Lanthanide crown optical glass, method for producing the same, and optical element

Abstract

This invention provides a lanthanum crown optical glass comprising the following composition based on cations: Si 4+ : 6-29%; B 3+ : 8-46.5%; La 3+ : 0-16%; Y 3+ : 0.2-15%; Ca 2+ : 0-16%; Sr 2+ 7-17%; Ba 2+ 0-4.5%; Zn 2+ 0-8.5%; Zr 4+ : 1-8.5%; Nb 5+ 0-3%; Ti 4+ : 0-2.3%; Sb 3+ 0-0.1%; all percentages are molar percentages. The lanthanum crown optical glass of the present invention has excellent crystallization performance, transmittance performance and chemical stability, low raw material cost, and excellent processing performance, making it suitable for secondary molding.

Description

Technical Field

[0001] This invention relates to a lanthanum crown optical glass, its preparation method, and optical elements, belonging to the field of optical glass. Background Technology

[0002] Lanthanum crown optical glass is mainly used in optical imaging devices such as automotive cameras, mobile phones, camcorders, projectors, and optical instruments. In recent years, with the continuous improvement of imaging quality and the strong demand from customers for durability and low cost, the development of high-performance, cost-effective lanthanum crown glass has become particularly important.

[0003] The optical glasses disclosed in patent applications CN1243683C, CN1967287A, CN101163648A, CN101293736A and CN107365068A contain a certain amount of Gd2O3. In particular, the optical glass disclosed in CN101163648A has a Gd2O3 content of more than 12.5%, which will cause a significant increase in the cost of the glass.

[0004] The optical glasses disclosed in patent applications CN100374386C, CN101970368A, CN104995144A, and CN109626818A contain a certain amount of P2O5, and in particular, the optical glass disclosed in CN109626818A even contains F. Low- to medium-refractive-index glasses containing P and F generally have poor chemical stability, exhibit significant corrosion of noble metal crucibles, and are prone to volatilization during preparation, making it difficult to control the stability of their optical constants. Furthermore, the presence of alkali metals further exacerbates the corrosion of the crucible.

[0005] The optical glass disclosed in patent application CN107512849A contains a certain amount of Ta2O5 and a large amount of ZnO. The former has a higher specific gravity, is easy to sink to the bottom, and has a higher melting temperature, while the latter causes more severe corrosion to the crucible.

[0006] The optical glass disclosed in patent applications CN101062833A and CN101439929A ​​contains a certain amount of Li2O. Due to the rising price of lithium carbonate raw materials, the introduction of Li2O will not only increase costs but also exacerbate crucible erosion. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In view of the technical problems existing in the prior art, the present invention first provides a lanthanum crown optical glass. The lanthanum crown optical glass of the present invention has excellent crystallization performance, transmittance performance and chemical stability, excellent processability, is suitable for secondary molding, and has low raw material cost, thus offering high cost performance.

[0009] Furthermore, the present invention also provides a method for preparing lanthanum crown optical glass, which is simple, easy to process, and easy to mass-produce.

[0010] Solution for solving the problem

[0011] This invention provides a lanthanum crown optical glass comprising the following components based on cations:

[0012] Si 4+ 6-29%, preferably 10-28%;

[0013] B 3+ : 8-46.5%, preferably 10-45%;

[0014] La 3+ : 0-16%, preferably 3-15%;

[0015] Y 3+ 0.2-15%, preferably 1-13%;

[0016] Ca 2+ : 0-16%, preferably 3-12%;

[0017] Sr 2+ 7-17%, preferably 8-15%;

[0018] Ba 2+ : 0-4.5%, preferably 0-2%;

[0019] Zn 2+ : 0-8.5%, preferably 2-8%;

[0020] Zr 4+ : 1-8.5%, preferably 2-8%;

[0021] Nb 5+ 0-3%, preferably 0-2%;

[0022] Ti 4+ : 0-2.3%, preferably 0-1%;

[0023] Sb 3+ : 0-0.1%, preferably 0-0.05%;

[0024] All percentages mentioned above are mole percentages.

[0025] According to the lanthanum crown optical glass of the present invention, wherein, in molar percentage, Si 4+ With B 3+ The sum of the contents of ∑Si 4+ +B 3+ The content is 29-67%, preferably 30-63%; and / or,

[0026] Si 4+ With B 3+ The ratio of Si content 4+ / B 3+ The ratio is 0.1 to 3.3, preferably 0.5 to 3.0.

[0027] According to the lanthanum crown optical glass of the present invention, wherein, in molar percentage, La 3+ With Y 3+ The sum of the contents of ∑La 3+ +Y 3+ The content is 2.5-27%, preferably 5-25%; and / or,

[0028] La 3+ With Y 3+ The ratio of La content 3+ / Y 3+ The value should be 13 or less, preferably 10 or less.

[0029] According to the lanthanum crown optical glass of the present invention, wherein, in molar percentage, Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The content is 12-42%, preferably 15-40%; and / or,

[0030] Ca 2+ 、Sr 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Zn 2+ The content is 8.5-37.5%, preferably 10-35%; and / or,

[0031] Ba 2+ With Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The ratio of the sum of Ba content 2+ / ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ It is below 0.3.

[0032] According to the lanthanum crown optical glass of the present invention, wherein, in molar percentage, Nb 5+ With Zr 4+The sum of the contents of ∑Nb 5+ +Zr 4+ The content is 1.5-11.5%, preferably 3-10%; and / or,

[0033] Nb 5+ With Zr 4+ The ratio of Nb content 5+ / Zr 4+ The ratio is 1.3 or less, preferably 1.0 or less; and / or,

[0034] Ti 4+ With Nb 5+ and Zr 4+ The sum of Ti content 4+ / ∑Nb 5+ +Zr 4+ The value should be below 0.8, preferably below 0.6.

[0035] According to the lanthanum crown optical glass of the present invention, wherein the refractive index n of the optical glass is... d The value is 1.69-1.791, preferably 1.70-1.77; Abbe number υ d The value is 42.5-53.4, preferably 44-53; and / or,

[0036] The tinting degree λ of the optical glass 80 λ in / λ5 80 The wavelength is below 372nm, preferably below 370nm; λ5 is below 304nm, preferably below 300nm.

[0037] According to the lanthanum crown optical glass of the present invention, the optical glass has a moisture resistance and water resistance of grade 1, and an alkali resistance of grade 1.

[0038] The acid resistance of the optical glass is not lower than level 3;

[0039] The washability of the optical glass is not lower than level 2;

[0040] The density of the optical glass is not higher than 4.1 g / cm³. 3 The preferred concentration is no higher than 4.08 g / cm³. 3 .

[0041] According to the lanthanum crown optical glass of the present invention, the refractive index temperature coefficient dn / dt of the optical glass at 20–40°C is 3.0 × 10⁻⁶. -6 Below / ℃, preferably 2.0×10 -6 / ℃ below;

[0042] The coefficient of thermal expansion α of the optical glass -50 / 80℃ Not higher than 80×10 -7 / K, preferably not higher than 75×10 -7 / K;

[0043] The transition temperature of the optical glass is not more than 655°C, preferably not more than 650°C;

[0044] The sag temperature of the optical glass is not higher than 685°C, preferably not higher than 680°C.

[0045] The present invention also provides a method for preparing lanthanum crown optical glass according to the present invention, which includes: weighing the raw materials of each component in proportion, mixing them evenly and then melting them, and then pouring or casting them into a molding die, or directly pressing them into shape.

[0046] The present invention also provides an optical element comprising the lanthanum crown optical glass according to the present invention.

[0047] The effects of the invention

[0048] The lanthanum crown optical glass of the present invention has excellent crystallization performance, transmission performance and chemical stability, low raw material cost, and excellent process performance, making it suitable for secondary molding.

[0049] The method for preparing the lanthanum crown optical glass of the present invention is simple, easy to process, and easy to mass-produce. Detailed Implementation

[0050] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0051] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0052] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0053] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0054] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0055] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0056] This invention uses Si 4+ -B 3+ -Ln 3+ -R 2+ (Where Ln represents La and Y, and R represents Ca, Sr, Ba, and Zn) Based on this system, we obtain glass that is suitable for secondary molding, has good crystallization performance, high transmittance, excellent chemical stability, and good processing performance.

[0057] This invention provides a lanthanum crown optical glass comprising the following components based on cations:

[0058] Si 4+ 6-29%, preferably 10-28%;

[0059] B 3+ : 8-46.5%, preferably 10-45%;

[0060] La 3+ : 0-16%, preferably 3-15%;

[0061] Y 3+ 0.2-15%, preferably 1-13%;

[0062] Ca 2+ : 0-16%, preferably 3-12%;

[0063] Sr 2+ 7-17%, preferably 8-15%;

[0064] Ba 2+ : 0-4.5%, preferably 0-2%;

[0065] Zn 2+ : 0-8.5%, preferably 2-8%;

[0066] Zr 4+ : 1-8.5%, preferably 2-8%;

[0067] Nb 5+0-3%, preferably 0-2%;

[0068] Ti 4+ : 0-2.3%, preferably 0-1%;

[0069] Sb 3+ : 0-0.1%, preferably 0-0.05%;

[0070] All percentages mentioned above are mole percentages.

[0071] The raw material introduction method employs various forms of compounds capable of introducing their corresponding amounts, such as carbonates, nitrates, and oxides. The lanthanum crown optical glass of this invention has an anion of O. 2- .

[0072] Si 4+ As a glass network generator, it not only enhances the glass network structure but also improves the glass's hardness and transmittance, and enhances its chemical stability, such as acid resistance and washability, making it an essential component. If Si... 4+ If the Si content is below 6%, the glass structure is loose, making it unable to incorporate sufficient alkaline earth metals and macromolecules. Consequently, the glass's devitrification resistance, mechanical properties, and chemical stability deteriorate drastically. If Si... 4+ If the Si content exceeds 29%, the expected optical constant will not be achieved, and the chemical stability, especially water resistance and moisture resistance, will also deteriorate. Furthermore, refractory foreign matter is easily generated during melting, reducing the internal quality of the glass. Therefore, this invention uses Si... 4+ The content is 6-29%, preferably 10-28%, further preferably 13-25%, even more preferably 15-23%, and even more preferably 18-20%.

[0073] B 3+ It is also an essential component that functions as a glass network generator, effectively improving glass meltability, lowering the glass transition temperature, and enhancing glass crystallization properties and chemical stability. However, if B... 3+ If the content of B is higher than 46.5%, the chemical stability of the glass, especially its water resistance, moisture resistance, and washability, will deteriorate sharply. It will also be prone to surface crystallization, and the viscosity will decrease, making it more difficult to eliminate streaks and obtain the desired optical glass. Conversely, if B... 3+ When the content of B is below 8%, the glass's meltability deteriorates, its temperature coefficient of refractive index increases, and its mechanical properties worsen. Therefore, B 3+ The content is 8-46.5%, preferably 10-45%, further preferably 13-42%, even more preferably 15-38%, even more preferably 18-35%, and even more preferably 20-30%.

[0074] B 3+ Si 4+As a glass network generator, Si 4+ With B 3+ The sum of the contents of ∑B 3+ +Si 4+ The value cannot be too high, otherwise the expected optical constant will not be achieved; however, at the same time, Si... 4+ With B 3+ The sum of the contents of ∑B 3+ +Si 4+ The value cannot be too low either, otherwise the glass structure will become loose, resulting in poor mechanical properties, crystallization properties, and chemical stability, and increasing the difficulty of processing. Therefore, in molar percentage, the ∑B of this invention... 3+ +Si 4+ The content is 29-67%, preferably 30-63%, more preferably 35-60%, even more preferably 40-55%, and even more preferably 43-53%.

[0075] Si 4+ With B 3+ The ratio of Si content 4+ / B 3+ It also has a significant impact on the properties of glass; if Si 4+ / B 3+ If the Si content is too high, the glass's melting and bending properties will deteriorate, as will its chemical stability, such as moisture and water resistance, making it difficult to obtain high-performance glass. If Si... 4+ / B 3+ If the viscosity is too low, the glass viscosity decreases, and its chemical stability, such as water resistance, acid resistance, and washability, deteriorates, while the transmittance shifts towards longer wavelengths. Therefore, in molar percentage, the Si of this invention... 4+ / B 3+ The value is 0.1-3.3, preferably 0.5-3.0, and even more preferably 1-2.

[0076] La 3+ It is an effective component for increasing the refractive index of glass and can also significantly improve the glass's resistance to devitrification, chemical stability, and mechanical properties. Due to its large ionic radius, if La... 3+ When the content of La exceeds 16%, the crystallization and chemical properties of the glass deteriorate. Therefore, La 3+ The content is below 16%, preferably 3-15%, more preferably 5-15%, and even more preferably 7-12%.

[0077] Y 3+ It is also an effective component for increasing the refractive index of glass, and can significantly improve the chemical stability and mechanical properties of glass. If Y 3+ If the content of Y is higher than 15%, the crystallization and chemical properties of the glass will deteriorate. 3+ If the content of Y is below 0.2%, it cannot effectively improve the mechanical properties, chemical stability, and crystallization properties of glass. Therefore, Y3+ The content is 0.2-15%, preferably 1-13%, more preferably 3-12%, and even more preferably 5-10%.

[0078] La 3+ With Y 3+ The sum of the contents of ∑La 3+ +Y 3+ Besides affecting the refractive index of glass, it also has a significant impact on mechanical properties, crystallization properties, and chemical stability. If ∑La 3+ +Y 3+ If the value is too low, it will not achieve the desired effects on mechanical properties and chemical stability; if ∑La 3+ +Y 3+ If the temperature is too high, the crystallization properties of the glass will deteriorate significantly. Therefore, in this invention, ∑La is expressed as a molar percentage. 3+ +Y 3+ The content is 2.5-27%, preferably 5-25%, more preferably 8-20%, and even more preferably 10-18%.

[0079] La 3+ With Y 3+ The ratio of La content 3+ / Y 3+ It also has a significant impact on the chemical stability and mechanical properties of glass. La 3+ / Y 3+ Excessive concentration leads to decreased chemical stability, especially acid resistance; La 3+ / Y 3+ If the value is too small, the crystallization performance deteriorates, and the cost increases. Therefore, in this invention, La is expressed as a molar percentage. 3+ / Y 3+ The value is 13 or less, preferably 10 or less, further preferably 8 or less, and even more preferably 5 or less.

[0080] Ca 2+ As commonly used alkaline earth metal ions, their small radius allows them to fill network gaps and improve the chemical stability of glass. However, if Ca... 2+ If the Ca content exceeds 16%, the glass's crystallization properties and mechanical properties will deteriorate, and its chemical stability will also worsen. This alone will affect the Ca content. 2+ The content is less than 16%, preferably 3-12%, and more preferably 5-10%.

[0081] Sr 2+ It is an essential component of the glass of this invention, effectively reducing the temperature coefficient of refractive index and improving the melting and crystallization properties of the glass. Additionally, Sr... 2+ It can improve the chemical stability and devitrification resistance of glass, and is beneficial for improving the internal transmittance and mechanical properties of glass. However, when Sr... 2+When the content of Sr is below 7%, it is detrimental to improving the colorimetry, transmittance, and chemical stability of glass, especially its acid resistance, moisture resistance, and water resistance; 2+ When the content of Sr exceeds 17%, the chemical stability of the glass, such as water resistance and washability, as well as its crystallization properties, all deteriorate significantly, and the density increases significantly. Therefore, Sr 2+ The content is 7-17%, preferably 8-15%, and even more preferably 10-15%.

[0082] Ba 2+ The function and Sr 2+ Similarly, when both are present, the mixed alkaline earth metal effect can improve various glass properties such as crystallization properties and chemical stability. If Ba 2+ A Ba content exceeding 4.5% not only increases density but also degrades the glass's transmittance and chemical stability. Therefore, this invention uses Ba... 2+ The content is controlled between 0-4.5%, preferably 0-2%, and even more preferably none.

[0083] Zn 2+ The role of Ca 2+ Ba 2+ 、Sr 2+ Similarly. Zn 2+ As a network intermediate, Zn can form a tetrahedral reinforced glass structure under sufficient free oxygen conditions. When introduced in appropriate amounts, it can improve the crystallization properties and chemical stability of the glass. However, if Zn... 2+ A Zn content exceeding 8.5% can actually worsen crystallization and chemical properties, particularly temperature and humidity resistance, and may even lead to glass coloring. Therefore, Zn... 2+ The content is below 8.5%, preferably 2-8%, and more preferably 3-7%.

[0084] Ca 2+ Ba 2+ 、Sr 2+ and Zn 2+ The introduction of Ca not only increases free oxygen in the glass, reducing glass coloration and improving transmittance, and enhances the network structure to improve crystallization performance, but also effectively reduces the refractive index temperature coefficient of the glass. However, Ca... 2+ 、Sr 2 + Ba 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+When an excessive amount is introduced, the network of external matter increases, the glass structure becomes loose, and the chemical stability and mechanical properties deteriorate significantly. Furthermore, the increased density fails to achieve the expected optical constants.

[0085] In this invention, if ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ If the oxygen content is too low, there will be insufficient free oxygen, and B may exist in a triangular form, while intermediates such as Ti may exist in an octahedral form. This not only makes it difficult to obtain the expected optical constants but also hinders the improvement of glass transmittance, chemical stability, and mechanical properties, and may even cause a deterioration in crystallization performance. Therefore, in molar percentage terms, ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The content is 12-42%, preferably 15-40%, more preferably 18-35%, and even more preferably 22-32%.

[0086] In this invention, if ∑Ca 2+ +Sr 2+ +Zn 2+ If the concentration is too high, the network of external particles increases, the stability of the glass structure deteriorates, and the crystallization performance, mechanical properties, and chemical stability all decrease, while the material properties also shorten and brittleness increases. Conversely, ∑Ca 2+ +Sr 2+ +Zn 2+ When the content is too low, there is insufficient free oxygen. Since glass contains variable-valence elements such as Nb, Ti, and B, this can lead to discoloration or a darkening of the glass. Furthermore, B may exist in trigonal form, while intermediates like Ti may exist in octahedral form, reducing the stability of the glass network structure and thus degrading various properties. Therefore, in molar percentage terms, ∑Ca 2+ +Sr 2+ +Zn 2+ The content is 8.5-37.5%, preferably 10-35%, more preferably 15-33%, and even more preferably 20-30%.

[0087] Ba 2+ With Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The ratio of the sum of Ba content 2+ / ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ It also has a significant impact on the properties of glass, when Ba 2+ / ∑Ca 2+ +Sr 2++Ba 2+ +Zn 2+ When the concentration is too high, the crystallization properties and chemical stability of the glass deteriorate, and its specific gravity increases. Therefore, in molar percentage terms, Ba... 2+ / ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ Below 0.3.

[0088] Zr 4+ Zr acts as a network intermediate. When there is sufficient free oxygen in the glass, it can enter the glass network structure, thereby improving the glass's crystallization properties, chemical stability, and mechanical properties. It can also increase the glass's viscosity and transmittance to visible wavelengths. However, due to Zr... 4+ Zr has a high melting point. 4+ A Zr content exceeding 8.5% will lead to increased melting and crystallization temperatures, decreased devitrification resistance, and the formation of foreign matter, affecting the internal quality of the glass. 4+ A Zr content below 1% is detrimental to the improvement of glass crystallization properties, chemical properties, and mechanical properties. Therefore, Zr... 4+ The content is 1-8.5%, preferably 2-8%, and more preferably 3-7%.

[0089] Nb 5+ It is an essential component for improving the refractive index and dispersion of glass; when added in appropriate amounts, it can improve devitrification resistance and chemical stability. However, if Nb... 5+ When the Nb content exceeds 3%, the refractive index temperature coefficient increases, the glass's devitrification resistance decreases sharply, the crystallization temperature rises, the crystallization rate accelerates, and foreign matter is easily generated during the production process, affecting the internal quality of the glass. Therefore, Nb 5+ The content is 0-3%, preferably 0-2%.

[0090] Ti 4+ It can increase the refractive index and dispersion of glass, and improve its chemical stability and devitrification resistance. However, if Ti... 4+ A Ti content higher than 2.3% will significantly reduce the transmittance in the short wavelength region of visible light and increase the temperature coefficient of refractive index; therefore, Ti 4+ The content is 0-2.3%, preferably 0-1%, and even more preferably, it can be absent.

[0091] Nb 5+ and Zr 4+ As a key component of this invention, it plays a crucial role in the optical properties of the glass. However, when Nb... 5+ With Zr 4+ The sum of the contents of ∑Nb 5+ +Zr 4+When the Nb level is too low, it is difficult to achieve the required high refractive index and high dispersion. 5+ With Zr 4+ The sum of the contents of ∑Nb 5+ +Zr 4+ When the temperature is too high, the glass's devitrification resistance, transmittance, and crystallization properties will all deteriorate, and the expected refractive index temperature coefficient will not be achieved. Therefore, ∑Nb 5+ +Zr 4+ The content is 1.5-11.5%, preferably 3-10%, and even more preferably 5-8%.

[0092] Nb 5+ With Zr 4+ The ratio of Nb content 5+ / Zr 4+ It also has a significant impact on the glass's crystallization properties, transmission properties, and chemical stability. If Nb 5+ / Zr 4+ If the concentration is too high, the chemical properties of the glass will decrease sharply, and its crystallization performance will deteriorate drastically. Therefore, in order to obtain optical glass with excellent crystallization performance and light transmission performance, in this invention, Nb is expressed as a molar percentage. 5+ / Zr 4+ The value is 1.3 or less, preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.5 or less.

[0093] Ti 4+ With Nb 5+ and Zr 4+ The sum of Ti content 4+ / ∑Nb 5+ +Zr 4+ It has a significant impact on transmittance. If Ti 4+ / ∑Nb 5+ +Zr 4+ If the concentration is too high, the transmittance will decrease significantly. Therefore, in molar percentage terms, Ti... 4+ / ∑Nb 5+ +Zr 4+ The value is below 0.8, preferably below 0.6, and even more preferably below 0.3.

[0094] Sb 3+ Excessive Sb content can worsen glass coloration, and when manufacturing glass preforms using pressure molding, the surface of the formed body is prone to unevenness and blurring, failing to meet the increasing requirements for optical design in recent years. Therefore, this invention uses Sb... 3+ The content is controlled at 0-0.1%, preferably 0-0.05%, and more preferably 0-0.02%.

[0095] Gd 3+ Ta 5+ 、Ge 4+Not only does this result in high glass density, but the raw materials used are also extremely expensive, which does not meet the modern demands for lightweight and low cost. Therefore, this application does not include these additives.

[0096] Yb 3+ Absorption in the near-infrared band is detrimental to improving glass transmittance; therefore, this application does not include it.

[0097] Th, Pb, As, Cd, Hg, Sn, Fe, Co, Ce, Te, S, V, Mo, Cr, Mn, Ni, Cu, Ag, etc. are harmful to the environment or easily color glass, and therefore, this application does not preferably add them.

[0098] F - Components that are volatile or hygroscopic will produce volatile streaks, increasing the difficulty of production. Preferably, this application does not add them.

[0099] Contains P 5+ Low- to medium-refractive-index glasses generally have poor chemical stability, are more likely to corrode precious metal crucibles, and are prone to volatilization during the preparation process, making it difficult to control the stability of their optical constants.

[0100] Due to the rising price of lithium carbonate raw materials, Li + The introduction of [Li] not only increases costs but also exacerbates crucible erosion; therefore, the present invention preferably does not contain Li. + .

[0101] To ensure the transmittance of the optical glass described in this invention, preferably, the optical glass provided in this invention does not contain elements such as Tl, Os, Be, and Se.

[0102] In this invention, the refractive index n of the optical glass d The Abbe number is 1.69-1.791, preferably 1.70-1.77, and more preferably 1.71-1.75; d The value is 42.5-53.4, preferably 44-53, and more preferably 46-52.

[0103] The tinting strength λ of the optical glass of this invention 80 λ in / λ5 80 The wavelength is below 372nm, preferably below 370nm, and more preferably below 365nm; λ5 is below 304nm, preferably below 300nm.

[0104] The optical glass of the present invention exhibits excellent chemical stability. Specifically, the optical glass has a moisture resistance and water resistance of grade 1, and an alkali resistance of grade 1; the optical glass has an acid resistance of not less than grade 3, for example, grade 3, grade 2, grade 1, etc.; and the optical glass has a washability of not less than grade 2, for example, grade 2, grade 1, etc.

[0105] Furthermore, the optical glass of the present invention has a low density, which is no higher than 4.1 g / cm³. 3 The preferred concentration is no higher than 4.08 g / cm³. 3 Further optimization is needed, with a concentration not exceeding 3.92 g / cm³. 3 .

[0106] The optical glass of the present invention has a refractive index temperature coefficient dn / dt of 3.0 × 10⁻⁶ at 20–40 °C. -6 Below / ℃, preferably 2.0×10 -6 / ℃ or below; the coefficient of thermal expansion α of the optical glass -50 / 80℃ Not higher than 80×10 -7 / K, preferably not higher than 75×10 -7 / K; the transition temperature of the optical glass is not more than 655°C, preferably not more than 650°C; the sag temperature of the optical glass is not more than 685°C, preferably not more than 680°C.

[0107] The wear degree F of the optical glass of the present invention A The hardness is 145-160, preferably 148-158; the hardness of the optical glass is 600×10⁻⁶. 7 Pa-620×10 7 Pa, preferably 604 × 10 7 Pa-614×10 7 Pa; the optical glass stripe grade is B or A; the number of optical glass bubbles is 0.

[0108] The present invention also provides a method for preparing lanthanum crown optical glass according to the present invention, which includes: weighing each component in proportion, mixing them evenly, melting them, and then pouring or casting them into a molding die, or directly pressing them into shape.

[0109] Specifically, each component is weighed and mixed evenly according to a specified ratio to form a batch material. The batch material is then put into a melting device made of precious metals such as platinum and rhodium. It is melted at a temperature of 1250-1400℃ for 5-8 hours, stirred and clarified at 1400-1450℃ for 8-12 hours, cooled to 1250℃-1300℃ and held for 0.5-2 hours, and then poured or poured into a molding die to form a shape, or directly pressed into a shape. Finally, after annealing and cooling, the optical glass of the present invention is obtained.

[0110] The present invention also provides an optical element comprising primary and secondary components made of lanthanum crown optical glass according to the present invention.

[0111] Example

[0112] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0113] Example 1-120

[0114] The raw materials corresponding to each component in Examples 1-120 in Tables 1-20, such as quartz sand, boric acid, lanthanum oxide, yttrium oxide, calcium carbonate, strontium carbonate, barium carbonate, zinc oxide, zirconium oxide, niobium pentoxide, titanium dioxide, and antimony trioxide, are weighed and mixed evenly in proportion to prepare a batch material. The prepared batch material is put into a precious metal crucible and melted at 1350°C for 6 hours. After stirring and clarifying at 1420°C for 10 hours, it is cooled to 1250°C and held for 1 hour before being removed from the furnace and poured into a mold to form the glass. After annealing and cooling, the optical glass of the present invention can be obtained.

[0115] Comparative AC

[0116] The raw materials corresponding to each component of Comparative Example AC in Table 21, namely quartz sand, boric acid, lanthanum oxide, yttrium oxide, calcium carbonate, strontium carbonate, barium carbonate, zinc oxide, zirconium oxide, niobium pentoxide, titanium dioxide, and antimony trioxide, were weighed according to the specified proportions and prepared using the same preparation method as in Examples 1-120 to obtain the optical glass of Comparative Example AC.

[0117] Performance testing

[0118] 1. Refractive index n d Abbe number υ d

[0119] The refractive index n of the obtained optical glass was determined according to the test method of GB / T7962.1-2010. d Abbe number υ d The determination of n listed in the table d υ d The data is for annealing at -25℃.

[0120] 2. Glass abrasion degree F A

[0121] Wear degree is measured according to the test method specified in GB / T 7962.19.

[0122] 3. Knoop hardness (HK) of glass

[0123] Knoop hardness was measured according to the test method specified in ISO 9385.

[0124] 4. The coefficient of thermal expansion of glass, α -50 / 80℃ Transformation temperature Tg and relaxation temperature Ts

[0125] The measurement shall be performed according to the method specified in GB / T 7962.16.

[0126] 5. Density ρ

[0127] The density of the obtained optical glass was determined according to the test method of GB / T7962.20-2010.

[0128] 6. Shading degree λ 80 / λ5

[0129] The short-wavelength transmission spectral characteristics of optical glass are expressed using colorimetric λ. 80 / λ5 represents λ. 70 λ5 refers to the wavelength corresponding to a glass transmittance of 80%, while λ5 refers to the wavelength corresponding to a glass transmittance of 5%. The light transmittance of a glass with a thickness of 10 ± 0.1 mm, ground on parallel surfaces, was measured according to the Japan Glass Industry Association's "Method for Measuring the Colorimetric Value of Optical Glass" JOGIS02.

[0130] 7. Moisture resistance RC, acid resistance RA (surface method)

[0131] Under conditions of 50℃ and 85% relative humidity, the stability of optical glass against humid atmospheres is classified into three levels based on the time required for hydrolysis spots to form on the polished glass surface, as shown in Table a below:

[0132] Table a. Moisture Resistance Grading Standards

[0133] level 1 2 3 Time (h) >20 5～20 <5

[0134] Under the action of acetic acid solution at 0.1N (pH=2.9) and 50℃, the acid resistance stability of optical glass is divided into three levels according to the time required for interference colors to appear on the polished glass surface, or for surface discoloration or peeling to occur, as shown in Table b below:

[0135] Table b Acid Resistance Grading Standards

[0136] level 1 2 3 Time (h) >5 1～5 <1

[0137] 8. Water resistance D W Acid resistance D A (Powder method)

[0138] The water resistance of the obtained optical glass was tested according to the test method of JB / T10576-2006. W Acid resistance D A Conduct the test.

[0139] 9. Alkali resistance R OH (S)

[0140] A 40mm × 40mm × 5mm sample, polished on all six sides, was immersed in a 0.01mol / L sodium hydroxide aqueous solution at a constant temperature of 50℃ ± 3℃ for 15 hours with thorough stirring. The leaching mass per unit area was calculated as mg / (cm²). 2 •15h), to improve the alkali resistance stability R of optical glass OH (S) is divided into five levels, as shown in Table c below:

[0141] Table c Alkali Resistance Grading Standard

[0142]

[0143] 10. Washability RP(S)

[0144] A 35mm × 35mm × 8mm sample, polished on all six sides, was immersed in Na₅P₃O₂ at a constant temperature of 50℃ ± 3℃ and a concentration of 0.01mol / L with thorough stirring. 10 In aqueous solution for 1 hour. Based on the average leaching mass per unit area, the unit is mg / (cm²). 2 The washability stability RP(S) of optical glass is divided into five levels, as shown in Table d below:

[0145] Table d Washability Grading Standards

[0146]

[0147] 12. Temperature coefficient of refractive index

[0148] The temperature coefficient of relative refractive index (dn / dt) of the glass in the embodiment was determined according to the minimum deviation angle method in the method described in the national standard GB7962.04-2010 "Test methods for colorless optical glass - Part 4: Temperature coefficient of refractive index". The temperature coefficient of relative refractive index was measured for light with a wavelength of 589.29 nm (d line) when the temperature was changed from 20°C to 40°C.

[0149] 13. Number of internal air bubbles

[0150] The internal air bubbles in the glass were tested according to the test method specified in GB / T7962.8-1987, and the result was 100cm. 3 The number of air bubbles in the glass, as well as stones, crystals and other inclusions, are also counted as air bubbles.

[0151] 14. Stripe density

[0152] The fringe intensity is checked using a parallel optical path fringe meter consisting of a point light source and a lens. By rotating the glass, the fringe image inside the glass cross-section, where fringes are most likely to occur, is examined and compared with a standard sample. The results are categorized into several levels as shown in Table e below:

[0153] Table e

[0154] level Stripe features A Stripeless Image B It has fine, dispersed stripes. C There are parallel fine stripes D There are parallel, slightly coarse stripes

[0155] The refractive index n of the optical glass prepared in Examples 1-120 d Abbe number υ d Wear degree F A Hardness HK, coefficient of thermal expansion α -50 / 80℃ Transition temperature T g , sag temperature Ts, density ρ, chromaticity λ 70 / λ5, Surface method moisture resistance RC, Surface method acid resistance RA, Powder method water resistance D W Powder method acid resistance D A Alkali resistance R OH The relative refractive index temperature coefficient of RP(S) and d-line at 20–40 °C, the number of internal bubbles and the striations are listed in Table 1-20; the data obtained by measuring the comparative example AC are listed in Table 21.

[0156] Table 1: Glass composition and performance parameters of Examples 1-6

[0157]

[0158] Table 2 Glass composition and performance parameters of Examples 7-12

[0159]

[0160] Table 3: Glass composition and performance parameters of Examples 13-18

[0161]

[0162] Table 4: Glass composition and performance parameters of Examples 19-24

[0163]

[0164] Table 5: Glass composition and performance parameters of Examples 25-30

[0165]

[0166] Table 6: Glass composition and performance parameters of Examples 31-36

[0167]

[0168] Table 7: Glass composition and performance parameters of Examples 37-42

[0169]

[0170] Table 8: Glass composition and performance parameters of Examples 43-48

[0171]

[0172] Table 9: Glass composition and performance parameters of Examples 49-54

[0173]

[0174] Table 10: Glass composition and performance parameters of Examples 55-60

[0175]

[0176] Table 11: Glass composition and performance parameters of Examples 61-66

[0177]

[0178] Table 12: Glass composition and performance parameters of Examples 67-72

[0179]

[0180] Table 13: Glass composition and performance parameters of Examples 73-78

[0181]

[0182] Table 14: Glass composition and performance parameters of Examples 79-84

[0183]

[0184] Table 15: Glass composition and performance parameters of Examples 85-90

[0185]

[0186] Table 16: Glass composition and performance parameters of Examples 91-96

[0187]

[0188] Table 17: Glass composition and performance parameters of Examples 97-102

[0189]

[0190] Table 18: Glass composition and performance parameters of Examples 103-108

[0191]

[0192] Table 19: Glass composition and performance parameters of Examples 109-114

[0193]

[0194] Table 20: Glass composition and performance parameters of Examples 115-120

[0195]

[0196] Table 21: Glass composition and performance parameters of Comparative Example AC

[0197]

[0198] As can be seen from Tables 1-20, the refractive index n of the optical glass in Examples 1-120 of the present invention is... d The range is 1.69-1.791; the Abbe number υ d Its value is 42.5-53.4; its chromaticity λ 80 / λ5 in λ 80 The wavelength is no more than 372 nm, and λ5 is no more than 304 nm; the density is 3.76-4.08 g / cm³. 3 Moisture resistance, water resistance, and alkali resistance all reach level 1; acid resistance is not lower than level 3; and washability is not lower than level 2; the coefficient of thermal expansion α -50 / 80℃ 68×10 -7 / K-80×10 -7 / K; Transition temperature Tg is 643-653℃; Relaxation temperature Ts is 672-682℃; The refractive index temperature coefficient dn / dt of optical glass at 20-40℃ is 0.6×10 -6 / ℃-3.0×10 -6 / ℃; Wear degree F A Its value is 148-158; its hardness is 604×10. 7 Pa-614×10 7 Pa; stripe grade B or A; number of bubbles 0. Excellent processability, suitable for mass production, especially good glass crystallization performance, suitable for secondary molding.

[0199] As can be seen from Table 21, Comparative Example A contains 60% of B. 3+ The chemical stability deteriorates significantly, and the viscosity decreases significantly, which is not conducive to the elimination of streaks; Comparative Example B contains more Ti. 4+ The glass color darkens significantly, which is detrimental to improving the clarity of the forming process. 4+ The content is also relatively high, making it prone to generating foreign matter during the melting process. Comparative example C contains a higher amount of B. 3+and Ba 2+ Zr 4+ The content is also relatively low, and the glass transition stability and crystallization performance are significantly worse.

[0200] Industrial availability

[0201] The lanthanum crown optical glass and its preparation method of the present invention can be produced industrially and can be processed into various optical components such as lenses and preforms through cold working, hot working and other methods, and applied to various optical systems such as video surveillance and projectors.

[0202] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0203] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A lanthanum crown optical glass, characterized in that, Includes the following components, calculated as cations: Si 4+ : 6-29% B 3+ ：8-46.5%； La 3+ : 0-16% Y 3+ ：0.3-15%； Ca 2+ : 0-16% Sr 2+ ：7-17%； Ba 2+ : 0-4.5%; Zn 2+ :0-8.5%; Zr 4+ ：3.02-8.5%； Nb 5+ :0-3%; Of 4+ :0-2.3%; Sb 3+ :0-0.1%; All percentages mentioned above are mole percentages; Of which, in mole percentage, La 3+ With Y 3+ The sum of the contents of ∑La 3+ +Y 3+ It is 2.89-27%, and La 3+ With Y 3+ The ratio of La content 3+ / Y 3+ Below 13 Nb in mole percentage 5+ With Zr 4+ The sum of the contents of ∑Nb 5+ +Zr 4+ 3-10%, Nb 5+ With Zr 4+ The ratio of Nb content 5 + / Zr 4+ Below 1.0 The lanthanum crown optical glass has a refractive index temperature coefficient dn / dt of 0.6 × 10⁻⁶ at 20–40 °C. -6 / ℃ or above and 3.0×10 -6 / ℃ below.

2. The lanthanum crown optical glass according to claim 1, characterized in that, Includes the following components, calculated as cations: And 4+ :10-28%; B 3+ ：10-45%； The 3+ 3-15%; Y 3+ ：1-13%； That 2+ :3-12%; Sr 2+ ：8-15%； Not 2+ :0-2%; Zn 2+ :2-8%; Zr 4+ ：3.02-8%； Nb 5+ :0-2%; Of 4+ :0-1%; Sb 3+ :0-0.05%, All percentages mentioned above are mole percentages.

3. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, In molar percentage, Si 4+ With B 3+ The sum of the contents of ∑Si 4+ +B 3+ 29-67%; and / or, Si 4+ With B 3+ The ratio of Si content 4+ / B 3+ The ratio is 0.1 to 3.

3.

4. The lanthanum crown optical glass according to claim 3, characterized in that, In molar percentage, Si 4+ With B 3+ The sum of the contents of ∑Si 4+ +B 3+ 30-63%; and / or, Si 4+ With B 3+ The ratio of Si content 4+ / B 3+ The ratio is 0.5 to 3.

0.

5. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, In mole percentage, La 3+ With Y 3+ The sum of the contents of ∑La 3+ +Y 3+ 5-25%; and / or, La 3+ With Y 3+ The ratio of La content 3+ / Y 3+ It is below 10.

6. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, In molar percentage, Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ For 12-42%; and / or, Ca 2+ 、Sr 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Zn 2+ The range is 8.5%-37.5%; and / or, Ba 2+ With Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The ratio of the sum of Ba content 2+ / ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ It is below 0.

3.

7. The lanthanum crown optical glass according to claim 6, characterized in that, In molar percentage, Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ 15-40%; and / or, Ca 2+ 、Sr 2+ and Zn 2+ The sum of the contents of ∑Ca 2+ +Sr 2+ +Zn 2+ It ranges from 10% to 35%.

8. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, In molar percentage, Ti 4+ With Nb 5+ and Zr 4+ The ratio of the sum of the contents of Ti 4+ / ∑Nb 5+ +Zr 4+ It is below 0.

6.

9. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, The refractive index n of the optical glass d The range is 1.69-1.791; the Abbe number υ d For 42.5-53.4; and / or, The tinting degree λ of the optical glass 80 λ in / λ5 80 Below 372nm; λ5 is below 304nm.

10. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, The refractive index n of the optical glass d The value is 1.70-1.77; the Abbe number υ d For 44-53; and / or, The tinting degree λ of the optical glass 80 λ in / λ5 80 Below 370 nm; λ5 is below 300 nm.

11. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, The optical glass has a moisture resistance and water resistance rating of Grade 1, and an alkali resistance rating of Grade 1. The optical glass has an acid resistance of not less than level 3; The washability of the optical glass is not lower than level 2; The density of the optical glass is not higher than 4.1 g / cm³. 3 .

12. The lanthanum crown optical glass according to claim 1 or 2, characterized in that, The refractive index temperature coefficient dn / dt of the optical glass is 2.0 × 10⁻⁶ at 20–40 °C. -6 / ℃ below; The coefficient of thermal expansion α of the optical glass -50 / 80℃ Not higher than 80×10 -7 / K; The transition temperature of the optical glass does not exceed 655°C; The sag temperature of the optical glass is not higher than 685°C.

13. The lanthanum crown optical glass according to claim 12, characterized in that, The coefficient of thermal expansion α of the optical glass -50 / 80℃ Not higher than 75×10 -7 / K; The transition temperature of the optical glass does not exceed 650°C; The sag temperature of the optical glass is not higher than 680°C.

14. A method for preparing lanthanum crown optical glass according to any one of claims 1-13, characterized in that, include: The raw materials of each component are weighed and mixed evenly according to the proportions, then melted and poured or poured into the molding mold, or directly pressed into shape.

15. An optical element, characterized in that, Including the lanthanum crown optical glass according to any one of claims 1-13.

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