阅读说明：本技术 光学玻璃 (Optical glass ) 是由 郝良振 匡波 毛露路 于 2019-12-20 设计创作，主要内容包括：本发明提供一种光学玻璃,其组分按重量百分比表示,含有：B<Sub>2</Sub>O<Sub>3</Sub>：20-40％；SiO<Sub>2</Sub>：10-30％；La<Sub>2</Sub>O<Sub>3</Sub>：10-30％；Gd<Sub>2</Sub>O<Sub>3</Sub>：0-10％；Y<Sub>2</Sub>O<Sub>3</Sub>：2-10％；BaO：10-20％；Li<Sub>2</Sub>O：0.5-5％。本发明通过引入适量比例的La<Sub>2</Sub>O<Sub>3</Sub>、Y<Sub>2</Sub>O<Sub>3</Sub>等具有高折射率低色散作用的稀土类氧化物组分,得到具有优异的耐候性的光学玻璃；通过合理控制稀土氧化物之间比例以及合理使用碱土金属氧化物,使玻璃具有较低的密度。(The invention provides optical glass, which comprises the following components in percentage by weight: b is 2 O 3 ：20‑40％；SiO 2 ：10‑30％；La 2 O 3 ：10‑30％；Gd 2 O 3 ：0‑10％；Y 2 O 3 ：2‑10％；BaO：10‑20％；Li 2 O: 0.5 to 5 percent. The invention introduces La with proper proportion 2 O 3 、Y 2 O 3 And the like, a rare earth oxide component having a high refractive index and a low dispersion action, to obtain an optical glass having excellent weather resistance; the glass has lower density by reasonably controlling the proportion of the rare earth oxides and reasonably using the alkaline earth metal oxides.)

1. Optical glass, characterized in that it comprises, in percentages by weight: b is₂O₃：20-40％；SiO₂：10-30％；La₂O₃：10-30％；Gd₂O₃：0-10％；Y₂O₃：2-10％；BaO：10-20％；Li₂O：0.5-5％。

2. The optical glass according to claim 1, wherein the composition, expressed in weight percent, further comprises: al (Al)₂O₃：0-5％；Yb₂O₃：0-10％；SrO：0-10％；CaO：0-10％；MgO：0-5％；ZnO：0-4％；ZrO₂：0-4％；Na₂O：0-5％；K₂O：0-5％；Sb₂O₃：0-1％。

3. Optical glass, characterized in that its composition, expressed in weight percentage, is represented by B₂O₃：20-40％；SiO₂：10-30％；La₂O₃：10-30％；Gd₂O₃：0-10％；Y₂O₃：2-10％；BaO：10-20％；Li₂O：0.5-5％；Al₂O₃：0-5％；Yb₂O₃：0-10％；SrO：0-10％；CaO：0-10％；MgO：0-5％；ZnO：0-4％；ZrO₂：0-4％；Na₂O：0-5％；K₂O：0-5％；Sb₂O₃: 0-1% of the composition.

4. An optical glass according to any of claims 1 to 3, wherein the content of each component satisfies one or more of the following 4 cases:

1)La₂O₃+Gd₂O₃+Y₂O₃15-35%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.04-0.4;

3)La₂O₃+ BaO is 25-45%;

4)ZnO+ZrO₂is 0-4%.

5. An optical glass according to any one of claims 1 to 3, characterised in that its composition is expressed in weight percentages in which: b is₂O₃: 25 to 38 percent; and/or SiO₂: 12 to 27 percent; and/or La₂O₃: 13 to 27 percent; and/or Gd₂O₃: 0 to 5 percent; and/or Y₂O₃: 2.5 to 9 percent; and/or BaO: 11 to 19 percent; and/or Li₂O: 0.8-4%; and/or Al₂O₃: 0 to 2 percent; and/or Yb₂O₃: 0 to 5 percent; and/or SrO: 0 to 5 percent; and/or CaO: 1 to 9 percent; and/or MgO: 0 to 3 percent; and/or ZnO: 0 to 3 percent; and/or ZrO₂：0-3％。

6. An optical glass according to any of claims 1 to 3, wherein the content of each component satisfies one or more of the following 4 conditions:

1)La₂O₃+Gd₂O₃+Y₂O₃18-32%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.06-0.35;

3)La₂O₃+ BaO is 27-43%;

4)ZnO+ZrO₂is 0-3%.

7. An optical glass according to any one of claims 1 to 3, characterised in that its composition is expressed in weight percentages in which: b is₂O₃: 30-36%; and/or SiO₂: 14 to 24 percent; and/or La₂O₃: 16 to 23 percent; and/or Y₂O₃: 3 to 8 percent; and/or BaO: 12 to 18 percent; and/or Li₂O: 1 to 3 percent; and/or CaO: 2 to 8 percent; and/or ZnO: 0 to 2 percent; and/or ZrO₂：0-2％。

8. An optical glass according to any of claims 1 to 3, wherein the content of each component satisfies one or more of the following 4 conditions:

1)La₂O₃+Gd₂O₃+Y₂O₃21-29%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.08-0.3;

3)La₂O₃+ BaO is 29-41%;

4)ZnO+ZrO₂is 0-2%.

9. An optical glass according to any of claims 1 to 3, wherein the refractive index of the optical glass is in the range of 1.62 to 1.68, preferably in the range of 1.63 to 1.67; the Abbe number is 55-62, preferably 56-61.

10. An optical glass according to any of claims 1 to 3, wherein the optical glass has a density of 3.55g/cm³The density is preferably 3.50g/cm or less³The following; and/or the acid resistance stability is more than 4 types, preferably the acid resistance stability is more than 3 types; and/or weather resistance stability of 2 or more, preferably 1.

11. A glass preform made of the optical glass according to any one of claims 1 to 10.

12. An optical element made of the optical glass according to any one of claims 1 to 10 or the glass preform according to claim 11.

13. An optical instrument comprising the optical glass according to any one of claims 1 to 10, or comprising the optical element according to claim 12.

Technical Field

The invention relates to optical glass, in particular to optical glass with a refractive index of 1.62-1.68 and an Abbe number of 55-62.

Background

With the rapid development of wearable equipment, the requirements of miniaturization, light weight and high performance of elements provided by photoelectric terminals are higher than those of traditional optical equipment, so that the demand of optical glass with high refraction, low dispersion and low density is larger and larger. However, most of these glasses are formed by adding a certain amount of rare earth oxide and alkaline earth oxide based on a borate glass system. When the content of rare earth oxide or alkaline earth metal oxide in the glass system is larger, the density of the glass is higherThe degree will be large. CN103771705A discloses an optical glass with a refractive index of 1.65-1.75 and an Abbe number of 50-60, the glass component of the optical glass contains 15-25% of La₂O₃Also contains 25-35% of BaO, and the minimum value of the density in the embodiment is 3.87g/cm³When the wearable device is applied, the weight of the wearable device can be increased, and the comfort of a user is affected.

After polishing the optical element, the optical part needs to be cleaned before coating. At present, ultrasonic cleaning is mainly adopted, and water on the surface of a part is evaporated in a drying dish after the cleaning is finished. In the process, the surface of the part is contacted with water for a certain time; in addition, CO in the air₂The gas and water on the surface of the glass form weakly acidic carbonic acid. Therefore, if the acid resistance of the glass is not good, the polished layer of the glass is damaged, which causes difficulty in the subsequent coating process. Therefore, the optical glass needs to have better chemical stability so as to improve the yield in the later processing and coating processes.

Disclosure of Invention

The invention aims to provide optical glass with low density and excellent weather resistance and acid resistance.

The technical scheme adopted by the invention for solving the technical problem is as follows:

optical glass, the composition of which, expressed in weight percent, comprises: b is₂O₃：20-40％；SiO₂：10-30％；La₂O₃：10-30％；Gd₂O₃：0-10％；Y₂O₃：2-10％；BaO：10-20％；Li₂O：0.5-5％。

Furthermore, the optical glass also comprises the following components in percentage by weight: al (Al)₂O₃：0-5％；Yb₂O₃：0-10％；SrO：0-10％；CaO：0-10％；MgO：0-5％；ZnO：0-4％；ZrO₂：0-4％；Na₂O：0-5％；K₂O：0-5％；Sb₂O₃：0-1％。

Optical glass, the composition of which is expressed in weight percent, consisting ofB₂O₃：20-40％；SiO₂：10-30％；La₂O₃：10-30％；Gd₂O₃：0-10％；Y₂O₃：2-10％；BaO：10-20％；Li₂O：0.5-5％；Al₂O₃：0-5％；Yb₂O₃：0-10％；SrO：0-10％；CaO：0-10％；MgO：0-5％；ZnO：0-4％；ZrO₂：0-4％；Na₂O：0-5％；K₂O：0-5％；Sb₂O₃: 0-1% of the composition.

Further, the content of each component of the optical glass meets more than one of the following 4 conditions:

1)La₂O₃+Gd₂O₃+Y₂O₃15-35%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.04-0.4;

3)La₂O₃+ BaO is 25-45%;

4)ZnO+ZrO₂is 0-4%.

Further, the optical glass comprises the following components in percentage by weight: b is₂O₃: 25 to 38 percent; and/or SiO₂: 12 to 27 percent; and/or La₂O₃: 13 to 27 percent; and/or Gd₂O₃: 0 to 5 percent; and/or Y₂O₃: 2.5 to 9 percent; and/or BaO: 11 to 19 percent; and/or Li₂O: 0.8-4%; and/or Al₂O₃: 0 to 2 percent; and/or Yb₂O₃: 0 to 5 percent; and/or SrO: 0 to 5 percent; and/or CaO: 1 to 9 percent; and/or MgO: 0 to 3 percent; and/or ZnO: 0 to 3 percent; and/or ZrO₂：0-3％。

Further, the content of each component of the optical glass meets more than one of the following 4 conditions:

1)La₂O₃+Gd₂O₃+Y₂O₃18-32%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.06-0.35;

3)La₂O₃+ BaO is 27-43%;

4)ZnO+ZrO₂is 0-3%.

Further, the optical glass comprises the following components in percentage by weight: b is₂O₃: 30-36%; and/or SiO₂: 14 to 24 percent; and/or La₂O₃: 16 to 23 percent; and/or Y₂O₃: 3 to 8 percent; and/or BaO: 12 to 18 percent; and/or Li₂O: 1 to 3 percent; and/or CaO: 2 to 8 percent; and/or ZnO: 0 to 2 percent; and/or ZrO₂：0-2％。

Further, the content of each component of the optical glass meets more than one of the following 4 conditions:

1)La₂O₃+Gd₂O₃+Y₂O₃21-29%;

2)Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.08-0.3;

3)La₂O₃+ BaO is 29-41%;

4)ZnO+ZrO₂is 0-2%.

Further, the refractive index of the optical glass is 1.62-1.68, preferably 1.63-1.67; the Abbe number is 55-62, preferably 56-61.

Further, the optical glass has a density of 3.55g/cm³The density is preferably 3.50g/cm or less³The following; and/or the acid resistance stability is more than 4 types, preferably the acid resistance stability is more than 3 types; and/or weather resistance stability of 2 or more, preferably 1.

The glass preform is made of the optical glass.

And the optical element is made of the optical glass or the glass prefabricated member.

An optical device comprising the above optical glass or the above optical element.

The invention has the beneficial effects that: by introducing La in appropriate proportion₂O₃、Y₂O₃And the like, a rare earth oxide component having a high refractive index and a low dispersion action, to obtain an optical glass having excellent weather resistance; the glass has lower density by reasonably controlling the proportion of the rare earth oxides and reasonably using the alkaline earth metal oxides.

Detailed Description

I, optical glass

The ranges of the respective components of the optical glass of the present invention are explained below. In the present specification, the contents of the respective components are all expressed in terms of weight percentage with respect to the total amount of glass matter converted into the composition of oxides, if not specifically stated. Here, the "composition converted to oxides" means that when oxides, complex salts, hydroxides, and the like used as raw materials of the optical glass composition component (component) of the present invention are decomposed in the melt and converted to oxides, the total amount of the oxides is 100%.

Unless otherwise indicated herein, the numerical ranges set forth herein include upper and lower values, and the terms "above" and "below" include the endpoints, and all integers and fractions within the range, and are not limited to the specific values listed in the defined range. The term "and/or" as used herein is inclusive, e.g., "a; and/or B "means A alone, B alone, or both A and B.

B₂O₃Is a glass network former, especially in high-refractive low-dispersion lanthanide glasses, B₂O₃Is an essential component for obtaining stable glass. On the other hand, B₂O₃The fluxing agent can reduce the difficulty of vitrification material, reduce the high-temperature viscosity of glass and reduce the transition temperature of glass after being introduced. More than 20 percent of B is introduced into the invention₂O₃In order to obtain the above-mentioned effects, it is preferable to introduce 25% or more of B₂O₃More preferably, 30% or more of B is introduced₂O₃. When B is present₂O₃Content (wt.)Above 40%, the weatherability of the glass is reduced, and therefore, B₂O₃The content is limited to 40% or less, preferably 38% or less, and more preferably 36% or less.

SiO₂Is also a glass network forming body, is a framework of optical glass, has the functions of improving the chemical stability of the glass and maintaining the devitrification resistance of the glass, and can be used as SiO₂When the content is less than 10%, the above-mentioned effects are hardly obtained. Thus SiO₂The lower limit of the content is 10%, and SiO is preferable₂The lower limit of the content is 12%, and SiO is more preferable₂The lower limit of the content is 14%. When SiO is present₂Above 30%, the glass becomes very refractory and the desired refractive index of the invention cannot be achieved. Thus, SiO₂The upper limit of the content of (B) is 30%, preferably 27%, more preferably 24%.

Introducing Al in a proper amount₂O₃Can improve the weather resistance of the glass, but can improve the melting temperature and high-temperature viscosity of the glass after being introduced, and increases the production difficulty. When Al is present₂O₃When the content exceeds 5%, the glass tends to have poor meltability and devitrification resistance tends to be low. Thus, Al of the invention₂O₃The content of (B) is 0 to 5%, preferably 0 to 2%, and further preferably not incorporated.

La₂O₃Is an essential component for obtaining the high-refractive low-dispersion characteristics required by the present invention. If the content is less than 10%, the optical constants are difficult to meet the design requirements, so that 10% or more of La is introduced in the present invention₂O₃Preferably, 13% or more of La is introduced₂O₃More preferably, 16% or more of La is introduced₂O₃. When La₂O₃When the content is more than 30%, the transition temperature of the glass is obviously increased, and the density is difficult to meet the design requirement. Thus, the La of the present invention₂O₃The content of (b) is 30% or less, preferably 27% or less, more preferably 23% or less.

Gd₂O₃Can be used for increasing refractive index and reducing dispersion to partially replace La₂O₃The devitrification resistance and the chemical stability of the glass can be improved. But expensive raw materialsThe price limits Gd₂O₃Use in glass. Thus, Gd₂O₃The content of (B) is 0 to 10%, preferably 0 to 5%, and more preferably not contained.

The component with high refraction and low dispersion of the invention also introduces Y₂O₃The glass can be improved in meltability and weather resistance. Compared with La₂O₃，Y₂O₃The refractive index of the glass can be greatly improved under the condition of not obviously improving the density of the glass, and the low-density and high-refraction glass can be obtained more favorably. When Y is₂O₃When the content is less than 2%, the above-mentioned effects are difficult to obtain; however, if the content exceeds 10%, the devitrification resistance of the glass is lowered. Thus, Y₂O₃The content is in the range of 2 to 10%, preferably in the range of 2.5 to 9%, more preferably in the range of 3 to 8%.

La₂O₃、Gd₂O₃And Y₂O₃The glass can play a role in improving the refractive index after being added, and the bearing capacity of a glass network consisting of borosilicate is exceeded when the glass is added too much, so that the devitrification resistance of the glass is poor. Therefore, the invention controls La₂O₃、Gd₂O₃、Y₂O₃The total content La of₂O₃+Gd₂O₃+Y₂O₃15 to 35% for controlling the balance between the optical constants and the devitrification resistance of the glass, preferably La₂O₃+Gd₂O₃+Y₂O₃Is 18 to 32%, more preferably 21 to 29%.

Further, in the present invention, Y is substituted by₂O₃And La₂O₃、Gd₂O₃、Y₂O₃Ratio of total content Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) 0.04-0.4, the glass can obtain the desired optical constant and lower density, and Y is preferred₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) In the range of 0.06-0.35, more preferably 0.08 to 0.3.

Yb₂O₃The refractive index of the glass can be improved by adding the glass, but the glass has an obvious absorption peak in a near infrared region, and when the glass is used as an element, the spectrum composition of transmitted light can be changed, so that the image reduction effect is influenced. Thus, Yb₂O₃The content range is defined as 0 to 10%, preferably 0 to 5%, and further preferably not incorporated.

BaO has low cost and easy acquisition of raw materials, and can well improve the refractive index of glass after being introduced into the glass, so the BaO is widely used in lanthanum crown glass. However, the introduction of BaO is disadvantageous in reducing the density of the glass, and when the amount of BaO added is too large, the weatherability of the glass is rapidly lowered. Therefore, the BaO content is limited to 10 to 20%, preferably 11 to 19%, more preferably 12 to 18%.

La₂O₃BaO can play a role in improving the refractive index, and the density of the glass can be sharply increased after the BaO is introduced. Therefore, it is necessary to apply La₂O₃And the introduction amount of BaO is comprehensively considered. The inventor finds that when La is used in repeated experiments₂O₃The total value La of BaO₂O₃When the content of BaO is between 25 and 45 percent, the density and the refractive index of the glass can meet the design requirements, and when the content of La is between 25 and 45 percent₂O₃When the + BaO is less than 25%, the refractive index of the glass is difficult to meet the requirement, while the La₂O₃When + BaO is higher than 45%, the density of the glass sharply increases, and La is preferred₂O₃The value of + BaO is 27 to 43%, more preferably 29 to 41%.

The introduction of an appropriate amount of SrO can improve the weatherability of the glass and reduce the density of the glass, but since SrO is expensive and the cost of the glass increases due to excessive introduction, the SrO content is limited to 0 to 10%, preferably 0 to 5%, and more preferably not contained.

After the CaO is introduced into the glass, the hardness, the mechanical strength and the weather resistance of the glass can be improved. More importantly, the introduction of CaO is more beneficial for the density reduction of the glass than BaO and SrO. However, when the amount of CaO added is too large, the glass is difficult to melt, and a calcium-rich crust is easily formed in the melting tank during the production process. Therefore, the CaO content is limited to 0 to 10%, preferably 1 to 9%, and more preferably 2 to 8%.

If the amount of MgO added is too large, although it contributes to improvement of the weatherability of the glass, 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 5%, preferably 0 to 3%, and more preferably not added.

ZnO can improve the acid resistance stability of the glass, improve the weather resistance of the glass and reduce the transition temperature of the glass. However, when the content of the additive is too high, the corrosion to platinum vessels in the smelting process is increased, and the service life of the smelting furnace is shortened. Accordingly, the ZnO content in the glass of the present invention is 0 to 4%, preferably 0 to 3%, and more preferably 0 to 2%.

ZrO₂Can improve the weather resistance of the glass and improve the crystallization resistance stability of the glass, but ZrO₂In this system, the glass has a low solubility and, when the content is too large, the glass tends to dissociate from the glass system to form crystallization nuclei, which in turn deteriorates the crystallization performance of the glass. Thus, ZrO of the present invention₂The content of (B) is 0 to 4%, preferably 0 to 3%, and more preferably 0 to 2%.

The invention controls ZrO₂ZnO + ZrO in total content with ZnO₂In the range of 0 to 4%, ZnO + ZrO is preferable because of the favorable lowering of the density of the glass₂Is 0 to 3%, more preferably 0 to 2%.

Li₂O belongs to alkali metal oxide and is a key component for reducing the production difficulty of the glass. Li₂O can be used as a fluxing agent, and the difficulty of vitrification can be reduced after the glass is introduced. Meanwhile, Li₂O can reduce the high-temperature viscosity of the glass, reduce the glass transition temperature and make the glass easier to produce and process. The inventors have intensively studied and found that a small amount of Li is added to lanthanum crown glass₂O, using Li₂The effect of the accumulation of O, in turn, can improve the weatherability of the glass. However, if the content is too high, the acid resistance of the glass is lowered. Thus, in the glasses according to the invention, Li₂The content of O is 0.5-5%, preferably 0.8-4%, more preferably 1-3%。

Na₂O and K₂O can also reduce the high temperature viscosity of the glass but causes a drastic reduction in chemical stability, and therefore Na in the glass of the present invention₂The content of O is 0-5%, preferably not containing; k₂The content of O is limited to 0 to 5%, and preferably not contained.

Sb₂O₃The clarifying agent is used in the invention, and the content of the clarifying agent is 0-1%.

In the glass of the present invention, even when a small amount of oxides of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo is contained singly or in combination, the glass is colored and absorbs at a specific wavelength in the visible light region, thereby impairing the property of the present invention to improve the effect of visible light transmittance.

In recent years, oxides of 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 disposal after commercialization. Therefore, when importance is attached to the influence on the environment, it is preferable that these components are not substantially contained except for inevitable mixing. Thereby, the optical glass becomes practically free from substances contaminating the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and discarded without taking special measures for environmental countermeasures.

In order to achieve environmental friendliness, the optical glass of the present invention does not contain As₂O₃And PbO. Although As₂O₃Has the effects of eliminating bubbles and better preventing the glass from coloring, but As₂O₃The addition of (b) increases the platinum attack of the glass on the furnace, particularly on the platinum furnace, resulting in more platinum ions entering the glass, which adversely affects the service life of the platinum furnace. PbO can significantly improve the high-refractivity and high-dispersion properties of the glass, but PbO and As₂O₃All cause environmental pollution.

The "no incorporation", "no inclusion", "no addition" and "0%" described herein mean that the compound, molecule, element or the like is not intentionally added as a raw material to the optical glass of the present invention; however, it is within the scope of the present invention that certain impurities or components which are not intentionally added may be present as raw materials and/or equipment for producing the optical glass and may be contained in the final optical glass in small or trace amounts.

The performance of the optical glass of the present invention will be described below.

< refractive index and Abbe number >

Refractive index (n) of optical glass_d) And Abbe number (v)_d) The test was carried out according to the method specified in GB/T7962.1-2010.

Refractive index (n) of the optical glass of the present invention_d) From 1.62 to 1.68, preferably from 1.63 to 1.67; abbe number (v)_d) From 55 to 62, preferably from 56 to 61.

< stability against acid Effect >

Stability of acid resistance of optical glass (D)_A) (powder method) the test was carried out according to the method prescribed in GB/T17129.

Stability of acid resistance of the optical glass of the present invention (D)_A) Is 4 or more, preferably 3 or more.

< weather resistance >

The weather resistance (CR) test method of the optical glass comprises the following steps: the sample was placed in a saturated water vapor atmosphere at a relative humidity of 90%, and the cycle was repeated alternately every one hour at 40 to 50 ℃ for 15 cycles. The weather resistance categories were classified according to the amount of change in turbidity before and after the sample was left, and Table 1 shows the weather resistance categories.

TABLE 1 weather resistance test grade Standard

The optical glass of the present invention has a weatherability (CR) of 2 or more, preferably 1.

< Density >

The density (. rho.) of the optical glass was measured by the method specified in GB/T7962.20-2010.

The optical glass of the present invention has a density (. rho.) of 3.55g/cm³Hereinafter, it is preferably 3.50g/cm³The following.

[ production method ]

The method for manufacturing the optical glass comprises the following steps: the glass is produced by adopting conventional raw materials and conventional processes, carbonate, nitrate, sulfate, hydroxide, oxide and the like are used as raw materials, the materials are mixed according to a conventional method, the mixed furnace burden is put into a smelting furnace at 1250-1400 ℃ for smelting, and after clarification, stirring and homogenization, homogeneous molten glass without bubbles and undissolved substances is obtained, and the molten glass is cast in a mold and annealed. Those skilled in the art can appropriately select the raw materials, the process method and the process parameters according to the actual needs.

II, glass preform and optical element

The glass preform can be produced from the optical glass produced by, for example, grinding or press molding such as reheat press molding or precision press molding. That is, the glass preform may be produced by machining the optical glass by grinding, polishing, or the like, or by producing a preform for press molding from the optical glass, subjecting the preform to reheat press molding, and then polishing, or by precision press molding the preform obtained by polishing.

It should be noted that the means for producing the glass preform is not limited to the above means. As described above, the optical glass of the present invention is useful for various optical elements and optical designs, and among them, it is particularly preferable to form a preform from the optical glass of the present invention, and use the preform for reheat press forming, precision press forming, or the like to produce optical elements such as lenses, prisms, or the like.

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 preform of the present invention has excellent characteristics possessed by optical glass; the optical element of the present invention has excellent characteristics of optical glass, and can provide optical elements such as various lenses and prisms having high optical values.

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.

III, optical instrument

The optical element formed by the optical glass can be used for manufacturing optical instruments such as photographic equipment, vehicle-mounted equipment, camera equipment, display equipment, monitoring equipment and the like.

The optical glass has the properties of excellent chemical stability, lower refractive index temperature coefficient and the like, and is particularly suitable for being applied to the fields of vehicle-mounted monitoring and security protection and the like.