 10%, the chemical stability of the glass is lowered. Thus, Li in the present invention₂O+Na₂O+K₂The total content of O is limited to 0 to 10%, preferably in the range of 0 to 5%, and more preferably in the range of 0 to 4%.

In the alkali metal oxides, Li₂O has a great effect on lowering the glass transition temperature, but the raw material cost is relatively high and mass production is not economical, so that the content thereof is limited to 10% or less, preferably 5% or less, and more preferably 3% or less.

Na₂O、K₂O is added for adjusting optical data, improving the melting property of the glass, and lowering the transition temperature of the glass, while Na is added for maintaining the resistance to devitrification and the chemical stability₂O、K₂The O content should be less than 10% each. Thus, Na₂O、K₂The content ranges of O are defined as 0 to 10%, preferably 0 to 5%, respectively.

BaO is an essential component for increasing the refractive index of the glass and improving the transmittance of the glass. When the content is less than 12%, the effect is not remarkable, but when the content exceeds 30%, the devitrification resistance and chemical stability of the glass are deteriorated. Therefore, the content thereof is limited to 12 to 30%, preferably 15 to 28%.

The mainstream technology for manufacturing the lens at present adopts a secondary compression method to manufacture a lens blank, and then the lens blank is polished to obtain a qualified glass lens. The "secondary press" processing technology of optical glass is that the blank glass is cut into small blocks, heated in furnace body to the temp. near the softening temp. of glass, then the glass is placed in mould, and pressurized under the action of external force to obtain proper lens shape. If the glass is devitrified in the process of secondary pressing, the pressed part can be scrapped. The inventor is attentive toResearch shows that BaO and SiO₂When a certain proportion exists between the two parts, the glass can be pressed and does not crystallize. When BaO and SiO₂Ratio of (BaO)/(SiO)₂When the temperature is less than 0.26, the glass is kept at the temperature of 700-900 ℃ for 20min, and crystallization is generated inside the glass; when BaO/SiO₂When the refractive index is more than 2, the refractive index of the glass is not satisfactory, and the chemical stability of the glass is deteriorated. Therefore, BaO/SiO is limited₂The range is 0.26 to 2, preferably 0.6 to 1.8, and more preferably 0.8 to 1.5.

CaO helps to increase the refractive index of the glass, and increases the mechanical strength and hardness of the glass. However, when CaO is added in an excessive amount, the glass tends to have a decreased devitrification resistance. Therefore, the CaO content is limited to 0 to 13%, preferably 0 to 10%, and more preferably 0 to 5%.

The addition of SrO to glass can adjust the refractive index and abbe number of glass, but if the addition amount is too large, the chemical stability and devitrification resistance of glass decrease, and the cost of glass also rapidly increases. Therefore, the SrO content is limited to 0 to 10%, preferably 0 to 5%, and more preferably 0 to 3.5%.

If the amount of MgO added is too large, it contributes to the improvement of the chemical stability of the glass, but the refractive index of the glass does not meet the design requirements, the devitrification resistance of the glass and the stability of the glass are deteriorated, and the cost of the glass is rapidly increased. Therefore, the MgO content is limited to 0 to 10%, preferably 0 to 5%, and more preferably not added.

BaO, SrO, CaO and MgO belong to alkaline earth metal oxides, belong to the external network body in the glass, and can adjust the refractive index and dispersion of the glass and reduce the high-temperature viscosity of the glass when added into the glass. However, once the loading of the network exosomes exceeds the load-bearing capacity of the network structure, the chemical stability of the glass is significantly degraded. Therefore, the total content of BaO, SrO, CaO and MgO, BaO + SrO + CaO + MgO, is limited to 18 to 36%, preferably 22 to 30%.

The inventors have found that, when the total content of BaO + SrO + CaO + MgO is in the above range, the devitrification resistance and transmittance of the glass are also in accordance with La₂O₃、Gd₂O₃、Y₂O₃Total content of La₂O₃+Gd₂O₃+Y₂O₃Have close relationship. When La₂O₃、Gd₂O₃、Y₂O₃Ratio of the total content of (A) to the total content of BaO, SrO, CaO and MgO (La)₂O₃+Gd₂O₃+Y₂O₃) When the ratio of (BaO + SrO + CaO + MgO) is in the range of 0.4 to 1.45, the devitrification resistance and transmittance of the glass can be brought into the optimum ranges, and it is preferable that

(La₂O₃+Gd₂O₃+Y₂O₃) The range of/(BaO + SrO + CaO + MgO) is 0.6 to 1.3, and more preferably 0.7 to 1.1.

ZrO₂The glass has the advantages that the glass can be improved in thermal stability and refractive index, but when the content of the glass is too high, the glass is difficult to melt, the melting temperature is increased, inclusions in the glass are easy to appear, the glass transmittance is reduced, the glass manufacturing cost is increased, and the product competitiveness is reduced. Thus, ZrO of the present invention₂The content of (B) is 0 to 10%, preferably 0.5 to 9%, and more preferably 1.1 to 4%.

ZnO is an effective component for improving the chemical stability of the glass, and the existence of ZnO can reduce the transition temperature of the glass, reduce the high-temperature viscosity of the glass and be beneficial to eliminating bubbles in the glass. ZnO can also reduce the high-temperature viscosity of the glass, so that the glass can be smelted at a lower temperature, and the transmittance of the glass can be improved. When the content is small, the above effects cannot be achieved; however, when the content is too large, on the one hand, the Abbe number of the glass is reduced and the requirement of the optical constant cannot be met, and on the other hand, the devitrification resistance and the chemical stability of the glass are reduced. Therefore, the content of ZnO is limited to 0 to 10%, preferably 0.5 to 9.5%, and more preferably 1 to 7%.

Al₂O₃The chemical stability of the glass can be improved, but when the content exceeds 10%, the dispersion of the glass increases and the meltability deteriorates. Thus, Al of the invention₂O₃The content of (B) is 0 to 10%, preferably 0 to 5%, more preferably 0 to 2%.

TiO₂The glass also has the effect of improving the refractive index of the glass, can participate in the formation of a glass network, can make the glass more stable by introducing a proper amount, but the dispersion of the glass is obviously increased after the introduction, and simultaneously, the transmissivity of a short wave part in a visible light area of the glass is reduced, and the coloring tendency of the glass is increased. Thus, the TiO of the present invention₂The content of (B) is 0 to 10%, preferably 0 to 5%, and further preferably not incorporated.

Nb₂O₅Has the functions of improving the refractive index and dispersion of the glass, and simultaneously has the functions of improving the crystallization resistance and chemical stability of the glass. If the content exceeds 10%, the dispersion of the glass increases, the optical characteristics of the glass of the present invention cannot be achieved, and the devitrification resistance of the glass deteriorates. Thus, Nb₂O₅The content of (b) is in the range of 0 to 10%, preferably 0 to 5%, further preferably not incorporated.

WO₃It can play a role of increasing the refractive index, but when the content thereof exceeds 10%, the dispersion is remarkably increased and the transmittance at the short wavelength side of the visible region of the glass is lowered. Thus, the present invention WO₃The content of (B) is 0 to 10%, preferably 0 to 5%, and more preferably not contained.

By adding small amounts of Sb₂O₃The component can improve the fining effect of the glass, but when Sb is used₂O₃When the content exceeds 1%, the glass tends to have a lowered fining property, and the corrosion of platinum or platinum alloy vessels for melting the glass and the deterioration of forming molds are promoted by its strong oxidizing action. Therefore, Sb is preferred in the present invention₂O₃The amount of (B) is 0 to 1%, more preferably 0 to 0.5%.

[ optical characteristics of optical glass ]

The optical glass of the present invention has a glass refractive index (nd) in the range of 1.62 to 1.70, preferably in the range of 1.64 to 1.68; abbe number (v) of the glass of the invention_d) In the range of 55 to 62, preferably in the range of 56 to 60.

[ coloring of optical glass ]

Coloring degree (. lamda.) for short-wave transmission spectral characteristics of the glass of the present invention₈₀) And (4) showing. Lambda [ alpha ]₈₀Refers to the wavelength corresponding to the glass transmittance of 80%, wherein₈₀Was measured using a glass having a thickness of 10. + -. 0.1nm with two opposing planes parallel to each other and optically polished, measuring the spectral transmittance in the wavelength region from 280nm to 700nm and showing a wavelength of transmittance of 80%. 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, λ₈₀A small value of (a) means that the glass itself is colored very little.

Optical glass lambda of the present invention₈₀Less than or equal to 370nm, preferably lambda₈₀Less than or equal to 360nm, and an optical element constituting an imaging optical system or a projection optical system excellent in color balance can be provided. Accordingly, the optical glass of the present invention is suitable as an optical element material constituting an imaging optical system and a projection optical system.

[ devitrification resistance of glass ]

Cutting the sample glass into the specification of 20 multiplied by 10mm, placing the sample glass into a muffle furnace with the temperature of 700 plus material of 900 ℃ for heat preservation for 30 minutes, taking the sample glass out, placing the sample glass into heat preservation cotton for slow cooling, polishing the surface, and observing the crystallization condition under a microscope.

[ stability of acid resistance of optical glass ]

The ability of the polished surface of an optical glass element to resist the corrosive action of an acid solution during the manufacturing and use thereof is referred to as the stability of the optical glass against the acid action.

Stability of the acid resistance of the glasses according to the invention D_A(powder method) is 4 kinds or more.

Stability against acid action D_A(powder method) according to GB/T17129 test method, calculated according to the following formula:

D_A＝(B-C)/(B-A)*100

in the formula: d_APercent glass leaching (%)

B-mass (g) of filter and sample

C-quality (g) of the filter and of the eroded sample

A-Filter Mass (g)

Stabilizing the acid resistance of the optical glass by the calculated leaching percentage D_AThe classification is 6 in the following table.

II, glass preform and optical element

The present invention also provides an optical glass preform and an optical element, which are formed from the above optical glass according to a method well known to those skilled in the art, and which can be applied to devices such as digital cameras, digital video cameras, camera phones, and the like.

Examples

The present invention is explained by the following examples, but the present invention should not be limited to these examples.

[ optical glass examples ]

First, in order to obtain glass nos. 1 to 30 having compositions shown in tables 1 to 3, carbonates, nitrates, sulfates, hydroxides, oxides, boric acid, etc. were used as raw materials, the raw materials corresponding to the optical glass components were weighed in proportion, and mixed thoroughly to obtain a blended raw material, the blended raw material was put into a platinum crucible, heated to 1250 to 1450 ℃, and clarified and stirred for 3 to 5 hours to obtain a uniform molten glass, and the molten glass was poured into a preheated mold, kept at 600 to 700 ℃ for 2 to 4 hours, and then slowly cooled to obtain the respective optical glasses of glass nos. 1 to 30.

The characteristics of each glass were measured by the following methods, and the measurement results are shown in tables 1 to 3.

(1) Refractive index (nd) and Abbe number (. nu.d)

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

(2) Degree of glass coloration (. lamda.)₈₀)

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.

(3) Devitrification resistance of glass

Cutting the sample glass into a specification of 20 multiplied by 10mm, placing the sample glass into a muffle furnace with the temperature of 700 plus one temperature of 900 ℃ for 30 minutes, taking out the sample glass, placing the sample glass into heat preservation cotton for slow cooling, polishing the surface, and observing the surface crystallization condition under a microscope, wherein the condition is expressed by K. No obvious crystallization is marked as "A", and obvious crystallization is marked as "B".

(4) Stability against acid action D_A

And measuring according to the test method of GB/T17129, and calculating according to a formula.

TABLE 1

TABLE 2

TABLE 3

[ optical preform examples ]

The optical glass obtained in example 1 in table 1 was cut into a predetermined size, and a mold release agent made of boron nitride powder was uniformly applied to the surface of the optical glass, and then heated, softened, and pressure-molded to produce preforms of 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.

[ optical element examples ]

The preforms obtained from the above optical preform examples were annealed to reduce the deformation in the glass and to fine-tune the optical properties such as refractive index to the desired values.

Next, 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, and prisms. The surface of the optical element may be coated with an antireflection film.

The glass of the invention has a refractive index of 1.62 to 1.7 and an Abbe number of 55 to 62. The optical glass has the advantages of low cost, good chemical stability, excellent anti-devitrification performance, good transmittance, good bubbles and stripes of the glass and easy stable production.

Claims

1. Optical glass, characterized in that it comprises, in weight%: SiO 2₂ 10-30％、B₂O₃20.35-45％、La₂O₃ 10-35％、Gd₂O₃ 0-10％、Y₂O₃ 0-10％、BaO 12-30％、ZrO₂ 0-10％、ZnO 0-10％、CaO 0-10％、SrO 0-10％、MgO 0-10％，SiO₂/La₂O₃0.7-2.7 of (La)₂O₃+Gd₂O₃+Y₂O₃) And (BaO + SrO + CaO + MgO) is 0.6-1.45, and tantalum is not contained.

2. The optical glass of claim 1, further comprising Yb₂O₃ 0-10％、Li₂O 0-10％、Na₂O 0-10％、K₂O 0-10％、Al₂O₃ 0-10％、TiO₂ 0-10％、Nb₂O₅ 0-10％、WO₃ 0-10％、Sb₂O₃ 0-1％。

3. The optical glass is characterized by comprising the following components in percentage by weight: SiO 2₂ 10-30％、B₂O₃20.35-45％、La₂O₃ 10-35％、BaO 12-30％、ZrO₂ 0-10％、ZnO 0.5-10％、Gd₂O₃ 0-10％、Y₂O₃ 0-10％、Yb₂O₃ 0-10％、Li₂O 0-10％、Na₂O 0-10％、K₂O 0-10％、CaO 0-10％、SrO 0-10％、MgO 0-10％、Al₂O₃ 0-10％、TiO₂ 0-10％、Nb₂O₅ 0-10％、WO₃ 0-10％、Sb₂O₃ 0-1％，(La₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.6-1.45.

4. An optical glass according to any of claims 1 to 3, characterised in that SiO is₂12 to 28 percent; and/or B₂O₃25 to 40 percent; and/or La₂O₃15 to 30 percent; and/or BaO 15-28%; and/or ZrO₂0.5-9%; and/or ZnO 0.5-9.5%; and \ or Gd₂O₃0 to 5 percent; and/or Y₂O₃0 to 5 percent; and/or Yb₂O₃0 to 5 percent; and/or Li₂0-5% of O; and/or Na₂0-5% of O; and/or K₂0-5% of O; and/or SrO 0-5%; and/or MgO 0-5%; and/or Al₂O₃0 to 5 percent; and/or TiO₂0 to 5 percent; and/or Nb₂O₅0 to 5 percent; and/or WO₃0 to 5 percent; and/or Sb₂O₃0-0.5％。

5. An optical glass according to any of claims 1 to 3, characterised in thatIn that Li₂O+Na₂O+K₂O is 0 to 10 percent; and/or SiO₂/La₂O₃0.7-2.7; and/or BaO/SiO₂0.26 to 2; and/or 18-36% of BaO + SrO + CaO + MgO.

6. An optical glass according to any of claims 1 to 3, characterised in that SiO is₂15 to 25 percent; and/or B₂O₃28 to 38 percent; and/or La₂O₃18 to 28 percent; and/or ZrO₂1.1-4%; and/or ZnO 1-7%; and/or Li₂0-3% of O; and/or CaO 0-5%; and/or SrO 0-3.5%; and/or Al₂O₃0 to 2 percent; and/or does not contain Y₂O₃、Yb₂O₃、MgO、TiO₂、Nb₂O₅、WO₃。

7. An optical glass according to any of claims 1 to 3, characterised in that Li₂O+Na₂O+K₂O is 0 to 5 percent; and/or SiO₂/La₂O₃0.75-2.5; and/or BaO/SiO₂0.6 to 1.8; and/or BaO + SrO + CaO + MgO is 22-30%; and/or (La)₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.6 to 1.3.

8. An optical glass according to any of claims 1 to 3, characterised in that Li₂O+Na₂O+K₂O is 0 to 4 percent; and/or SiO₂/La₂O₃0.85-2.3; and/or BaO/SiO₂0.8 to 1.5; and/or (La)₂O₃+Gd₂O₃+Y₂O₃) and/(BaO + SrO + CaO + MgO) is 0.7 to 1.1.

9. An optical glass according to any of claims 1 to 3, wherein the refractive index of the optical glass is from 1.62 to 1.70; the abbe number of the optical glass is 55-62.

10. An optical glass according to any of claims 1 to 3, wherein the refractive index of the optical glass is from 1.64 to 1.68; the abbe number of the optical glass is 56-60.

11. An optical glass according to any of claims 1 to 3, wherein the optical glass λ₈₀Less than or equal to 370 nm; stability of acid resistance of optical glass D_AAre of class 4 or more.

12. An optical glass according to any of claims 1 to 3, wherein the optical glass λ₈₀Less than or equal to 360 nm.

13. A glass preform made of the optical glass according to any one of claims 1 to 12.

14. An optical element made of the optical glass according to any one of claims 1 to 12.