Heavy flint optical glass, method for producing the same, and optical element

Abstract

This invention provides a heavy flint optical glass, its preparation method, and an optical element thereof. Based on 100% of the total mass of the heavy flint optical glass, the glass contains the following components: P₂O₅: 20%–45%; B₂O₃: 0%–10%; Na₂O: 0%–15%; K₂O: 2%–18%; CaO: 0%–15%; SrO: 10%–30%; BaO: 1%–10%; TiO₂: 15%–25%; the refractive index n of the heavy flint optical glass is… d The Abbe number is υ, which ranges from 1.65 to 1.70. d The relative refractive index temperature coefficient of the heavy flint optical glass of the present invention is suitable, which can correct the temperature drift of the lens and improve the image quality. Therefore, it is mainly used in lens assemblies to correct temperature drift and improve image quality. At the same time, the heavy flint optical glass of the present invention has the characteristics of low tinting strength, good stability, excellent processability, and suitability for mass production.

Description

TECHNICAL FIELD

[0001] The present application relates to a heavy flint optical glass, a preparation method thereof and an optical element, in particular to an environmentally friendly heavy flint optical glass with a negative refractive index temperature coefficient, a preparation method thereof and an optical element, and belongs to the field of optical glass. BACKGROUND

[0002] With the development of the photoelectric industry, optical elements are required to be small, light, high-performance and high-definition. Temperature changes will cause a sharp decline in the imaging quality of the optical system, mainly due to changes in the parameters of the optical system caused by temperature changes, which mainly manifest as: 1) changes in the refractive index of the optical element; the refractive index of the optical element will change with temperature. 2) changes in the surface shape and center thickness of the optical element; the refractive surface of the optical element will deform due to thermal expansion and contraction when the temperature changes, and the thickness of the optical element will also change. 3) changes in the spacing between optical elements; the distance between the optical elements will change due to thermal expansion and contraction of the mechanical material between the optical elements.

[0003] In view of the influence of temperature changes on the parameters of the optical system, the negative refractive index temperature coefficient glass can be used to compensate and correct. In particular, for long focal length zoom lenses, if the temperature drift of the lens is not corrected, the small changes in the optical parameters caused by temperature changes will have a greater impact than when the focal length is short, reducing the imaging quality. Refractive index n d in 1.65-1.70, Abbe number υ d The optical glass with a negative refractive index temperature coefficient of 25-33 can be combined with the optical glass with a positive refractive index temperature coefficient to stabilize the refractive index at different temperatures, correct the temperature drift of the lens, and keep the performance of the optical system stable within a certain temperature range, thereby improving the imaging quality.

[0004] Patent application CN110316962A discloses an optical glass with a refractive index n d in 1.65-1.73, Abbe number υ d in 25-35, which contains (35-50)% SiO2, resulting in a high melting temperature and an uncertain refractive index temperature coefficient.

[0005] Patent application CN110240400A discloses an optical glass with a refractive index n d in 1.68-1.75, Abbe number υ d in 25-32, which contains (1-15)wt% Nb2O5, resulting in a high cost of glass raw materials.

[0006] Patent application CN105948482A discloses an optical glass with a refractive index nd in 1.66-1.73, Abbe number υd The optical glass and optical element with 25-35 wt% of Nb2O5 cause high cost of raw materials.

[0007] Patent application CN111183122A discloses an optical glass with a refractive index n d The relative refractive index is 1.65-1.80, and the Abbe number υ d The optical glass, optical element and optical instrument with 25-40 wt% of Nb2O5 cause high cost of raw materials. -6 The relative refractive index is 1.65-1.80, and the Abbe number υ -6 The optical glass, optical element and optical instrument with 25-40 wt% of Nb2O5 cause high cost of raw materials.

[0008] Patent application CN110234612A discloses an optical glass with a refractive index n d The relative refractive index is 1.70 or more, and the Abbe number υ d The optical glass, optical element and optical instrument with 25-40 wt% of Nb2O5 cause high cost of raw materials. -6 The relative refractive index is 1.65-1.80, and the Abbe number υ -6 The optical glass, optical element and optical instrument with 25-40 wt% of Nb2O5 cause high cost of raw materials.

[0009] Patent application CN116514393A discloses an optical glass with a refractive index n d The relative refractive index is 1.60-1.75, and the Abbe number υ d The optical glass with 2-10 wt% of Al2O3, 0-5 wt% of Nb2O5, 0-15 wt% of Ta2O5 and 0-5 wt% of Bi2O3, which increases the melting temperature of the glass and accelerates the corrosion of P2O5 to platinum gold vessels during the melting process.

[0010] Patent application CN116507594A discloses an optical glass with a refractive index n d The relative refractive index is 1.60-1.75, and the Abbe number υ dThe optical glass has a refractive index nD of 20-35, and the content of Bi2O3 is 0% or more and 30% or less, and the ratio (BaO+TiO2) / P2O5 of the total content of BaO and TiO2 to the content of P2O5 is preferably 0.40-1.50. SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] The present application aims to provide a heavy flint optical glass with a refractive index nD d of 1.65-1.70, an Abbe number υD d of 25-33, and a negative refractive index temperature coefficient, and the heavy flint optical glass can be used to manufacture optical elements.

[0013] The present application also provides a preparation method of the heavy flint optical glass.

[0014] SOLUTIONS TO PROBLEMS

[0015] The present application provides a heavy flint optical glass, which contains the following components, with the total mass of the heavy flint optical glass being 100%:

[0016] P2O5: 20%-45%, preferably 25%-35%;

[0017] B2O3: 0%-10%, preferably 0%-8%;

[0018] Na2O: 0%-15%, preferably 1%-10%;

[0019] K2O: 2%-18%, preferably 3%-17%;

[0020] CaO: 0%-15%, preferably 2%-10%;

[0021] SrO: 10%-30%, preferably 13%-25%;

[0022] BaO: 1%-10%, preferably 1.5%-9.5%;

[0023] TiO2: 15%-25%, preferably 17%-23%;

[0024] The refractive index n of the heavy flint optical glass d is 1.65 to 1.70, and the Abbe number v is d 25 to 33.

[0025] According to the heavy flint optical glass of the present application, the sum ∑(P2O5+B2O3) of the content of P2O5 and the content of B2O3 is 22% to 40%, preferably 26% to 38%; and / or,

[0026] the sum ∑(Na2O+K2O) of the content of Na2O and the content of K2O is 3% to 30%, preferably 5% to 25%; and / or,

[0027] the ratio Na2O / K2O of the content of Na2O to the content of K2O is less than 1.

[0028] According to the heavy flint optical glass of the present application, the sum ∑(CaO+SrO+BaO) of the content of CaO, the content of SrO and the content of BaO is 20% to 40%, preferably 25% to 37%; and / or,

[0029] the ratio ∑(TiO2+CaO+SrO+BaO) / ∑(P2O5+B2O3) of the sum of the content of TiO2, the content of CaO, the content of SrO and the content of BaO to the sum of the content of P2O5 and the content of B2O3 is more than 1.50.

[0030] According to the heavy flint optical glass of the present application, the heavy flint optical glass does not contain one or a combination of two or more of SiO2, Al2O3, Nb2O5, ZrO2, Bi2O3, GeO2, Ta2O5, WO3, Li2O, TeO2, La2O3, Y2O3, Gd2O3, Yb2O3.

[0031] According to the heavy flint optical glass of the present application, the ratio O / Ti of the mole percentage of oxygen atoms to the mole percentage of titanium atoms is 5.0 to 12.0, preferably 7.0 to 10.0, in terms of mole percentage of elements.

[0032] According to the heavy flint optical glass of the present application, the ratio O / P of the mole percentage of oxygen atoms to the mole percentage of phosphorus atoms is 3.0 to 7.0, preferably 4.3 to 6.5, in terms of mole percentage of elements.

[0033] According to the heavy flint optical glass of the present application, the ratio P / Ti of the mole percentage of phosphorus atoms to the mole percentage of titanium atoms is 1.0 to 3.0, preferably 1.5 to 2.5, in terms of mole percentage of elements.

[0034] The heavy flint optical glass according to the present application, wherein the temperature coefficient of the relative refractive index of the heavy flint optical glass at the d line is -5.3x10 -6 / ℃ to -3.3x10 -6 / ℃ at 0-20℃.

[0035] The present application also provides a preparation method of the heavy flint optical glass according to the present application, which comprises: weighing and mixing the component raw materials according to the proportion, then melting, and then pouring or pouring into a forming mold for forming, or directly pressing into a shape, or precisely molding.

[0036] The present application further provides an optical element comprising the optical glass according to the present application.

[0037] Effects of the present application

[0038] The heavy flint optical glass according to the present application has a suitable temperature coefficient of the relative refractive index, can correct the temperature drift of a lens, and improve the imaging quality, and is mainly used in a lens group to correct the temperature drift and improve the imaging quality; meanwhile, the heavy flint optical glass according to the present application has a small color degree, good stability, excellent process performance, and can be suitable for batch production.

[0039] The preparation method of the heavy flint optical glass according to the present application is simple and easy to implement, the raw materials are easy to obtain, and the heavy flint optical glass has a low liquidus temperature and good process performance. DETAILED DESCRIPTION

[0040] 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.

[0041] In addition, in order to better illustrate the present application, numerous specific details are given in the following detailed description. Those skilled in the art will understand that the present application can be implemented without certain specific details. In some other examples, methods, means, apparatuses and steps that are well known to those skilled in the art are not described in detail in order to highlight the main idea of the present application.

[0042] Unless otherwise stated, the units used in the present specification are international standard units, and the numerical values and numerical value ranges appearing in the present application should be understood to include systematic errors that are inevitable in industrial production.

[0043] In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0044] 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.

[0045] 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.

[0046] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0047] This invention provides a heavy flint optical glass, which, based on 100% of its total mass, contains the following components:

[0048] P2O5: 20%–45%, preferably 25%–35%;

[0049] B2O3: 0%–10%, preferably 0%–8%;

[0050] Na2O: 0%–15%, preferably 1%–10%;

[0051] K2O: 2%–18%, preferably 3%–17%;

[0052] CaO: 0%–15%, preferably 2%–10%;

[0053] SrO: 10%–30%, preferably 13%–25%;

[0054] BaO: 1%–10%, preferably 1.5%–9.5%;

[0055] TiO2: 15%–25%, preferably 17%–23%;

[0056] The refractive index n of the heavy flint optical glass d The Abbe number is υ, which is between 1.65 and 1.70. d It is 25-33.

[0057] The heavy flint optical glass of the present invention with a negative refractive index temperature coefficient is selected for each component in the above-mentioned amounts for the reasons described below. In the following description, the range of the content of each component is based on 100% of the total mass of the heavy flint optical glass.

[0058] P2O5 is the main component of the network structure of heavy flint optical glass, and is a necessary component for maintaining the stability of heavy flint optical glass. It can improve the chemical stability and viscosity of the glass, so that the glass forming is easy to control. When the content of P2O5 is less than 20%, the glass will have a sharp decrease in the ability to dissolve alkaline earth metal, which is not conducive to the reduction of the refractive index temperature coefficient, and the heavy flint optical glass with negative refractive index temperature coefficient has poor crystallization performance, which is not conducive to industrial production. In addition, when the content of P2O5 exceeds 45%, it is difficult to obtain the target value of the refractive index n d Therefore, the content of P2O5 is limited to 20% to 45%, preferably 25% to 35%, more preferably 26% to 33%, and particularly preferably 27% to 32%.

[0059] B2O3 is also a glass former, and a small amount of addition can help improve the melting performance and homogenization of the glass, and can also improve the weather resistance of the glass. However, when the content of B2O3 exceeds 10%, it will affect the melting amount of TiO2, so that the optical constants of the present application cannot be achieved. Therefore, the content of B2O3 component is limited to 0% to 10%, preferably 0% to 8%, and more preferably 0% to 5%.

[0060] The present inventors have found through a large number of experiments that in the heavy flint optical glass of the present application, the sum of the content of P2O5 and the content of B2O3, ∑(P2O5+B2O3), has an effect on the formation characteristics of the glass. If the content of ∑(P2O5+B2O3) is too high, the optical constants of the present application cannot be achieved; if the content of ∑(P2O5+B2O3) is too low, the chemical stability of the glass will be affected. Therefore, the sum of the content of P2O5 and the content of B2O3, ∑(P2O5+B2O3), is 22% to 40%, preferably 26% to 38%, and more preferably 28% to 32%.

[0061] CaO is used to adjust the refractive index and Abbe number of heavy flint optical glass, which is conducive to adjusting the refractive index temperature coefficient to the negative direction, and its appropriate amount can ensure the optical performance. At the same time, CaO can improve the resistance to devitrification, light transmission, chemical stability and mechanical properties of the glass. CaO can also improve the chemical stability, thermal stability of heavy flint optical glass and reduce its density, and has a fluxing effect. However, when the content of CaO is higher than 15%, the devitrification tendency of the glass increases. Therefore, the content of CaO is 0% to 15%, preferably 2% to 10%, and more preferably 2% to 5%.

[0062] SrO has the effect of adjusting optical constant, which is beneficial to adjust the refractive index temperature coefficient to the negative direction, and its appropriate existence can not only ensure the optical performance, but also improve the glass resistance to devitrification, light transmittance, chemical stability and mechanical properties. When the content of SrO exceeds 30%, the density of the glass will increase. When the content of SrO is less than 10%, the effect of negative refractive index temperature coefficient cannot be achieved. Therefore, the content of SrO in the application is 10% to 30%, preferably 13% to 25%, and more preferably 15% to 20%.

[0063] BaO is a component for adjusting various properties of heavy flint optical glass, and BaO has the effect of enhancing the weather resistance of heavy flint optical glass. When the content of BaO exceeds 10%, the liquidus temperature of the optical glass will increase, the weather resistance will deteriorate, and the density will increase. When the content of BaO is less than 1%, the relative partial dispersion Pg, F value of the application cannot be achieved. Therefore, the content of BaO is limited to 1% to 10%, preferably 1.5% to 9.5%, more preferably 2% to 9%, and particularly preferably 3% to 8%.

[0064] CaO, SrO and BaO are beneficial to reduce the refractive index temperature coefficient of the glass, but in the application they belong to macromolecular oxides, which are not conducive to the reduction of the density of the glass. Due to the mixed alkali earth metal effect, the coexistence of CaO, SrO and BaO can significantly improve the crystallization performance and chemical stability of the glass. In the application, if the sum of the content of CaO, the content of SrO and the content of BaO ∑(CaO+SrO+BaO) is too low, the refractive index temperature coefficient cannot meet the specified range; if the sum of the content of CaO, the content of SrO and the content of BaO ∑(CaO+SrO+BaO) is too high, the density of the heavy flint optical glass will be higher than 3.10 g / cm 3 . Therefore, ∑(CaO+SrO+BaO) is controlled to be 20% to 40%, preferably 25% to 37%, and more preferably 27% to 35%.

[0065] Alkali metal oxide Na2O can improve the melting performance of the glass, has the effect of reducing the transition temperature of heavy flint optical glass, and is an effective component for reducing the refractive index temperature coefficient of the glass. When the content of Na2O exceeds 15%, the chemical stability of the glass will deteriorate. Therefore, the content of Na2O is limited to 0% to 15%, preferably 1% to 10%, more preferably 2% to 9%, and particularly preferably 3% to 8%.

[0066] The alkali metal oxide K2O can improve the melting performance of the glass, has the effect of reducing the transition temperature of the heavy flint optical glass and improving the crystallization performance of the glass, and is an effective component for reducing the temperature coefficient of the refractive index of the glass. When the content of K2O exceeds 18%, the chemical stability of the glass becomes poor. When the content of K2O is lower than 2%, the crystallization performance of the glass deteriorates, which is not conducive to the production of the glass. Therefore, the content of K2O is limited to 2% to 18%, preferably 3% to 17%, more preferably 5% to 15%, and particularly preferably 13.2% to 14.9%.

[0067] Although Na2O and K2O are beneficial to reducing the transition temperature of the heavy flint optical glass and improving the melting performance of the glass, a large amount of introduction of Na2O and K2O will reduce the chemical stability of the glass. Due to the mixed alkali effect, the coexistence of Na2O and K2O can significantly improve the crystallization performance and chemical stability of the glass. When the total content of Na2O and K2O is too high, it is difficult to obtain the required optical constants, and the stability of the glass will also deteriorate. When the total content of Na2O and K2O is too low, the refractive index temperature coefficient of the heavy flint optical glass of the present application cannot be achieved. Therefore, the sum of the contents of Na2O and K2O ∑(Na2O+K2O) is 3% to 30%, preferably 5% to 25%, particularly preferably 8% to 24%, and further preferably 15% to 23%.

[0068] It is found through a large number of experiments that in the heavy flint optical glass of the present application, the ratio of the content of Na2O to the content of K2O Na2O / K2O is less than 1, for example, 0 to 0.99. When Na2O / K2O is less than 1, it is beneficial to the improvement of the chemical stability of the glass.

[0069] TiO2 is a necessary component for obtaining the heavy flint optical glass of the present application, and within a suitable range, it helps to improve the crystallization performance of the glass. If the content of TiO2 is lower than 15%, it is difficult to obtain the required optical constants; if the content of TiO2 exceeds 25%, the crystallization performance of the glass deteriorates, and the glass is colored and darkened. Therefore, in the present application, the content of TiO2 is 15% to 25%, preferably 17% to 23%, particularly preferably 19% to 22%, and further preferably 20% to 21.5%.

[0070] In the present application, the ratio of the sum of the content of TiO2, the content of CaO, the content of SrO and the content of BaO to the sum of the content of P2O5 and the content of B2O3 ∑(TiO2+CaO+SrO+BaO) / ∑(P2O5+B2O3) is greater than 1.50, for example, 1.501 to 3. When ∑(TiO2+CaO+SrO+BaO) / ∑(P2O5+B2O3) is too low, the optical constants of the heavy flint optical glass are not within the scope of the present application.

[0071] Through extensive experiments, this invention has discovered that the molar percentage ratios of oxygen atoms to titanium atoms (O / Ti), oxygen atoms to phosphorus atoms (O / P), and phosphorus atoms to titanium atoms (P / Ti) have a significant impact on the external transmittance and temperature coefficient of refractive index of glass.

[0072] The negative refractive index temperature coefficient heavy flint glass of this invention belongs to the phosphate glass system and contains variable valence titanium ions. The polymer formed by the arrangement of [PO4] tetrahedral units is generally denoted by Qn, where n is the number of bridging oxygen (POP) in the tetrahedron. Different network structures are formed with varying Ti content, causing Qn to change and thus affecting the glass's external transmittance and refractive index temperature coefficient. Therefore, in this invention, based on elemental molar percentages, O / Ti is 5.0–12.0, preferably 7.0–10.0; O / P is 3.0–7.0, preferably 4.3–6.5; and P / Ti is 1.0–3.0, preferably 1.5–2.5.

[0073] Sb₂O₃ can be added arbitrarily as a defoaming agent, but its content of 0.5% or less is sufficient. If the content of Sb₂O₃ exceeds 0.5%, the tinting strength will become very high, and the Abbe number of the heavy flint optical glass will decrease. In this invention, the absence of Sb₂O₃ is advantageous for improving the transmittance of the heavy flint optical glass. Therefore, the content of Sb₂O₃ is limited to 0 to 0.5%, preferably 0 to 0.1%, and more preferably none.

[0074] At 0–20°C, the relative refractive index temperature coefficient of the heavy flint optical glass at the d-line (589.29 nm) is -5.3 × 10⁻⁶. -6 / ℃~-3.3×10 -6 / ℃.

[0075] At 20°C, the relative partial dispersion Pg,F of the heavy flint optical glass is 0.5500 to 0.6500.

[0076] When the external transmittance of heavy flint optical glass is 80%, the wavelength λ 80 The wavelength λ5 is below 420nm, and when the external transmittance is 5%, the wavelength λ5 is below 380nm. The density of the heavy flint optical glass is less than 3.10g / cm³. 3 The transition temperature of the heavy flint optical glass is below 520°C, the sag temperature is below 580°C, and the liquidus temperature is below 900°C.

[0077] The water resistance stability D of the heavy flint optical glass W (Powder method), stability against humid atmosphere R C(S) (surface method), alkali resistance stability R OH (S) (surface method) are both 2 or above (e.g. 1 or 2) ; acid resistance stability D A (powder method) and acid resistance stability R A (S) (surface method) is not less than 3 (e.g. 1, 2 or 3) ; washing resistance stability R P (S) is 1. The number of Pt-containing foreign matters in the heavy flint optical glass is less than 1 / 100 cm 3 .

[0078] Further, the negative refractive index temperature coefficient heavy flint optical glass of the present application preferably does not contain TeO2 component which easily causes volatile streaks, avoids the generation of volatile streaks; preferably does not introduce expensive Nb2O5, GeO2, Ta2O5, Gd2O3, WO3 and other components; preferably does not contain rare earth oxides La2O3, Y2O3 and other components which increase the density of the glass.

[0079] In addition, in order to better achieve the purpose of the present application, the present application preferably does not contain Li2O component which has an erosive effect on the smelting device and can destroy the glass network structure and make the glass crystallization performance worse, and Yb2O3 which has an absorption peak in the violet light band. Bi2O3 is not only expensive, but also increases the smelting difficulty of the glass due to the reaction of Bi2O3 with Pt at 1200-1250℃, which is not conducive to smelting high-quality glass. Therefore, Bi2O3 is preferably not contained. In addition, Al2O3 also increases the smelting difficulty of the glass, so Al2O3 is also preferably not contained. ZrO2 easily leads to glass crystallization and is not easy to produce stably, so ZrO2 is preferably not contained.

[0080] The heavy flint optical glass of the present application also preferably does not artificially introduce SiO2. The introduction of SiO2 leads to an increase in melting temperature, accelerates the volatilization of alkali metal oxides during glass melting, and is not conducive to the stability of the optical performance of the product. At the same time, the introduction of SiO2 is not conducive to the manufacture of glass blanks that meet the inclusion level requirements in GB903-2019 standard, due to the poor mutual solubility of silicates and phosphates.

[0081] Based on the above reasons, the heavy flint optical glass of the present application preferably does not contain one or a combination of two or more of SiO2, Al2O3, Nb2O5, ZrO2, Bi2O3, GeO2, Ta2O5, WO3, Li2O, TeO2, La2O3, Y2O3, Gd2O3, Yb2O3 and the like.

[0082] In addition, in order to ensure the external transmittance of the heavy flint optical glass, the heavy flint optical glass with negative refractive index temperature coefficient provided by the present application does not artificially introduce other colorable elements other than the above components: V, Mo, Cr, Mn, Fe, Co, Ni, Cu and Ag. Meanwhile, it also does not artificially introduce compounds containing the following harmful elements: Th, Cd, Tl, Os, Be, Se, Pb, As, Hg and fluoride.

[0083] The present application also provides a preparation method of the heavy flint optical glass with negative refractive index temperature coefficient according to the present application, comprising: weighing and mixing the components in proportion, then melting, and then pouring or pouring into a forming mold, or directly pressing into shape.

[0084] Further, in the present application, the preparation method comprises the following steps:

[0085] The raw materials of the components of the heavy flint optical glass are added into a platinum container for melting, preferably at a temperature of 1150-1200°C, to obtain a glass liquid; then the temperature of the glass liquid is raised and the glass liquid is stirred and homogenized, preferably the temperature of the glass liquid is raised to 1250-1300°C, to obtain a homogenized liquid; and then the temperature of the homogenized liquid is lowered, preferably to 1000-1050°C, to form a block.

[0086] Since P2O5 has strong water absorption, it is easy to absorb moisture during storage and batching, causing inaccuracy in weighing. Meanwhile, during the mixing process of P2O5 raw materials with other raw materials, large heat flow is generated, which requires a high mixing container and is easy to damage the mixing container, and increases volatilization during melting. Direct contact of P2O5 with platinum crucible will make the platinum brittle, affect the service life of platinum, increase the content of metal ions in the glass product, and the scattering of ions will affect the quality of the imaging system.

[0087] The glass raw materials of the present application can be introduced by replacing the content of BaO, CaO, TiO2 and P2O5 with metaphosphate or pyrophosphate as the component of the glass raw materials, and it is preferred to combine TiO2 and P2O5 into titanium pyrophosphate. K2O, Na2O and SrO can be introduced by carbonates or other available salts. B2O3 can be introduced in the form of boric acid.

[0088] Examples

[0089] The embodiments of the present application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0090] The raw materials of BaO, CaO, K2O, Na2O, B2O3, SrO, TiO2 and P2O5 in each group of Examples 1-63 in Table 1-9 were selected from barium metaphosphate, calcium metaphosphate, titanium pyrophosphate, potassium carbonate, sodium carbonate, strontium carbonate, boric acid and TiO2, etc. with purity greater than 99% used in heavy flint optical glass. The raw materials were weighed and mixed uniformly to form a batch, and the batch was put into a platinum crucible to be melted into a glass liquid at a temperature of 1150-1200℃, and then the temperature was raised to 1250-1300℃ to homogenize and remove bubbles, and then the temperature was lowered to 1000-1050℃ to adjust the viscosity of the glass liquid. After about 5 hours, the glass liquid was poured into a mold and slowly cooled to obtain the glass samples. Then the glass samples were processed into heavy flint optical glass samples with negative refractive index temperature coefficient.

[0091] In Table 1-9, O / Ti, O / P and P / Ti are all molar percentage ratios.

[0092] Performance tests

[0093] 1. Refractive index n d , Abbe number υ d and relative partial dispersion Pg,F

[0094] The heavy flint optical glass obtained was tested according to the test method of GB / T 7962.1-2010 to determine the refractive indexes n d , n F , n C and n g of d (helium lamp, wavelength 587.56 nm), F (hydrogen lamp, wavelength 486.13 nm), C (hydrogen lamp, wavelength 656.27 nm) and g (mercury lamp, wavelength 435.84 nm). Then the Abbe number υ d and the relative partial dispersion Pg,F were calculated.

[0095] The Abbe number υ d was calculated using the formula .

[0096] The relative partial dispersion Pg,F was calculated using the formula

[0097] Wherein, n d , υ d and Pg,F are data after annealing at -4℃.

[0098] 2. Relative refractive index temperature coefficient

[0099] The relative refractive index temperature coefficient (dn / dt) of the glass of the embodiment was measured according to the minimum deviation angle method in the method described in national standard GB7962.04-2010 "Test methods for colorless optical glass Part 4: Refractive index temperature coefficient", the value of the temperature coefficient of the relative refractive index was measured at a wavelength of 589.29 nm (d line) when the temperature was changed from 0°C to 20°C.

[0100] 3. Transition temperature (Tg) and sag temperature (Ts) of heavy flint optical glass

[0101] The transition temperature (Tg) and sag temperature (Ts) of heavy flint optical glass were tested by using a TMA tester of PE Company, USA.

[0102] 4. Density (p) of heavy flint optical glass

[0103] The measurement was carried out according to the method specified in GB / T7962.20-87.

[0104] 5. λ 80 λ5

[0105] A glass sample with a thickness of 10±0.1 mm and mutually parallel planes that were optically polished was prepared, and a light beam with an intensity of Iin was shot into the glass sample from a direction perpendicular to the above-mentioned planes, the intensity of the transmitted light beam Iout was measured, and the intensity ratio Iout / Iin was referred to as the external transmittance of the glass.

[0106] In the range of wavelengths from 200 to 700 nm, the wavelength corresponding to the external transmittance of 80% was referred to as λ80. 80 The wavelength corresponding to the external transmittance of 5% was referred to as λ5.

[0107] 6. Water action resistance stability D W (powder method)

[0108] 10 g±0.0001 g of powdered glass with a particle size of 425-560 μm (passed through a 40-32 mesh sieve) was loaded into a filter, and was immersed in a quartz glass flask containing 80 mL of distilled water (pH=6.5-7.5) in a water bath at 98-100°C for 60 minutes, and the glass particles were all transferred to the filter with constant weight, and were washed with 80 mL of anhydrous ethanol, and were dried at 120±5°C until constant weight. According to the formula: the glass leaching percentage was calculated. In the formula: D W — glass leaching percentage (%); B — mass of the filter and sample (unit: g); C — mass of the filter and sample after erosion (unit: g); A — mass of the filter (unit: g). According to the mass leaching percentage, the water action resistance stability D W Grading was carried out according to the following table A.

[0109] Table A

[0110]

[0111] 7. Acid resistance stability D A (Powder method)

[0112] With D W The determination method is similar; a 0.01 mol / L nitric acid aqueous solution is added to the flask for treatment, according to the formula: Calculate the glass leaching percentage. Where: D A — Percentage of glass leaching (%); B— Mass of filter and sample (in g); C— Mass of filter and etched sample (in g); A— Mass of filter (in g).

[0113] Based on the percentage of leaching by mass, the acid resistance stability (DA) of heavy flint optical glass is classified according to Table B below.

[0114] Table B

[0115]

[0116] 8. Stability against humid atmospheres (R) C (S)(Surface Method)

[0117] Under conditions of 50℃ and 85% relative humidity, the stability of heavy flint optical glass against humid atmospheres is divided into three levels based on the time required for hydrolysis spots to form on the glass polished surface, as shown in Table C below.

[0118] Table C

[0119]

[0120] 9. Stability against acid (R) A (S)(Surface Method)

[0121] Under the action of acetic acid solution at 0.1N (pH=2.9) and 50℃, the acid resistance stability of heavy flint optical glass is divided into three levels according to the time required for interference colors to appear on the polished glass surface, or for the surface to show discoloration or peeling, as shown in Table D below.

[0122] Table D

[0123]

[0124] 10. Alkali resistance stability R OH (S)(Surface Method)

[0125] A six-surface-polished sample having a size of 40 mm x 40 mm x 5 mm was immersed in a 0.01 mol / 1 aqueous sodium hydroxide solution which was constantly stirred and had a temperature of 50°C ± 3°C for 15 hours. The alkali resistance R 2 (S) of the dense-flint optical glass was classified into five grades in accordance with the average value of the leached mass per unit area, in mg / (cm OH (S), as shown in Table E below.

[0126] Table E

[0127]

[0128] 11. The washing resistance R P (S) (surface method)

[0129] A six-surface-polished sample having a size of 35 mm x 35 mm x 8 mm was immersed in a 0.01 mol / 1 aqueous Na5P3O 10 solution which was constantly stirred and had a temperature of 50°C ± 3°C for 1 hour. The washing resistance R 2 (S) of the dense-flint optical glass was classified into five grades in accordance with the average value of the leached mass per unit area, in mg / (cm P h), as shown in Table F below.

[0130] Table F

[0131]

[0132] 12. The liquidus temperature Lt of the dense-flint optical glass

[0133] The GM-N16P gradient furnace manufactured by Honma Corporation, Japan was used to measure the liquidus temperature Lt.

[0134] 13. The number of Pt-containing foreign matters (pieces / 100 cm 3 )

[0135] A glass sample having a size of 300 mm x 160 mm x 15 mm was used to confirm the Pt-containing foreign matters, and the Pt-containing foreign matters were converted into the number of Pt-containing foreign matters per 100 cubic centimeters. Specifically, the number of Pt-containing foreign matters was confirmed under a 200-fold polarizing microscope, and the number of Pt-containing foreign matters per 100 cubic centimeters was calculated by dividing the number of Pt-containing foreign matters by the volume of the glass sample.

[0136] The refractive index n d and Abbe number υ d, relative partial dispersion Pg,F, relative refractive index temperature coefficient dn / dt at 0-20°C wavelength of 589.29 nm (d line), transition temperature Tg, sag temperature Ts, liquidus temperature Lt, density p, wavelength λ at which external transmittance reaches 80% 80 , wavelength λ5 at which external transmittance reaches 5%, water resistance stability D W , acid resistance stability D A , humidity atmosphere resistance stability R C , acid resistance stability R A , alkali resistance stability R OH , washing resistance stability R P , washing resistance stability R and Pt foreign substance number in glass, are listed in Tables 1-9.

[0137] Table 1: Examples 1-7

[0138]

[0139] Table 2: Examples 8-14

[0140]

[0141] Table 3: Examples 15-21

[0142]

[0143] Table 4: Examples 22-28

[0144]

[0145] Table 5: Examples 29-35

[0146]

[0147] Table 6: Examples 36-42

[0148]

[0149] Table 7: Examples 43-49

[0150]

[0151] Table 8: Examples 50-56

[0152]

[0153] Table 9: Examples 57-63

[0154]

[0155] As can be seen from Tables 1-9, the heavy flint optical glasses of Examples 1-63 of the present application not only have the refractive index (n d ) and Abbe number (υ d ) in the required range, but also have the d-line relative refractive index temperature coefficient in the range of (0-20) °C of -5.3 x 10 -6 / °C to -3.3 x 10 -6 / °C. The heavy flint optical glass of the present application has the wavelength λ 80 of 420 nm or less when the external transmittance is 80%, and the wavelength of 380 nm or less when the external transmittance is 5%; the density is not higher than 3.10 g / cm 3 , and the glass liquidus temperature is not higher than 900 °C, and has low liquidus temperature, good processability and good chemical stability. In addition, the heavy flint optical glass of the present application has the Pt foreign matter content of less than 1 per 100 cm 3 , and is suitable for mass production.

[0156] It should be noted that although the technical solutions of the present application are described with specific examples, those skilled in the art can understand that the present application should not be limited thereto.

[0157] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical application or improvement of technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A heavy flint optical glass, characterized by, comprises, based on the total mass of the heavy flint optical glass being 100%: P2O5: 20% to 37.9%; B2O3: 0% to 10%; Na2O: 0% to 9.9%; K2O: 2% to 18%; CaO: 0% to 15%; SrO: 10% to 30%; BaO: 1% to 10%; TiO2: 15% to 25%; the heavy flint optical glass does not contain Al2O3 and Nb2O5; the ratio of the mole percentage of oxygen atoms to the mole percentage of titanium atoms, O / Ti, is 5.0 to 12.0, the ratio of the mole percentage of oxygen atoms to the mole percentage of phosphorus atoms, O / P, is 3.0 to 7.0, and the ratio of the mole percentage of phosphorus atoms to the mole percentage of titanium atoms, P / Ti, is 1.0 to 3.0, based on the mole percentage of elements; The refractive index n of the heavy flint optical glass d The Abbe number is υ, which is between 1.65 and 1.

70. d It is 25-33.

2. Heavy flint optical glass according to claim 1, characterized in that comprises, based on the total mass of the heavy flint optical glass being 100%: P2O5: 25% to 35%; B2O3: 0% to 8%; Na2O: 1% to 9.9%; K2O: 3% to 17%; CaO: 2% to 10%; SrO: 13% to 25%; BaO: 1.5% to 9.5%; TiO2: 17% to 23%.

3. Optical flint glass according to claim 1 or 2, characterized in that the sum of the content of P2O5 and the content of B2O3, ∑(P2O5+B2O3), is 22% to 40%; and / or, the sum of the content of Na2O and the content of K2O, ∑(Na2O+K2O), is 3% to 30%; and / or, the ratio of the content of Na2O to the content of K2O, Na2O / K2O, is less than 1.

4. Optical flint glass according to claim 3, characterized in that the sum of the content of P2O5 and the content of B2O3, ∑(P2O5+B2O3), is 26% to 38%; and / or, the sum of the content of Na2O and the content of K2O, ∑(Na2O+K2O), is 5% to 25%.

5. Optical flint glass according to claim 1 or 2, characterized in that the sum of the content of CaO, the content of SrO, and the content of BaO, ∑(CaO+SrO+BaO), is 20% to 40%; and / or, the ratio of the sum of the content of TiO2, the content of CaO, the content of SrO, and the content of BaO, ∑(TiO2+CaO+SrO+BaO), to the sum of the content of P2O5 and the content of B2O3, ∑(P2O5+B2O3), ∑(TiO2+CaO+SrO+BaO) / ∑(P2O5+B2O3), is greater than 1.

50.

6. Heavy flint optical glass according to claim 5, characterized in that the sum of the content of CaO, the content of SrO, and the content of BaO, ∑(CaO+SrO+BaO), is 25% to 37%.

7. Optical flint glass according to claim 1 or 2, characterized in that the heavy flint optical glass does not contain one or a combination of two or more of SiO2, ZrO2, Bi2O3, GeO2, Ta2O5, WO3, Li2O, TeO2, La2O3, Y2O3, Gd2O3, and Yb2O3.

8. Optical flint glass according to claim 1 or 2, characterized in that the ratio of the mole percentage of oxygen atoms to the mole percentage of titanium atoms, O / Ti, is 7.0 to 10.0, based on the mole percentage of elements.

9. Optical flint glass according to claim 1 or 2, characterized in that the ratio of the mole percentage of oxygen atoms to the mole percentage of phosphorus atoms, O / P, is 4.3 to 6.5, based on the mole percentage of elements.

10. Optical flint glass according to claim 1 or 2, characterized in that the ratio of the mole percentage of phosphorus atoms to the mole percentage of titanium atoms, P / Ti, is 1.5 to 2.5, based on the mole percentage of elements.

11. Optical flint glass according to claim 1 or 2, characterized in that The d-line relative refractive index temperature coefficient of the heavy flint optical glass is -5.3 x 10 -6 / ℃ to -3.3 x 10 -6 / ℃ at 0-20℃.

12. A method of producing a heavy flint optical glass according to any one of claims 1 to 11, characterized in that, comprises: The components are weighed according to the proportion, mixed uniformly, then smelted, and then poured or poured into a forming mold for forming, or directly pressed into a forming mold, or formed by precision molding.

13. An optical element, characterized by, An optical glass according to any one of claims 1 to 11.

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