Optical glass, method for producing the same, and use thereof

Abstract

The application provides an optical glass and a preparation method and application thereof. The preparation method comprises the following steps: (1) weighing raw materials and mixing uniformly; the optical glass comprises, in terms of mass percentage of oxides, 40-50% of La2O3, 15-25% of Nb2O5, 10-20% of Gd2O3, 5-10% of GeO2, 5-10% of B2O3, 1-6% of TiO2 and 0.1-1% of K2O; (2) melting the mixture to obtain a glass liquid, and then bubbling an atmosphere into the glass liquid; the gas comprises an inert gas and a reducing gas; the specific gravity of the inert gas is greater than that of air under the same temperature and gas pressure; the reducing gas makes the redox index of the glass liquid range from-120 to-5; and after stopping the bubbling, the glass liquid is homogenized and clarified under stirring. The technical problem to be solved is how to provide a preparation method of an optical glass, so that the obtained optical glass not only has a high refractive index but also has a high light transmittance in the visible light region, thereby facilitating popularization and use.

Description

Technical Field

[0001] This invention belongs to the field of glass, specifically relating to an optical glass, its preparation method, and its application. Background Technology

[0002] As electronic products and components evolve towards thinner, lighter, more portable, and higher-performance designs, the field of view (FOV) of optical systems made with traditional optical glass is affected, leading to a decrease in optical clarity. Since the refractive index of optical glass is a crucial parameter affecting the FOV of an optical system, a high refractive index is beneficial for improving the optical clarity of electronic products and components. Therefore, high-refractive-index glass, especially glass with a refractive index n... d The application of ultra-high refractive index optical glass with a refractive index of ≥2.0 is becoming increasingly widespread.

[0003] In the prior art, in order to increase the refractive index n of optical glass d For optical glass with a transmittance ≥2.0, TiO2 is typically added. However, during the melting process, TiO2-containing glass undergoes a reaction, resulting in intensified coloration of the glass. Consequently, TiO2-containing optical glass often exhibits poor light transmittance at wavelengths of 420-460 nm. To address this issue, some literature reports the addition of a decolorizing agent, fluoride RF3 (R selected from one or both of La and Ga), and carbon (C) to the optical glass for decolorization. This is followed by high-temperature melting under nitrogen protection, using a Pt-20Rh crucible and a Pt-30Rh stirrer to improve the internal transmittance. However, the transmittance of the optical glass prepared by this method remains less than 94%. Summary of the Invention

[0004] The main objective of this invention is to provide an optical glass, its preparation method, and its applications. The technical problem to be solved is how to provide a method for preparing optical glass that results in an optical glass with not only a high refractive index (n...) d It has a transmittance of ≥2.0) and high transmittance in the visible light region (internal transmittance ≥94.2%), which facilitates its widespread use.

[0005] The objective of this invention and the technical problem it solves are achieved through the following technical solution. According to this invention, a method for preparing optical glass is proposed, comprising the following steps:

[0006] (1) Preparation of raw materials: Weigh the raw materials and mix them evenly; the optical glass comprises, by mass percentage of oxides: 40-50% La2O3, 15-25% Nb2O5, 10-20% Gd2O3, 5-10% GeO2, 5-10% B2O3, 1-6% TiO2, and 0.1-1% K2O; wherein the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2 and TiO2 is 82-92%;

[0007] (2) Melting: The batch material is melted to obtain molten glass, and then gas is introduced into the molten glass for atmospheric bubbling; the gas includes an inert gas and a reducing gas; at the same temperature and gas pressure, the specific gravity of the inert gas is greater than that of air; the reducing gas makes the redox index of the molten glass -120 to -5; after bubbling is stopped, the molten glass is homogenized and clarified under stirring conditions; the container and stirrer that come into contact with the molten glass during the melting process are made of platinum-containing material;

[0008] (3) Glass forming and annealing.

[0009] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0010] Preferably, in the aforementioned preparation method, the inert gas is selected from at least one of argon, krypton, and xenon; and the reducing gas is selected from at least one of hydrogen, nitric oxide, hydrogen sulfide, sulfur monoxide, and carbon monoxide.

[0011] Preferably, in the aforementioned preparation method, the inert gas is argon and the reducing gas is hydrogen.

[0012] Preferably, in the aforementioned preparation method, the volume percentage of hydrogen in the gas is 1-3%, the flow rate of the mixed gas introduced per liter of molten glass is 1-4 L / min, and the aeration time is 0.5-1 h.

[0013] Preferably, in the aforementioned preparation method, the optical glass contains 5-8% B2O3 and 1-5% TiO2 by mass percentage.

[0014] Preferably, in the aforementioned preparation method, the melting temperature is 1380–1420°C, and the time is 5–8 hours; a frame stirrer is used for stirring, the stirrer speed is 50–80 rpm, and the stirring time is 2–4 hours.

[0015] Preferably, in the aforementioned preparation method, the glass is formed by a blown glass forming method, the forming temperature is 1200-1250℃, the glass annealing temperature is 700-750℃, and the annealing time is 8-10h.

[0016] Preferably, in the aforementioned preparation method, the optical glass further comprises ZrO2 and Ta2O5, based on oxides, with ZrO2 accounting for 1-6% and Ta2O5 accounting for 1-6% by mass percentage.

[0017] The objective of this invention and the solution to its technical problem are further achieved by the following technical solution. According to this invention, an optical glass comprises, by mass percentage of oxides: 40-50% La₂O₃, 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-10% B₂O₃, 1-6% TiO₂, 0.1-1% K₂O, 5-8% B₂O₃, and 1-5% TiO₂; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82-92%; the refractive index n of the optical glass is... d ≥2.02, and transmittance ≥94.2% in the visible light region.

[0018] The objective of this invention and the technical problem it solves are also achieved by the following technical solution: An application of optical glass according to this invention in the fields of virtual reality, digital cameras, or automotive displays.

[0019] By employing the above technical solutions, the optical glass, its preparation method, and its applications proposed in this invention have at least the following advantages:

[0020] 1. This invention provides a method for preparing optical glass, wherein the optical glass contains a large amount of La2O3, Nb2O5, Gd2O3, and GeO2, and a small amount of TiO2, and the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2, and TiO2 is 82-92%, thereby enabling the prepared optical glass to achieve an extremely high refractive index (n0.05 at a wavelength of 587.6 nm). d ≥2.02).

[0021] Since TiO2 not only increases the refractive index of glass but also reduces its density, making it thinner and lighter, this invention incorporates TiO2 into optical glass. However, TiO2 can significantly increase the coloration of glass. This invention rationally uses and limits the TiO2 content in optical glass and coordinates its use with other oxides of this invention to give the optical glass of this invention an extremely high refractive index and reduce the coloration of the glass, thereby making the extremely high refractive optical glass of this invention have good light transmittance in the visible light region. In addition, the prepared optical glass has a low density, and products made using this optical glass are easy to make thinner and lighter.

[0022] In the process of optical glass manufacturing, it is inevitable that impurities such as iron (Fe) will be introduced along with the batch materials. These impurities can react with oxygen (O2) during the high-temperature melting of the glass to undergo a redox reaction, mainly forming Fe2+.2+ and Fe 3+ Due to the Fe in the glass 3+ The absorption of visible light near the ultraviolet region gives the glass a brownish-yellow hue; while Fe... 2+ The absorption in the visible light region near the ultraviolet region is not significant, and the optical glass contains TiO2 and Fe. 3+ During the high-temperature melting process, Fe-O-Ti complex groups can be formed with TiO2, and these Fe-O-Ti complex groups can enhance the coloration of the glass. Therefore, in order to make the optical glass of this invention have high light transmittance in the visible light region, on the one hand, Fe is reduced or even avoided. 3+ On the one hand, it generates Fe; on the other hand, it inhibits or even avoids the formation of Fe-O-Ti complex groups in the glass. The specific solution is as follows:

[0023] First, the optical glass of the present invention uses GeO2 and B2O3 to provide the glass network forging, avoiding the presence of SiO2 components, thereby lowering the glass melting temperature and shortening the melting time, and thus suppressing the reaction of impurity Fe with oxygen to form Fe. 3+ This also shortens the reaction time between impurity Fe and oxygen, reducing the amount of Fe in the molten glass. 3+ The content of.

[0024] Secondly, in the high-temperature melting process of this invention, after the batch material has melted, gas is introduced into the molten glass to create an atmosphere of bubbling. This gas includes inert and reducing gases. At the same temperature and atmospheric pressure, the inert gas has a higher specific gravity than air. After the inert gas overflows from the molten glass, it can accumulate around the molten glass to form a protective gas layer, preventing gas exchange between the outside and inside of the molten glass, blocking oxygen from entering the molten glass, and inhibiting the reaction of Fe impurities in the molten glass with O2 to form Fe. 3+ And Fe in the molten glass 3+ The reduced content also helps to inhibit Fe 3+ The complexation reaction with TiO2 reduces or even prevents the formation of Fe-O-Ti complex groups in the glass. Furthermore, the reducing gas introduced into the molten glass maintains a redox index range of -120 to -5, creating a weakly reducing environment. This not only helps suppress the rate and extent of the redox reaction between impurity Fe and O2, but also reduces the Fe content in the molten glass. 2+ It is not easily oxidized and remains stable in molten glass, thereby reducing or even eliminating iron and Fe impurities in the glass. 3+ It exists in this form; it also helps to suppress Fe. 3+The rate and extent of the complexation reaction with TiO2 are controlled, thereby reducing or even preventing the formation of Fe-O-Ti complex groups in the glass. Furthermore, a mixture of inert and reducing gases is introduced into the molten glass. The inert gas forms a protective gas layer around the molten glass, preventing some of the reducing gas introduced into the molten glass from diffusing to the outside, which could slow down the formation of a weakly reducing environment in the molten glass. Based on the above, simultaneously introducing inert and reducing gases into the molten glass not only helps to rapidly suppress or prevent the formation of Fe complex groups in the molten glass. 3+ The formation of Fe-O-Ti complex groups also helps to reduce the amount of reducing gas used during the melting process, thus saving costs.

[0025] The optical glass prepared using the glass preparation method of this invention achieves an extremely high refractive index (n0.05 at a wavelength of 587.6 nm). d It has a transmittance of ≥2.02) and high transmittance in the visible light region (internal transmittance at wavelength 440nm ≥94.2%), which facilitates its widespread use.

[0026] 2. The present invention also provides a glass preparation method. In addition to containing La2O3, Nb2O5, Gd2O3, GeO2 and TiO2 to provide ultra-high refractive index, GeO2 and B2O3 to form glass network forging, and K2O to increase whiteness, the optical glass can also contain Ta2O5 and ZrO2 to make the optical glass have alkali resistance stability of A1 level and acid resistance stability of 1 level, and have good chemical resistance.

[0027] 3. The optical glass provided by this invention comprises, by mass percentage of oxides: 40-50% La₂O₃, 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-10% B₂O₃, 1-6% TiO₂, 0.1-1% K₂O, 5-8% B₂O₃, and 1-5% TiO₂; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82-92%; the optical glass not only possesses an extremely high refractive index (nn at a wavelength of 587.6 nm) but also exhibits a very high refractive index. d It has a light transmittance of ≥2.02 and high transmittance in the visible light region (internal transmittance at wavelength 440nm ≥94.2%), and can be used in virtual reality, digital cameras and automotive displays.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0029] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following are preferred embodiments, detailing the optical glass, its preparation method, its application, and specific implementation methods according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features in one or more embodiments can be combined in any suitable form.

[0030] In the preparation of ultra-high refractive index glasses, most of the components used to increase the glass's refractive index enhance its optical coloring properties, which in turn leads to a decrease in light transmittance. To obtain an optical glass that not only possesses an ultra-high refractive index (n...),... d The present invention provides a method for preparing optical glass with a transmittance ≥2 and high transmittance in the visible light region (internal transmittance ≥94%), thereby reducing or even avoiding the presence of components that increase glass coloring in the optical glass, thereby reducing glass coloring and improving the transmittance of the glass in the visible light region.

[0031] This invention provides a method for preparing optical glass, comprising the following steps:

[0032] (1) Preparation of raw materials: Weigh the raw materials and mix them evenly; the optical glass comprises, by mass percentage of oxides: 40-50% La2O3, 15-25% Nb2O5, 10-20% Gd2O3, 5-10% GeO2, 5-10% B2O3, 1-6% TiO2, and 0.1-1% K2O; wherein the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2 and TiO2 is 82-92%;

[0033] (2) Melting: The batch material is melted to obtain molten glass, and then gas is introduced into the molten glass for atmospheric bubbling; the gas includes an inert gas and a reducing gas; at the same temperature and gas pressure, the specific gravity of the inert gas is greater than that of air; the reducing gas makes the redox index of the molten glass -120 to -5; after bubbling is stopped, the molten glass is homogenized and clarified under stirring conditions; the container and stirrer that come into contact with the molten glass during the melting process are made of platinum-containing material;

[0034] (3) Glass forming and annealing.

[0035] The optical glass preparation method provided by this invention uses GeO2 and B2O3 as essential components for glass formation. The GeO2 and B2O3 components are important network formations in the optical glass. Strictly controlling the mass percentage of the GeO2 component to 5-10% not only helps to obtain a homogeneous glass body but also contributes to achieving a high refractive index in the optical glass. Without this component, the glass-forming ability deteriorates; if the mass percentage exceeds 10%, the refractive index of the glass decreases. Similarly, strictly controlling the mass percentage of the B2O3 component to 5-10% not only results in good glass-forming performance but also helps to improve the refractive index of the optical glass. If the mass percentage of this component is below 5%, the glass-forming ability deteriorates; if the mass percentage exceeds 10%, the refractive index of the glass decreases. The optical glass of this invention avoids the presence of SiO2, a traditional component used in glass formation, thus lowering the glass melting temperature and reducing the formation of Fe from Fe impurities and oxygen in the molten glass. 3+ This is to reduce glass staining.

[0036] The optical glass preparation method provided by this invention contains a large amount of La2O3, Nb2O5, Gd2O3, GeO2, and a small amount of TiO2, all of which are essential components for achieving a high refractive index in the optical glass. High levels of these components are beneficial for achieving an extremely high refractive index in the glass; however, the amount of these components used is also limited, for the following reasons:

[0037] The La2O3 component helps improve the glass-forming properties and refractive index of optical glass. This invention uses La2O3 as the main component to improve the refractive index. If the mass percentage of La2O3 is less than 40%, it is difficult to guarantee the refractive index n of the optical glass. d ≥2.0. If the mass percentage of La2O3 exceeds 50%, it will lead to a deterioration in glass formation properties. Strictly controlling the mass percentage of La2O3 to 40-50% enables the optical glass of this invention to achieve a high refractive index and good glass formation properties. Furthermore, this invention uses La2O3 as the main component to improve the refractive index of the optical glass. Compared to other glass components used to improve the refractive index, La2O3 is more stable, less prone to redox reactions during melting, and has no significant coloring effect on the glass, which is beneficial for improving the overall light transmittance of the glass. Moreover, this component is inexpensive, making the glass products easier to mass-produce.

[0038] The Nb₂O₅ component helps improve the glass-forming properties and refractive index of optical glass, and also has a positive effect on improving glass density. In this invention, the content of this component is strictly controlled at 15-25% by mass, which helps to increase the refractive index of the glass and makes it easier to achieve a refractive index n. d≥2.0; and the glass has good optical uniformity. If the Nb2O5 content is less than 15%, the improvement in the refractive index of the glass is not significant; if the Nb2O5 content exceeds 25%, this component is difficult to fully melt in the glass melt, and the optical uniformity of the glass deteriorates.

[0039] Gd₂O₃ is an essential component for achieving a high refractive index in the optical glass of this invention. If the mass percentage of Gd₂O₃ is less than 10%, it is difficult to guarantee a refractive index ≥ 2.0 in the glass. If the mass percentage of Gd₂O₃ exceeds 20%, it will lead to a deterioration in the glass's glass-forming properties. This invention strictly controls the mass percentage of this component to be 10-20%, which not only facilitates the achievement of a high refractive index in the optical glass but also improves its glass-forming properties.

[0040] Strictly controlling the mass percentage of GeO2 component to 5-10% not only helps to obtain a homogeneous glass body in this invention, but also helps to achieve a high refractive index in optical glass. Without this component, the glass-forming ability deteriorates; if the mass percentage of this component exceeds 10%, the refractive index of the glass will decrease.

[0041] TiO2 is an essential component for the high refractive index of the optical glass of this invention. If the mass percentage of TiO2 is less than 1%, it is difficult to guarantee a refractive index ≥ 2.0. If the mass percentage of TiO2 exceeds 6%, it will intensify the glass coloration and reduce the light transmittance of the optical glass. This invention strictly controls the mass percentage of this component to 1-6%, which is beneficial not only for ensuring the refractive index n of the glass. d The concentration is ≥2.0, and it can alleviate glass coloration caused by TiO2, thereby improving the transmittance of optical glass in the visible light region. Furthermore, the addition of the TiO2 component has a positive effect on reducing glass density, thus products further prepared using the optical glass obtained by this invention are easily made thinner and lighter.

[0042] The optical glass preparation method provided by the present invention also contains K2O. K2O is an essential component for improving the glass's glass-forming properties and whiteness. The mass percentage of this component is controlled at 0.1% to 1%. If the mass percentage of K2O is less than 0.1%, it is difficult to guarantee the glass's glass-forming properties and whiteness. If the mass percentage of K2O exceeds 1%, it will lead to a decrease in the glass's refractive index.

[0043] This invention strictly controls the sum of the mass percentages of the components La2O3, Nb2O5, Gd2O3, GeO2, and TiO2 to be 82-92%, enabling the optical glass to achieve a high refractive index (refractive index n at wavelength 587.6 nm). d (≥2.02), and makes the glass-forming properties good.

[0044] This invention further improves the internal transmittance of optical glass in the visible light region by optimizing the glass melting process.

[0045] Because the preparation of optical glass inevitably introduces impurities such as Fe into the batch, these impurities can undergo a redox reaction with oxygen (O2) during the high-temperature melting process. When oxygen is sufficient and the reaction environment provides adequate energy, the impurities Fe can react with oxygen (O2) to form Fe2+. 3+ Conversely, when oxygen content is insufficient or the reaction environment cannot provide enough energy, impurity iron (Fe) can undergo a redox reaction with oxygen (O2) to form Fe2+. 2+ However, Fe 2+ Poor stability, easily oxidized to form Fe 3+ Due to the Fe in the glass 3+ The absorption of visible light near the ultraviolet region gives the glass a brownish-yellow hue; while Fe... 2+ The absorption in the visible light region near the ultraviolet region is not significant, and the optical glass contains TiO2 and Fe. 3+ During the high-temperature melting process, Fe-O-Ti complex groups can be formed with TiO2, and these complex groups can enhance the glass coloration. Therefore, in order to achieve high light transmittance in the visible light region in the optical glass of this invention, on the one hand, the oxygen content in the molten glass is reduced, thereby suppressing the reaction between impurity Fe and O2 to form Fe. 3+ On the other hand, creating a weakly reducing environment in the molten glass not only inhibits but also prevents Fe from being absorbed. 3+ The formation of Fe-O-Ti complex groups also makes Fe 2+ It is not easily oxidized and remains stable in molten glass.

[0046] Furthermore, during the high-temperature melting process of the batch, in the initial stage of melting, the various components of the batch decompose and release a large amount of gas, which can be discharged into the environment. Only a small amount of gas remains in the molten glass, existing in the form of visible bubbles, physical dissolution, or chemical bonding. The visible bubbles and physically dissolved gases are in a certain balance with the external gases in the molten glass. As the high-temperature melting continues, the iron (Fe) impurities in the molten glass can undergo a redox reaction with oxygen (O2). When oxygen is sufficient, Fe2+ is easily produced. 3+ When oxygen in the molten glass is consumed, the balance between the visible gas bubbles and physically dissolved gases in the molten glass and the gases outside the molten glass is disrupted. Oxygen from outside the molten glass enters the molten glass, allowing the reaction between the Fe impurities in the molten glass and oxygen to continue, thus making the coloring of the glass more severe.

[0047] This invention involves introducing gas into the molten glass after the batch material has melted to obtain molten glass, performing atmospheric bubbling. The gas used for bubbling includes inert and reducing gases. Under the same temperature and atmospheric pressure, the inert gas has a higher specific gravity than air. This ensures that most of the impurity gases released during the melting process are expelled into the outside of the molten glass before atmospheric bubbling, reducing gaseous impurities inside the molten glass. Because the inert gas introduced in this invention has a higher specific gravity than air (at the same atmospheric pressure and temperature), it can overflow from the molten glass and accumulate around it to form a protective gas layer, isolating the molten glass from gas exchange with the outside environment. If introduced before the batch material melts, it would affect the diffusion of gases from the batch material decomposition to the outside of the molten glass, thus retaining a large amount of impurity gases inside the molten glass.

[0048] Before bubbling, this invention mixes an inert gas with a reducing gas to form a mixed gas. During the bubbling process, this mixed gas is introduced into the molten glass. Because the inert gas has low solubility in the molten glass, the introduced inert gas can overflow and accumulate around the molten glass, forming a protective gas layer. This prevents gas exchange between the inside of the molten glass and the outside environment, blocking external gases from entering the molten glass. This reduces the oxygen content inside the molten glass, thereby inhibiting the reaction of impurities (Fe) and oxygen (O2) to form Fe. 3+ Furthermore, Fe in the molten glass 3+ The reduction in Fe content helps suppress the formation of Fe-O-Ti complex groups in the molten glass. Therefore, the inert gas introduced during atmospheric bubbling helps suppress or even prevent Fe from forming in the molten glass. 3+ The formation of complex groups Fe-O-Ti helps reduce glass coloration and improve the transmittance of optical glass in the visible light region.

[0049] Furthermore, the reducing gas introduced into the molten glass creates a weakly reducing environment. This invention strictly controls the redox index of the molten glass to -120 to -5, reducing the degree of redox reactions between the components in the molten glass. This helps to suppress the rate and extent of redox reactions of impurities iron (Fe) and oxygen (O2) in the molten glass. Moreover, the weakly reducing environment also helps to reduce the oxidation-reduction reaction rate of already generated Fe in the molten glass. 2+ It is not easily oxidized and remains stable in molten glass; in addition, it helps to suppress Fe in molten glass. 3+ The rate and extent of the complexation reaction with TiO2 are influenced by the fact that introducing a reducing gas helps to suppress or even prevent Fe from forming in the molten glass. 3+The formation of TiO2 reduces glass coloration. If the redox index of the molten glass is below -120, the reducing atmosphere formed by the molten glass is too significant, and the containers and stirrers in contact with the molten glass during the melting process are easily corroded. When using containers and stirrers containing Pt, Pt flash point is easily generated, which is detrimental to improving the refractive index and transmittance of optical glass. If the redox index of the molten glass is above -5, the weak reducing property of the molten glass is insufficient, which is not conducive to suppressing Fe. 3+ The generation of Fe-O-Ti complexes and the inhibition of their formation are detrimental, which in turn hinders the improvement of the transmittance of optical glass in the visible light region.

[0050] The redox index of molten glass is one of the indicators describing the ability and rate of electron transfer in a chemical substance. The redox index of the molten glass in this invention refers to the sum of the redox indices of all components in the molten glass. Since the glass components of this invention are all neutral oxides, the inert gas is neutral, and the chemical properties are stable, the redox index of the molten glass in this invention is mainly calculated by the redox index of the reducing gas introduced into the molten glass.

[0051] The redox index of the glass melt of this invention is calculated as follows:

[0052] S = KRT

[0053] Where K is the atmosphere coefficient, which is the change in the redox index of the glass melt when 1L of reducing gas is introduced into the glass melt.

[0054] R is the flow rate of reducing gas introduced into the molten glass per unit time;

[0055] T represents the time it takes to introduce a reducing gas into the molten glass.

[0056] The redox index described in this invention is not limited to integers, but can be any value in the range of -120 to -5.

[0057] Furthermore, during the atmosphere bubbling process, the inert gas introduced into the molten glass can form a protective gas layer around it, preventing some of the reducing gas introduced into the molten glass from diffusing to the outside, thus slowing down the formation of a weakly reducing environment in the molten glass. Therefore, the synergistic effect of the inert gas and reducing gas simultaneously introduced into the molten glass helps to quickly suppress or even prevent Fe from entering the molten glass. 3+ The formation of Fe-O-Ti complex groups reduces glass coloration and increases the transmittance of optical glass in the visible light region. Furthermore, the simultaneous introduction of inert and reducing gases into the molten glass helps reduce the amount of reducing gas used during the melting process, thus saving costs.

[0058] Furthermore, in the high-temperature melting process of this invention, the containers and stirrers in contact with the molten glass are made of platinum (Pt)-containing materials. Since the special optical glass of this invention contains a certain amount of heavy metals, and the molten glass is in a weakly reducing environment during melting, it is inherently corrosive. This invention controls the materials of the containers and stirrers in contact with the molten glass during melting to be platinum (Pt)-containing materials to resist the corrosiveness of the molten glass. The platinum-containing material mentioned in this invention can be pure platinum or a platinum alloy, such as a platinum-tungsten alloy (with a tungsten mass percentage ≤ 5%) or a platinum-ytterbium alloy (with a ytterbium mass percentage ≤ 5%). By strictly controlling the materials of the containers and stirrers in contact with the molten glass during the melting process, this invention improves the corrosion resistance of the containers and stirrers to the molten glass, preventing corrosion of the containers and stirrers by the molten glass. This, in turn, avoids adverse effects on the optical uniformity, refractive index, and transmittance of the special optical glass caused by the erosion of the containers and stirrers.

[0059] This invention does not impose specific limitations on the apparatus used to heat and melt the batch material during the high-temperature melting process, as long as it enables the high-temperature melting process of this invention. In some embodiments, this invention adds the batch material to a pure platinum (Pt) crucible, and then places the pure platinum (Pt) crucible containing the batch material in a high-temperature melting furnace for heating and melting.

[0060] The optical glass preparation method provided by this invention, through rational design of the batch materials, not only achieves an extremely high refractive index but also reduces or even eliminates the content of components that increase glass coloration in the optical glass. Furthermore, an inert gas is used to form a protective gas layer around the molten glass, suppressing or even eliminating Fe in the molten glass. 3+ Furthermore, the formation of Fe-O-Ti complex groups is achieved; additionally, a reducing gas is used to make the redox index of the molten glass -120 to -5, enabling the molten glass to form a weakly reducing environment, suppressing the rate and extent of the redox reaction between Fe impurities and oxygen in the molten glass during high-temperature melting, and reducing the Fe content in the molten glass. 2+ It is not easily oxidized and remains stable in molten glass, reducing or even eliminating Fe in optical glass. 3+ The generation of Fe can be inhibited at the same time. 3+ The complexation reaction with TiO2 reduces or even eliminates the formation of Fe-O-Ti complex groups in the molten glass. During atmospheric bubbling, the inert and reducing gases work synergistically to suppress or even eliminate Fe in the molten glass. 3+ The formation of Fe-O-Ti complex groups reduces the coloration of the glass, resulting in optical glass with an extremely high refractive index (at a wavelength of 587.6 nm). dThe glass exhibits a transmittance of ≥2.02 g / L and high transmittance in the visible light region (≥94.2% transmittance at 440 nm), resulting in excellent surface quality. Furthermore, compared to existing technologies that use corrosive fluoride and carbon decolorizing agents to reduce glass coloration, the inert and reducing gases introduced in this invention leave less residue of decolorizing agents in the molten glass, thus having a smaller impact on the quality of the optical glass (e.g., purity, clarity). The La2O3 raw material, the main component of the optical glass prepared by this invention, is inexpensive, resulting in low production costs, facilitating mass production, and promoting its use and adoption.

[0061] The apparent quality of the glass mainly includes indicators that can be directly observed with the naked eye, such as the content of microbubbles within the glass, the uniformity of the glass appearance, the glass coloring, and whether it has a Pt flash point. This invention classifies optical glass with no microbubbles, a uniform appearance, and no Pt flash point as having good apparent quality.

[0062] Based on the fact that this invention contains oxides that reduce glass density, the density of the optical glass prepared by this invention was determined using the water displacement method. The density of the optical glass prepared by this invention is ≤5.21 g / cm³. 3 Products further prepared using the optical glass obtained by this invention are easily made thinner and lighter.

[0063] In some embodiments, the aforementioned inert gas is selected from at least one of argon, krypton, and xenon. These inert gases have low solubility in molten glass and relatively large atomic diameters, making them less susceptible to capture and retention by the network formations in the molten glass during atmospheric bubbling. Therefore, after being introduced into the molten glass, these inert gases can quickly overflow, causing them to rapidly accumulate around the molten glass to form a protective gas layer. Furthermore, these gases are all monatomic gases, making them less prone to reaction during the high-temperature melting of optical glass. Their stable physicochemical properties minimize their impact on the melting process. More importantly, these gases have poor thermal conductivity. After forming a protective gas layer around the molten glass, they reduce the heat transfer between the inside and outside of the molten glass to a certain extent, lowering the required melting temperature during the melting process. This helps suppress redox reactions between substances in the molten glass, thereby reducing glass coloration and increasing the internal transmittance of the glass in the visible light region. In addition, these inert gases can form large bubbles in molten glass. During the clarification process, small impurity molecules remaining in the molten glass form small bubbles. These small bubbles can be engulfed and dissolved by the large bubbles formed by the inert gases, allowing the small impurity molecules to be carried to the surface of the molten glass and eliminated. Since bubbles in molten glass affect its transparency, causing unevenness or deformation, and also reduce its strength, making it brittle or prone to breakage, it is essential to eliminate residual gases in the molten glass as much as possible.

[0064] In some embodiments, the aforementioned reducing gas is selected from at least one of hydrogen, nitric oxide, hydrogen sulfide, sulfur monoxide, and carbon monoxide. These reducing gases have a certain solubility in the molten glass, which makes it easy to create a weakly reducing environment in the molten glass.

[0065] Preferably, in the high-temperature melting process of this invention, the inert gas used for atmosphere bubbling is argon (Ar), and the reducing gas is hydrogen (H2). Compared with krypton and xenon, argon used in this invention is cheaper on the market, thereby reducing the production cost of glass and improving its economic efficiency. Compared with nitric oxide, hydrogen sulfide, sulfur monoxide, and carbon monoxide, this invention uses H2 as the reducing gas because H2 has the smallest relative molecular mass. During the clarification process, the bubbles formed by H2 in the molten glass are small, and these bubbles are more easily swallowed by the larger bubbles formed by Ar in the molten glass. During the clarification process, Ar can easily carry the residual H2 in the molten glass to the surface and break up, thus effectively eliminating the H2 in the molten glass. As mentioned above, eliminating residual gases in the molten glass as much as possible is beneficial to improving the quality of optical glass (e.g., transparency, uniformity, etc.).

[0066] In some embodiments, before atmosphere bubbling, argon (Ar) and hydrogen (H2) are mixed to form a mixed gas, which is then stored in a gas cylinder. The mixed gas contains 1-3% hydrogen by volume. During atmosphere bubbling, the mixed gas is introduced into the molten glass at a flow rate of 1-4 L / min per liter of molten glass, for a duration of 0.5-1 h. This invention strictly controls the volume percentage of hydrogen in the mixed gas, the flow rate, and the bubbling time. This not only ensures that sufficient Ar is introduced into the molten glass to form a protective gas layer around it, thus preventing gas exchange between the molten glass and the outside environment, but also ensures that an appropriate amount of H2 is introduced, resulting in a redox index of -120 to -5, thereby enabling the formation and maintenance of a weak reducing atmosphere in the molten glass. If, during the atmosphere bubbling process, the volume percentage of H2 in the mixed gas introduced into the molten glass is too low, the gas flow rate is too small, or the gas flow time is insufficient, the amount of H2 introduced into the molten glass will be insufficient, and the reducing atmosphere formed in the molten glass will be insignificant. This is detrimental to improving the transmittance of the optical glass of this invention in the visible light region. Conversely, if the volume percentage of hydrogen in the mixed gas is too high, and the gas flow rate introduced into the molten glass is too high, and the gas flow time is too long, excessive H2 will be introduced into the molten glass, and the reducing atmosphere formed in the molten glass will be too significant. This can cause Ti ions in the glass to mainly exist as Ti. 3+ The presence of this substance causes the glass to turn purple, reducing the transmittance of optical glass in the visible light region; furthermore, if the volume of H2 introduced into the molten glass is too high, there is a risk of explosion upon contact with fire.

[0067] In the aforementioned preparation method, when a mixture of argon and hydrogen is introduced into the molten glass, and the volume percentage of hydrogen in the mixture is 1-3%, the change in the redox index of the molten glass is approximately -4.17 when 1L of hydrogen is introduced into the molten glass. That is, the K value in the calculation of the redox index of the molten glass is -4.17.

[0068] Preferably, the aforementioned preparation method uses a bubbler to introduce a mixed gas into the molten glass for bubbling. This invention, by introducing a mixed gas into the molten glass using a bubbler for atmospheric bubbling, not only rapidly and uniformly diffuses the mixed gas within the molten glass, allowing Ar to quickly escape and form a protective gas layer around the molten glass, but also promotes the uniform diffusion of H2 within the molten glass, rapidly creating a weakly reducing environment.

[0069] In some embodiments, the optical glass comprises, by mass percentage of oxides, 40–50% La₂O₃, 15–25% Nb₂O₅, 10–20% Gd₂O₃, 5–10% GeO₂, 5–8% B₂O₃, 1–5% TiO₂, and 0.1–1% K₂O, wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82–92%. During the melting process, argon and hydrogen are introduced into the molten glass to create an atmosphere of bubbling, resulting in a redox index of -120 to -5, forming a weakly reducing environment. By further optimizing the content of the above components, the present invention produces an optical glass with a higher refractive index (n0.05 at wavelength 587.6 nm). d It has a transmittance of ≥2.05 in the visible light region (internal transmittance at wavelength 440nm ≥94.2%).

[0070] In some embodiments, during the preparation of optical glass, the melting temperature is 1380–1420°C, and the melting time is 5–8 hours. By limiting the high-temperature melting temperature and time within a reasonable range, and ensuring that the raw materials are completely melted after high-temperature heating, the lowest possible melting temperature and shortest melting time are used to suppress the reaction of Fe impurities in the glass with oxygen to form Fe. 3+ This shortens the reaction time between Fe impurities and oxygen, thereby inhibiting or even preventing Fe from entering the glass. 3+ The generation of Fe-O-Ti complexes indirectly inhibits or even avoids the formation of complex groups, thereby reducing glass coloration and improving the transmittance of optical glass in the visible light region.

[0071] In some embodiments, a frame stirrer is used during the melting process to promote the clarification and homogenization of the glass melt. The stirrer speed is 50-80 rpm and the stirring time is 2-4 hours.

[0072] The present invention selects a suitable stirrer, stirring speed and stirring time, which not only helps to quickly eliminate residual gas in the glass solution and make the glass liquid clear, but also helps to accelerate the homogenization of the glass liquid and improve the preparation efficiency.

[0073] In some embodiments, glass forming is performed using a die casting method, with a forming temperature of 1200–1250°C.

[0074] The molten glass prepared by the method described above has a relatively low viscosity, resulting in good fluidity. This allows for smooth molding using a drip molding method, producing glass with a smooth surface. Furthermore, a suitable molding temperature helps improve molding efficiency.

[0075] In some embodiments, the glass annealing temperature is 700–750°C, and the annealing time is 8–10 hours.

[0076] By limiting the annealing temperature and annealing time to a reasonable range, it is beneficial to better eliminate stress in optical glass and improve the transmittance and mechanical strength of the glass in the visible light region.

[0077] In some embodiments, the optical glass comprises, by mass percentage of oxides: 40–50% La₂O₃, 15–25% Nb₂O₅, 10–20% Gd₂O₃, 5–10% GeO₂, 5–10% B₂O₃, 1–6% TiO₂, 0.1–1% K₂O, 5–8% B₂O₃, 1–5% TiO₂, 1–6% ZrO₂, and 1–6% Ta₂O₅; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82–92%; it also comprises 1–6% ZrO₂ and 1–6% Ta₂O₅; during the melting process, argon and hydrogen are introduced into the molten glass to create an atmosphere of bubbling, resulting in a redox index of -120 to -5 for the molten glass, thus forming a weakly reducing environment. This invention improves the chemical stability of optical glass by further adding Ta₂O₅ and ZrO₂, thereby enhancing its alkali and acid resistance. However, when the mass percentage of ZrO₂ exceeds 6%, it easily leads to glass crystallization, deteriorating the glass's glass-forming properties. Furthermore, the complete dissolution of a large amount of ZrO₂ requires a high temperature, thus increasing the melting temperature and promoting the reaction of Fe impurities in the molten glass with oxygen to produce Fe²⁺. 3+ This is detrimental to improving the transmittance of optical glass in the visible light region; if the mass percentage of ZrO2 component is less than 1%, the improvement in chemical stability of optical glass is not significant. Therefore, this invention strictly controls the mass percentage of ZrO2 component to 1-6%, which can make the obtained optical glass not only have good chemical resistance, but also good glass-forming properties, low melting temperature, and good transmittance in the visible light region. When the mass percentage of Ta2O5 component exceeds 6%, it easily leads to glass crystallization, which deteriorates the glass-forming properties of optical glass; when the mass percentage of Ta2O5 component is less than 1%, its improvement in chemical stability of optical glass is not significant; therefore, this invention strictly controls the mass percentage of Ta2O5 component to 1-6%, which can make the prepared optical glass not only have good chemical resistance, but also good glass-forming properties. The refractive index n of the optical glass prepared by this invention is... d The glass exhibits a pH value ≥2.02, achieving an alkali resistance level of A1 and an acid resistance level of 1, demonstrating excellent chemical resistance. Furthermore, it possesses high light transmittance in the visible light region (≥94.2% transmittance within 440nm), and exhibits good surface quality. The optical glass prepared by this invention has a density ≤5.21 g / cm³. 3 Products made using the optical glass of this invention are easy to make thin and light.

[0078] This invention provides an optical glass comprising, by mass percentage of oxides: 40-50% La₂O₃, 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-10% B₂O₃, 1-6% TiO₂, 0.1-1% K₂O, 5-8% B₂O₃, and 1-5% TiO₂; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82-92%; and the refractive index n of the optical glass is... d The optical glass exhibits a density ≥2.02 g / cm³ and a transmittance ≥94.2% in the visible light region. The glass also possesses good apparent quality; the density of the optical glass prepared according to this invention is ≤5.21 g / cm³. 3 Products made using the optical glass of this invention are easily made thinner and lighter. This optical glass can be widely used in virtual reality, digital cameras, or automotive displays.

[0079] Preferably, the aforementioned optical glass, based on the mass percentage of oxides, further comprises 1-6% ZrO2 and 1-6% Ta2O5; the resulting optical glass has a refractive index n. d The glass exhibits a density ≥2.02 g / cm³, with a transmittance ≥94.2% in the visible light region, and demonstrates alkali resistance grade A1 and acid resistance grade 1. The glass possesses good apparent quality, and the optical glass prepared according to this invention has a density ≤5.21 g / cm³. 3 Products made using the optical glass of this invention are easily made thinner and lighter. This optical glass is not only beneficial for applications in virtual reality, digital cameras, or automotive displays, but also, due to its A1-level alkali resistance and 1-level acid resistance, it is further resistant to various chemical reagents, thus enhancing the durability of the products.

[0080] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0081] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0082] In the glasses provided in the embodiments and comparative examples of this invention, B2O3 and GeO2 are the basic components, and the corresponding raw materials are boric acid and germanium oxide, respectively; La2O3, Gd2O3, Nb2O5, TiO2, ZrO2, Ta2O5, and K2O are the functional components of the glasses provided in the embodiments and comparative examples of this invention. These functional components can all be the oxides themselves, the corresponding carbonates, or the corresponding nitrates. These basic components and functional components are used together to prepare ultra-high refractive index optical glass.

[0083] Example 1

[0084] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 97%, and the volume percentage of hydrogen is 3%, with a flow rate of 1 L / min, and the bubbling is continued for 2 hours. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 60 rpm for 3 hours to homogenize and clarify the glass. The melting temperature is 1380℃, and the melting time is 5 hours. The homogenized and clarified molten glass is formed into a preheated mold using a pouring method at a forming temperature of 1250℃. The formed glass is annealed at 710℃ for 10 hours, and then the annealing furnace power is turned off. Finally, the prepared glass was subjected to performance testing.

[0085] Example 2

[0086] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 99%, and the volume percentage of hydrogen is 1%, with a flow rate of 1 L / min, and the bubbling is continued for 2.5 h. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at a speed of 50 rpm for 4 h to homogenize and clarify the glass. The melting temperature is 1400℃, and the melting time is 6.5 h. The homogenized and clarified molten glass is then formed into a preheated mold using a pouring method at a forming temperature of 1200℃. The formed glass was annealed at 700℃ for 8 hours, and the power to the annealing furnace was turned off. Finally, the performance of the prepared glass was tested.

[0087] Example 3

[0088] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 98%, and the volume percentage of hydrogen is 2%, with a flow rate of 2 L / min, and the bubbling is continued for 3 hours. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 80 rpm for 2 hours to homogenize and clarify the glass. The melting temperature is 1420℃, and the melting time is 5 hours. The homogenized and clarified molten glass is then formed into a preheated mold using a pouring method at a forming temperature of 1220℃. The formed glass was annealed at 750℃ for 10 hours, and the power to the annealing furnace was turned off. Finally, the performance of the prepared glass was tested.

[0089] Example 4

[0090] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 97%, and the volume percentage of hydrogen is 3%, with a flow rate of 3 L / min, and the bubbling is continued for 2 hours. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 70 rpm for 3 hours to homogenize and clarify the glass. The melting temperature is 1400℃, and the melting time is 5 hours. The homogenized and clarified molten glass is then formed into a preheated mold using a pouring method at a forming temperature of 1240℃. The formed glass was annealed at 730℃ for 8 hours, and the power to the annealing furnace was turned off. Finally, the performance of the prepared glass was tested.

[0091] Example 5

[0092] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 97%, and the volume percentage of hydrogen is 3%, with a flow rate of 3 L / min, and the bubbling is continued for 3 hours. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 60 rpm for 3 hours to homogenize and clarify the glass. The melting temperature is 1420℃, and the melting time is 6 hours. The homogenized and clarified molten glass is then poured into a preheated mold using a pouring method at a forming temperature of 1250℃. The formed glass was annealed at 710℃ for 9 hours, and the power to the annealing furnace was turned off. Finally, the performance of the prepared glass was tested.

[0093] Example 6

[0094] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 97%, and the volume percentage of hydrogen is 3%, with a flow rate of 4 L / min, and the bubbling is continued for 3.5 h. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 80 rpm for 2 h to homogenize and clarify the glass. The melting temperature is 1380℃, and the melting time is 5.5 h. The homogenized and clarified molten glass is then formed into a preheated mold using a pouring method at a forming temperature of 1200℃. The formed glass was annealed at 720℃ for 10 hours, and the power to the annealing furnace was turned off; finally, the performance of the prepared glass was tested.

[0095] Example 7

[0096] Weigh the corresponding mass of raw materials according to the glass composition in Table 1, and mix them evenly to obtain a batch. Add the batch to a Pt crucible, and then place the Pt crucible containing the batch in a high-temperature melting furnace to melt the batch. After the batch has melted, 4 L of molten glass is obtained. A mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 98%, and the volume percentage of hydrogen is 2%, with a flow rate of 2 L / min, and the bubbling is continued for 2 hours. After the bubbling is stopped, the molten glass is mechanically stirred using a Pt stirrer at 60 rpm for 3 hours to homogenize and clarify the glass. The melting temperature is 1400℃, and the melting time is 5 hours. The homogenized and clarified molten glass is then poured into a preheated mold using a pouring method at a forming temperature of 1250℃. The formed glass was annealed at 750℃ for 8 hours, and the power to the annealing furnace was turned off. Finally, the performance of the prepared glass was tested.

[0097] Example 8

[0098] Weigh the raw materials according to the glass components in Table 1, and the glass preparation method is the same as in Example 7.

[0099] Example 9

[0100] Weigh the raw materials according to the glass components in Table 1, and the glass preparation method is the same as in Example 7.

[0101] Comparative Example 1

[0102] Weigh the raw materials according to the glass components in Table 2, and the glass preparation method is the same as in Example 7.

[0103] Comparative Example 2

[0104] Weigh the raw materials according to the glass components in Table 2, and the glass preparation method is the same as in Example 7.

[0105] Comparative Example 3

[0106] Weigh the corresponding mass of raw materials according to the glass composition in Table 2. The glass preparation method is the same as in Example 7. During the glass preparation process, only Ar at a volume ratio of 95% is introduced into the molten glass through a bubbler to create an atmosphere for bubbling.

[0107] Comparative Example 4

[0108] Weigh the corresponding mass of raw materials according to the glass components in Table 2. The glass formulation and preparation method are the same as in Example 7. Bubbling is not performed during the glass preparation process.

[0109] Comparative Example 5

[0110] Weigh the corresponding mass of raw materials according to the glass composition in Table 2. The glass formulation and preparation method are the same as in Example 7. During the glass preparation process, a mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 97%, the volume percentage of hydrogen is 3%, the gas flow rate is 4 L / min, and the gas is continuously circulated for 4.5 h. The melting temperature is 1400℃, and the melting time is 7.5 h.

[0111] Comparative Example 6

[0112] Weigh the corresponding mass of raw materials according to the glass composition in Table 2. The glass formulation and preparation method are the same as in Example 7. During the glass preparation process, a mixture of argon and hydrogen gas is bubbled into the molten glass using a bubbler. The volume percentage of argon in the mixture is 99%, the volume percentage of hydrogen is 1%, the gas flow rate is 1 L / min, and the gas is continuously circulated for 1.5 h. The melting temperature is 1400℃, and the melting time is 4.5 h.

[0113] Comparative Example 7

[0114] Weigh the corresponding mass of raw materials according to the glass components in Table 2. The glass formulation and preparation method are the same as in Example 7. The difference from Example 7 is that, during the glass preparation process, the batch material is added to the corundum crucible, and after the gas is stopped, the glass melt is mechanically stirred using a corundum stirrer.

[0115] Comparative Example 8

[0116] Weigh the raw materials according to the glass components in Table 2, and the glass preparation method is the same as in Example 7.

[0117] The ultra-high refractive index optical glasses prepared in the embodiments and comparative examples of the present invention were tested for performance using the following methods. The specific performance test results are shown in Table 1 and Table 2.

[0118] The refractive index was tested according to the method in GB / T7962.1-2010 "Test methods for colorless optical glass - Part 1: Refractive index and dispersion coefficient".

[0119] Internal transmittance was tested according to the method in GB / T7962.12-2010 "Test methods for colorless optical glass - Part 12: Spectral internal transmittance".

[0120] Alkali resistance stability was tested according to the method in GB / T6580-2021 "Test method and classification of glass resistance to boiling mixed alkaline aqueous solution corrosion".

[0121] The acid resistance stability was tested according to the method of GB / T6581-2007 "Flame emission or atomic absorption spectrometry method for determining the resistance of glass to hydrochloric acid erosion at 100℃".

[0122] Table 1. Composition and performance test results of optical glass

[0123]

[0124] Table 2. Composition and performance test results of optical glass in the comparative examples

[0125]

[0126]

[0127] Note:

[0128] The oxide contents in Tables 1 and 2 are all mass percentages, in %; the glass refractive index n in Tables 1 and 2 is... d The detection wavelength is 587.6 nm; the detection wavelength for glass internal transmittance (%) is 440 nm; the units for acid resistance and alkali resistance in Tables 1 and 2 are grades; the unit for glass density is g / cm³. 3 .

[0129] As can be seen from Examples 1-9, Table 1, and Table 2, the optical glass prepared by the method described in this invention comprises, by mass percentage of oxides: 40-50% La2O3, 15-25% Nb2O5, 10-20% Gd2O3, 5-10% GeO2, 5-10% B2O3, 1-6% TiO2, and 0.1-1% K2O; wherein the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2, and TiO2 is 82-92%; and during the high-temperature melting process of the batch, after the batch melts, Ar and H2 are introduced into the glass melt for atmosphere bubbling, so that the redox index of the glass melt is -120 to -5, and the obtained optical glass has an extremely high refractive index (refractive index n at a wavelength of 587.6 nm). d It has a glass density of ≥2.02 g / cm³, and high transmittance in the visible light region (internal transmittance at 440 nm ≥94.2%), and a glass density of ≤5.21 g / cm³. 3 Furthermore, the optical glass prepared has good surface quality.

[0130] As can be seen from Examples 1-9 and Comparative Example 1, when the optical glass contains only B2O3 and lacks GeO2, the glass fails to form. This is because the GeO2 component is an important network formation in the optical glass provided by this invention, which can improve the glass's glass-forming ability. The B2O3 component is also an important network formation in the optical glass provided by this invention and is an essential component for improving the glass's glass-forming ability.

[0131] As can be seen from Examples 1-9 and Comparative Example 2, the optical glass, based on the mass percentage of oxides, comprises: 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-10% B₂O₃, 1-6% TiO₂, and 0.1-1% K₂O; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82-92%; and during the high-temperature melting process of the batch, after the batch melts, Ar and H₂ are introduced into the glass melt for atmospheric bubbling, so that the redox index of the glass melt is -120 to -5. However, if the mass percentage of La₂O₃ is less than 40%, the refractive index n of the prepared optical glass is... d <2.0.

[0132] As can be seen from Examples 1-9 and Comparative Examples 3 and 4, using the optical preparation method described in this invention, when Ar and H2 are introduced during high-temperature melting, the redox index of the glass melt is -120 to -5, creating a weakly reducing environment. This significantly improves the transmittance of the optical glass in the visible light region (transmittance ≥94.2% at a wavelength of 440 nm). Comparative Example 3 shows that in the optical glass preparation process of this invention, only Ar is introduced during high-temperature melting, creating a neutral atmosphere in the glass melt. The glass melt does not form a weakly reducing environment, resulting in improved transmittance in the visible light region (90.2% transmittance at a wavelength of 440 nm). However, compared to Examples 1-9, there is still room for improvement in the transmittance of the glass in the visible light region. This is because Comparative Example 3 did not use a mixture of Ar and H2 gas, thus the glass melt did not form a reducing atmosphere, leading to the formation of more Fe impurities in the glass. 3 + This further increases the content of Fe-O-Ti complex groups, intensifies glass coloring, and consequently reduces the internal transmittance of the glass. In Comparative Example 4, no atmospheric bubbling was performed during the optical glass melting process, preventing the formation of a weakly reducing environment in the molten glass. Furthermore, the connection between the molten glass and the external atmospheric environment was not blocked during the high-temperature melting process, allowing for oxygen exchange between the molten glass and the external environment. The molten glass remained consistently rich in oxygen, resulting in a prolonged and complete oxidation reaction between the Fe impurities and oxygen. The oxidation products in the molten glass contained Fe... 3+ The increased content leads to a higher Fe content in the glass. 3+ The formation of complex groups Fe-O-Ti results in a darker glass color, leading to poorer internal transmittance of the prepared optical glass.

[0133] As can be seen from Examples 1-7 and 8-9, the optical glass includes 40-50% La2O3, 15-25% Nb2O5, 10-20% Gd2O3, 5-10% GeO2, 5-10% B2O3, 1-6% TiO2, and 0.1-1% K2O; wherein the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2, and TiO2 is 82-92%; and during the high-temperature melting process of the batch, after the batch melts, Ar and H2 are introduced into the glass melt for atmospheric bubbling, so that the redox index of the glass melt is -120 to -5. It also includes ZrO2 and Ta2O5, with ZrO2 accounting for 1-6% and Ta2O5 accounting for 1-6% by mass percentage. The prepared optical glass not only has an extremely high refractive index (refractive index n at a wavelength of 587.6 nm), but also contains ZrO2 and Ta2O5. d It has a strength of ≥2.02 g / cm³, and exhibits high transmittance in the visible light region (internal transmittance at 440 nm ≥94.2%). It also possesses excellent alkali resistance (A1 grade) and acid resistance (Grade 1), and a glass density ≤5.21 g / cm³. 3 The appearance quality is good.

[0134] Referring to Examples 1-9, Tables 1 and 2, the optical glass raw material includes the following components by mass percentage: 40-50% La₂O₃, 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-8% B₂O₃, 1-5% TiO₂, 1-6% ZrO₂, and 1-6% Ta₂O₅. Furthermore, during the high-temperature melting process, Ar and H₂ are introduced for bubbling, resulting in a redox index of -120 to -5 for the molten glass, creating a weakly reducing environment. The resulting optical glass exhibits a higher refractive index (n0.05 at a wavelength of 587.6 nm). d It has a high transmittance in the visible light region (internal transmittance at a wavelength of 440nm ≥94.2%), and excellent alkali resistance (A1 grade) and acid resistance (1 grade), with better overall performance.

[0135] As can be seen from Examples 1-9, Comparative Examples 5 and 6, during the glass preparation process, glass is prepared according to the batching material of the present invention, and Ar and H2 are used during the atmospheric bubbling of the glass melt to create a weakly reducing environment with a redox index of -120 to -5. The prepared optical glass not only has a high refractive index (n0.05 at a wavelength of 587.6 nm), but also... dThe glass exhibits high transmittance in the visible light region (≥2.02%) (transmittance ≥94.2% at 440nm). If excessive H2 is introduced during melting, the redox index of the molten glass falls below -120, resulting in an overly pronounced weak reducing property. This corrodes the Pt material used in the melting and stirring processes, leading to the glass having a Pt flash point. Conversely, insufficient H2 introduces an redox index above -5, resulting in insufficient weak reducing property, intensified coloration, and a transmittance of less than 90% in the visible light region.

[0136] Based on Examples 1-9 and Comparative Example 7, it can be seen that the container and stirrer in contact with the molten glass during the melting process do not contain platinum material. The melting device and stirrer using only corundum are not strong enough to resist the corrosion of the molten glass. Therefore, the glass does not form properly during the optical glass preparation process.

[0137] Based on Examples 1-9 and Comparative Example 8, it can be seen that if the sum of the mass percentages of La2O3, Nb2O5, Gd2O3, GeO2 and TiO2 in the optical glass prepared by the method of the present invention is less than 82%, the refractive index of the prepared optical glass will not reach 2.0.

[0138] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0139] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing optical glass, characterized in that, It includes the following steps: (1) Preparation of batch: Weigh the raw materials and mix them evenly; Based on the mass percentage of oxides, the optical glass comprises: 40-50% La₂O₃, 15-25% Nb₂O₅, 10-20% Gd₂O₃, 5-10% GeO₂, 5-10% B₂O₃, 1-6% TiO₂, and 0.1-1% K₂O; wherein the sum of the mass percentages of La₂O₃, Nb₂O₅, Gd₂O₃, GeO₂, and TiO₂ is 82-92%. (2) Melting: The batch material is melted to obtain molten glass, and then gas is introduced into the molten glass for atmospheric bubbling; the gas includes an inert gas and a reducing gas; at the same temperature and gas pressure, the specific gravity of the inert gas is greater than that of air; the reducing gas makes the redox index of the molten glass -120 to -5; after bubbling is stopped, the molten glass is homogenized and clarified under stirring conditions; the container and stirrer in contact with the molten glass during the melting process are made of platinum-containing material; the reducing gas is hydrogen; by volume, the hydrogen volume percentage in the gas is 1 to 3%, the gas flow rate per liter of molten glass is 1 to 4 L / min, and the gas blowing time is 0.5 to 1 h; the melting temperature is 1380 to 1420 °C, and the time is 5 to 8 h; (3) Glass forming and annealing.

2. The preparation method according to claim 1, characterized in that, The inert gas is selected from at least one of argon, krypton, and xenon.

3. The preparation method according to claim 2, characterized in that, The inert gas is argon.

4. The preparation method according to claim 1, characterized in that, By mass percentage, optical glass contains 5-8% B2O3 and 1-5% TiO2.

5. The method according to claim 1, characterized in that, Use a frame mixer at a speed of 50-80 rpm for 2-4 hours.

6. The preparation method according to claim 1, characterized in that, The glass is formed using a blown glass forming method, with a forming temperature of 1200~1250℃, a glass annealing temperature of 700~750℃, and an annealing time of 8~10h.

7. The preparation method according to claim 1, characterized in that, The optical glass, based on oxides, also includes ZrO2 and Ta2O5, with ZrO2 comprising 1-6% and Ta2O5 comprising 1-6% by mass percentage.

8. An optical glass obtained by the preparation method according to any one of claims 1 to 7, characterized in that, The refractive index n of the optical glass d ≥2.02, and transmittance ≥94.2% in the visible light region.

9. An application of the optical glass according to claim 8 in the fields of virtual reality, digital cameras or automotive displays.

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