Optical glass, preparation method thereof and optical element

Abstract

The invention provides optical glass, a preparation method thereof and an optical element. The optical glass comprises the following components in percentage by mole of oxides: 42-55.5% of SiO2; 12 to 20 percent of TiO2; 5 to 15 percent of Na2O; 0.5 to 5 percent of K2O; 6 to 14 percent of CaO; 2 to 8 percent of SrO; 2 to 10.5 percent of Li2O; 0 to 5 percent of Al2O3; 0 to 5 percent of MgO; 0 to 5 percent of Y2O3; the refractive index of the optical glass ranges from 1.62 to 1.72, and the abbe number of the optical glass ranges from 30 to 38. The optical glass provided by the invention has the characteristics of low transformation temperature, excellent devitrification resistance, chemical stability and weather resistance and small specific gravity. Therefore, the optical glass provided by the invention is easy to produce by precise mould pressing, has excellent chemical stability, and can meet the requirements of modern novel photoelectric products.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical glass, a preparation method thereof and an optical element, and belongs to the field of optical glasses. BACKGROUND

[0002] In recent years, with the progress of science and technology, the continuous updating of optoelectronic information products, the demand for optical glass has gradually increased, and higher requirements for the performance of optical glass have been put forward. At present, the mainstream method for manufacturing optical glass into optical elements is precision molding (including direct molding method and secondary molding method), which reduces the consumption of raw materials, reduces the cost of manpower and material resources, and reduces environmental pollution. This technology can produce optical elements in large quantities at low cost.

[0003] When precision molding is performed, in order to copy the high-precision mold surface on the glass finished product, the glass preform needs to be formed under high temperature and pressure. At this time, the mold surface is easily oxidized and eroded under high temperature and pressure, even in a protective gas. In order to prolong the service life of the mold and inhibit the damage of the high-temperature environment to the mold, it is necessary to reduce the molding temperature. Therefore, the transition temperature (Tg) of the glass material used for molding needs to be as low as possible.

[0004] Optical glasses with a refractive index of 1.62-1.72 and an Abbe number of 30-38 are widely used in imaging, projection, long-distance communication, optical communication engineering and laser technology application fields. Since optical glasses are widely used in vehicle-mounted, monitoring and security fields, optical glasses are in contact with external complex natural environment for a long time, and even in extreme environment, which requires optical glasses to have excellent weather resistance to improve the service life of optical glasses.

[0005] The optical glasses disclosed in patent applications CN117945653A, CN110770183B and CN106430950A all contain P2O5, which is easy to erode platinum and other precious metal containers. Especially, phosphate glasses containing alkali metals have stronger eroding property. P2O5 is also easy to volatilize, which affects the optical stability of the glass.

[0006] The optical glasses disclosed in patent applications CN118954943A and CN118930039A contain a high content of BaO. The relative molecular mass of BaO is large, and a high content of BaO will cause the specific gravity of the glass to be too large, and BaO will erode the melting equipment. SUMMARY

[0007] Problems to be solved by the application

[0008] In view of the technical problems disclosed in the prior art, the present application first provides an optical glass. The optical glass has a refractive index of 1.62-1.72, a low transition temperature, excellent resistance to devitrification, chemical stability, and a small specific gravity, and is suitable for precision mold pressing and easy mass production.

[0009] The present application also provides a preparation method of the optical glass, which is simple and easy to implement, raw materials are easy to obtain, and is suitable for mass production.

[0010] The present application also provides an optical element.

[0011] Solution for solving the problem

[0012] The present application first provides an optical glass, which comprises the following components in terms of oxide molar percentage:

[0013] SiO2: 42-55.5%;

[0014] TiO2: 12-20%;

[0015] Na2O: 5-15%;

[0016] K2O: 0.5-5%;

[0017] CaO: 6-14%;

[0018] SrO: 2-8%;

[0019] Li2O: 2-10.5%;

[0020] Al2O3: 0-5%;

[0021] MgO: 0-5%;

[0022] Y2O3: 0-5%;

[0023] The optical glass has a refractive index of 1.62-1.72 and an Abbe number of 30-38.

[0024] The optical glass according to the present application comprises the following components in terms of oxide molar percentage:

[0025] SiO2: 42-53%;

[0026] TiO2: 13-19%;

[0027] Na2O: 6-14%;

[0028] K2O: 1-4%;

[0029] CaO: 7-13%;

[0030] SrO: 3-7%;

[0031] Li2O: 2.5 to 9.5%;

[0032] Al2O3: 0 to 3%;

[0033] MgO: 0 to 3%;

[0034] Y2O3: 0 to 3%.

[0035] The optical glass according to the present application comprises the following components in terms of molar percentage of oxides:

[0036] SiO2: 43 to 51%;

[0037] TiO2: 14 to 19%;

[0038] Na2O: 7 to 13%;

[0039] K2O: 1 to 4%;

[0040] CaO: 7 to 12%;

[0041] SrO: 3 to 7%;

[0042] Li2O: 3.5 to 8.5%;

[0043] Al2O3: 0 to 1%;

[0044] MgO: 0 to 1%;

[0045] Y2O3: 0 to 1%.

[0046] The optical glass according to the present application, wherein the optical glass does not contain one or a combination of two or more of F element, P2O5, BaO, Ta2O5, Gd2O3, GeO2, TeO2, Nb2O5, ZrO2, ZnO, B2O3, As2O3, or PbO.

[0047] The optical glass according to the present application, wherein the ratio of the molar percentage content of TiO2 to that of SiO2, TiO2 / SiO2, is 0.17 to 0.45, preferably 0.18 to 0.43, more preferably 0.20 to 0.41;

[0048] The sum of the molar percentage contents of Li2O, Na2O, and K2O, ∑(Li2O+Na2O+K2O), is 30% or less, preferably 27% or less;

[0049] The ratio of the sum of the molar percentage contents of Li2O, Na2O, and K2O to the molar percentage content of SiO2, ∑(Li2O+Na2O+K2O) / SiO2, is 0.2 to 0.7, preferably 0.25 to 0.65;

[0050] the ratio of the sum of the molar percentages of Na2O and K2O to the sum of the molar percentages of Li2O, Na2O and K2O, ∑(Na2O+K2O) / ∑(Li2O+Na2O+K2O), is 0.3 to 0.9, preferably 0.4 to 0.85, more preferably 0.5 to 0.80;

[0051] the ratio of the sum of the molar percentages of SiO2, Li2O, Na2O and K2O to the molar percentage of TiO2, ∑(SiO2+Li2O+Na2O+K2O) / TiO2, is 3.1 to 5.5, preferably 3.5 to 5.0;

[0052] the sum of the molar percentages of MgO, CaO and SrO, ∑(MgO+CaO+SrO), is 8.5 to 25%, preferably 9 to 23%, more preferably 10 to 20%.

[0053] The optical glass according to the present application, wherein the optical glass further comprises a fining agent, preferably the molar percentage of the fining agent is 0 to 0.10%, preferably 0 to 0.05%.

[0054] The optical glass according to the present application, wherein,

[0055] the density ρ of the optical glass is 3.00 g / cm 3 The following;

[0056] the coloration degree λ 80 / λ5 of the optical glass, wherein λ 80 is 395 nm or less and λ5 is 365 nm or less;

[0057] the hardness HK of the optical glass is 580 x 10 7 Pa or more.

[0058] The optical glass according to the present application, wherein,

[0059] the bubble degree of the optical glass is 0 to 1 grade;

[0060] the transition temperature Tg of the optical glass is 545°C or less;

[0061] the sag temperature Ts of the optical glass is 585°C or less;

[0062] the anti-crystallization property of the optical glass is B grade or more.

[0063] The present application also provides a method for preparing the optical glass according to the present application, which comprises: uniformly mixing raw materials of each component of the optical glass, then melting, and then pouring or casting in a forming mold and annealing, or directly press forming.

[0064] The present application also provides an optical element comprising the optical glass according to the present application.

[0065] Effects of the Invention

[0066] The optical glass according to the present application has a refractive index of 1.62 to 1.72, low transition temperature, excellent resistance to devitrification, chemical stability, weather resistance and low specific gravity. Therefore, the optical glass according to the present application is an optical glass which is easy to be precisely molded and has excellent chemical stability, and can meet the needs of modern new photoelectric products.

[0067] The method for preparing the optical glass according to the present application is simple and easy to operate, and the raw materials are easy to obtain, which is suitable for mass production. DETAILED DESCRIPTION

[0068] Various exemplary embodiments, features, and aspects of the present application will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0069] In addition, for the purpose of better illustrating the present application, numerous specific details are set forth in the following detailed description. Those skilled in the art will appreciate that the present application can be practiced without some or all of the specific details. In other instances, well known methods, apparatuses, materials and steps have not been described in detail in order to avoid obscuring the application.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The meaning of "a", "an", and "the" includes plural references. The meaning of "in" includes "in" and "on." The use of "including", "comprising", "having" and "with" are not limiting. The use of "or" means "and / or". The use of parentheses means "and". The use of "based on" does not mean "based only on" and is intended to allow for being based on indirect, as well as direct, stimuli, e.g., events, changes, results, etc.

[0071] In this specification, the meaning expressed by "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0072] In this specification, references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc. mean that the particular element(s) described is included in at least one embodiment described herein, and can or can not be present in other embodiments. In addition, it is to be understood that the described elements can be combined in any suitable manner in the various embodiments.

[0073] In this specification, the numerical range expressed by "numerical value A to numerical value B" means a range including the end point values A, B.

[0074] The present application provides an optical glass comprising the following components in terms of mole percent of oxides:

[0075] SiO2: 42 to 55.5%;

[0076] TiO2: 12 to 20%;

[0077] Na2O: 5 to 15%;

[0078] K2O: 0.5 to 5%;

[0079] CaO: 6 to 14%;

[0080] SrO: 2 to 8%;

[0081] Li2O: 2 to 10.5%;

[0082] Al2O3: 0 to 5%;

[0083] MgO: 0 to 5%;

[0084] Y2O3: 0 to 5%;

[0085] The optical glass has a refractive index of 1.62 to 1.72 and an Abbe number of 30 to 38.

[0086] The composition of the optical glass of the present application is described in detail below. The content of each glass component, the total content, is expressed in mole percent unless otherwise specified. In the following description, the term "not more than" or "not less than" a specified value includes the specified value.

[0087] SiO2is the skeleton of the optical glass and functions as a glass network former to maintain the chemical stability of the glass and improve the resistance of the glass to devitrification. When the mole percent content of SiO2is less than 42%, the above effects are difficult to achieve, and therefore the lower limit of the mole percent content of SiO2is 42%, preferably 43%. When the content of SiO2is more than 55.5%, the glass melting property is reduced and the transition temperature is increased, and therefore the upper limit of the mole percent content of SiO2is 55.5%, preferably 53%, more preferably 51%.

[0088] TiO2functions to increase the refractive index and dispersion of the glass and participates in the formation of the glass network. The appropriate amount of TiO2can make the glass more stable and reduce the viscosity of the glass. In the present application, the mole percent content of TiO2is 12% or more to achieve the above effects. The lower limit of the mole percent content of TiO2is preferably 13%, more preferably 14%. However, the introduction of a large amount of TiO2can reduce the transmittance in the short-wave portion of the visible light region of the glass and increase the tendency of the glass to crystallize, and therefore the upper limit of the mole percent content of TiO2is 20%, preferably 19%.

[0089] In some embodiments of the present application, when the molar percentage content ratio of TiO2 / SiO2 is too low, the melting property of the glass is reduced and the striation degree is poor, and when TiO2 / SiO2 is too high, the chemical stability and optical transmittance of the glass are reduced and the density is increased, therefore, in the present application, TiO2 / SiO2 is 0.17-0.45, preferably, TiO2 / SiO2 is 0.18-0.43, and more preferably, TiO2 / SiO2 is 0.20-0.41.

[0090] Li2O can reduce the transition temperature of the glass and improve the melting property of the glass, but when the content of Li2O is too high, it is not good for the striation degree, anti-crystallization property and chemical stability of the glass, and the hardness is reduced. In addition, if the content of Li2O is too low, the corresponding effect cannot be achieved. Therefore, in the present application, the molar percentage content of Li2O is 2-10.5%, preferably, 2.5-9.5%, and more preferably, 3.5-8.5%.

[0091] Na2O has the effect of improving the melting property of the glass, and has obvious effect on improving the melting effect, and can also reduce the transition temperature of the glass. In the present application, Na2O with a molar percentage content of more than 5% is introduced to achieve the above effect, and the lower limit of the molar percentage content of Na2O is 6%, and more preferably, the lower limit is 7%. When the molar percentage content of Na2O is more than 15%, the chemical stability and weather resistance of the glass are reduced, therefore, the upper limit of the molar percentage content of Na2O is 15%, preferably, the upper limit is 14%, and more preferably, the upper limit is 13%.

[0092] K2O has the effect of improving the thermal stability and melting property of the glass, but when the molar percentage content of K2O is more than 5%, the resistance to devitrification of the glass is reduced and the density of the glass is increased, therefore, in the present application, the molar percentage content of K2O is 5% or less. In the present application, the molar percentage content of K2O is 0.5-5%, and preferably, 1-4%. In addition, if the content of K2O is too low, the corresponding effect cannot be achieved.

[0093] Li2O, Na2O and K2O are good glass fluxes, and appropriate introduction can reduce the transition temperature of the glass, improve the melting property of the glass, and obtain optical glass with good uniformity, but when the sum of the molar percentage contents of Li2O, Na2O and K2O, ∑(Li2O+Na2O+K2O), is too high, the durability of the glass is damaged and the expansion of the glass is increased. Through a large number of experiments, it is found that when ∑(Li2O+Na2O+K2O) is controlled to be 30% or less, the glass has good chemical stability, and preferably, ∑(Li2O+Na2O+K2O) is controlled to be 27% or less.

[0094] In some embodiments of the present application, the ratio of the sum of the molar percentage contents of Li2O, Na2O and K2O, ∑(Li2O+Na2O+K2O), to the molar percentage content of SiO2, ∑(Li2O+Na2O+K2O) / SiO2, directly affects the stability of the glass. If ∑(Li2O+Na2O+K2O) / SiO2is too high, the non-bridging oxygen of the glass will increase, the network stability and strength will be poor, resulting in poor glass crystallization resistance, chemical stability, and hardness. If ∑(Li2O+Na2O+K2O) / SiO2is too low, there is not enough free oxygen, and part of the Ti will exist in the form of [TiO6] in the glass structure, resulting in deepened glass color, decreased transmittance, and increased glass transition temperature and softening temperature, which is not conducive to hot-press forming. Therefore, ∑(Li2O+Na2O+K2O) / SiO2is controlled to be between 0.2 and 0.7, preferably between 0.25 and 0.65.

[0095] In some embodiments of the present application, if the ratio of the sum of the molar percentage contents of Na2O and K2O to the sum of the molar percentage contents of Li2O, Na2O and K2O, ∑(Na2O+K2O) / ∑(Li2O+Na2O+K2O), is too high, the partial dispersion ratio of the glass will increase, the re-press forming performance will decrease, the chemical stability will be poor, the viscosity will increase, the melting performance will also be poor, and the elastic modulus and mechanical strength will also decrease. If ∑(Na2O+K2O) / ∑(Li2O+Na2O+K2O) is too low, the glass crystallization resistance, hot-press forming performance, and chemical stability will be significantly poor. Therefore, in the present application, ∑(Na2O+K2O) / ∑(Li2O+Na2O+K2O) is 0.3 to 0.9, preferably 0.4 to 0.85, and more preferably 0.5 to 0.80.

[0096] In some embodiments of the present application, when the ratio of the sum of the molar percentage contents of SiO2, Li2O, Na2O and K2O to the molar percentage content of TiO2, ∑(SiO2+Li2O+Na2O+K2O) / TiO2, is between 3.1 and 5.5, sufficient free oxygen can be provided to make Ti ions construct the glass network in a colorless high-valence state, thereby reducing the coloring degree of the glass, improving the glass's devitrification resistance and chemical stability, and reducing the density of the glass; if ∑(SiO2+Li2O+Na2O+K2O) / TiO2 is too high, not only the refractive index of the glass cannot meet the standard, but also the devitrification resistance or the melting performance will be poor; when ∑(SiO2+Li2O+Na2O+K2O) / TiO2 is too low, there is insufficient free oxygen, and Ti ions destroy the glass structure in the form of low-valence network outside bodies, resulting in poor transmittance, devitrification resistance, chemical stability and mechanical properties of the glass, therefore, in the present application, ∑(SiO2+Li2O+Na2O+K2O) / TiO2 is 3.1-5.5, preferably 3.5-5.0.

[0097] CaO is an essential component that can effectively reduce the devitrification temperature, the conversion temperature and the specific gravity. In the present application, by containing 6% or more of CaO, the above-mentioned effects can be obtained, and preferably the content of CaO is 7% or more; but if the content is too high, the devitrification resistance will be easily deteriorated. Therefore, the content of CaO is limited to 14% or less, preferably 13% or less, and more preferably 12% or less.

[0098] SrO is an arbitrary component for reducing the devitrification temperature, increasing the stability of the glass, improving the devitrification resistance of the glass and adjusting the refractive index, and in the present application, by containing 2% or more of SrO in terms of the molar percentage content, the above-mentioned effects can be obtained, and preferably the molar percentage content of SrO is 3% or more; but if the content is too high, the devitrification resistance will be easily deteriorated. Therefore, the molar percentage content of SrO is limited to 8% or less, preferably 7% or less.

[0099] BaO is strong in corrosion to the melting device and affects the density of the glass in the present application, and therefore, it is preferably not introduced in the present application.

[0100] MgO can improve the chemical stability of the glass, and if the molar percentage content of MgO is higher than 5%, the devitrification resistance of the glass will rapidly decrease. Therefore, the molar percentage content of MgO is limited to 5% or less, preferably 3% or less, more preferably 1% or less, and further preferably, MgO is not contained.

[0101] MgO, CaO and SrO are components capable of improving the optical constants of optical glass, reducing the crystallization temperature of glass and improving the resistance of glass to devitrification. The sum of the molar percentage contents of MgO, CaO and SrO, ∑(MgO+CaO+SrO), directly affects the upper limit of the crystallization temperature of glass and the chemical stability and water resistance of glass. When ∑(MgO+CaO+SrO) is too high, the chemical stability and water resistance of the obtained optical glass become poor, and the process difficulty increases; when ∑(MgO+CaO+SrO) is too low, the transmittance, Abbe number and color degree λ 80 / λ5 of the optical glass are all difficult to reach the ideal state, and the upper limit of the crystallization of glass increases, directly affecting the melting of glass. Therefore, the sum of the molar percentage contents of MgO, CaO and SrO, ∑(MgO+CaO+SrO), is controlled to be between 8.5% and 25%, preferably between 9% and 23%, and more preferably between 10% and 20%.

[0102] ZrO2 can improve the refractive index and resistance to devitrification of glass, and improve the chemical stability and mechanical properties of glass. If the content of ZrO2 is too high, the melting difficulty of glass increases, which easily leads to the presence of inclusions in the glass and the decrease of light transmittance, and reduces the anti-crystallization performance of glass. Therefore, the application preferably does not introduce ZrO2.

[0103] Nb2O5 is a high-refractive high-dispersive component, which can improve the resistance to devitrification of glass and reduce the thermal expansion coefficient of glass. If the content of Nb2O5 is too high, the weather resistance and light transmittance of glass decrease, and the transition temperature of glass increases. For cost considerations, the application does not introduce Nb2O5.

[0104] Al2O3 can improve the chemical stability of glass to a certain extent, but if the content of Al2O3 is too large, the resistance to devitrification and melting of glass decrease. Therefore, the molar percentage content of Al2O3 is less than 5%, preferably less than 3%, and more preferably less than 1%.

[0105] Y2O3 is a component for improving the refractive index and chemical stability of glass, and is an optional component in the optical glass of the application. By controlling the molar percentage content of Y2O3 to be less than 5%, the resistance to devitrification of glass can be improved, and the desired refractive index and Abbe number can be obtained. Therefore, in the optical glass of the application, the upper limit of the range of the molar percentage content of Y2O3 is 5%, preferably the upper limit is 3%, and more preferably the upper limit is 1%.

[0106] The glass of the present invention can use a small amount of clarifying agent to improve the bubble content of the glass, such as one or more of Sb₂O₃, SnO₂, SnO, CeO₂, NaCl, and sulfates, wherein the molar percentage content of the clarifying agent is limited to 0-0.10%, preferably 0-0.05%, and more preferably none. From the perspective of existing production technology, Sb₂O₃ is preferably used as the clarifying agent. When Sb₂O₃ is used as the clarifying agent, its molar percentage content can be 0-0.02%, preferably 0-0.01%.

[0107] In the optical glass of the present invention, even if oxides of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained in small amounts, either alone or in combination, the glass will be colored and absorb at specific wavelengths in the visible light region, thereby reducing the visible light transmittance of the present invention. Therefore, it is preferable that the optical glass, especially for optical glass where transmittance in the visible light region is required, does not contain these oxides.

[0108] Elements such as Th, Cd, Tl, Os, Be, and Se have been increasingly subject to controlled use in recent years due to their status as hazardous chemical substances. Environmental protection measures are essential not only in the glass manufacturing process but also in its processing and post-product disposal. Therefore, given the importance of environmental impact, it is preferable to avoid the presence of these elements, except where their contamination is unavoidable. Consequently, the optical glass of the present invention does not contain any substances that pollute the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and disposed of even without special environmental countermeasures.

[0109] To achieve environmental friendliness, the optical glass of this invention does not contain As₂O₃ or PbO. Although As₂O₃ has the effect of eliminating bubbles and preventing glass discoloration, its addition will increase the corrosion of platinum in the furnace, especially in platinum furnaces, leading to more platinum ions entering the glass and adversely affecting the service life of the platinum furnace. PbO can significantly improve the high refractive index and high dispersion properties of glass, but both PbO and As₂O₃ are substances that cause environmental pollution.

[0110] In some specific embodiments, the optical glass preferably does not contain one or more of the following elements: sulfur (F), P2O5, Ta2O5, Gd2O3, GeO2, and TeO2. When sulfur is present, its volatilization during the melting process leads to environmental pollution, unstable optical constants, and defects such as streaks. Furthermore, it can cause fogging on the surface of the optical glass during precision molding. Therefore, this invention preferably excludes sulfur. P2O5 readily corrodes precious metal containers such as platinum, especially phosphate glasses containing alkali metals, which are even more corrosive. Moreover, P2O5 readily volatilizes at high temperatures, affecting the optical stability of the glass. Therefore, this invention preferably excludes P2O5. Ta2O5, Gd2O3, GeO2, and TeO2 are expensive, and this invention preferably excludes them.

[0111] The terms "not introduced," "not containing," and "0%" used herein mean that the compound, molecule, or element was not intentionally added to the optical glass of this invention as a raw material; however, as raw materials and / or equipment used in the production of optical glass, there may be certain unintentionally added impurities or components that may be present in small or trace amounts in the final optical glass, and such cases are also within the scope of protection of this patent.

[0112] In this invention, the density ρ of the optical glass is 3.00 g / cm³. 3 The following describes the tinting degree λ of the optical glass. 80 In / λ5, λ 80 The wavelength is below 395nm, and λ5 is below 365nm; the hardness HK of the optical glass is 580×10⁻⁶. 7 The optical glass exhibits a water resistance stability D above Pa. W Grade 1, acid resistance stability D A The moisture resistance stability R of the optical glass is rated as level 1. C (S) is grade 1, acid resistance R A (S) is level 1; the washability stability R of the optical glass P (S) is grade 1, alkali resistance R OH (S) is grade 1; the transition temperature Tg of the optical glass is below 545℃, the sag temperature Ts of the optical glass is below 585℃; the bubble degree of the optical glass is grade 0~1.

[0113] In some embodiments, the optical glass of the present invention has a crystallization resistance of grade B or higher, preferably grade A, exhibiting excellent crystallization resistance and superior devitrification resistance.

[0114] Furthermore, the present invention also provides a method for preparing optical glass, which includes mixing the raw materials of each component evenly and then melting them, then pouring or casting them into a molding die and annealing them, or directly pressing them into shape.

[0115] Specifically, the raw materials of each component of optical glass (such as oxides, hydroxides, carbonates, nitrates, etc.) are mixed evenly and then placed in a melting furnace (such as a platinum crucible, alumina crucible, etc.) at 1200-1400℃. After melting, smelting, clarifying, stirring and homogenizing, a homogeneous molten glass without bubbles and undissolved substances is obtained. This molten glass is then cast in a mold (pouring or casting) and annealed, or directly pressed into shape.

[0116] The present invention also provides an optical preform or optical element formed from the aforementioned optical glass using methods well known to those skilled in the art. Since the optical glass has a medium refractive index, the optical element also has a medium refractive index and can be applied to devices such as digital cameras, digital video cameras, and camera phones.

[0117] Example

[0118] 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.

[0119] To further understand the technical solution of the present invention, embodiments of the optical glass of the present invention will now be described. It should be noted that these embodiments do not limit the scope of protection of the present invention.

[0120] Examples 1-32

[0121] The optical glasses shown in Tables 1 to 5 (Examples 1 to 32) are obtained by mixing raw materials (such as silicon dioxide, calcium carbonate, calcium nitrate, aluminum hydroxide, zirconium oxide, sodium carbonate, potassium carbonate, lithium sulfate, magnesium carbonate, barium carbonate, strontium carbonate, and antimony oxide) according to the contents of each example shown in Tables 1 to 5. The mixed raw materials are placed in a platinum crucible of a melting device and melted at a temperature of 1250°C. After homogenization, the mixture is clarified at a temperature of 1360°C to allow the bubbles to rise fully. Then, the temperature of the glass melt is lowered to about 1130°C, and the glass is poured or poured through a cylindrical pipe into a forming mold. After annealing and cooling, the optical glass of the present invention is obtained.

[0122] Comparative Examples 1-2

[0123] The glass was processed according to the glass composition of Comparative Examples 1 to 2 in Table 5, referring to the processing methods of Examples 1 to 32.

[0124] Performance testing

[0125] 1. Refractive index n d Abbe number υ d

[0126] 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 -4℃.

[0127] 2. Knoop Hardness (HK)

[0128] Knoop hardness was measured according to the test method specified in ISO 9385.

[0129] 3. Transition temperature Tg and relaxation temperature Ts

[0130] The measurement shall be performed according to the method specified in GB / T7962.16.

[0131] 4. Density ρ

[0132] The density of the obtained optical glass was determined according to the test method of GB / T7962.20-2010.

[0133] 5. Colorimetric λ 80 / λ5

[0134] The short-wavelength transmission spectral characteristics of optical glass are expressed using colorimetric λ. 80 / λ5 represents this. Where λ... 80 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 "Method for Measuring the Colorimetric Index of Optical Glass" (JOGIS02-2003) of the Japan Glass Industry Association.

[0135] 6. Moisture resistance stability R C (S), acid resistance R A (S)

[0136] Under conditions of 50℃ and 85% relative humidity, the moisture resistance R of optical glass was determined based on the time required for hydrolysis spots to form on the polished glass surface. C (S) is divided into three levels, and the grading standards are detailed in Table A.

[0137] Table A

[0138]

[0139] Under the action of acetic acid solution at 0.1N (pH=2.9) and 50℃, the acid resistance R of optical glass is determined based on the time required for interference colors to appear on the polished glass surface, or for surface discoloration or peeling to occur. A (S) is divided into three levels, and the grading standards are detailed in Table B.

[0140] Table B

[0141]

[0142] 7. Water resistance stability D W

[0143] The chemical stability and water resistance of the obtained optical glass were tested according to the test method of GB / T 17129. W Run the test.

[0144] 8. Acid resistance stability D A

[0145] The acid resistance of the obtained optical glass was tested according to the test method of GB / T 17129. A Run the test.

[0146] 9. Washing resistance stability R P (S), Alkali resistance R OH (S)

[0147] 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 molars per unit area were calculated, in mg / (cm²). 2 •15h), to improve the alkali resistance stability R of optical glass OH (S) is divided into five levels, and the grading standards are detailed in Table C.

[0148] Table C

[0149]

[0150] 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 15 hours. Based on the average leached moles per unit area, the unit is mg / (cm²). 2 • 15h), the wash resistance stability R of optical glass P (S) is divided into five levels, and the grading standards are detailed in Table D.

[0151] Table D

[0152]

[0153] 10. Bubble density

[0154] The bubble content of the obtained optical glass was tested according to GB / T7962.8-2010 Test Methods for Colorless Optical Glass Part 8: Bubble Content.

[0155] 11. Anti-crystallization properties

[0156] The experimental sample was processed to a size of 20×20×10mm and polished on both sides. The sample was then placed in a crystallization furnace at a temperature of 200℃ (the sample's transformation temperature Tg) and kept at that temperature for 30 minutes. After cooling, the sample was polished on both sides again. The anti-crystallization performance of the glass was judged according to Table E below, with Grade A being the best and Grade E being the worst.

[0157] Table E: Grading and Judgment Criteria for Resistance to Crystallization

[0158]

[0159] The refractive index n of the optical glasses prepared in Examples 1-32 and Comparative Examples 1-2 d Abbe number υ d Hardness HK, transformation temperature Tg, sag temperature Ts, density ρ, and chromaticity λ 80 And λ5, water resistance stability D W Acid resistance stability D A Moisture resistance stability R C (S), acid resistance R A (S), Washability R P (S), Alkali resistance R OH (S), anti-crystallization properties, and bubble density are listed in Table 1-5.

[0160] Table 1: Glass composition and performance parameters of Examples 1-7

[0161]

[0162] Table 2: Glass composition and performance parameters of Examples 8-14

[0163]

[0164] Table 3: Glass composition and performance parameters of Examples 15-21

[0165]

[0166] Table 4: Glass composition and performance parameters of Examples 22-28

[0167]

[0168] Table 5: Glass composition and performance parameters of Examples 29-32 and Comparative Examples 1-2

[0169]

[0170] As can be seen from the above embodiments, the refractive index (n) of the optical glass of the present invention is... d The value is 1.62–1.72, and the Abbe number (υ) is... d The concentration is 30-38, and the density ρ is 3.00 g / cm³. 3 The following is the hardness (HK) of optical glass: 580 × 10⁻⁶. 7 Above Pa, water resistance stability D W Grade 1, acid resistance stability D A Grade 1, moisture resistance stability R C (S) is grade 1, acid resistance stability R A (S) is grade 1, and the washability stability R P (S) is grade 1, alkali resistance stability R OH (S) is level 1; the tinting degree λ of the optical glass 80 In / λ5, λ 80 The wavelength is below 395nm, and the λ5 is below 365nm. The optical glass has a transition temperature (Tg) below 585℃ and a sag temperature (Ts) below 545℃. Its bubble density is 0-1, making it suitable for widespread use in digital cameras, digital camcorders, and camera phones. The optical glass exhibits excellent anti-crystallization properties (grade B or higher) and devitrification resistance.

[0171] The optical glass of Comparative Example 1 has a low TiO2 content, which is not within the range required by this invention, so the required refractive index and Abbe number cannot be obtained; the optical glass of Comparative Example 2 has an excessively high Li2O content, which is not within the range required by this invention, so the glass has poor chemical stability, poor resistance to crystallization, and low hardness.

[0172] 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.

[0173] 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. An optical glass, characterized by comprising: It comprises the following components in mole percent of oxides: SiO2: 42-55.5%; TiO2: 12-20%; Na2O: 5-15%; K2O: 0.5-5%; CaO: 6-14%; SrO: 2-8%; Li2O: 2-10.5%; Al2O3: 0-5%; MgO: 0-5%; Y2O3: 0-5%; The optical glass has a refractive index of 1.62-1.72 and an Abbe number of 30-38.

2. The optical glass according to claim 1, characterized by It comprises the following components in mole percent of oxides: SiO2: 42-55.5%; TiO2: 12-20%; Na2O: 5-15%; K2O: 0.5-5%; CaO: 6-14%; SrO: 2-8%; Li2O: 2-10.5%; Al2O3: 0-5%; MgO: 0-5%; Y2O3: 0-5%; 3. Optical glass according to claim 2, characterized in that The optical glass has a refractive index of 1.62-1.72 and an Abbe number of 30-38. It comprises the following components in mole percent of oxides: SiO2: 42-55.5%; TiO2: 12-20%; Na2O: 5-15%; K2O: 0.5-5%; CaO: 6-14%; SrO: 2-8%; Li2O: 2-10.5%; Al2O3: 0-5%; MgO: 0-5%; 4. Optical glass according to any one of claims 1 to 3, characterized in that Y2O3: 0-5%; 5. Optical glass according to any one of claims 1 to 4, characterized in that The optical glass has a refractive index of 1.62-1.72 and an Abbe number of 30-38. The optical glass does not contain one or a combination of more than two of F element, P2O5, BaO, Ta2O5, Gd2O3, GeO2, TeO2, Nb2O5, ZrO2, ZnO, B2O3, As2O3 or PbO. The ratio of the mole percent content of TiO2 to that of SiO2, TiO2 / SiO2, is 0.17-0.45, preferably 0.18-0.43, and more preferably 0.20-0.41; The sum of the mole percent contents of Li2O, Na2O and K2O, ∑(Li2O+Na2O+K2O), is 30% or less, preferably 27% or less; The ratio of the sum of the mole percent contents of Li2O, Na2O and K2O to the mole percent content of SiO2, ∑(Li2O+Na2O+K2O) / SiO2, is 0.2-0.7, preferably 0.25-0.65; The ratio of the sum of the mole percent contents of Na2O and K2O to the sum of the mole percent contents of Li2O, Na2O and K2O, ∑(Na2O+K2O) / ∑(Li2O+Na2O+K2O), is 0.3-0.9, preferably 0.4-0.85, and more preferably 0.5-0.80; 6. The optical glass according to any one of claims 1 to 5, characterized by The ratio of the sum of the mole percent contents of SiO2, Li2O, Na2O and K2O to the mole percent content of TiO2, ∑(SiO2+Li2O+Na2O+K2O) / TiO2, is 3.1-5.5, preferably 3.5-5.0; The sum of the mole percent contents of MgO, CaO and SrO, ∑(MgO+CaO+SrO), is 8.5-25%, preferably 9-23%, and more preferably 10-20%. The optical glass further comprises a fining agent, and preferably the mole percent content of the fining agent is 0-0.10%, and more preferably 0-0.05%.

7. The optical glass according to any one of claims 1 to 6, characterized in that, The optical glass has a density p of 3.00 g / cm 3 The following: The optical glass has a color degree λ 80 In λ 80 395 nm or below, and λ5 is 365 nm or below. The optical glass has a hardness HK of 580 x 10 7 Pa or more.

8. The optical glass according to any one of claims 1 to 7, characterized in that, the optical glass has a bubble degree of 0 to 1 level; the optical glass has a transition temperature Tg of 545°C or lower; the optical glass has a sag temperature Ts of 585°C or lower; the optical glass has a crystallization resistance of B level or higher.

9. A method of producing an optical glass according to any one of claims 1 to 8, characterized by, comprising: the raw materials of the components of the optical glass are mixed uniformly, then melted, and then cast or poured into a molding mold and annealed, or directly pressed into shape.

10. An optical element, characterized by, the optical glass according to any one of claims 1 to 8. the optical glass according to any one of claims 1 to 8.

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