Fluorophosphate optical glass, preparation method thereof and optical element

Abstract

The invention provides fluorophosphate optical glass, a preparation method thereof and an optical element. The fluorophosphate optical glass comprises cations and anions, the cations comprise 45 to 52 mol% of P < 5 + >, 12 to 20 mol% of Al < 3 + >, 1 to 4 mol% of Sr < 2 + >, 13 to 18 mol% of Ba < 2 + >, 2.5 to 7 mol% of Ca < 2 + >, 5 to 11 mol% of Mg < 2 + > and 10.1 to 15.1 mol% of Li < + >; and the negative ions comprise 65 to 75 mol percent of O2 <-> and 25 to 34.9 mol percent of F <->, preferably 30 to 34.9 mol percent of F <->. The fluorophosphate optical glass provided by the invention has enough high internal transmittance in a visible light range.

Description

Technical Field

[0001] The present invention relates to a fluorophosphate optical glass, a preparation method thereof, and an optical element, and belongs to the field of optical glass. Background Art

[0002] Fluorophosphate optical glass is an optical material that combines the advantages of fluoride glass and phosphate glass. The most prominent feature is the tunability of optical properties brought about by the wide range of compositional tunability. It has ultra-low refractive index, ultra-low dispersion, and a relatively high specific partial dispersion value, and has excellent achromatic performance. It is especially indispensable for long focal length apochromatic lenses, and has thus become an essential component material in related optical designs.

[0003] Patent application CN105036550A discloses an optical glass with a refractive index (n d ) of 1.5 or more and a high Abbe number (υ d ) of 70 or more. However, the glass disclosed therein contains 5.0 - 30.0 mol% of Sr 2+ , and an appropriate amount of Sr 2+ enhances the network structure of the glass. When the introduction amount is excessive, the crystallization performance of the glass will deteriorate instead.

[0004] Patent application CN102260043A discloses an optical glass with a refractive index n d above 1.50 and an Abbe number υ d above 65. However, the glass disclosed therein contains 8.8 - 11.1% of Ca 2+ , and excessive introduction of Ca 2+ will deteriorate the chemical stability of the glass. At the same time, excessive introduction of Ca 2+ will also limit the reduction of the abrasion degree of the glass.

[0005] Patent application CN104276759A discloses an optical glass with a refractive index n d above 1.50 and an Abbe number υ d above 65. However, the glass disclosed therein contains 14 mol% - 24 mol% of Ca 2+ , and excessive introduction of Ca 2+ will deteriorate the chemical stability of the glass. At the same time, excessive introduction of Ca 2+ will also limit the reduction of the abrasion degree of the glass. Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The object of the present invention is to provide a fluorophosphate optical glass, a preparation method thereof and an optical element. The fluorophosphate optical glass has good chemical stability, high visible light transmittance and a low glass transition temperature, and can eliminate the defects of high melting temperature and difficult control of volatilization streaks of existing optical glasses, and can also achieve stable batch production.

[0008] Solution to the problem

[0009] The present invention provides a fluorophosphate optical glass, which comprises: cations and anions, wherein the cations comprise:

[0010] P 5+ : 45-52 mol%, preferably 45.1-48 mol%,

[0011] Al 3+ : 12-20 mol%, preferably 12-16 mol%,

[0012] Sr 2+ : 1-4 mol%, preferably 1-3 mol%,

[0013] Ba 2+ : 13-18 mol%, preferably 13-16 mol%,

[0014] Ca 2+ : 2.5-7 mol%, preferably 2.5-5 mol%,

[0015] Mg 2+ : 5-11 mol%, preferably 5-9 mol%,

[0016] Li + : 10.1-15.1 mol%, preferably 11-15.1 mol%;

[0017] The anions comprise:

[0018] O 2- : 65-75 mol%, preferably 65-70 mol%,

[0019] F - : 25-34.9 mol%, preferably 30-34.9 mol%.

[0020] According to the fluorophosphate optical glass of the present invention, wherein, in terms of mole percentage, the content of Ba 2+ and the ratio of the sum of the contents of Ba 2+ , Mg 2+ , Sr 2+ and Mg 2+ is n(Ba 2+ ) / n(Ba2+ +Ca 2+ +Sr 2+ +Mg 2+ ) is 0.5 to 0.7; preferably 0.5 to 0.65.

[0021] For the fluorophosphate optical glass according to the present invention, wherein the refractive index n of the fluorophosphate optical glass d is 1.53 to 1.56, and the Abbe number υ d is 62 to 73.

[0022] For the fluorophosphate optical glass according to the present invention, wherein the crystallization temperature Lt of the fluorophosphate optical glass is less than or equal to 690 °C, the devitrification resistance Tg / Lt is greater than 0.622, and the glass transition temperature is below 445 °C.

[0023] For the fluorophosphate optical glass according to the present invention, wherein when the thickness of the fluorophosphate optical glass is 10 mm, the internal transmittance at a wavelength of 700 nm is greater than or equal to 99.8%, the internal transmittance at a wavelength of 400 nm is greater than or equal to 99.8%, and the internal transmittance at a wavelength of 350 nm is greater than or equal to 95.0%.

[0024] For the fluorophosphate optical glass according to the present invention, wherein the density of the fluorophosphate optical glass is below 3.75 g / cm 3 ; and / or,

[0025] The abrasion degree F of the fluorophosphate optical glass a is less than or equal to 430.

[0026] For the fluorophosphate optical glass according to the present invention, wherein the water resistance D of the fluorophosphate optical glass w is Grade 1, the acid resistance D A is Grade 3 or above, and the acid erosion ratio is less than or equal to 0.65%.

[0027] The present invention also provides a preparation method of the fluorophosphate optical glass according to the present invention, which includes: weighing and mixing each component in proportion, then melting, and then casting or pouring into a molding die, or directly press-molding.

[0028] The present invention also provides an optical element, which includes the fluorophosphate optical glass according to the present invention.

[0029] Effects of the invention

[0030] The fluorophosphate optical glass of the present invention has a sufficiently high internal transmittance in the visible light range, with an internal transmittance of ≥99.8% at a wavelength of 700 nm, ≥99.8% at a wavelength of 400 nm, and ≥95.0% at a wavelength of 350 nm.

[0031] Moreover, the fluorophosphate optical glass of the present invention not only has a low cost, but also has good chemical stability and coloring degree; the glass transition temperature is relatively low, which is beneficial to precision molding; its density is relatively low, reducing the weight of the glass element and the optical system; it has excellent achromatic performance, which can improve the imaging quality of the optical system; at the same time, the crystallization temperature is relatively low, making it easier to achieve mass production. Detailed implementation manners

[0032] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The special word "exemplary" here means "serving as an example, an embodiment or an illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0033] 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 be implemented without some specific details. In 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.

[0034] Unless otherwise specified, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0035] In this specification, the meaning expressed by using "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0036] In this specification, the "some specific / preferred implementation manners", "other specific / preferred implementation manners", "implementation manners", etc. mentioned refer to the specific elements (for example, features, structures, properties and / or characteristics) related to the implementation manner described are included in at least one of the implementation manners described here, and may or may not exist in other implementation manners. In addition, it should be understood that the elements can be combined in various implementation manners in any suitable manner.

[0037] In this specification, the numerical range expressed by using "numerical value A to numerical value B" refers to the range including the endpoint numerical values A and B.

[0038] When the fluorophosphate optical glass is in a molten state, fluorine in the glass is extremely volatile. This volatility easily causes compositional differences between the glass surface layer and the interior of the glass, thereby making the glass exhibit optical inhomogeneity, namely glass streaks. And the volatilization of fluorine is related to the temperature of the glass melt. The higher the temperature, the greater the degree of volatilization. Therefore, in order to reduce the formation of streaks, the forming temperature of the glass when it is taken out of the furnace should be minimized. However, a lower forming temperature when the glass is taken out of the furnace is also more likely to cause devitrification of the fluoride glass.

[0039] The fluorophosphate optical glass designed by the present invention can overcome the above technical problems and obtain glass with good stability and not easily devitrified. In addition, another object of the present invention is to provide an optical glass with a low refractive index and low dispersion required in optical design. Moreover, because different optical designs have different requirements for the matching degree of refractive index and dispersion, therefore, obtaining a low-refractive-index and low-dispersion glass that can flexibly match the refractive index and dispersion is also an object of the present invention.

[0040] Hereinafter, various embodiments of the present invention will be described in detail.

[0041] The present invention provides a fluorophosphate optical glass, comprising: cations and anions, wherein the cations include:

[0042] P 5+ : 45 - 52 mol%, preferably 45.1 - 48 mol%,

[0043] Al 3+ : 12 - 20 mol%, preferably 12 - 16 mol%,

[0044] Sr 2+ : 1 - 4 mol%, preferably 1 - 3 mol%,

[0045] Ba 2+ : 13 - 18 mol%, preferably 13 - 16 mol%,

[0046] Ca 2+ : 2.5 - 7 mol%, preferably 2.5 - 5 mol%,

[0047] Mg 2+ : 5 - 11 mol%, preferably 5 - 9 mol%,

[0048] Li + : 10.1 - 15.1 mol%, preferably 11 - 15.1 mol%;

[0049] The anions include:

[0050] O 2- : 65 - 75 mol%, preferably 65 - 70 mol%,

[0051] F - : 25 to 34.9 mol%, preferably 30 to 34.9 mol%.

[0052] It should be noted that the mol% of the component in the cation is the ratio of the cation to the total molar number of all cations. Similarly, the mol% of the component in the anion is the ratio of the anion to the total molar number of all anions.

[0053] In the present invention, the refractive index n of the fluorophosphate optical glass d is 1.53 to 1.56, and the Abbe number υ d is 62 to 73.

[0054] P 5+ is a network former and is a component that constitutes the glass skeleton. Therefore, P 5+ is an essential component for maintaining the glass stability and can effectively improve the mechanical properties of the glass. In the present invention, when the content of P 5+ is less than 45 mol%, the crystallization tendency of the glass gradually increases and the stability becomes poor; while when the content of P 5+ is higher than 52%, it is difficult to obtain the desired optical properties. Therefore, to obtain the optical glass described in the present invention, the content of P 5+ is 45 to 52%, preferably 45.1 to 48%.

[0055] Al 3+ is a component that constitutes the glass network skeleton. Al 3+ is effective in improving the devitrification resistance and chemical stability of the glass, and is also of great significance for improving the mechanical properties and linear expansion coefficient of the glass. In the glass system of the present invention, when the content of Al 3+ is less than 12 mol%, it is difficult to achieve the goal of increasing the Abbe number due to the reduction of fluorine element in the glass, that is, it is difficult to achieve the matching relationship between the refractive index and the Abbe number; while when the content of Al 3+ is higher than 20 mol%, the glass transition temperature Tg will increase significantly, resulting in an increase in the forming temperature. In addition, an excessive content of Al 3+ will also increase the opacification tendency, brittleness and abrasion degree of the glass. Therefore, the content of Al 3+ is 12 to 20 mol%, preferably 12 to 16 mol%.

[0056] Ba 2+ is beneficial to improving the devitrification resistance and refractive index n d of the glass. Appropriate introduction can reduce the crystallization temperature Lt of the glass and improve the crystallization performance. At the same time, Ba 2+ is also an essential component for improving the meltability of the glass. In the present invention, when Ba 2+When the content of [component name] is less than 13 mol%, the chemical stability and devitrification resistance of the glass deteriorate; but when the content of Ba 2+ is higher than 18 mol%, it will increase the refractive index of the glass, making it difficult to achieve the expected optical properties. At the same time, it will also increase the density of the glass, increasing the weight of the designed optical lens. Therefore, in the present invention, the content of Ba 2+ is 13 - 18 mol%, preferably 13 - 16 mol%.

[0057] Sr 2+ is an essential component of the present invention. Introducing an appropriate amount of Sr 2+ can improve the chemical stability of the glass. In the present invention, when the content of Sr 2+ is less than 1 mol%, the effect of improving chemical stability cannot be achieved; when the content of Sr 2+ is higher than 4 mol%, the crystallization resistance of the glass decreases. Therefore, in the present invention, the content of Sr 2+ is 1 - 4 mol%, preferably 1 - 3 mol%.

[0058] Ca 2+ The introduction of [component name] can form a hybridization effect with Sr 2+ , Ba 2+ , Mg 2+ to enhance the network structure of the glass and improve the crystallization resistance of the glass. When its content is less than 2.5 mol%, the effect is not obvious; when its content is higher than 7 mol%, both the chemical stability and refractive index of the glass decrease. Therefore, in the present invention, the content of Ca 2+ is 2.5 - 7 mol%, preferably 2.5 - 5 mol%.

[0059] Mg 2+ On the one hand, it has the function of improving the thermal grinding performance of the glass, and on the other hand, it can also form a hybridization effect with Sr 2+ , Ba 2+ , Ca 2+ to improve the crystallization performance; however, when its content is higher than 11 mol%, the refractive index of the glass cannot reach the target. Therefore, in the present invention, the content of Ca 2+ is 5 - 11 mol%, preferably 5 - 9 mol%.

[0060] Furthermore, the inventors of the present invention have found through a large amount of research that, in terms of molar percentage, controlling the ratio of the content of Ba 2+ to the sum of the contents of Ba 2 + , Mg 2+ , Sr 2+ and Mg 2+ n(Ba 2+ ) / n(Ba 2+ +Ca2+ +Sr 2+ +Mg 2+ ). It can further improve the anti-crystallization performance and chemical stability of the glass. Therefore, in the present invention, n(Ba 2+ ) / n(Ba 2+ +Ca 2+ +Sr 2+ +Mg 2+ ) is 0.5 to 0.7, preferably 0.5 to 0.65.

[0061] Li + can reduce the transformation temperature Tg, and at the same time has the effect of reducing dispersion and increasing the Abbe number υ d , but a relatively large amount of Li + will reduce the stability of the glass, increase the crystallization tendency of the glass, and will gradually deteriorate the chemical stability of the glass. Therefore, the content of Li + is 10.1 to 15.1 mol%, and the preferred range is 11 to 15.1 mol%.

[0062] F - is a key component for the glass to have low dispersion and anomalous dispersion. If its content is less than 25 mol%, it is difficult to achieve the required performance; if its content is greater than 34.9 mol%, the anti-crystallization performance of the glass decreases. Therefore, in the present invention, the content of F - is 25 to 34.9 mol%, and the preferred range is 30 to 34.9 mol%.

[0063] The fluorine (F) content in the glass is effective for reducing the refractive index nd and dispersion of the glass. If the fluorine (F) content is too low, the refractive index and dispersion tend to increase, and the goal of low refractive index and low dispersion cannot be achieved. On the contrary, if the fluorine (F) content is too high, the ionic bonds in the glass will increase, and the characteristic of small ionic bond energy will lead to the instability of the glass skeleton, which will make the glass more likely to devitrify, and too much fluorine (F) content will also increase the abrasion degree of the product, and too large an abrasion degree value is not conducive to the tolerance control during the fine grinding and polishing process of the glass. In the present invention, the fluorine (F) in the glass is introduced by the composite addition of AlF3, BaF2, and LiF. In addition, no other fluorides are artificially introduced in the present invention.

[0064] O 2- is an essential component for constructing the glass network structure of the present invention. When its content is less than 65 mol%, the anti-crystallization performance decreases and it is difficult to achieve the refractive index required by the invention; if its content is higher than 75 mol%, it is difficult to obtain low dispersion and anomalous dispersion. Therefore, in the present invention, the content of O 2- is 65 to 75 mol%, and the preferred range is 60 to 70 mol%.

[0065] Fluorophosphate optical glass In the present invention, the crystallization temperature Lt of the fluorophosphate optical glass is less than or equal to 690 °C, the devitrification resistance Tg / Lt is greater than 0.62, and the glass transition temperature is below 445 °C. When the thickness of the fluorophosphate optical glass is 10 mm, the internal transmittance at a wavelength of 700 nm is greater than or equal to 99.8%, the internal transmittance at a wavelength of 400 nm is greater than or equal to 99.8%, and the internal transmittance at a wavelength of 350 nm is greater than or equal to 95.0%.

[0066] In the present invention, the density of the fluorophosphate optical glass is below 3.75 g / cm 3 ; and / or, the abrasion degree F of the fluorophosphate optical glass a is less than or equal to 430.

[0067] Furthermore, in the present invention, the water resistance D of the fluorophosphate optical glass w is grade 1, and the acid resistance D A is grade 3 or above, and the acid erosion ratio is less than or equal to 0.65%.

[0068] The present invention also provides a preparation method of the fluorophosphate 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 to form, or directly pressing into shape.

[0069] Specifically, weigh respectively according to the specified proportion, mix into a batch material, and then melt in a platinum crucible at a temperature of 800 - 900 °C. After the raw materials are melted into glass liquid, raise the temperature to 900 - 1000 °C and start a platinum stirrer to stir and homogenize. The stirring time is controlled within 3 - 8 h. After stirring is completed, raise the temperature to 1000 - 1050 °C and keep it warm for 4 - 9 h for clarification to make the bubbles fully float up, then lower the temperature to 700 - 800 °C and cast or pour into a molding die or press-mold, and finally obtain the optical glass of the present invention after annealing and processing.

[0070] Due to the large amount of fluorine contained, the fluorophosphate optical glass has strong volatility. In order to weaken the optical inhomogeneity (striations) generated on the glass surface due to fluorine volatilization and environmental pollution, preferably, in the production of the fluorophosphate optical glass, a cooling cover plate is added to the upper surface of the molding die where the glass liquid flows through, and an inert gas is passed through the cooling cover plate to the surface of the glass liquid to make the glass liquid cool and form as soon as possible. In addition, to prevent the glass from eroding the melting crucible, preferably, melt in a non-reducing atmosphere, and specifically, oxygen can be introduced into the melting crucible or an oxidation bath can be added during operation.

[0071] The present invention also provides an optical element, which comprises the fluorophosphate optical glass according to the present invention. The optical element can be produced by performing primary or secondary press molding on the fluorophosphate optical glass, and the optical element can be used in the optical systems of various optical instruments.

[0072] Examples

[0073] The embodiments of the present invention will be described in detail below 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 construed as limiting the scope of the present invention. For those not specified in the examples, the operations are carried out under conventional conditions or conditions recommended by the manufacturer. All reagents or instruments not specified by the manufacturer can be obtained through commercial purchase and are conventional products.

[0074] The present invention will be described more specifically below through examples, but the present invention is not limited to these examples. Examples 1-20 in the table are typical experiments of the present invention for obtaining fluorophosphate optical glass with a refractive index n d of 1.53-1.56 and an Abbe number υ d of 70-74.

[0075] Examples 1-20

[0076] The components in Tables 1, 2, 3 and 4 below are calculated, weighed and mixed in the form of AlF3, BaF2, CaF2, SrF2, MgF2, LiF, Ba(PO3)3, Al(PO3)3 according to the proportions specified for each ion in the table, and then put into a crucible made of platinum and melted at a temperature of 850 °C. During the melting process, O2 is introduced into the crucible to protect the platinum surface from being eroded. After the raw materials are melted into glass liquid, the temperature is raised to 950 °C and a stirrer made of platinum is started to stir and homogenize. The stirring time is controlled at 5 h. After stirring is completed, the temperature is raised to 1000 °C and held for 6 h for clarification to allow the bubbles to float up fully. Then the temperature is lowered to 750 °C and poured or drawn into a molding die, and the above-mentioned cooling cover plate is added to the molding die. Inert gas is passed through the cooling cover plate to the surface of the glass liquid to solve the problem of volatilization stripes caused by fluorine loss. Finally, the optical glass or optical element of Examples 1-20 is obtained through annealing and processing.

[0077] Comparative Examples A, B

[0078] The raw materials corresponding to the components in Table 4 below are weighed respectively according to the specified proportions, and are prepared by the same preparation method as that of Examples 1-20 to obtain the optical glass of Comparative Examples A and B.

[0079] The various properties of the obtained fluorophosphate optical glass are measured by the following methods.

[0080] Measure the refractive index n d and Abbe number υ d of the optical glass according to the test method of GB / T7962.1-2010.

[0081] The short-wave transmission spectral characteristics of the optical glass are represented by the coloring degree λ 80 / λ5. λ 80 refers to the wavelength corresponding to a spectral transmittance of 80%, and λ5 refers to the wavelength corresponding to a spectral transmittance of 5%. Measure the light transmittance of the glass with a thickness of 10 ± 0.1 mm that has been ground parallel on both sides according to the "Method for Measuring the Coloring Degree of Optical Glass" of the Japan Glass Industry Association JOGIS02-2003.

[0082] Measure the internal transmittance (τ 10 , sample thickness is 10 ± 0.1 mm) at wavelengths of 700 nm, 400 nm, and 350 nm according to the test method of GB / T7962.12-2010.

[0083] Test the density of the obtained optical glass according to the test method of GB / T7962.20-2010.

[0084] Test the transformation temperature Tg of the obtained optical glass according to the test method of GB / T7962.16-2010.

[0085] 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.

[0086] Test the water resistance D W and acid resistance D A of the obtained optical glass according to the test method of JB / T10576-2006. And test the D A erosion ratio of the obtained optical glass according to JB / T10576-2006.

[0087] Test the abrasion degree Fa of the obtained optical glass according to the test method of GB / T7962.19-2010.

[0088] Table 1: Glass components and performance parameters of Examples 1-6

[0089]

[0090] Table 2: Glass components and performance parameters of Examples 7-12

[0091]

[0092] Table 3: Glass compositions and performance parameters of Examples 13 to 18.

[0093]

[0094] Table 4: Glass compositions and performance parameters of Examples 19 to 20 and Comparative Examples A and B.

[0095]

[0096] As can be seen from Tables 1 - 4, for the fluorophosphate optical glass of the present invention, the crystallization temperature Lt of the fluorophosphate optical glass is less than or equal to 690 °C, the devitrification resistance Tg / Lt is greater than 0.62, and the glass transition temperature is below 445 °C.

[0097] When the thickness of the fluorophosphate optical glass of the present invention is 10 mm, the internal transmittance at a wavelength of 700 nm is greater than or equal to 99.8%, the internal transmittance at a wavelength of 400 nm is greater than or equal to 99.8%, and the internal transmittance at a wavelength of 350 nm is greater than or equal to 95.0%.

[0098] The density of the fluorophosphate optical glass of the present invention is at 3.75 g / cm 3 Hereinafter, the abrasion degree F a is less than or equal to 430. The water resistance D w of the fluorophosphate optical glass is Grade 1, the acid resistance D A is Grade 3 or above, and the acid erosion ratio is less than or equal to 0.65%.

[0099] As can be seen from Table 4, in Comparative Example A, the content of Li + is too high and the content of Al 3+ is too low, resulting in an increase in the abrasion degree of the glass, which is not conducive to the tolerance control during the fine grinding and polishing process of the glass. At the same time, the chemical stability and crystallization performance of the glass become worse.

[0100] In Comparative Example B, except for Mg 2+ , the contents of other ions are not within the scope of the present application, resulting in a significant increase in the acid erosion ratio (D A ), indicating that the chemical stability of the glass is severely deteriorated and the crystallization performance is deteriorated.

[0101] Weigh and mix these raw materials according to the ratios provided in the present invention, put the batch into a melting device made of platinum, and carry out melting by adopting appropriate oxidation, stirring, clarification, and cooling processes. Then, adopt appropriate forming processes such as pouring, inert gas cooling protection, and cooling and solidification. Finally, through post-treatment such as annealing and processing, it is possible to stably produce a non-devitrified glass with a refractive index n d of 1.53 - 1.56 and an Abbe number υ dIt is a low-refractive-index and low-dispersion optical glass with a refractive index of 70 to 74.

[0102] The optical glass of the present invention has ultra-low refractive index, ultra-low dispersion and a relatively high specific partial dispersion value, and has excellent achromatic performance. This optical glass also has a relatively low softening point and can be made into an aspherical lens through secondary press molding, making it an excellent optical material for producing digital products.

[0103] Industrial Applicability

[0104] The fluorophosphate optical glass of the present invention and its preparation method can be industrially produced, and the optical elements of the present invention can be used in the optical systems of various optical instruments.

[0105] 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.

[0106] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes 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 selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications or improvements to the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the disclosed embodiments.

Claims

1. A fluorophosphate optical glass, characterized in that, Comprising: A cation and an anion, wherein the cation comprises: P 5+ : 45 to 52 mol%, preferably 45.1 to 48 mol%, Al 3+ : 12 to 20 mol%, preferably 12 to 16 mol%, Sr 2+ : 1 to 4 mol%, preferably 1 to 3 mol%, Ba 2+ : 13 to 18 mol%, preferably 13 to 16 mol%, Ca 2+ : 2.5 to 7 mol%, preferably 2.5 to 5 mol%, Mg 2+ : 5 to 11 mol%, preferably 5 to 9 mol%, Li + : 10.1 to 15.1 mol%, preferably 11 to 15.1 mol%; The anion comprises: O 2- : 65 to 75 mol%, preferably 65 to 70 mol%, F - : 25 to 34.9 mol%, preferably 30 to 34.9 mol%.

2. The fluoro-phosphate optical glass according to claim 1, characterized in that, The content of Ba in mole percentage 2+ and the ratio n(Ba 2+ ) / n(Ba 2+ +Mg 2+ +Sr 2+ +Mg 2+ ) to the sum of the contents of Ba 2+ , Ca 2+ , Sr 2+ and Mg 2+ is 0.5 to 0.7; preferably 0.5 to 0.

65.

3. The fluorophosphate optical glass according to claim 1 or 2, characterized in that, The refractive index n of the fluorophosphate optical glass d is 1.53 to 1.56, and the Abbe number υ d is 62 to 73.

4. The fluorophosphate optical glass according to any one of claims 1-3, characterized in that, The crystallization temperature Lt of the fluorophosphate optical glass is less than or equal to 690 °C, the devitrification resistance Tg / Lt is greater than 0.622, and the glass transition temperature is below 445 °C.

5. The fluorophosphate optical glass according to any one of claims 1-4, characterized in that, When the thickness of the fluorophosphate optical glass is 10 mm, the internal transmittance at a wavelength of 700 nm is greater than or equal to 99.8%, the internal transmittance at a wavelength of 400 nm is greater than or equal to 99.8%, and the internal transmittance at a wavelength of 350 nm is greater than or equal to 95.0%.

6. The fluorophosphate optical glass according to any one of claims 1-5, characterized in that, The density of the fluorophosphate optical glass is below 3.75 g / cm 3 ; and / or, The abrasion degree F of the fluorophosphate optical glass a is less than or equal to 430.

7. The fluorophosphate optical glass according to any one of claims 1-6, characterized in that, The water resistance D of the fluorophosphate optical glass w is Grade 1, and the acid resistance D A is Grade 3 or above, and the acid erosion ratio is less than or equal to 0.65%.

8. A method for preparing a fluorophosphate optical glass according to any one of claims 1-7, characterized in that, Comprising: Weigh and mix each component in proportion, then carry out melting, and then pour or leak cast into a molding die, or directly press into shape.

9. An optical element, characterized in that, Comprising the fluorophosphate optical glass according to any one of claims 1-7.

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