Environmentally friendly heavy lanthanum flint optical glass, its preparation method and optical element

Abstract

The present invention provides an environmentally friendly heavy lanthanum flint optical glass, a preparation method thereof, and an optical element. The environmentally friendly heavy lanthanum flint optical glass comprises the following components in terms of compounds: SiO2: 17-23%; B2O3: 1.5-5%; La2O3: 8.5-13%; TiO2: 17-23%; Nb2O5: 8-12%; ZrO2: 3-7%; BaO: 23-28%; Na2O: 1-5%; the total percentage of the above components is greater than 99%, and the above percentages are weight percentages; the refractive index n d of the environmentally friendly heavy lanthanum flint optical glass is 1.83-1.91, and the Abbe number υ d is 25-30. The environmentally friendly heavy lanthanum flint optical glass of the present invention has a sufficiently high internal transmittance in the visible light range. The environmentally friendly heavy lanthanum flint optical glass of the present invention not only has a low cost, but also has good chemical stability and coloring degree.

Description

Technical Field

[0001] The present invention relates to an environmentally friendly heavy lanthanum flint optical glass, a preparation method thereof and an optical element, belonging to the field of optical glass. Background Art

[0002] With the development of the optoelectronic industry, optical elements tend to be more miniaturized, lightweight and high-performance. High refractive index glass with a refractive index above 1.81 is suitable as the optical glass material for such optical elements. Optical glass needs to have a high refractive index and a low Abbe number, so as to achieve the purpose of compensating and correcting chromatic aberration in the design of special optical systems; in addition, it also needs to have high strength and wear resistance to extend its service life and ensure product quality. However, most of the existing products often only focus on pursuing a high refractive index while ignoring other properties that optical glass needs to possess.

[0003] Patent application CN 107601850A discloses an optical glass with a refractive index n d in the range of 1.85 to 1.98 and an Abbe number υ d in the range of 25 to 35. However, the glass disclosed therein contains 30 to 50% La2O3. Excessive introduction of La2O3 will deteriorate the chemical stability of the glass and at the same time lead to poor anti-crystallization performance of the glass.

[0004] Patent application CN 109502964 A discloses an optical glass with a refractive index of 1.82 to 1.96 and an Abbe number not lower than 25 to 30. However, the content of B2O3 in the glass disclosed therein is 0 to 10%, and its glass former is mainly SiO2. Therefore, it results in a relatively high glass melting temperature and a relatively high glass transition temperature T g , and a relatively high glass transition temperature is not conducive to glass forming and annealing to eliminate stress. Summary of the Invention

[0005] Problems to be Solved by the Invention

[0006] The purpose of the present invention is to provide an environmentally friendly heavy lanthanum flint optical glass, a preparation method thereof and an optical element. The refractive index n d of the environmentally friendly heavy lanthanum flint optical glass is 1.83 - 1.91, and the Abbe number v d is 25 - 30. The environmentally friendly heavy lanthanum flint optical glass of the present invention has good chemical stability and excellent anti-crystallization performance, and can eliminate the defect of high melting temperature of the existing optical glass, and at the same time can achieve stable batch production.

[0007] Solutions for Solving the Problems

[0008] The present invention relates to an environmentally friendly heavy lanthanum flint optical glass, which comprises the following components in terms of compounds:

[0009] SiO2: 17 - 23%, preferably 18 - 23%;

[0010] B2O3: 1.5 - 5%, preferably 2.5 - 5%;

[0011] La2O3: 8.5 - 13%, preferably 9 - 13%;

[0012] TiO2: 17 - 23%, preferably 18 - 22%;

[0013] Nb2O5: 8 - 12%, preferably 9 - 12%;

[0014] ZrO2: 3 - 7%, preferably 4 - 7%;

[0015] BaO: 23 - 28%, preferably 24 - 28%;

[0016] Na2O: 1 - 5%, preferably 1 - 4%;

[0017] The total percentage of the above components is greater than 99%, and the above percentages are by weight;

[0018] The refractive index n of the environmentally friendly heavy lanthanum flint optical glass described in the present invention d is 1.83 - 1.91, and the Abbe number υ d is 25 - 30.

[0019] For the environmentally friendly heavy lanthanum flint optical glass described in the present invention, wherein, by weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and Nb2O5, (SiO2 + TiO2) / (B2O3 + Nb2O5), is 2.0 - 3.05, preferably 2.5 - 3.05; and / or

[0020] The ratio of the content of La2O3 to the content of BaO, La2O3 / BaO, is 0.2 - 0.48, preferably 0.3 - 0.48.

[0021] For the environmentally friendly heavy lanthanum flint optical glass described in the present invention, wherein, by weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and La2O3, (SiO2 + TiO2) / (B2O3 + La2O3), is 2.0 - 3.5, preferably 2.5 - 3.5; and / or

[0022] The ratio of the content of SiO2 to the content of B2O3, SiO2 / B2O3, is 5.5 - 10, preferably 5.5 - 8.

[0023] For the environmentally friendly heavy lanthanum flint optical glass according to the present invention, the ratio (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3) of the sum of the contents of SiO2, TiO2 and Nb2O5 to the sum of the contents of B2O3 and La2O3 is 3.2 to 4.5, preferably 3.2 to 4.5; and / or

[0024] The ratio La2O3 / SiO2 of the content of La2O3 to the content of SiO2 is 0.3 to 0.6, preferably 0.4 to 0.6.

[0025] For the environmentally friendly heavy lanthanum flint optical glass according to the present invention, the upper crystallization temperature Lt of the environmentally friendly heavy lanthanum flint optical glass is 1085 °C or lower, and the glass transition temperature T g is 720 °C or lower; and / or, the devitrification resistance T g / Lt of the environmentally friendly heavy lanthanum flint optical glass is greater than 0.64.

[0026] For the environmentally friendly heavy lanthanum flint optical glass according to the present invention, the coloring degree λ 70 / λ5 in which λ 70 is 435 nm or lower, and λ5 is 380 nm or lower.

[0027] For the environmentally friendly heavy lanthanum flint optical glass according to the present invention, the specific gravity of the environmentally friendly heavy lanthanum flint optical glass is 4.09 g / cm 3 or lower.

[0028] For the environmentally friendly heavy lanthanum flint optical glass according to the present invention, the water resistance D w of the environmentally friendly heavy lanthanum flint optical glass is grade 2 or above, and the acid resistance D A is grade 1.

[0029] The present invention also provides a preparation method of the environmentally friendly heavy lanthanum flint optical glass according to the present invention, which includes: weighing and mixing each component in proportion, then melting, and then pouring or injecting into a molding die, or directly pressing into shape.

[0030] The present invention further provides an optical element, which includes the environmentally friendly heavy lanthanum flint optical glass according to the present invention.

[0031] Effects of the Invention

[0032] The environmentally friendly heavy lanthanum flint optical glass of the present invention has a sufficiently high internal transmittance in the visible light range.

[0033] The environmentally friendly heavy lanthanum flint optical glass of the present invention not only has low cost, but also has good chemical stability and coloring degree.

[0034] The specific gravity of the environmentally friendly heavy lanthanum flint optical glass of the present invention is relatively low, reducing the weight of glass components and optical systems.

[0035] The environmentally friendly heavy lanthanum flint optical glass of the present invention has excellent achromatic aberration performance, which can improve the imaging quality of optical systems; at the same time, it has excellent devitrification performance, making it easier to achieve mass production. Detailed implementation manners

[0036] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The special term "exemplary" here means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" here does not necessarily have to be construed as superior to or better than other embodiments.

[0037] In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present invention can also be implemented without certain specific details. In some other instances, methods, means, equipment, and steps well-known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0038] The present invention first provides an environmentally friendly heavy lanthanum flint optical glass, which comprises the following components in terms of compounds:

[0039] SiO2: 17 - 23%, preferably 18 - 23%;

[0040] B2O3: 1.5 - 5%, preferably 2.5 - 5%;

[0041] La2O3: 8.5 - 13%, preferably 9 - 13%;

[0042] TiO2: 17 - 23%, preferably 18 - 22%;

[0043] Nb2O5: 8 - 12%, preferably 9 - 12%;

[0044] ZrO2: 3 - 7%, preferably 4 - 7%;

[0045] BaO: 23 - 28%, preferably 24 - 28%;

[0046] Na2O: 1 - 5%, preferably 1 - 4%;

[0047] The total percentage of the above components is greater than 99%, and the above percentages are weight percentages;

[0048] The refractive index n of the environmentally friendly heavy lanthanum flint optical glass d is 1.83 - 1.91, and the Abbe number υ d is 25 - 30.

[0049] The raw material introduction method adopts various forms that can introduce compounds with their corresponding contents. As described below, the contents of each component are expressed in weight percentages.

[0050] SiO2 is a glass network former, which can enhance the anti-crystallization ability of glass, improve the wear resistance and chemical stability of glass; however, when the content of SiO2 exceeds 23%, the glass will become very refractory and the refractive index required by the present invention cannot be obtained; when the content of SiO2 is lower than 17%, the anti-crystallization performance of the glass deteriorates and it is difficult to form glass. Therefore, the content range of SiO2 in the present invention is 17% - 23%, preferably 18 - 23%, for example: 17.5%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, etc.

[0051] B2O3 is a glass network forming component, which has the function of improving the fusibility of glass and reducing the glass transition temperature. In order to achieve the above effects, the present invention introduces more than 1.5% of B2O3, but when the content of B2O3 exceeds 5%, the stability of the glass will decrease and the refractive index of the glass will be reduced, and the high refractive index required by the present invention cannot be obtained. Therefore, the content of B2O3 in the present invention is 1.5 - 5%, preferably in the range of 2.5 - 5%, for example: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0052] SiO2 and B2O3, as two glass network components, not only have their own unique functions, but also restrict each other and affect the glass formation stability and glass transition temperature (T g ) of the glass. When the content ratio of SiO2 to B2O3, SiO2 / B2O3, is higher than 5.5, the glass transition temperature (T g ) deteriorates, and when SiO2 / B2O3 is lower than 10, the glass formation stability decreases. Therefore, in the present invention, SiO2 / B2O3 is set to 5.5 - 10, more preferably 5.5 - 8.0, for example: 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, etc.

[0053] TiO2 has the function of increasing the refractive index and dispersion of glass, and can participate in the formation of the glass network. When the content of TiO2 is higher than 23%, the glass will be severely colored and the transmittance in the short-wave part of visible light will decrease; when the content of TiO2 is lower than 17%, the high refractive index and high dispersion required by the present invention cannot be obtained. Therefore, the content of TiO2 in the present invention is 17 - 23%, preferably 18 - 22%, for example: 17.5%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, etc.

[0054] Nb2O5 also has the effect of increasing the refractive index and dispersion of the glass, and at the same time can improve the anti-crystallization performance of the glass. When the content of Nb2O5 is less than 8%, the above effects cannot be achieved. When the content of Nb2O5 exceeds 12%, the dispersion of the glass will increase, and the optical properties of the present invention cannot be achieved. At the same time, it will cause the deterioration of the anti-crystallization performance of the glass, and the price of Nb2O5 is expensive. Therefore, in the present invention, the content range of Nb2O5 is 8-12%, preferably 9-12%, for example: 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, etc.

[0055] Furthermore, through the research of the inventor, it is found that when the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and Nb2O5, (SiO2 + TiO2) / (B2O3 + Nb2O5), is less than 2, the glass stability becomes poor, the crystallization performance becomes poor, the cost increases, and the specific gravity of the glass increases, making it difficult to achieve the goal of light weight; however, when this ratio is greater than 3.05, it will cause the transmittance of the glass to decrease and the coloring tendency to increase significantly. Therefore, the ratio (SiO2 + TiO2) / (B2O3 + Nb2O5) is limited to 2.0-3.05, preferably 2.5-3.05, for example: 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, etc.

[0056] La2O3 helps to increase the refractive index of the glass. However, when the content of La2O3 is less than 8.5%, the expected optical constants cannot be obtained. When the content of La2O3 is higher than 13%, the chemical stability and anti-crystallization ability of the glass decrease. Therefore, in the present invention, the content range of La2O3 is 8.5-13%, preferably 9-13%, for example: 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, etc.

[0057] Furthermore, the inventor found that the ratio of the content of La2O3 to the content of SiO2, La2O3 / BaO, has a great influence on the chemical stability and crystallization performance. When the value of La2O3 / BaO is greater than 0.48, the melting properties of the glass decrease, and the chemical stability and crystallization performance of the glass will deteriorate; when the value of La2O3 / BaO is less than 0.2, the glass cannot achieve the required high refractive index. Therefore, the ratio La2O3 / BaO is limited to 0.2-0.48, preferably 0.3-0.48, for example: 0.22, 0.25, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, etc.

[0058] In addition, the present inventors also found that the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and La2O3, i.e., (SiO2 + TiO2) / (B2O3 + La2O3), is closely related to the devitrification property of the glass. When the value of (SiO2 + TiO2) / (B2O3 + La2O3) is greater than 3.5, the devitrification property of the glass deteriorates; when the value of (SiO2 + TiO2) / (B2O3 + La2O3) is less than 2.0, the glass cannot meet the performance requirements of high refractive index and high dispersion. Therefore, in the present invention, (SiO2 + TiO2) / (B2O3 + La2O3) can be 2.0 to 3.5, preferably 2.5 to 3.5, for example: 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, etc.

[0059] Furthermore, the present inventors also studied the relationship between the ratio of the sum of the contents of SiO2, TiO2 and Nb2O5 to the sum of the contents of B2O3 and La2O3, i.e., (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3), and the properties of the glass, and found that when the value of (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3) is less than 3.2, the glass cannot meet the required dispersion requirements and the devitrification property will deteriorate; when the value of (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3) is greater than 4.5, the coloring degree of the glass deteriorates. Therefore, in the present invention, the value of (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3) is 3.2 to 4.5, preferably 3.2 to 4.2, for example: 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, etc.

[0060] Meanwhile, in the present invention, the ratio of the content of La2O3 to the content of SiO2, i.e., La2O3 / SiO2, is also important. In the silicate system, the introduction of lanthanum oxide deteriorates the devitrification property and the melting property of the glass. When the value of La2O3 / SiO2 is greater than 0.6, the devitrification property of the glass decreases and the melting characteristics deteriorate; when the value of La2O3 / SiO2 is less than 0.3, the refractive index and dispersion of the glass cannot meet the requirements. Therefore, in the present invention, the value of La2O3 / SiO2 is 0.3 to 0.6, for example: 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, etc.

[0061] BaO helps to improve the anti - crystallization performance of the glass, and can enhance the chemical stability of the glass. At the same time, in the present invention, due to the need to obtain optical glass with high refractive index and high dispersion, the content of alkali metal oxides is insufficient. Therefore, BaO can effectively reduce the melting temperature of the glass in the present invention. Therefore, in the present invention, the content range of BaO is 23 - 28%, preferably 24 - 28%, for example: 23.5%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, etc.

[0062] ZrO2 is an oxide with high refractive index and low dispersion. In the present invention, ZrO2 can play a role in adjusting the optical properties. At the same time, ZrO2 below 7% can improve the anti - crystallization performance and chemical stability of the glass; however, when its content exceeds 7%, the melting temperature of the glass increases and the melting difficulty increases. Therefore, in the present invention, the content range of ZrO2 is 3 - 7%, preferably 4 - 7%, for example: 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, etc.

[0063] Na2O can effectively reduce the melting temperature of the glass, but when the content of Na2O is too high, it will reduce the refractive index, dispersion of the glass, and also reduce the anti - crystallization performance of the glass. Therefore, in the present invention, the content range of Na2O is 1 - 5%, preferably 1 - 4%, for example: 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, etc.

[0064] In the present invention, the upper crystallization temperature Lt of the environmentally friendly heavy lanthanum flint optical glass is below 1085 °C, and the glass transition temperature T g is below 720 °C; the devitrification resistance T g / Lt is greater than 0.64. The coloring degree λ 70 / λ5 of the environmentally friendly heavy lanthanum flint optical glass, where λ 70 is below 435 nm and λ5 is below 380 nm. The specific gravity of the environmentally friendly heavy lanthanum flint optical glass is below 4.09 g / cm 3 . The water resistance D w of the environmentally friendly heavy lanthanum flint optical glass is grade 2 or above, and the acid resistance D A is grade 1.

[0065] The present invention also provides a preparation method of the environmentally friendly heavy lanthanum flint optical glass according to the present invention, including: weighing and mixing each component in proportion, then melting, and then casting or pouring into a molding die for molding, or directly pressing for molding.

[0066] Specifically, weigh the components according to the specified ratios respectively, mix them into a batch material, and then melt them in a platinum crucible at a temperature of 1200 - 1250 °C. After the raw materials are melted into glass liquid, raise the temperature to 1250 - 1300 °C and start a stirrer made of platinum to stir and homogenize. The stirring time is controlled within 3 - 8 h. After stirring is completed, raise the temperature to 1300 - 1400 °C and hold for 4 - 9 h for clarification to allow the bubbles to fully float up. Then lower the temperature to 1200 - 1250 °C and pour or leak cast it into a forming mold or form it by die pressing. Finally, obtain the optical glass of the present invention after annealing and processing.

[0067] The present invention also provides an optical element, which includes the environmentally friendly heavy lanthanum flint optical glass according to the present invention. The optical element can be produced by one-time or two-time press molding of the environmentally friendly heavy lanthanum flint optical glass, and the optical element can be used in the optical systems of various optical instruments.

[0068] Examples

[0069] The following will describe the embodiments of the present invention in detail in conjunction with the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the examples, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained commercially.

[0070] Examples 1 - 12

[0071] Calculate, weigh, and mix the components in Tables 1 and 2 below according to the specified ratios, and put them into a platinum crucible to melt at a temperature of 1320 °C. After the raw materials are melted into glass liquid, raise the temperature to 1350 °C and start a stirrer made of platinum to stir and homogenize. The stirring time is controlled within 5 h. After stirring is completed, raise the temperature to 1380 °C and hold for 6 h for clarification to allow the bubbles to fully float up. Then lower the temperature to 1200 °C and pour or leak cast it into a forming mold. Finally, obtain the optical glass or optical element of Examples 1 - 10 after annealing and processing.

[0072] Comparative Examples A, B

[0073] Weigh the raw materials corresponding to the components in Table 2 below respectively according to the specified ratios, and use the same preparation method as in Examples 1 - 12 to prepare the optical glass of Comparative Examples A and B.

[0074] The various properties of the obtained fluorophosphate optical glass are measured by the following methods.

[0075] Measure the refractive index nd and Abbe number υd of the optical glass according to the test method of GB / T7962.1 - 2010.

[0076] The short - wave transmission spectral characteristics of the optical glass are represented by the coloring degree λ 70 / λ5. λ 70 refers to the wavelength corresponding to when the spectral transmittance reaches 70%, and λ5 refers to the wavelength corresponding to when the spectral transmittance reaches 5%. According to the "Method for Measuring the Coloring Degree of Optical Glass" of the Japan Glass Industry Association JOGIS02 - 2003, the light transmittance of the glass with a thickness of 10 ± 0.1 mm ground parallel on both sides is measured.

[0077] The specific gravity of the obtained optical glass is tested according to the test method of GB / T7962.20 - 2010.

[0078] The glass transition temperature Tg of the obtained optical glass is tested according to the test method of GB / T7962.16 - 2010.

[0079] Lt is the liquidus temperature, that is, the upper limit temperature of crystallization. Its test is carried out by the DTA (differential thermal analysis) method. The temperature corresponding to the highest heat absorption peak in the DTA curve is Lt.

[0080] The water resistance D W and acid resistance D A of the obtained optical glass are tested according to the test method of JB / T10576 - 2006. The D A erosion ratio of the obtained optical glass is tested according to the national standard test method.

[0081] Table 1: Glass components and performance parameters of Examples 1 - 6.

[0082]

[0083] Table 2: Glass components and performance parameters of Examples 7 - 12.

[0084]

[0085] Table 3: Glass components and performance parameters of Comparative Examples A - B.

[0086]

[0087] Therefore, as can be seen from Table 1 and Table 2, by weighing and mixing these raw materials according to the ratios provided in the present invention, putting the batch into a melting device made of platinum, and carrying out melting by adopting appropriate oxidation, stirring, clarification, and cooling processes, then adopting appropriate forming processes such as pouring, inert gas cooling protection, and cooling and solidification, and finally carrying out post - treatments such as annealing and processing, it is possible to stably produce a non - devitrifying optical glass with a refractive index n d ranging from 1.83 to 1.91 and an Abbe number υ dIt is a high refractive index and high dispersion optical glass with a refractive index of 25-30, so that in the design of special optical systems, the purpose of compensating for and correcting chromatic aberration can be achieved.

[0088] As can be seen from Table 3, in Comparative Example A, the content of SiO2 is higher than the range defined in the present invention, and the content of Na2O is slightly lower than the range defined in the present invention. The refractive index of the glass is low, and the devitrification performance of the glass becomes poor. In Comparative Example B, the contents of B2O3 and La2O3 are higher than the range defined in the present invention, and the content of BaO is lower than the range defined in the present invention. The Abbe number υ of the glass d is within the scope of the present invention, but the chemical stability and devitrification performance of the glass become poor.

[0089] Industrial Applicability

[0090] The environmentally friendly heavy lanthanum flint optical glass and its preparation method of the present invention can be industrially produced, and the optical elements of the present invention can be used in the optical systems of various optical instruments.

[0091] It should be noted that although the technical solutions of the present invention are introduced by specific examples, those skilled in the art can understand that the present invention should not be limited thereto.

[0092] The above have described the embodiments of the present invention. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skill in the art in the technical field to understand the disclosed embodiments.

Claims

1. An environmentally friendly heavy lanthanum flint optical glass, characterized in that, Comprising the following components by compound: SiO2: 17 - 23%; B2O3: 1.5 - 5%; La2O3: 10.1 - 13%; TiO2: 17 - 23%; Nb2O5: 8 - 12%; ZrO2: 3 - 7%; BaO: 23 - 28%; Na2O: 1 - 5%; The total percentage of the above components is greater than 99%, and the above percentages are weight percentages; The refractive index n of the environmentally friendly heavy lanthanum flint optical glass d is 1.83 to 1.91, and the Abbe number υ d is 25 to 30.

2. The environmentally friendly heavy lanthanum flint optical glass according to claim 1, characterized in that, Comprising the following components by compound: SiO2: 18 - 23%; B2O3: 2.5 - 5%; La2O3: 10.1 - 13%; TiO2: 18 - 22%; Nb2O5: 9 - 12%; ZrO2: 4 - 7%; BaO: 24 - 28%; Na2O: 1 - 4%.

3. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, By weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and Nb2O5, (SiO2 + TiO2) / (B2O3 + Nb2O5), is 2.0 - 3.05; and / or The ratio of the content of La2O3 to the content of BaO, La2O3 / BaO, is 0.36 - 0.

48.

4. The environmentally friendly heavy lanthanum flint optical glass according to claim 3, characterized in that, By weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and Nb2O5, (SiO2 + TiO2) / (B2O3 + Nb2O5), is 2.5 - 3.05; and / or The ratio of the content of La2O3 to the content of BaO, La2O3 / BaO, is 0.38 - 0.

48.

5. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, By weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and La2O3, (SiO2 + TiO2) / (B2O3 + La2O3), is 2.0 - 3.5; and / or The ratio of the content of SiO2 to the content of B2O3, SiO2 / B2O3, is 5.5 - 10.

6. The environmentally friendly heavy lanthanum flint optical glass according to claim 5, characterized in that By weight percentage, the ratio of the sum of the contents of SiO2 and TiO2 to the sum of the contents of B2O3 and La2O3, (SiO2 + TiO2) / (B2O3 + La2O3), is 2.5 - 3.5; and / or The ratio of the content of SiO2 to the content of B2O3, SiO2 / B2O3, is 5.5 - 8.

7. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, The ratio of the sum of the contents of SiO2, TiO2 and Nb2O5 to the sum of the contents of B2O3 and La2O3, (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3), is 3.2 - 4.5; and / or The ratio of the content of La2O3 to the content of SiO2, La2O3 / SiO2, is 0.45 - 0.

6.

8. The environmentally friendly heavy lanthanum flint optical glass according to claim 7, characterized in that, The ratio of the sum of the contents of SiO2, TiO2 and Nb2O5 to the sum of the contents of B2O3 and La2O3, (SiO2 + TiO2 + Nb2O5) / (B2O3 + La2O3), is 3.2 - 4.5; and / or The ratio of the content of La2O3 to the content of SiO2, La2O3 / SiO2, is 0.48 - 0.

6.

9. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, The crystallization upper limit temperature Lt of the environmentally friendly heavy lanthanum flint optical glass is below 1085 °C, and the glass transition temperature T g is below 720 °C.

10. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, The coloring degree λ of the environmentally friendly heavy lanthanum flint optical glass 70 in λ / λ5 70 is below 435 nm, and λ5 is below 380 nm.

11. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, The specific gravity of the environmentally friendly heavy lanthanum flint optical glass is 4.09 g / cm 3 or less.

12. The environmentally friendly heavy lanthanum flint optical glass according to claim 1 or 2, characterized in that, The water resistance D of the environmentally friendly heavy lanthanum flint optical glass w is level 2 or above, and the acid resistance D A is level 1.

13. A preparation method of the environmentally friendly heavy lanthanum flint optical glass according to any one of claims 1-12, characterized in that, Comprising: Weigh each component according to the ratio, mix them evenly, then carry out smelting, and then pour or ladle into a molding die, or directly press into shape.

14. An optical element, characterized in that, Comprising the environmentally friendly heavy lanthanum flint optical glass according to any one of claims 1 - 12.

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