Heavy lanthanum flint glass, its preform, optical element, and optical device

Abstract

To provide a heavy lanthanum flint glass having high transmittance and imaging quality, an excellent temperature coefficient of refractive index, and a low upper limit of crystallization temperature.SOLUTION: There are provided a heavy lanthanum flint glass, a preform thereof, an optical element and an optical instrument. The heavy lanthanum flint glass comprises, by weight%,: SiO2: 12-28%; Ln2O3: 10-25%, the Ln2O3 being the total content of La2O3, Gd2O3, Y2O3 and Yb2O3; TiO2+Nb2O5+WO3+Bi2O3: 10.5-40%; B2O3: 0-10%; RO: 20-35%, the RO being one or more from among BaO, CaO, MgO and SrO; and ZrO2: 0.5-10%, wherein (SiO2+TiO2 / (B2O3+Nb2O5) is 1-30. The glass has a refractive index (nd) of 1.86-1.92 and an Abbe number (vd) of 25-30.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention belongs to the technical field of optical glass, and in particular to heavy lanthanum flint glass, its preform, optical element, and optical instrument. [Background technology]

[0002] Heavy lanthanum flint glasses with refractive indices (nd) of 1.86 to 1.92 and Abbe numbers (vd) of 25 to 30 are widely used in lenses for precision optical instruments. These heavy lanthanum flint glasses can meet the requirements of modern precision compression molding technology, but existing heavy lanthanum flint glasses have a high refractive index temperature coefficient.

[0003] The refractive index of optical glass is a function of temperature, i.e., the change in refractive index per unit temperature, i.e., the refractive index temperature coefficient of the glass. It is an important performance parameter for measuring the effect of temperature on the refractive index of optical glass. As the temperature increases, the glass expands thermally, decreasing its density and refractive index.

[0004] In optical equipment used in the medical, night photography, and integrated circuit photoetching technologies, the ambient temperature of optical lenses increases over time, significantly changing the refractive index of the glass, significantly reducing the imaging quality and affecting system resolution. Thermal aberration correction technology is typically required for the design. For example, the lithography lens of a photoetching machine is constructed using a combination of a movable lens and a thermal aberration correction element. However, these high technical thresholds are only understood by a small number of manufacturers worldwide, significantly limiting the application and adoption of related technologies, shaping market competition, and negatively impacting the high cost of precision equipment.

[0005] Furthermore, the high upper limit of the crystallization temperature, the low stability during high-temperature treatment, and the significant difficulty of heat treatment techniques limit the range of use of these existing heavy lanthanum flint glasses.

[0006] Moreover, the existing heavy lanthanum flint glass with high density and high coloring cannot meet people's demands for lighter and smaller instruments and devices with higher transmittance.

[0007] Therefore, there is a need to develop heavy lanthanum flint glasses that have high transmittance and imaging quality, excellent temperature coefficient of refractive index, and low upper limit of crystallization temperature. Summary of the Invention

[0008] Regarding the problems of the prior art, the present invention aims to provide a heavy lanthanum flint glass having a refractive index (nd) of 1.86 to 1.92 and an Abbe number (vd) of 25 to 30, which can meet the optical performance required for precision instruments, has excellent crystallization resistance and a low refractive index temperature coefficient, and can effectively reduce thermal aberration caused by temperature differences.

[0009] The present invention further provides preforms, optical elements, and optical instruments made from heavy lanthanum flint glass.

[0010] In order to achieve the above objectives, the technical solutions of the present invention are as follows:

[0011] Heavy lanthanum flint glass contains, by weight, 12-30% SiO2, 10-25% Ln2O3, where the Ln2O3 is a total content of La2O3, Gd2O3, Y2O3, and Yb2O3, 10.5-40% TiO2+Nb2O5+WO3+Bi2O3, 0-10% B2O3, 20-35% RO, where the RO is one or more of BaO, CaO, MgO, and SrO, and 0.5-10% ZrO2, and (SiO2+TiO2) / (B2O3+Nb2O5) is 1-30.

[0012] Furthermore, the heavy lanthanum flint glass contains, by weight, 0 to 8% Rn2O, the Rn2O being one or more of Li2O, Na2O, and K2O, 0 to 1% Sb2O3, 0 to 7% ZnO, 0 to 10% Ta2O5, and 0 to 10% Al2O3.

[0013] The heavy lanthanum flint glass is composed of, by weight, 12 to 30% SiO2, 10 to 25% Ln2O3, the Ln2O3 being a total content of La2O3, Gd2O3, Y2O3, and Yb2O3, 10.5 to 40% TiO2 + Nb2O5 + WO3 + Bi2O3, and 20 to 35% RO, the RO being one or more of BaO, CaO, MgO, and SrO. and contains 0.5-10% ZrO2, 0-10% B2O3, 0-8% Rn2O, the Rn2O being one or more of Li2O, Na2O, and K2O, 0-1% Sb2O3, 0-7% ZnO, 0-10% Ta2O5, and 0-10% Al2O3, and (SiO2+TiO2) / (B2O3+Nb2O5) is 1-30.

[0014] Furthermore, the heavy lanthanum flint glass satisfies one or more of the following four conditions in terms of the content of all components. 1) B2O3 / TiO2 is greater than 0 but less than or equal to 1; 2) BaO / B2O3 is greater than 0 but less than or equal to 70; 3) (La2O3 + TiO2 + ZrO2) / SiO2 is 0.7 to 6, 4) (SiO2+La2O3+ZrO2) / TiO2 is 0.75~6.5.

[0015] Furthermore, according to the heavy lanthanum flint glass, the SiO2 is 15 to 25%, and / or the Ln2O3 is 12 to 22%, and / or the TiO2 + Nb2O5 + WO3 + Bi2O3 is 17 to 33%, and / or the RO is 22 to 32%, and / or the ZrO2 is 2 to 8%, and / or the B2O3 is 0.5 to 6%, and / or the Rn2O is 0.5 to 6%, and / or the Sb2O3 is 0 to 0.5%, and / or the ZnO is 0 to 5%, and / or the Ta2O5 is 0 to 5%, and / or the Al2O3 is 0 to 5%.

[0016] Furthermore, the heavy lanthanum flint glass has a total content of all components that satisfies one or more of the following five conditions: 1) B2O3 / TiO2 is 0.02 to 0.4, 2) BaO / B2O3 is 3.6 to 64; 3) (La2O3 + TiO2 + ZrO2) / SiO2 is 1.2 to 5, 4) (SiO2 + La2O3 + ZrO2) / TiO2 is 1.1 to 3.7, 5) (SiO2+TiO2) / (B2O3+Nb2O5) is 2.15~20.

[0017] Furthermore, the contents of all components of the heavy lanthanum flint glass satisfy one or two of the following two conditions. 6) SiO2 + TiO2 is 30-50%; 7) B2O3 / SiO2 is 0.02 to 0.4.

[0018] Furthermore, according to the heavy lanthanum flint glass, the SiO2 is 18 to 23%, and / or the Ln2O3 is 13 to 18%, and / or the TiO2+Nb2O5+WO3+Bi2O3 is 22 to 31%, and / or the RO is 23 to 30%, and / or the ZrO2 is 2 to 6%, and / or the B2O3 is 1 to 4%, and / or the Rn2O is 1 to 5%, and / or the Sb2O3 is 0 to 0.2%, and / or the ZnO is 0 to 3%, and / or the Ta2O5 is not contained, and / or the Al2O3 is not contained.

[0019] Furthermore, the heavy lanthanum flint glass has a total content of all components that meets one or more of the following five conditions: 1) B2O3 / TiO2 is 0.02-0.23, 2) BaO / B2O3 is 5-30, 3) (La2O3+TiO2+ZrO2) / SiO2 is 1.5-4, 4) (SiO2+La2O3+ZrO2) / TiO2 is 1.2-2, and 5) (SiO2+TiO2) / (B2O3+Nb2O5) is 3.36-12.

[0020] Furthermore, the heavy lanthanum flint glass has a total content of all components that satisfies one or two of the following two conditions: 6) SiO2+TiO2 is 37-50%, and 7) B2O3 / SiO2 is 0.02-0.34.

[0021] Furthermore, according to the heavy lanthanum flint glass, the TiO2 is 10 to 30% and / or the Nb2O5 is 0.5 to 10%, preferably the TiO2 is 15 to 25% and / or the Nb2O5 is 2 to 8%, and more preferably the TiO2 is 19 to 24% and / or the Nb2O5 is 3 to 7%.

[0022] Furthermore, according to the heavy lanthanum flint glass, the La2O3 is 10 to 25%, and / or the BaO is 20 to 35%, and / or the Na2O is 0 to 8%, preferably the La2O3 is 12 to 22%, and / or the BaO is 22 to 32%, and / or the Na2O is 0.5 to 6%, and more preferably the La2O3 is 13 to 18%, and / or the BaO is 23 to 30%, and / or the Na2O is 1 to 5%.

[0023] Furthermore, according to the heavy lanthanum flint glass, the λ 70 is 450 nm or less, preferably 440 nm or less, more preferably 430 nm or less, λ5 is 390 nm or less, preferably 385 nm or less, more preferably 380 nm or less, and the density (ρ) of the glass is 4.5 g / cm 3 or less, preferably 4.3 g / cm 3 or less, more preferably 4.25 g / cm 3The upper limit of the crystallization temperature of the glass is 1,200°C or less, preferably 1,180°C or less, and the refractive index temperature coefficient of the glass is 2.4 × 10 -6 / °C or less, preferably 2.3 x 10 -6 / ℃ or less.

[0024] Furthermore, the heavy lanthanum flint glass has a refractive index (nd) of 1.86 to 1.92, preferably 1.86 to 1.91, more preferably 1.87 to 1.90, and an Abbe number (vd) of 25 to 30, preferably 25 to 29, more preferably 26 to 29.

[0025] Furthermore, the heavy lanthanum flint glass has a glass conversion temperature (Tg) of 720°C or less, preferably 710°C or less, more preferably 705°C or less, and a water resistance (D W ) is grade 2 or higher, preferably 1, and acid resistance (D A ) is grade 2 or higher, preferably grade 1. A glass preform is made from the heavy lanthanum flint glass.

[0026] Optical elements are fabricated from the heavy lanthanum flint glass or the glass preform.

[0027] An optical instrument is made from the optical element.

[0028] The present invention has the following beneficial effects: The heavy lanthanum flint glass has an excellent refractive index temperature coefficient, an upper limit of the crystallization temperature, λ 2 , and a desirable refractive index and Abbe number, and a reasonable ratio of components. 70 , λ5, and chemical stability, which allows it to be applied to precision instruments that require high transmittance, imaging quality, and low thermal aberration. DETAILED DESCRIPTION OF THE INVENTION

[0029] Heavy Lantern Flint Glass The following paragraphs detail the composition of the heavy lanthanum flint glass according to the present invention. Unless otherwise specified, the contents of all glass components and their total contents refer to weight contents expressed in weight percent, which is the percentage of the weight of a particular component or the total weight of several components relative to the total weight of the optical glass. The ratio of all glass components or the total ratio of several components is the ratio of the corresponding weight contents or the total weight contents.

[0030] The heavy lanthanum flint glass of the present invention contains, by weight, 12-30% SiO2, 10-25% Ln2O3, where Ln2O3 is the total content of La2O3, Gd2O3, Y2O3, and Yb2O3, 10.5-40% TiO2+Nb2O5+WO3+Bi2O3, 0-10% B2O3, 20-35% RO, where RO is one or more of BaO, CaO, MgO, and SrO, and 0.5-10% ZrO2, and (SiO2+TiO2) / (B2O3+Nb2O5) is 1-30.

[0031] In the glass of the present invention, SiO2 is a network-forming component of the glass and a major component constituting the glass frame. The SiO2 content is closely related to the crystallization resistance, transmittance, refractive index, and dispersion of the glass. If the SiO2 content is lower than 12%, the refractive index and dispersion of the glass will not reach the design expectations, while the crystallization resistance and transmittance of the glass will be significantly reduced. If the SiO2 content is higher than 30%, the melting property and crystallization resistance of the glass will be reduced, while the refractive index and dispersion will not reach the design expectations. Therefore, according to the present invention, the SiO2 content is set to 12 to 30%, preferably 15 to 25%, and more preferably 18 to 23%.

[0032] B2O3 is also an optional component in forming the glass network in the present invention. In some embodiments of the present invention, B2O3 can be introduced to improve the meltability and devitrification resistance of the glass. However, if the amount is higher than 10%, the glass forming stability and refractive index decrease. Therefore, the B2O3 content in the present invention is set to 0 to 10%, preferably 0.5 to 6%, and more preferably 1 to 4%.

[0033] As two glass network components, SiO2 and B2O3 not only have their own unique functions, but also mutually limit the glass-forming stability and glass transition temperature (Tg). A B2O3 / SiO2 ratio higher than 0.4 reduces the glass transition temperature (Tg), while a B2O3 / SiO2 ratio lower than 0.02 reduces the glass-forming stability. Therefore, in some embodiments of the heavy lanthanum flint glass containing B2O3 of the present invention, the B2O3 / SiO2 ratio is set to 0.02 to 0.4, more preferably 0.02 to 0.34.

[0034] The rare earth oxides Ln2O3 (La2O3, Gd2O3, YO3, and Yb2O3) are beneficial for improving the refractive index of glass. If their total content is less than 10%, the expected optical constants cannot be obtained. However, if their total content is greater than 25%, the chemical stability and devitrification resistance of the glass decrease, and the raw material costs of the glass increase. Therefore, the total content of La2O3, Gd2O3, YO3, and Yb2O3, Ln2O3, is set to 10 to 25%, preferably 12 to 22%, and more preferably 13 to 18%. In some embodiments, the rare earth oxides of the present invention may contain 10 to 25% La2O3, preferably 12 to 22% La2O3, and more preferably 13 to 18% La2O3, to further improve the refractive index, visible spectrum transmittance, and devitrification resistance of the glass and to reduce the temperature coefficient of refractive index of the glass.

[0035] TiO2, Nb2O5, WO3, and Bi2O3 are effective in improving the refractive index and dispersion. Therefore, if the content of TiO2 + Nb2O5 + WO3 + Bi2O3 is higher than 40%, the dispersion of the glass will obviously increase, the coloring tendency of the glass will increase, but the transmittance will decrease. Therefore, the upper limit of TiO2 + Nb2O5 + WO3 + Bi2O3 is set to 40%, preferably 33%, and more preferably 31%. However, if the content of TiO2 + Nb2O5 + WO3 + Bi2O3 is too low, the thermal stability and compressibility of the glass will decrease. Therefore, the lower limit is set to 10.5%, preferably 17%, and more preferably 22%.

[0036] In the heavy lanthanum flint glass of the present invention, a combination of TiO2 and Nb2O5 is preferred to obtain better refractive index and Abbe number. To increase the crystallization resistance of the glass, more than 10% of TiO2 may be added to the glass of the present invention to participate in the formation of the glass network, partially replacing expensive Nb2O5, WO3, and Bi2O3. However, if the TiO2 content is higher than 30%, the glass transmittance decreases but the glass's tendency to color increases. Nb2O5 may be appropriately incorporated to make the glass more stable and improve its devitrification resistance. Taking this into consideration, the TiO2 content of the heavy lanthanum flint glass of the present invention is set to 10-30%, preferably 15-25%, and more preferably 19-24%. The Nb2O5 content is set to 0.5-10%, preferably 2-8%, and more preferably 3-7%.

[0037] Furthermore, the inventors have found through their research that the ratio of B2O3 / TiO2 in the components B2O3 and TiO2 affects the λ of the glass. 70It was discovered that the B2O3 / TiO2 ratio affects λ5, the upper limit of the crystallization temperature, and the temperature coefficient of the refractive index, and that a B2O3 / TiO2 ratio greater than 1 increases the upper limit of the crystallization temperature and the temperature coefficient of the refractive index. According to the present invention, to obtain optical glass with high transmittance and other excellent properties, B2O3 / TiO2 is preferably greater than 0 but not greater than 1, more preferably 0.02 to 0.4, and even more preferably 0.02 to 0.23.

[0038] The total content of SiO2 and TiO2 is 70 , λ5, water resistance (D W ), and acid resistance (D A ) has a significant effect. When the SiO2+TiO2 content is greater than 50%, the visible transmittance of the glass decreases, the coloring increases, and the water resistance (D W ) and acid resistance (D A ) decreases. Therefore, if the content of SiO2 + TiO2 is lower than 30%, the glass forming stability deteriorates and the thermal expansion coefficient increases. Therefore, according to the present invention, SiO2 + TiO2 is preferably 30 to 50%, more preferably 37 to 50%.

[0039] Furthermore, the inventors have found that if the ratio of (SiO2 + TiO2) / (B2O3 + Nb2O5) is less than 1, the stability of the glass deteriorates, the upper limit of the crystallization temperature rises, the thermal aberration increases, and the refractive index temperature coefficient and glass ratio increase, making it difficult to achieve the goal of weight reduction. However, if the ratio is greater than 30, the glass transmittance decreases, but the tendency to color increases significantly. Therefore, the ratio of (SiO2 + TiO2) / (B2O3 + Nb2O5) is defined to be 1 to 30, preferably 2.15 to 20, and more preferably 3.36 to 12.

[0040] The alkaline earth metal oxides R0 include one or more of CaO, MgO, SrO, and BaO. For the heavy lanthanum flint glass of the present invention, the addition of more than 20% alkaline earth metal oxides can improve the Young's modulus of the glass, reduce the high-temperature viscosity of the glass, and balance the components of the glass to improve the meltability of the glass. However, if the total R0 content is higher than 35%, the excess alkaline earth metal oxides can reduce the crystallization resistance of the glass. Therefore, according to the present invention, the R0 value is set to 20 to 35%, preferably 22 to 32%, and more preferably 23 to 30%. In some embodiments, the alkaline earth metal oxides of the present invention may contain 20 to 35% BaO, preferably 22 to 32%, and more preferably 23 to 30% BaO, to further reduce the temperature coefficient of refractive index of the glass and improve the devitrification resistance and chemical stability of the glass.

[0041] In some embodiments, the proportions of BaO and B2O3 added affect the temperature coefficient of refractive index of the glass, the water resistance (D W ) and acid resistance (D A ) has a significant effect on the glass meltability. When BaO / B2O3 is greater than 0, the glass meltability is improved and the temperature coefficient of refractive index and thermal aberration of the glass are reduced. However, when BaO / B2O3 is greater than 70, the glass's acid resistance, water resistance, and crystallization resistance are reduced. Therefore, BaO / B2O3 is greater than 0 but not greater than 70, preferably 3.6 to 64, and more preferably 5 to 30.

[0042] ZrO2 is an oxide with high reflectivity and low dispersion, and is a necessary component in the present invention. More than 0.5% ZrO2 may be added to the glass to improve the refractive index and adjust its dispersion. Meanwhile, the crystallization resistance and chemical stability of the glass can be improved. However, in the heavy lanthanum flint glass of the present invention, if the ZrO2 content is higher than 10%, the glass becomes difficult to melt, the melting temperature increases, and obstructions easily form in the glass, reducing its transmittance. Therefore, the ZrO2 content is set to 0.5 to 10%, preferably 2 to 8%, and more preferably 3 to 7%.

[0043] ZrO2 in the glass of the present invention, in combination with the components La2O3, SiO2, and TiO2, contributes to the nd, vd, λ of the glass. 70 , and λ5, as well as the upper limit of the crystallization temperature and the refractive index temperature coefficient. 70 When λ and λ5 are adjusted by the ratio of (La2O3+TiO2+ZrO2) / SiO2, the preferred ratio range is 0.7 to 6. If the ratio is less than 0.7, the meltability and stability of the glass deteriorate, and the refractive index decreases. If (La2O3+TiO2+ZrO2) / SiO2 is higher than 6, the transmittance of the glass in the visible light region decreases, and its coloring deteriorates. More preferably, the ratio of (La2O3+TiO2+ZrO2) / SiO2 is in the range of 1.2 to 5, and most preferably in the range of 1.5 to 4. λ 70 When the upper limit of the crystallization temperature and the refractive index temperature coefficient of the glass are adjusted by adjusting the ratio of (SiO2 + La2O3 + ZrO2) / TiO2, the preferable ratio is in the range of 0.75 to 6.5. When the ratio is 6.5 or less, better light transmittance and better crystallization resistance can be obtained. However, when the ratio is less than 0.75 or more than 6.5, the refractive index temperature coefficient becomes 2.4 × 10 -6 / °C, the optical performance and crystallization resistance are obviously deteriorated. In a preferred solution, the ratio of (SiO2 + La2O3 + ZrO2) / TiO2 is in the range of 1.1 to 3.7, and most preferably in the range of 1.2 to 2.

[0044] RnO, which belongs to the alkaline earth metal oxides, can be one or more of LiO, NaO, and KO and is an optional component of the present invention. In the glass system of the present invention, an approximate amount of alkali metal oxide may be added to obtain the expected high-temperature viscosity. Meanwhile, the coexistence of an approximate amount of alkali metal oxide with B2O3 improves the compactness of the B2O3 network, resulting in better light transmittance. However, excessive alkali metal oxide significantly impairs the crystallization resistance of the glass. Therefore, according to the present invention, the RnO value is set to 0-8%, preferably 0.5-6%, and more preferably 1-5%. In some embodiments, the alkali metal oxide according to the present invention contains 0-8% Na2O, preferably 0.5-6%, and more preferably 1-5% Na2O, which can further lower the glass's conversion temperature and improve its meltability.

[0045] ZnO can adjust the refractive index and dispersion of glass, lower the glass conversion temperature, and improve the crystallization resistance and chemical stability of glass. ZnO also reduces the high-temperature viscosity of glass, allowing the glass to be melted at a lower temperature and increasing the glass transmittance. However, if excessive ZnO is added, the crystallization resistance of the glass decreases and the high-temperature viscosity is relatively low, which poses challenges to molding. In the glass system of the present invention, ZnO may be an optional component, and its content is 0 to 7%, preferably 0 to 5%, and more preferably 0 to 3%.

[0046] Ta2O5 increases the refractive index but can decrease dispersion, and is an optional component in the heavy lanthanum flint glass of the present invention, with a content of 0 to 10%, preferably 0 to 5%. Due to its high cost, it is preferable that Ta2O5 is not included.

[0047] Al2O3 can reduce the thermal expansion coefficient of glass and improve the thermal stability of glass. However, a high Al2O3 concentration generally reduces the liquidus viscosity of glass. According to the present invention, its content is set to 0 to 10%, preferably 0 to 5%, and more preferably, Al2O3 is not included.

[0048] Furthermore, the heavy lanthanum flint glass of the present invention may contain 0 to 1%, preferably 0 to 0.5%, of a fining agent Sb2O3.

[0049] Other components, including P2O5, TeO2, GeO2, and Lu2O3, may be added in small amounts as needed, provided they do not impair the glass properties of the present invention. However, transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo, whether contained singly or in the form of a compound, color the glass and absorb specific wavelengths in the visible light range, thereby reducing the present invention's characteristic of improving visible light transmittance. Therefore, it is particularly preferable to avoid these components for optical glasses that have a requirement for wavelength transmittance within the visible range.

[0050] Compounds of Pb, As, Th, Cd, Tl, Os, Be, and Se have recently been used under controlled conditions as hazardous chemicals, but these are necessary not only in the glass manufacturing process but also in processing procedures and post-manufacturing disposal for environmental protection measures. Therefore, when environmental impact is a major concern, it is preferable that they are not actually included except in unavoidable incorporation. As a result, the optical glass does not actually contain substances that pollute the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and disposed of without special environmental measures being taken.

[0051] The terms "not incorporated," "not containing," and "0%" used herein refer to the fact that no raw material compounds, molecules, or elements are intentionally added to the heavy lanthanum flint glass of the present invention. The raw materials and / or equipment used to manufacture the glass may contain impurities or components that are not intentionally added, and small or trace amounts of these may be present in the final heavy lanthanum flint glass. This state also falls within the scope of patent protection for the invention.

[0052] According to the above paragraphs, it can be seen that a certain component affects multiple performances of the glass in the glass system according to the present invention. When the same component optimizes one performance, other performances may be reduced. Therefore, the mutual coordination and limitation of multiple components in the entire glass system is particularly important. According to experimental studies, the heavy lanthanum flint glass obtained by the present inventors has excellent nd, vd, λ 70 , λ5, ρ, upper limit of crystallization temperature, refractive index temperature coefficient, D W , D A , glass-forming stability, or conversion temperature (Tg).

[0053] The various figures of merit of the heavy lanthanum flint glasses according to the present invention are analyzed in the following manner.

[0054] [Refractive Index] The refractive index (nd) is analyzed according to the method of GB / T7962.1-2010.

[0055] Dispersion Coefficient The dispersion coefficient (i.e., Abbe number, vd) is analyzed according to the method of GB / T7962.1-2010.

[0056] [Glass coloring] λ 70 λ refers to the wavelength when the glass transmittance reaches 70%, and λ5 refers to the wavelength when the glass transmittance reaches 5%. 70 is analyzed using optically polished glass with a thickness of 10±0.1 mm on two parallel, opposing planes, and analyzes the spectral transmittance in the wavelength range from 280 nm to 700 nm and the wavelength that represents 70% transmittance.

[0057] [Temperature coefficient of refractive index] The refractive index temperature coefficient from 20 to 40°C is analyzed according to the method specified in GB / T7962.4-2010.

[0058] [Glass transition temperature] The glass conversion temperature (Tg) is in °C and is analyzed according to the method specified in GB / T7962.16-2010.

[0059] [Upper limit of crystallization temperature] The method for analyzing the upper limit of crystallization temperature involves analyzing the crystallization characteristics of glass using a temperature gradient furnace process. The process involves preparing a 180 x 10 x 10 mm sample of glass, polishing it horizontally, placing it in a furnace with a temperature gradient (5°C / cm) and heating it to 1,400°C. After holding the temperature for four hours, the sample is removed and allowed to cool naturally to room temperature. Observing the crystallization of the glass under a microscope, the upper limit of the crystallization temperature of the glass is determined when the highest temperature of the glass corresponding to crystallization is found. The lower the upper limit of the crystallization temperature of the glass, the stronger the glass's stability at high temperatures and the better the performance of the manufacturing process.

[0060] [Chemical stability] Water resistance (D W ) is analyzed according to the method of GB / T17129.

[0061] Acid resistance (D A ) is analyzed according to the method of GB / T17129.

[0062] [density] The density (ρ) is analyzed according to the method of Colorless Optical Glass Test Methods-Density (GB / T7962.20-1987).

[0063] According to analysis, the heavy lanthanum flint glass of the present invention has the following properties: a refractive index (nd) of 1.86 to 1.92, preferably 1.86 to 1.91, more preferably 1.87 to 1.90, an Abbe number (vd) of 25 to 30, preferably 25 to 29, a conversion temperature (Tg) of 720°C or less, preferably 710°C or less, more preferably 705°C or less, and a λ 70 is 450 nm or less, preferably 440 nm or less, more preferably 430 nm or less, λ5 is 390 nm or less, preferably 385 nm or less, more preferably 380 nm or less, and density (ρ) is 4.5 g / cm3 or less, preferably 4.3 g / cm 3 or less, more preferably 4.25 g / cm 3 Water resistance (D W ) is grade 2 or higher, preferably 1, acid resistance (D A ) is grade 2 or higher, preferably 1, the upper limit of the crystallization temperature is 1,200°C or lower, preferably 1,180°C or lower, and the refractive index temperature coefficient is 2.4 × 10 -6 / °C or less, preferably 2.3 x 10 -6 / ℃ or less.

[0064] The glass preform, optical element, and optical instrument of the present invention will be described below.

[0065] The glass preform and optical element of the present invention are both formed from the heavy lanthanum flint glass of the present invention. The glass preform of the present invention has a high refractive index and a low temperature coefficient of refractive index. The optical element of the present invention has a high refractive index and a low temperature coefficient of refractive index, and can provide optical elements such as various lenses and prisms with high optical values.

[0066] Examples of lenses include various lenses such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses.

[0067] Also, due to the fairly high refractive index, prisms are incorporated in optical camera systems to achieve compact wide-angle optical systems by folding the light path to face the desired direction.

[0068] Optical elements formed from the optical glass of the present invention can be used in the manufacture of optical equipment such as photographic devices, camera devices, display devices, and monitoring devices.

[0069] [Double Lanthanum Flint Glass Embodiment] For the purpose of more clearly describing and illustrating the technical solutions of the present invention, the following non-limiting embodiments are provided.

[0070] To obtain glasses having the compositions shown in Tables 1-6, optical glasses are made using carbonates, nitrates, hydroxides, oxides, and boric acid as raw materials. All raw materials are proportionally weighed according to the composition of the optical glass and mixed uniformly to obtain a mixed raw material. The mixed raw materials are placed in a platinum crucible and heated to 1,200-1,450°C. A uniform molten glass is formed by melting, stirring, and fining. After cooling, the molten glass is poured into a preheated mold and slowly heated at 650-700°C for 2-4 hours. Furthermore, the properties of various glasses are analyzed using the method of the present invention, and the analysis results are shown in Tables 1-6. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7]

[0071] [Embodiment of Glass Preform] The heavy lanthanum flint glass obtained in any of the embodiments 1 to 36 is cut to a predetermined size, and a release agent is uniformly applied to the surface. Thereafter, a mold is heated and softened to be press-molded to produce various lenses and prisms, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. Alternatively, the heavy lanthanum flint glass obtained in any of the embodiments 1 to 36 is formed into a pre-molded product for precision press molding, and then precision press-molded into the shape of a lens or prism through precision press molding and processing to produce a preform.

[0072] [Embodiments of Optical Elements] These preforms, obtained in the glass preform embodiment, are annealed to fine-tune the optical properties, such as refractive index, to desired values while reducing the strain in the glass.

[0073] Each preform is then ground and polished to produce various lenses, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. An anti-reflective coating may be applied to the surface of the resulting optical element.

[0074] [Embodiment of Optical Device] The optical components or optical elements are formed by optical elements obtained in the embodiment of the optical element through optical design or through one or more optical elements. The optical components or optical elements can be used in imaging devices, sensors, microscopes, medical technology, digital projection, communications, optical communication technology / information transmission, optics / illumination in the automotive field, photolithography, excimer lasers, wafers, computer chips, integrated circuits, and electronic devices containing such circuits and chips, in particular camera equipment and devices in the automotive field.

Claims

1. 12 to 27% by weight of SiO ２ and 10 to 25% Ln ２ O ３ and the Ln ２ O ３ La ２ O ３ , Gd ２ O ３ , Y ２ O ３ , and Yb ２ O ３ The total content of TiO is 21.1 to 40%. ２ +Nb ２ O ５ +WO ３ +Bi ２ O ３ and 0-10% B ２ O ３ and 20 to 35% RO, wherein the RO is one or more of BaO, CaO, MgO, and SrO, and 0.5 to 10% ZrO. ２ and BaO / B ２ O ３ is 5 to 70, (SiO ２ + TiO ２ ) / (B ２ O ３ +Nb ２ O ５ ) is 4.30 to 30.

2. Further, by weight, 0 to 8% Rn ２ O and the Rn ２ O is Li ２ O, Na ２ O and K ２ One or more of O and 0-1% Sb ２ O ３ , 0-7% ZnO, and 0-10% Ta ２ O ５ and 0-10% Al ２ O ３ 2. The heavy lanthanum flint glass of claim 1, further comprising:

3. 12 to 27% by weight of SiO ２ and 10 to 25% Ln ２ O ３ and the Ln ２ O ３ La ２ O ３ , Gd ２ O ３ , Y ２ O ３ , and Yb ２ O ３ The total content of TiO is 21.1 to 40%. ２ +Nb ２ O ５ +WO ３ +Bi ２ O ３ and 20 to 35% RO, wherein the RO is one or more of BaO, CaO, MgO, and SrO, and 0.5 to 10% ZrO. ２ and 0-10% B ２ O ３ and 0-8% Rn ２ O and the Rn ２ O is Li ２ O, Na ２ O and K ２ One or more of O and 0-1% Sb ２ O ３ , 0-7% ZnO, and 0-10% Ta ２ O ５ and 0-10% Al ２ O ３ and BaO / B ２ O ３ is 5 to 70, (SiO ２ + TiO ２ ) / (B ２ O ３ +Nb ２ O ５ ) is 4.30 to 30.

4. The heavy lanthanum flint glass according to any one of claims 1 to 3, characterized in that the contents of all components satisfy one or more of the following four conditions: 1) B ２ O ３ / TiO ２ is greater than 0 but less than or equal to 1, 2) BaO / B ２ O ３ is 5 to 64, 3) (La ２ O ３ + TiO ２ + ZrO ２ ) / SiO ２ is 0.7 to 6, 4) (SiO ２ +La ２ O ３ + ZrO ２ ) / TiO ２ is 0.75 to 6.

5.

5. The SiO ２ is 15 to 25%, and / or the Ln ２ O ３ is 12 to 22%, and / or the TiO ２ +Nb ２ O ５ +WO ３ +Bi ２ O ３ is 21.1 to 33%, and / or the RO is 22 to 32%, and / or the ZrO ２ is 2 to 8%, and / or the B ２ O ３ is 0.5 to 6%, and / or the Rn ２ O is 0.5 to 6%, and / or the Sb ２ O ３ is 0 to 0.5%, and / or the ZnO is 0 to 5%, and / or the Ta ２ O ５ is 0 to 5%, and / or the Al ２ O ３ 4. The heavy lanthanum flint glass according to claim 2, wherein the content of lanthanum in the flint glass is 0 to 5%.

6. The heavy lanthanum flint glass according to any one of claims 1 to 3, characterized in that the contents of all components satisfy one or more of the following five conditions: 1) B ２ O ３ / TiO ２ is 0.02 to 0.4, 2) BaO / B ２ O ３ is 5 to 30, 3) (La ２ O ３ + TiO ２ + ZrO ２ ) / SiO ２ is 1.2 to 5, 4) (SiO ２ +La ２ O ３ + ZrO ２ ) / TiO ２ is 1.1 to 3.7, 5) (SiO ２ + TiO ２ ) / (B ２ O ３ +Nb ２ O ５ ) is 4.30 to 20.

7. The SiO ２ is 18 to 23%, and / or the Ln ２ O ３ is 13 to 18%, and / or the TiO ２ +Nb ２ O ５ +WO ３ +Bi ２ O ３ is 22 to 31%, and / or the RO is 23 to 30%, and / or the ZrO ２ is 2 to 6%, and / or the B ２ O ３ is 1 to 4%, and / or the Rn ２ O is 1 to 5%, and / or the Sb ２ O ３ is 0 to 0.2%, and / or the ZnO is 0 to 3%, and / or the Ta ２ O ５ and / or the Al ２ O ３ 4. The heavy lanthanum flint glass according to claim 2, wherein the glass is free of:

8. The heavy lanthanum flint glass according to any one of claims 1 to 3, characterized in that the contents of all components satisfy one or more of the following four conditions: 1) B ２ O ３ / TiO ２ is 0.02 to 0.23, 2) (La ２ O ３ + TiO ２ + ZrO ２ ) / SiO ２ is 1.5 to 4, 3) (SiO ２ +La ２ O ３ + ZrO ２ ) / TiO ２ is 1.2 to 2.0, 4) (SiO ２ + TiO ２ ) / (B ２ O ３ +Nb ２ O ５ ) is 4.30 to 12.

00.

9. The TiO ２ and / or the Nb ２ O ５ 4. The heavy lanthanum flint glass according to claim 1, wherein the content of lanthanum in the flint glass is 0.5 to 10%.

10. The TiO ２ and / or the Nb ２ O ５ 4. The heavy lanthanum flint glass according to claim 1, wherein the content of lanthanum in the flint glass is 3 to 7%.

11. The La ２ O ３ is 10 to 25%, and / or the BaO is 20 to 35%, and / or the Na ２ 4. The heavy lanthanum flint glass according to claim 2, wherein the O content is 0 to 8%.

12. The La ２ O ３ is 13 to 18%, and / or the BaO is 23 to 30%, and / or the Na ２ 4. The heavy lanthanum flint glass according to claim 2, wherein the O content is 1 to 5%.

13. The λ of the glass ７０ is 450 nm or less, and the λ ５ is 390 nm or less, and the density (ρ) of the glass is 4.5 g / cm ３ The upper limit of the crystallization temperature of the glass is 1,200°C or less, and the refractive index temperature coefficient of the glass is 2.4 × 10 －６ / °C or less, the refractive index (nd) of the glass is 1.86 to 1.92, the Abbe number (vd) is 25 to 30, the conversion temperature (Tg) of the glass is 720°C or less, and the water resistance (D Ｗ ) is grade 2 or higher, acid resistance (D Ａ 4. The heavy lanthanum flint glass according to claim 1, wherein the luminous flux density (μm) is 2 or higher.

14. The λ of the glass ７０ is 440 nm or less, and the λ ５ is 385 nm or less, and the density (ρ) of the glass is 4.3 g / cm ３ the upper limit of the crystallization temperature of the glass is 1,180°C or less, and the refractive index temperature coefficient of the glass is 2.3 × 10 －６ / °C or less, the refractive index (nd) of the glass is 1.86 to 1.91, the Abbe number (vd) is 25 to 29, the conversion temperature (Tg) of the glass is 710°C or less, and the water resistance (D Ｗ ) is grade 1, acid resistance (D Ａ 4. The heavy lanthanum flint glass according to claim 1, wherein the luminous flux density is 1.

15. The λ of the glass ７０ is 430n or less, and the λ ５ is 380 nm or less, and the density (ρ) of the glass is 4.25 g / cm ３ The heavy lanthanum flint glass according to any one of claims 1 to 3, characterized in that the refractive index (nd) of the glass is 1.87 to 1.90, the Abbe number (vd) is 26 to 29, and the conversion temperature (Tg) of the glass is 705°C or lower.

16. A glass preform made from the heavy lanthanum flint glass according to any one of claims 1 to 15.

17. An optical element produced from the heavy lanthanum flint glass according to any one of claims 1 to 15 or the glass preform according to claim 16.

18. An optical instrument made from the optical element according to claim 17.

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