CN110255891B

CN110255891B - Optical glass

Info

Publication number: CN110255891B
Application number: CN201910593972.9A
Authority: CN
Inventors: 赖德光; 何波
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2016-11-21
Filing date: 2016-11-21
Publication date: 2022-01-25
Anticipated expiration: 2036-11-21
Also published as: CN106517766A; CN106517766B; CN110255891A

Abstract

The invention provides an optical glass with excellent internal quality and excellent transmittance, which comprises the following components in percentage by weight: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8‑20％；La³⁺：40‑60％；Gd³⁺：20‑35％；Y³⁺：2‑15％；Nb⁵⁺: 0 to 8 percent; the anion of which contains F^‑And O^2‑In which F is^‑/O^2‑Is 0.15-0.55. The invention reduces the volatilization of F content through reasonable component design, effectively controls the problems of stripes, optical constant fluctuation and the like of glass caused by F volatilization. Through reasonable formula design, the optical glass has the advantages of 1.71-1.78 refractive index and 52-58 Abbe number, and excellent internal quality and transmittance.

Description

Optical glass

The present application is a divisional application of an invention patent application having application number 201611021333.8, application date 2016, 11, 21 and named "optical glass".

Technical Field

The invention relates to optical glass, in particular to high-refraction low-dispersion optical glass, a glass prefabricated member and an optical element.

Background

In the case of optical glass, the refractive index, Abbe number and transmittance are core optical characteristics. The basic functions of the glass are determined by the refractive index and the Abbe number, the optical glass with the refractive index of 1.71-1.78 and the Abbe number of 51-58 belongs to high-refractive-index low-dispersion optical glass, and the application of the high-performance glass in an optical system can shorten the length of a lens and improve the imaging quality.

Optical glass must have excellent internal quality (striae, bubbles, inclusions, etc.) in addition to the optical properties to be set. In some cases, the quality of the inside of the glass depends on the composition of the glass, and an optical glass having a large F content is liable to cause striae and fluctuations in optical constants because F has a certain volatility during melting. On the other hand, the internal quality of glass also depends on the production conditions of the glass. In the production of optical glass, platinum or a platinum alloy is generally used as a melting tool, and when a glass raw material is melted by a platinum-based melting tool at a high melting temperature or for a long melting time, platinum is dissolved into a molten glass, and inclusions are generated in the glass.

Disclosure of Invention

The technical problem to be solved by the invention is to provide an optical glass with excellent internal quality and excellent transmittance.

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: optical glass, the composition of which is expressed by weight percentage, the cation of which contains: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％；

The anion of which contains F^-And O^2-In which F is^-/O^2-Is 0.15-0.55.

Furthermore, the composition of the cationic polymer also comprises the following components in percentage by weight: zn²⁺：0-8％；Zr⁴⁺：0-8％；Al³⁺：0-5％；Sb³⁺：0-1％。

An optical glass comprising a fluoride and an oxide, wherein the weight ratio of the fluoride content to the oxide content is 0.2 to 0.5 in terms of weight percent, and cations thereof contain: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％。

The optical glass comprises the following components in percentage by weight: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％；Zn²⁺：0-8％；Zr⁴⁺：0-8％；Al³⁺：0-5％；Sb³⁺：0-1％；

The anion of which is represented by F^-And O^2-Is formed of wherein F^-/O^2-Is 0.15-0.55.

Further, does not contain alkali metal ion Li⁺、Na⁺、K⁺(ii) a Does not contain alkaline earth metal ion Ba²⁺、Sr²⁺、Ca²⁺And Mg²⁺(ii) a Does not contain Ge⁴⁺。

Further, wherein: si⁴⁺: 0.5 to 5 percent; and/or B³⁺: 10 to 18 percent; and/or La³⁺: 43 to 58 percent; and/or Gd³⁺: 22 to 32 percent; and/or Y³⁺: 3 to 13 percent; and/or Nb⁵⁺: 0 to 5 percent; and/or Zn²⁺: 0 to 5 percent; and/or Zr⁴⁺: 0 to 5 percent; and/or Al³ ⁺: 0 to 3 percent; and/or Sb³⁺：0-0.5％。

Further, wherein: si⁴⁺: 1 to 4 percent; and/or B³⁺: 12 to 18 percent; and/or La³⁺: 45 to 54 percent; and/or Gd³⁺: 24 to 30 percent; and/or Y³⁺: 4 to 10 percent; and/or Nb⁵⁺: 0 to 3 percent; and/or Zn²⁺: 0 to 3 percent; and/or Zr⁴⁺: 0 to 3 percent; and/or Al³ ⁺：0-2％。

Further, the ion content in the components meets one or more than one of the following 5 conditions:

1)Si⁴⁺/B³⁺0.02-0.6;

2)Y³⁺/(Si⁴⁺+B³⁺) 0.1 to 1;

3)Zn²⁺/Si⁴⁺below 1;

4)La³⁺+Gd³⁺+Y³⁺more than 70 percent;

5)F^-/O^2-is 0.2-0.5.

1)Si⁴⁺/B³⁺0.05-0.5;

2)Y³⁺/(Si⁴⁺+B³⁺) 0.2 to 0.7;

3)Zn²⁺/Si⁴⁺below 0.5;

4)La³⁺+Gd³⁺+Y³⁺is more than 75 percent;

5)F^-/O^2-is 0.25-0.45.

Further, the anion weight percentage contains: f^-：15-35％；O^2-：65-85％。

Further, the anion weight percentage contains: f^-：15-30％；O^2-：70-85％。

Further, the anion weight percentage contains: f^-：18-28％；O^2-：72-82％。

Further, the weight ratio of the fluoride content to the oxide content is 0.25-0.48.

Further, the weight ratio of the fluoride content to the oxide content is 0.3-0.45.

Further, the refractive index is 1.71-1.78; abbe number is 52-58; the transition temperature is below 660 ℃; wavelength lambda corresponding to transmittance of 80%₈₀A wavelength lambda of less than or equal to 400nm and a transmittance of 5%₅Less than or equal to 320 nm.

The glass preform is made of the optical glass.

The optical element is made of the optical glass.

The invention has the beneficial effects that: through reasonable component design, the volatilization of the F content is reduced, and the problems of stripes, optical constant fluctuation and the like of the glass caused by the volatilization of the F are effectively controlled. Through reasonable formula design, the optical glass has the advantages of 1.71-1.78 refractive index and 52-58 Abbe number, and excellent internal quality and transmittance.

Detailed Description

I, optical glass

In the present specification, the contents of the respective components are, unless otherwise specified, expressed as cationic component contents in terms of the total weight of the cations and anionic component contents in terms of the total weight of the anions. In the following description, the predetermined value is included when the predetermined value is equal to or less than the predetermined value or equal to or more than the predetermined value.

Note that the ion valence of each component is a representative value used for convenience, and is not different from other ion valence. The ion valence of each component present in the optical glass may be other than the representative value. For example, since Si is usually present in the glass in a state of an ionic valence of 4, Si is referred to as "Si" in the present specification⁴⁺"as a representative value, there is a possibility that the ion valence is in other states, and this is within the scope of the present invention.

[ with respect to the cationic component ]

B³⁺Is a glass network forming component, has the functions of improving glass meltability and devitrification resistance and reducing glass transition temperature and density, and in order to achieve the above-mentioned effects, the invention introduces more than 8% of B³⁺Preferably, more than 10% of B is introduced³⁺More preferably, 12% or more of B is introduced³⁺(ii) a However, when the amount of incorporation exceeds 20%, the glass stability and chemical durability are lowered, and the refractive index is lowered, so that the high refractive index of the present invention cannot be obtained, and therefore, B of the present invention³⁺The upper limit of the content of (2) is 20%, preferably 18%.

Si⁴⁺Also a glass former, and Si of more than 0 is introduced in the present invention⁴⁺Can improve the stability of the glass, and simultaneously Si⁴⁺The introduction of the silicon-containing silicon can also improve the high-temperature viscosity and the anti-devitrification performance of the glass, so that the Si in the glass of the invention⁴⁺The content of (a) is more than 0, preferably 0.5% or more, more preferably 1% or more; if, however, Si⁴⁺Since an excessively large content of (b) increases the glass transition temperature and lowers the glass meltability, the upper limit of the content is 6%, preferably 5%, and more preferably 4%.

In the present invention, Si is controlled⁴⁺、B³⁺Ratio of Si⁴⁺/B³⁺In the range of 0.02 to 0.6, not only the meltability of the raw material and the glass stability can be increased, but also the increase of the average linear expansion coefficient can be suppressed, and further, Si can be controlled⁴⁺/B³⁺In the range of 0.05 to 0.5, the network structure of the glass can be optimized to give the glass more excellent weather resistance and devitrification resistance, and Si is more preferable⁴⁺/B³⁺Is 0.08-0.3.

La³⁺Is an effective component for improving the refractive index and Abbe number of the glass, and La is preferred in the present invention³⁺Below 40%, it is difficult to obtain a desired refractive index and abbe number, and at the same time, by introducing 40% or more of La³⁺The chemical durability and the mechanical strength of the glass can be improved; however, when the content exceeds 60%, the devitrification tendency of the glass increases and the liquidus temperature rises. Therefore, La in the present invention³⁺The content is defined as 40 to 60%, preferably 43 to 58%, more preferably 45 to 54%.

Gd³⁺It is possible to improve the stability and durability of the glass and to increase the mechanical strength while appropriately increasing the refractive index. If the content exceeds 35%, the liquidus temperature and transition temperature of the glass increase and the stability also decreases; when Gd is present in the glass of the invention³⁺When the content is more than 20%, the devitrification resistance of the glass can be remarkably improved, and the glass forming property can be improved. Thus, Gd of the present invention³⁺The content is in the range of 20 to 35%, preferably 22 to 32%, and more preferably 24 to 30%.

Y³⁺The refractive index and Abbe number of the glass can be improved, and more than 2 percent of Y is introduced into the glass³⁺The melting property and the devitrification resistance of the glass can be improved, and the upper limit temperature and the specific gravity of the glass crystallization can be reduced; however, if the content exceeds 15%, the stability and devitrification resistance of the glass are rather lowered. Thus, Y³⁺The content is in the range of 2 to 15%, preferably in the range of 3 to 13%, more preferably in the range of 4 to 10%.

The inventor finds that when La is used as the main component through a large amount of experimental research³⁺、Gd³⁺、Y³⁺The total amount La of³⁺+Gd³⁺+Y³⁺At 70% or more, the dispersion property of the glass can be reduced and a high refractive index can be obtained, while the devitrification resistance and the light transmittance of the glass are optimized, and La is preferable in the present invention³⁺+Gd³⁺+Y³⁺Is 75% or more, more preferably 80% or more.

The inventor discovers that Y is obtained through research³⁺The proper ratio of the introduced amount of the network-forming component(s) can reduce the liquid phase temperature of the glass, inhibit the volatilization of F in the glass to a certain extent, and reduce the problems of internal striae of the glass, unstable optical constants and the like caused by the volatilization of F. Through further experimental analysis, Y is controlled³⁺、(Si⁴⁺+B³⁺) Ratio Y of³⁺/(Si⁴⁺+B³⁺) In the range of 0.1 to 1, preferable effects are obtained, preferably 0.2 to 0.7, more preferably 0.25 to 0.5.

Nb⁵⁺Has excellent effect of improving the refractive index of the glass and reducing the liquid phase temperature, and simultaneously has the function of improving the crystallization resistance and the chemical durability of the glass. If the content exceeds 8%, the glass dispersion increases and the optical characteristics of the glass of the present invention cannot be achieved. Thus, Nb⁵⁺The content of (b) is in the range of 0 to 8%, preferably in the range of 0 to 5%, more preferably in the range of 0 to 3%.

Zn²⁺Is an optional component in the invention, and can improve the chemical stability of the glass and simultaneously reduce the high-temperature viscosity and Tg temperature of the glass when being added into the glass in a proper amount. However, in the present invention, if Zn is present²⁺When the addition amount exceeds 8%, the devitrification resistance of the glass is reduced, and the high-temperature viscosity is small, which brings difficulty to molding. Thus, Zn²⁺The content of (B) is limited to 0 to 8%, preferably 0 to 5%, more preferably 0 to 3%.

In the invention, Zn is controlled²⁺、Si⁴⁺Ratio of (Zn)²⁺/Si⁴⁺A viscosity of 1 or less is preferable because the glass can have an appropriate high-temperature viscosity and can be easily molded, and Zn is preferable²⁺/Si⁴⁺Is 0.5 or less, and Zn is more preferable²⁺/Si⁴⁺Is 0.3 or less, and Zn is more preferable²⁺/Si⁴⁺Is 0.2 or less.

Zr⁴⁺The glass is a high-refraction low-dispersion component, can improve the refractive index of the glass and adjust the dispersion when added into the glass, and can also properly improve the devitrification resistance and the glass forming stability of the glass. In the present invention, when the content is more than 8%, the glass becomes hard to melt, the melting temperature increases, and inclusions in the glass and the transmittance easily decrease. Thus, Zr in the present invention⁴⁺The content is 0 to 8%, preferably 0 to 5%, and more preferably 0 to 3%.

Introducing small amount of Al³⁺The stability and chemical stability of the formed glass can be improved, but when the content exceeds 5%, the glass melting property is deteriorated and the devitrification resistance is lowered, so that the Al of the present invention³⁺The content of (B) is 0 to 5%, preferably 0 to 3%, more preferably 0 to 2%, further preferably not incorporated.

By adding small amounts of Sb³⁺The component can improve the fining effect of the glass, but when Sb is used³⁺When the content exceeds 1%, the glass tends to have a reduced devitrification resistance and an increased dispersion risk, and at the same time, the deterioration of the molding die is promoted by its strong oxidation, so Sb is preferable in the present invention³⁺The amount of (B) is 0 to 1%, more preferably 0 to 0.5%, further preferably not added.

[ concerning the anionic component ]

F^-Is a component for lowering the glass transition temperature and sag temperature, is an essential component of the optical glass of the present invention, and is obtained by introducing F in an amount of 15% or more^-The method is used for reducing the temperature coefficient of the refractive index and the Tg temperature and improving the Abbe number and the abnormal dispersibility. If the content exceeds 35%, the glass tends to be deteriorated in stability, to increase in thermal expansion coefficient and abrasion, particularly during melting, F^-The volatilization of the glass can not only pollute the environment, but also cause the optical data of the glass to exceed the design range and cause the generation of stripes. Thus, F^-The content is 15 to 35%, preferably 15 to 30%, and more preferably 18 to 28%.

The optical glass of the present invention contains O^2-Especially by containing more than 65% of O^2-The devitrification of the glass and the increase in the abrasion degree can be suppressed. Thus, it is possible to provide，O^2-The content of (b) is limited to a lower limit of 65%, preferably 70%, and more preferably 72%. On the other hand, by mixing O^2-The content of (B) is limited to 85% or less, which contributes to the improvement of the glass formability, and therefore, the present invention limits 85% to O^2-The upper limit of the content is preferably 82%.

From the viewpoint of suppressing devitrification of glass, F^-And O^2-The total content of (b) is preferably 98% or more, more preferably 99% or more, and still more preferably 99.5% or more. In addition, F^-Content and O^2-Content percentage by weight F^-/O^2-0.15 to 0.55, not only can the glass of the invention have optical properties of high refraction and low dispersion, but also the glass of the invention can have excellent thermal stability and low transition temperature. Especially when F^-/O^2-When the amount is 0.2 to 0.5, the transmittance of the glass is significantly optimized, and F is more preferable^-/O^2-Is 0.25-0.45.

In the present invention, it is preferable to introduce the glass in the form of oxide and fluoride to obtain the optical glass of the present invention by high-temperature melting, wherein the ratio of the fluoride content to the oxide content is 0.2 to 0.5 in terms of weight percent, which is advantageous for the improvement of the glass transmittance and the suppression of the volatilization of F, thereby controlling the generation of striae, and it is preferable that the ratio of the fluoride content to the oxide content is 0.25 to 0.48, and more preferable that the ratio of the fluoride content to the oxide content is 0.3 to 0.45.

[ other Components ]

Due to Li⁺The platinum or platinum alloy vessel is easy to corrode, and the finished glass generates more platinum-containing foreign matters, thereby causing the quality of the glass to be reduced. Containing Li⁺When the glass is used in the precision press molding process, the glass is likely to react with carbon in the mold release agent to form a rough opaque film layer on the surface of the glass element, and therefore, in the present invention, it is preferable that Li is not contained⁺；Na⁺The deterioration of the devitrification resistance of the glass can be accelerated, and the time for changing the glass from a liquid state to a solid state can be prolonged during cooling forming, so that conditions are created for devitrification; k⁺Leading to deterioration of water resistance. Therefore, it is preferred in the present invention that it does not containWith Li⁺、Na⁺、K⁺And the alkali metal ions are subjected to plasma treatment. Ba²⁺、Sr²⁺、Ca²⁺And Mg²⁺Since the incorporation of alkaline earth metal ions leads to a decrease in devitrification resistance of the glass of the present invention, it is preferable that Ba is not contained in the glass of the present invention²⁺、Sr²⁺、Ca²⁺And Mg²⁺And the like alkaline earth metal ions. Ge (germanium) oxide⁴⁺The incorporation of Ge is preferred to the glasses of the invention because it does not significantly optimize the performance of the glasses of the invention, but significantly increases the cost of the glasses⁴⁺。

[ Components which should not be contained ]

If necessary, other components not mentioned above can be added within a range not impairing the characteristics of the glass of the present invention. However, even when a small amount of a transition metal component such as Ce, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, or Mo is contained alone or in combination, the glass is colored and absorbs at a specific wavelength in the visible light region, thereby reducing the effect of improving the visible light transmittance of the present invention.

In recent years, cations of Pb, Th, Cd, Tl, Os, Be, and Se tend to Be used as harmful chemical substances in a controlled manner, and measures for protecting the environment are required not only in the glass production process but also in the processing process and the disposal after the production. Therefore, when the environmental protection is regarded as important, it is preferable that the additive is not substantially contained except for inevitable mixing. Thus, the optical glass contains virtually no substances contaminating the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and discarded without taking special environmental protection measures.

[ optical constants of optical glass ]

The optical glass is high-refractivity low-dispersion glass, and a lens made of the high-refractivity low-dispersion glass is combined with a lens made of the low-refractivity high-dispersion glass in many cases and is used for chromatic aberration correction. The optical glass of the present invention has a refractive index nd of a range of the glass from the viewpoint of optical characteristics suitable for the use thereofA circumference of 1.71-1.78, preferably in the range of 1.72-1.77, more preferably in the range of 1.73-1.77; abbe number v of the glass of the invention_dIn the range of 52 to 58, preferably in the range of 53 to 57.

[ coloring of optical glass ]

Coloring degree (. lamda.) for short-wave transmission spectral characteristics of the glass of the present invention₈₀/λ₅) And (4) showing. Lambda [ alpha ]₈₀Refers to the wavelength, lambda, corresponding to a glass having a transmittance of 80%₅The wavelength corresponding to the glass transmittance of 5% is referred to. Wherein λ is₈₀Was measured using a glass having a thickness of 10. + -. 0.1mm 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 another plane_outIn the case of light of (1), by_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 400nm, preferably lambda₈₀In the range of less than or equal to 395nm, more preferably lambda₈₀Is less than or equal to 390 nm. Lambda [ alpha ]₅Less than or equal to 320nm, preferably lambda₅In the range of 315nm or less, more preferably lambda₅Is less than or equal to 310 nm.

[ transition temperature of optical glass ]

The optical glass gradually changes from a solid state to a plastic state in a certain temperature interval. The transition temperature is a temperature corresponding to an intersection point where extensions of straight line portions of a low temperature region and a high temperature region of a glass sample, which is heated from room temperature to a sag temperature, intersect.

The glass according to the invention has a Tg of 660 ℃ or less, preferably 655 ℃ or less, more preferably 650 ℃ or less.

II, glass preform and optical element

The glass preform of the present invention and the optical element are each formed of the above-described optical glass of the present invention. The glass prefabricated member has the characteristics of high refractive index and low dispersion; the optical element of the present invention has high refractive index and low dispersion characteristics, and can provide optical elements such as various lenses and prisms having high optical values at low cost.

Examples of the lens include various lenses such as a concave meniscus lens, a convex meniscus lens, a double convex lens, a double concave lens, a plano-convex lens, and a plano-concave lens, each of which has a spherical or aspherical lens surface.

This lens is combined with a lens made of a high refractive index and high dispersion glass, can correct chromatic aberration, is suitable as a lens for chromatic aberration correction, and is also effective for making an optical system compact.

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.

III example

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

The melting and shaping methods for producing the optical glass may employ techniques well known to those skilled in the art. The preparation method comprises the steps of weighing and mixing glass raw materials (carbonate, nitrate, metaphosphate, fluoride, oxide and the like) according to the proportion of each ion of the glass, putting the mixture into a smelting device (such as a platinum crucible), then carrying out appropriate stirring, clarification and homogenization at 1000-1350 ℃, cooling to below 1150 ℃, pouring or leaking and injecting the mixture into a forming die, and finally carrying out post-treatment such as annealing and processing or directly carrying out compression forming by a precise compression technology.

[ optical glass examples ]

The characteristics of each glass of the present invention were measured by the following methods, and the measurement results are shown in tables 1 to 4.

(1) Refractive index nd and Abbe number vd

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、λ₅)

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) Glass transition temperature (Tg)

The measurement was carried out according to the method specified in GB/T7962.16-2010.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

[ glass preform examples ]

The optical glasses obtained in examples 1 to 40 in tables 1 to 4 were cut into a predetermined size, and then a release agent was uniformly applied to the surface of the optical glass, followed by heating, softening, and press-molding to prepare 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 glass preform examples were annealed to reduce the internal deformation of the glass and to perform fine adjustment so that the optical properties such as refractive index and the like could be brought to 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 resulting optical element may be coated with an antireflection film.

The invention is the optical glass with low cost, excellent chemical stability, high refraction and low dispersion, the refractive index is 1.71-1.78, the Abbe number is 52-58, and the optical element formed by the glass can meet the requirements of modern novel photoelectric products.

Claims

1. Optical glass is characterized in that the composition components are expressed by weight percentage, wherein cations comprise: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％；Si⁴⁺/B³⁺0.02-0.5;

the anion of which contains F^-And O^2-In which F is^-/O^2-Is 0.15-0.55.

2. The optical glass according to claim 1, wherein the composition comprises, in weight percent, cations of the glass further comprising: zn² ⁺：0-8％；Zr⁴⁺：0-8％；Al³⁺：0-5％；Sb³⁺：0-1％。

3. Optical glass, characterized in that it consists of a fluoride and an oxide, the weight ratio of the fluoride content to the oxide content, expressed in weight percentage, being 0.25-0.5, the cation of which contains: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％。

4. The optical glass according to claim 3, wherein the composition comprises, in weight percent, cations of the glass further comprising: zn² ⁺：0-8％；Zr⁴⁺：0-8％；Al³⁺：0-5％；Sb³⁺：0-1％。

5. The optical glass is characterized in that the optical glass comprises the following components in percentage by weight: si⁴⁺: greater than 0 but less than or equal to 6%; b is³⁺：8-20％；La³⁺：40-60％；Gd³⁺：20-35％；Y³⁺：2-15％；Nb⁵⁺：0-8％；Zn²⁺：0-8％；Zr⁴⁺：0-8％；Al³⁺：0-5％；Sb³⁺：0-1％；Si⁴⁺/B³⁺0.02-0.5;

6. An optical glass according to any of claims 1 to 5, characterised in that it does not contain Li⁺(ii) a And/or does not contain Na⁺(ii) a And/or does not contain K⁺(ii) a And/or do not contain Ba²⁺(ii) a And/or does not contain Sr²⁺(ii) a And/or does not contain Ca²⁺(ii) a And/or does not contain Mg² ⁺(ii) a And/or does not contain Ge⁴⁺。

7. The optical glass of any one of claims 1-5, wherein: si⁴⁺: 0.5 to 5 percent; and/or B³⁺: 10 to 18 percent; and/or La³⁺: 43 to 58 percent; and/or Gd³⁺: 22 to 32 percent; and/or Y³⁺: 3 to 13 percent; and/or Nb⁵⁺: 0 to 5 percent; and/or Zn²⁺: 0 to 5 percent; and/or Zr⁴⁺: 0 to 5 percent; and/or Al³⁺: 0 to 3 percent; and/or Sb³⁺：0-0.5％。

8. The optical glass of any one of claims 1-5, wherein: si⁴⁺: 1 to 4 percent; and/or B³⁺: 12 to 18 percent; and/or La³⁺: 45 to 54 percent; and/or Gd³⁺: 24 to 30 percent; and/or Y³⁺: 4 to 10 percent; and/or Nb⁵⁺: 0 to 3 percent; and/or Zn²⁺: 0 to 3 percent; and/or Zr⁴⁺: 0 to 3 percent; and/or Al³⁺：0-2％。

9. An optical glass according to any of claims 1 to 5, characterised in that its composition has an ion content which satisfies one or more of the following 4 conditions:

1)Y³⁺/(Si⁴⁺+B³⁺) 0.1 to 1;

2)Zn²⁺/Si⁴⁺below 1;

3)La³⁺+Gd³⁺+Y³⁺more than 70 percent;

4)F^-/O^2-is 0.2-0.5.

10. An optical glass according to any of claims 1 to 5, characterised in that its composition has an ion content which satisfies one or more of the following 5 conditions:

1)Si⁴⁺/B³⁺0.05-0.5;

2)Y³⁺/(Si⁴⁺+B³⁺) 0.2 to 0.7;

3)Zn²⁺/Si⁴⁺below 0.5;

4)La³⁺+Gd³⁺+Y³⁺is more than 75 percent;

5)F^-/O^2-is 0.25-0.45.

11. An optical glass according to any one of claims 1 to 5, characterised in that it contains, in percentages by weight of anions: f^-：15 to 35 percent; and/or O^2-：65-85％。

12. An optical glass according to any one of claims 1 to 5, characterised in that it contains, in percentages by weight of anions: f^-: 15 to 30 percent; and/or O^2-：70-85％。

13. An optical glass according to any one of claims 1 to 5, characterised in that it contains, in percentages by weight of anions: f^-: 18 to 28 percent; and/or O^2-：72-82％。

14. An optical glass according to any of claims 1 to 5, characterised in that the weight ratio of the fluoride content to the oxide content is between 0.25 and 0.48.

15. An optical glass according to any of claims 1 to 5, characterised in that the weight ratio of the fluoride content to the oxide content is between 0.3 and 0.45.

16. The optical glass of any of claims 1-5, wherein the refractive index is from 1.71 to 1.78; abbe number is 52-58; the transition temperature is below 660 ℃; wavelength lambda corresponding to transmittance of 80%₈₀A wavelength lambda of less than or equal to 400nm and a transmittance of 5%₅Less than or equal to 320 nm.

17. A glass preform made of the optical glass according to any one of claims 1 to 16.

18. An optical element made of the optical glass according to any one of claims 1 to 16.