Fluorophosphate optical glass, optical preforms and optical elements

Abstract

The fluorophosphate optical glass according to the present invention, when the components are expressed in mol%, as the cation component, Al 3+ : 30 to 42%, Mg 2+ : 3 to 10%, Ca 2+ : 15 to 27%, Sr 2+ : 15 to 30%, Ba 2+ : 1 to 10%, Y 3+ : 1 to 6%, Li + : 2 to 6%, P 5+ : 1 to 9%, and as the anion component, O 2- : 1.5 to 20%, F - : 80 to 98.5%. By rationally designing the components, the optical glass of the present invention has a higher Abbe number and high crystallization resistance.

Description

[Technical Field]

[0001] This invention relates to the field of optical glass, and more specifically to ultra-low dispersion fluorophosphate optical glass. [Background technology]

[0002] Compact optical systems such as camera lenses and telescopes are often manufactured using low-dispersion, low-refractive-index materials and high-refractive-index materials. Fluorophosphate glass is an optical glass that can achieve low dispersion and has higher productivity compared to fluorine glass.

[0003] Regarding fluorophosphate glasses, one direction of development is to achieve ultra-low dispersion, i.e., Abbe number greater than 95, in order to realize excellent achromatic and apochromatic capabilities and improve the imaging quality of optical systems. Prior art includes patents disclosing fluorophosphate glasses with Abbe numbers greater than 95. For example, Chinese patent CN103708727A discloses fluorophosphate optical glass with an Abbe number of 90-100, and Chinese patent CN102300823A discloses fluorophosphate optical glass with an Abbe number of 85 or higher. However, the glass components in these patents are not sufficiently optimized, and there is room for improvement in their resistance to crystallization. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The technical problem that this invention aims to solve is to provide fluorophosphate optical glass with a higher Abbe number and excellent resistance to crystallization. [Means for solving the problem]

[0005] The technical means used by this invention to solve the technical problems are as follows:

[0006] In fluoro-phosphate optical glass, when the components are expressed in mole percentages, as the cation component, Al 3+ : 30 to 42%, Mg 2+ : 3 to 10%, Ca 2+ : 15 to 27%, Sr 2+ : 15 to 30%, Ba 2+ : 1 to 10%, Y 3+ : 1 to 6%, Li + : 2 to 6%, P 5+ : 1 to 9% are contained, and as the anion component, O 2- : 1.5 to 20%, F - : 80 to 98.5% are contained.

[0007] Furthermore, in the fluoro-phosphate optical glass, when the components are expressed in mole percentages, as the cation component, La 3+ : 0 to 3%, and / or Gd 3+ : 0 to 3%, and / or Na + : 0 to 3% are further contained.

[0008] In fluoro-phosphate optical glass, when the components are expressed in mole percentages, the cation component is Al 3+ : 30 to 42%, Mg 2+ : 3 to 10%, Ca 2+ : 15 to 27%, Sr 2+ : 15 to 30%, Ba 2+ : 1 to 10%, Y 3+ : 1 to 6%, Li + : 2 to 6%, P 5+ : 1 to 9%, La 3+ : 0 to 3%, Gd 3+ : 0 to 3%, Na + : consisting of 0 to 3%, the anion component is O 2- : 1.5 to 20%, F - : 80 to 98.5%, Cl - : consisting of 0 to 0.5%.

[0009] Furthermore, in the fluoro-phosphate optical glass, when the components are expressed in mole percentages, Ca 2+ / Sr 2+The ratio is 0.6 to 1.6, preferably Ca 2+ / Sr 2+ The ratio is 0.7 to 1.4, and more preferably Ca 2+ / Sr 2+ The range is 0.75 to 1.35.

[0010] Furthermore, in the fluorophosphate optical glass, the components are expressed in mole percentages as follows: Y 3+ +La 3+ +Gd 3+ The percentage is 1.5-7%, preferably Y 3+ +La 3+ +Gd 3+ The percentage is 2-6%, and more preferably Y 3+ +La 3+ +Gd 3+ The percentage is 2.5-4.5%.

[0011] Furthermore, in the fluorophosphate optical glass, the components are expressed in mole percentages as follows: Y 3+ / (La 3+ +Gd 3+ ) is 1.0 or greater, preferably Y 3+ / (La 3+ +Gd 3+ ) is 2.0 or higher, more preferably Y 3+ / (La 3+ +Gd 3+ ) is between 2.0 and 15.0.

[0012] Furthermore, in the fluorophosphate optical glass, the components are expressed in mole percentages as follows: Li + / Mg 2+ The ratio is 0.28 to 0.8, preferably Li + / Mg 2+ The ratio is 0.3 to 0.75, and Li is more preferable. + / Mg 2+ The values ​​are between 0.32 and 0.7.

[0013] Furthermore, in the fluorophosphate optical glass, the components are expressed in mole percentages as follows: Li + / ( Li + +Na +) is 0.5 or more, preferably Li + / (Li + +Na + ) is 0.6 or more, more preferably Li + / (Li + +Na + ) is 0.75 or more.

[0014] Furthermore, in the fluorophosphate optical glass, when the components are expressed in mole percentages, O 2- / P 5+ is 2.5 to 3.5, preferably O 2- / P 5+ is 2.5 to 3.25, more preferably O 2- / P 5+ is 2.5 to 3.0.

[0015] Furthermore, in the fluorophosphate optical glass, when the components are expressed in mole percentages, Al 3+ : 33 to 41%, preferably Al 3+ : 36 to 40%, and / or Mg 2+ : 4 to 9%, preferably Mg 2+ : 5 to 8%, and / or Ca 2+ : 16 to 25%, preferably Ca 2+ : 17 to 23%, and / or Sr 2+ : 16 to 28%, preferably Sr 2+ : 17 to 26%, and / or Ba 2+ : 2 to 8%, preferably Ba 2+ : 3 to 6%, and / or Y 3+ : 1.5 to 5%, preferably Y 3+ : 2 to 4%, and / or Li + : 2.5 to 5.5%, preferably Li + : 3 to 5%, and / or P 5+ : 2 to 8.5%, preferably P 5+ : 3 to 8%, and / or La 3+ : 0.2 to 2.5%, preferably La 3+ : 0.3 to 2%, and / or Gd 3+ : 0.1 to 2.5%, preferably Gd 3+ : 0.2 to 2%, and / or Na +: 0.3 to 2%, preferably Na + : is 0.4 to 1%.

[0016] Furthermore, in the fluorophosphate optical glass, when the components are expressed in mole percentages, O 2- : 4 to 18%, preferably O 2- : 7 to 16%, and / or F - : 82 to 96%, preferably F - : is 84 to 93%.

[0017] Furthermore, in the fluorophosphate optical glass, when the components are expressed in mole percentages, Cl - : 0 to 0.5%, preferably Cl - : 0 to 0.2%, more preferably Cl - : is 0 to 0.1%.

[0018] Furthermore, in the fluorophosphate optical glass, as the components, K + is not contained, and / or Zr 4+ is not contained, and / or Zn 2+ is not contained, and / or Be 2+ is not contained, and / or Pb 2+ is not contained, and / or Tl + is not contained, and / or Rb + is not contained, and / or Cs + is not contained.

[0019] Furthermore, in the fluorophosphate optical glass, the refractive index n d is 1.4200 to 1.4350, and the Abbe number ν d is 95 to 99. Preferably, the refractive index n d and the Abbe number ν dIn the diagram of the optical glass region, it is located in the region enclosed by lines connecting four points: a point with a refractive index of 1.425 and an Abbe number of 95.50, a point with a refractive index of 1.4340 and an Abbe number of 96.50, a point with a refractive index of 1.4210 and an Abbe number of 97.80, and a point with a refractive index of 1.43170 and an Abbe number of 98.50, and more preferably, the refractive index n d and the Abbe number ν d In the diagram of the optical glass region, it is located in the region enclosed by lines connecting four points: a point with a refractive index of 1.4255 and an Abbe number of 96.10; a point with a refractive index of 1.4335 and an Abbe number of 96.80; a point with a refractive index of 1.4330 and an Abbe number of 97.55; and a point with a refractive index of 1.4317 and an Abbe number of 98.20.

[0020] Furthermore, in the fluorophosphate optical glass, (T x -T g ) / (T m -T g ) is 0.36 or more, preferably 0.38 or more, more preferably 0.40 or more, and in the formula, the T g This is the temperature at the junction between the lowest endothermic peak and the baseline in the differential thermal analysis curve, and the T x This is the temperature corresponding to the peak position of the lowest crystallization exothermic peak in the differential thermal analysis curve, and T m This is the temperature at which the temperature in the differential thermal analysis curve corresponds to the peak position of the highest crystallization exothermic peak, and / or water resistance D w It is grade 3 or higher, preferably grade 2 or higher, and / or acid-resistant D A The level is 4 or higher, preferably 3 or higher.

[0021] The optical preform is manufactured using the above-mentioned fluorophosphate optical glass.

[0022] The optical element is manufactured from the above-mentioned fluorophosphate optical glass or optical preform. [Effects of the Invention]

[0023] The beneficial effects of the present invention are as follows: By rationally designing the components, the optical glass of the present invention has a higher Abbe number and high resistance to crystallization. [Modes for carrying out the invention]

[0024] The embodiments of the fluorophosphate optical glass of the present invention will be described in detail below, but the present invention is not limited to the embodiments described below and can be modified as appropriate within the scope of the object of the present invention. In addition, redundant explanations may be omitted as appropriate, but this does not limit the gist of the present invention, and in the following content, the fluorophosphate optical glass of the present invention may be abbreviated as optical glass or glass.

[0025] [Fluorophosphate optical glass] The following describes the range of each component (element) of the optical glass of the present invention. In this specification, unless otherwise specified, the content of cationic components is expressed as the molar percentage (mol%) of the cation relative to the total cationic components, the content of anionic components is expressed as the molar percentage of the anion relative to the total anionic components, the ratio of the content of cationic components is the ratio of the molar percentages of each cationic component, the ratio of the content of anionic components is the ratio of the molar percentages of each anionic component, and the total content is expressed in mole percentages of ions. Note that the ionic valencies of each component in this invention are representative values ​​used for convenience and are not distinguishable from other ionic valencies. Some elements mentioned in the following description may have one or more possible valencies, and in this specification, the representative valency of the element is used for description.

[0026] In this invention, when describing the relationship between the content of each component, and when dealing with multiplication and / or division, the content of the component is calculated using the actual numerical value corresponding to its percentage. For example, if the percentage of the component's content is 10%, it is calculated as 0.1 in the multiplication and / or division relationship.

[0027] Unless otherwise specified, the ranges of numbers listed herein include upper and lower limits, and “greater than or equal to” and “less than or equal to” include endpoint values ​​and all integers or fractions within that range, but are not limited to specific values ​​listed within a limited range. In this specification, “and / or” is inclusive; for example, “A and / or B” means A only, or B only, or both A and B.

[0028] The glass of the present invention, based on aluminum fluoride-based glass, can achieve ultra-low dispersion by appropriately designing its composition and rationally adding additional components. Furthermore, it has a relatively high refractive index and can be applied to compact, high-image-quality optical systems. In addition, the fluorophosphate glass of the present invention has higher productivity.

[0029] <Cationic components> The cation content of the glass of this invention is 100% in total. Impurity elements are not included in the cation content.

[0030] Al 3+ Al has high glass-forming properties in fluoride-based glasses. 3+ This helps increase the Abbe number of glass, but Al 3+ When the content exceeds a certain limit, AlF3 crystals tend to precipitate in the glass, and the crystallization resistance of the glass decreases significantly. Therefore, Al 3+ The content is 30-42%, preferably 33-41%, and more preferably 36-40%.

[0031] In the glass of the present invention, Mg 2+ This helps to obtain low dispersion properties by increasing the Abbe number of the glass. However, Mg 2+ When the content exceeds a certain limit, the crystallization resistance of the glass deteriorates significantly. Therefore, Mg 2+ The content is 3-10%, preferably 4-9%, and more preferably 5-8%.

[0032] Ca2+ Ca has higher glass-forming properties in fluoride glass. In the glass of the present invention, Ca 2+ The content of Ca must exceed a certain range to ensure that other components in the glass are present in appropriate amounts and that the glass has higher crystallization resistance. 2+ When the content of Ca is high, CaAlF5 crystals are more likely to form in the glass, and the crystallization resistance of the glass decreases. Therefore, Ca 2+ The content is 15-27%, preferably 16-25%, and more preferably 17-23%.

[0033] Sr 2+ The glass-forming properties of Ca 2+ It is almost identical to the present invention. In the glass of the present invention, due to the matching relationship of cation radii, within a certain range, Sr 2+ By increasing the content of Sr, the crystallization resistance of glass can be improved. 2+ The presence of Sr makes it difficult for CaAlF5 crystals to precipitate in the glass, and the reason for this is that 2+ Ca in CaAlF5 crystal 2+ Because it can occupy that position, the difficulty of CaAlF5 crystal precipitation in the glass can be appropriately increased. Therefore, Sr 2+ The content is 15-30%, preferably 16-28%, and more preferably 17-26%.

[0034] In some embodiments, Ca 2+ / Sr 2+ By controlling the value within the range of 0.6 to 1.6, the tendency for CaAlF5 and SrAlF5 crystals to precipitate in the glass is low, ensuring excellent crystallization resistance of the glass and higher acid resistance. Therefore, Ca 2+ / Sr 2+ The value is preferably 0.6 to 1.6, more preferably 0.7 to 1.4, and even more preferably 0.75 to 1.35.

[0035] Ba 2+While it can improve the crystallization resistance of glass, Ba 2+ If the content of Ba is too high, it becomes difficult to obtain glass with a high Abbe number. Therefore, 2+ The content is 1-10%, preferably 2-8%, and more preferably 3-6%.

[0036] Y 3+ This is a necessary component for the glass of the present invention. The glass contains an appropriate amount of Y. 3+ The inclusion of Y helps improve the chemical stability and crystallization resistance of the glass. 3+ The contribution of Ca to the Abbe number is 2+ Sr 2+ Ba 2+ Because it is superior to other components, glass contains a certain amount of Y 3+ Including Y has a greater effect on increasing the Abbe number of the glass. However, Y 3+ If the content exceeds a certain limit, the glass composition falls outside the glass-forming range, and glass cannot be formed. Therefore, Y 3+ The content is 1-6%, preferably 1.5-5%, and more preferably 2-4%.

[0037] La 3+ The ability of glass to increase its Abbe number and its ability to improve its crystallization resistance are both Y 3+ It is slightly lower. However, glass contains a small amount of La 3+ The presence of [this substance] helps to reduce the crystallization tendency of glass. Therefore, La 3+ The content is 0-3%, preferably 0.2-2.5%, and more preferably 0.3-2%.

[0038] Gd 3+ The ability to improve the crystallization resistance of glass, its influence on the refractive index of glass, and its ability to increase the Abbe number are all related to La 3+ It is similar to glass with a small amount of Gd 3+ The presence of Gd helps to reduce the crystallization tendency of glass. Therefore, Gd 3+The content is 0-3%, preferably 0.1-2.5%, and more preferably 0.2-2%.

[0039] In some embodiments, Y 3+ +La 3+ +Gd 3+ By controlling this to a range of 1.5-7%, the glass can achieve higher crystallization resistance. Therefore, Y 3+ +La 3+ +Gd 3+ The content is preferably 1.5 to 7%, more preferably 2 to 6%, and even more preferably 2.5 to 4.5%.

[0040] In some embodiments, Y 3+ / (La 3+ +Gd 3+ Controlling Y to 1.0 or higher helps improve the crystallization resistance and water resistance of the glass. Therefore, 3+ / (La 3+ +Gd 3+ ) is preferably 1.0 or higher, more preferably 2.0 or higher, and even more preferably 2.0 to 15.0.

[0041] Li + Li is a necessary component of the glass of the present invention. In fluoride glass, Li + This can significantly increase the Abbe number of glass. In terms of process, glass is Li + The inclusion of helps in the melting of the glass raw materials and indirectly reduces the volatilization of fluorine during the melting process, thereby contributing to an increase in the Abbe number of the glass of the present invention. However, Li + It significantly reduces the viscosity of the glass and has negative properties in fluoride glass, making it difficult to control the viscosity of the molten glass and reducing the molding window. On the other hand, Li has a relatively high content. + This reduces the refractive index of glass, thus limiting the application of glass in the achromatic field. Also, Li +When the content exceeds a certain range, Li-containing crystals tend to appear in the glass. Therefore, Li in the glass of the present invention + The content is 2-6%, preferably 2.5-5.5%, and more preferably 3-5%.

[0042] In some embodiments, Li + / Mg 2+ By controlling the value within the range of 0.28 to 0.8, the tendency for Li2MgF4 crystals to precipitate in the glass is reduced, resulting in higher crystallization resistance. Therefore, Li + / Mg 2+ Preferably, it is 0.28 to 0.8, more preferably 0.3 to 0.75, and even more preferably 0.32 to 0.7.

[0043] In the glass of the present invention, Na + As the content of increases, the Abbe number of the glass decreases. However, the glass of the present invention is Li + If it contains Na in glass, + The presence of Li improves the refractive index of the glass with almost no decrease in the Abbe number, causing the refractive index of the glass to deviate from the typical refractive index-Abbe number relationship of fluorophosphate glasses, which further benefits its application in achromatic optical design. + If it contains Na in glass, + The presence of Na also helps to improve the chemical stability of the glass. However, + If the content of Na is too high, not only will the Abbe number of the glass decrease significantly, but the chemical stability of the glass will also decrease. Therefore, the Na content in the glass of the present invention is + The content is 0-3%, preferably 0.3-2%, and more preferably 0.4-1%.

[0044] In some embodiments, Li + / ( Li + +Na +By controlling this to 0.5 or higher, preferably 0.6 or higher, and more preferably 0.75 or higher, the refractive index and Abbe number of the glass are more likely to reach the target values ​​of the present invention.

[0045] P 5+ This is a necessary component for the glass of the present invention. In fluorophosphate glass, within a certain range, P 5+ By increasing the content of P, the crystallization resistance of the glass can be significantly improved. However, P 5+ If the content is too high, the Abbe number of the glass will decrease significantly. Therefore, P 5+ The content is 1-9%, preferably 2-8.5%, and more preferably 3-8%.

[0046] K + , Zr 4+ This severely impairs the crystallization resistance of the glass. Therefore, the glass of the present invention preferably has K + It does not contain and / or Zr 4+ It does not contain [the specified ingredient].

[0047] Zn 2+ It can perform the functions of modifying glass, giving it gloss, and improving the chemical stability of glass. However, ZnF2 is a highly toxic raw material. Therefore, the present invention preferably uses Zn 2+ It does not contain [the specified ingredient].

[0048] The glass of the present invention is biotoxic to Be 2+ Pb 2+ , Tl + , and expensive Rb + , Cs + It does not contain ingredients such as those listed above.

[0049] <Anionic components> O 2- It is a component that forms a glass network. 2- This helps improve the crystallization resistance and productivity of glass. However, O 2-If the content of is too high, it becomes difficult to achieve the desired refractive index and dispersion characteristics of the glass of the present invention. Therefore, O 2- The content is 1.5 to 20%, preferably 4 to 18%, and more preferably 7 to 16%.

[0050] F - F can combine with cations contained in the glass of the present invention to form an ionic glass. However, F - If the content of F is too high, the crystallization resistance and productivity of the glass will decrease. Therefore, F - The content is 80-98.5%, preferably 82-96%, and more preferably 84-93%.

[0051] Cl - It has a certain clarifying effect in glass, and Cl - The content range is 0 to 0.5%, preferably 0 to 0.2%, and more preferably 0 to 0.1%.

[0052] O 2- / P 5+ The value of O is mainly related to the form of phosphorus introduction into the glass, and corresponds to different introduction forms. 2- / P 5+ They are different. O on glass 2- If all of it is introduced in the form of phosphorus oxide, then O in glass 2- / P 5+ It is 2.5. 2- / P 5+ If the value of is too large, free oxygen will be present in the glass, and since the free oxygen will be located in the fluorine network, the crystallinity of the glass will decrease. However, in glass, O 2- / P 5+ If the value of is too small, the corresponding raw material is mainly introduced in the form of phosphorus oxide, phosphoric acid, etc., which is easily hygroscopic, toxic, and does not help in protecting the safety of personnel in the production process or controlling the refractive index stability of the glass. Therefore, in the glass of the present invention, O 2- / P 5+Preferably, it is 2.5 to 3.5, more preferably 2.5 to 3.25, and even more preferably 2.5 to 3.0.

[0053] The performance of the optical glass of the present invention will be described below.

[0054] <Refractive index and Abbe number> Refractive index of glass (n d ) and Abbe number (ν d ) is measured by the standard method specified in GB / T 7962.1-2010.

[0055] In some embodiments, the refractive index (n) of the glass of the present invention d ) is 1.4200~1.4350, and the Abbe number (ν d The preferred refractive index (n) of the glass of the present invention is 95 to 99. d ) and Abbe number (ν d ) is located in the region enclosed by the lines connecting the four points (refractive index 1.425, Abbe number 95.50), (refractive index 1.4340, Abbe number 96.50), (refractive index 1.4210, Abbe number 97.80), and (refractive index 1.43170, Abbe number 98.50) in the diagram of the optical glass region. A more preferred refractive index of the glass of the present invention is (n d ) and Abbe number (ν d In the diagram of the optical glass region, it is located in the region enclosed by lines connecting the four points (refractive index 1.4255, Abbe number 96.10), (refractive index 1.4335, Abbe number 96.80), (refractive index 1.4330, Abbe number 97.55), and (refractive index 1.4317, Abbe number 98.20).

[0056] <Crystallization resistance> For fluorophosphate glasses, especially ultra-low dispersion fluorophosphate glasses, crystallization resistance is the most important performance characteristic, directly determining whether a stable product can be formed and applied to optical design. Low crystallization resistance leads to problems such as a high number of inclusions in the glass, low production yield, difficulty in controlling the melting and molding processes, and unsuitability for hot working processes.

[0057] This invention characterizes the crystallization resistance of glass using differential thermal analysis. A sample of glass free of crystals, internal defects, and a casting surface layer is pulverized into a powder, and differential thermal analysis is performed, with the heating rate fixed at 10°C / min. The glass transition temperature (T) of the glass is determined from the differential thermal analysis curve. g ), main crystallization peak temperature (T x ), the lower limit temperature of the liquid phase of glass (T m ) is obtained. In the present invention, the relationship between the above temperature and the differential thermal analysis curve is as follows.

[0058] T g : The temperature at the junction between the lowest endothermic peak and the baseline in the differential thermal analysis curve. T x : The temperature corresponding to the peak position of the lowest crystallization exothermic peak in the differential thermal analysis curve. In fluorophosphate glasses, this crystallization peak is generally the main crystallization peak. T m : The temperature corresponding to the peak position of the highest crystallization exothermic peak in the differential thermal analysis curve. The crystallization resistance of glass (T x -T g ) / (T m -T g ) is evaluated. Here, (T x -T g The larger the (T) value, the more the glass can withstand a higher degree of supercooling without crystallizing, indicating a stronger ability to resist crystallization during the molding process. m -T g The larger the ) is, the more rapidly the temperature of the molten glass needs to be lowered during the molding process to avoid crystallization, and as a result the glass becomes T x They stay in the vicinity for longer periods and have a weaker resistance to crystallization.

[0059] In some embodiments, the glass of the present invention (T x -T g ) / (T m -T gThe ratio is 0.36 or higher, preferably 0.38 or higher, and more preferably 0.40 or higher.

[0060] <Water resistance> Water resistance of glass (D w ) is measured according to the method specified in GB / T 17129.

[0061] In some embodiments, the water resistance of the glass of the present invention (D w ) is at least Grade 3, preferably Grade 2 or higher.

[0062] <Acid resistance> Acid resistance of glass (D A ) is measured according to the method specified in GB / T 17129.

[0063] In some embodiments, the acid resistance (D) of the glass of the present invention is determined to be the same as that of the present invention. A ) is at least Grade 4, preferably Grade 3 or higher.

[0064] [Manufacturing method] The method for manufacturing the glass of the present invention is as follows: Depending on the composition of the glass, ordinary glass raw materials (e.g., fluorides, phosphates, metaphosphates, phosphorus oxides, phosphoric acid, oxides, hydroxides, etc.) are weighed and mixed. The mixed raw materials are placed in a melting apparatus, heated, and melted. The melting process of the glass raw materials of the present invention is generally completed in a platinum chamber. Before the start of the melting process, in order to avoid the glass raw materials absorbing moisture, it is necessary to dry the glass raw materials in a heating furnace having a certain drying temperature, preferably a drying temperature higher than 120°C. The melting temperature of the glass raw materials of the present invention (material melting temperature) is preferably 800 to 1100°C, more preferably 825 to 1050°C, and even more preferably 850 to 1000°C. After the above raw materials have been completely melted and vitrified, the glass temperature is raised or lowered to its clarification temperature and held for a certain period of time to clarify the molten glass. The clarification temperature for the glass of the present invention is preferably 750 to 1100°C, more preferably 775 to 1050°C, and even more preferably 800 to 1000°C. The clarification time is preferably 0.2 to 12 hours, more preferably 0.5 to 11 hours, and even more preferably 1 to 10 hours. The molten glass after the clarification process is homogenized by stirring, continuously supplied to a glass outflow pipeline and discharged, rapidly cooled and solidified in a glass mold to obtain a glass composition, or the molten glass is poured from a molten container into a mold of a specific shape, and glass is obtained through a process of rapid cooling, solidification, and annealing.

[0065] In the melting and clarification process of the glass of the present invention, it is necessary to use appropriate equipment and process methods in order to avoid the volatilization of element F as much as possible. Similarly, in the mixing, weighing, and melting process of the raw materials of the glass of the present invention, it is necessary to use appropriate equipment and processes in order to avoid moisture absorption by the raw materials. Within the scope of the above principles and process parameters, a person skilled in the art can appropriately select the raw materials, process methods, and process parameters according to the characteristics of the equipment and the actual needs.

[0066] <Examples of optical glass applications> To provide a clearer interpretation and explanation of the technical means of the present invention, the following non-limiting examples are provided. In these examples, optical glass having the compositions shown in Tables 1 to 4 was obtained using the optical glass manufacturing method described above. Furthermore, the properties of each glass were measured using the measurement method described in the present invention, and the measurement results are shown in Tables 1 to 4.

[0067] [Table 1]

[0068] [Table 2]

[0069] [Table 3]

[0070] [Table 4]

[0071] <Examples of optical preforms> The optical glass obtained in Examples 1 to 24 of Tables 1 to 4 was cut to a predetermined size, a release agent consisting of boron nitride powder was uniformly applied to the surface, and then it was heated, softened, and press-molded to produce various lens and prism preforms such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses.

[0072] <Examples of optical elements> By annealing these preforms obtained in the above-described examples of optical preforms, and by reducing and fine-tuning the internal deformation of the glass, the optical properties such as the refractive index reached the desired values.

[0073] Next, each preform was ground and polished 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. An anti-reflective coating may be applied to the surface of the resulting optical elements.

Claims

1. When the components are expressed in mole percentages, the cationic component is Al ３＋ :30-42%, Mg ２＋ : 3-10%, Ca ２＋ :15~27%, Sr ２＋ :15-30%, Ba ２＋ : 1-10%, Y ３＋ : 1-6%, Li ＋ : 2-6%, P ５＋ : Contains 1-9%, As an anion component, O ２－ : 1.5 to 20%, F － : containing 80 to 98.5%, Fluorophosphate optical glass characterized by the following features.

2. The components are expressed in mole percentages as follows: The cation component is La ３＋ : 0-3%, and / or Gd ３＋ : 0-3%, and / or Na ＋ : Contains an additional 0-3%, The fluorophosphate optical glass according to feature 1.

3. When the components are expressed in mole percentages, the cationic component is Al ３＋ :30~42%, Mg ２＋ : 3-10%, Ca ２＋ :15~27%, Sr ２＋ :15-30%, Ba ２＋ : 1-10%, Y ３＋ : 1-6%, Li ＋ : 2-6%, P ５＋ : 1-9%, La ３＋ : 0-3%, Gd ３＋ : 0-3%, Na ＋ : Consists of 0-3%, The anionic component is O ２－ :1.5~20%,F － :80-98.5%, Cl － : Consists of 0-0.5%, Fluorophosphate optical glass characterized by the following features.

4. The above components are expressed in mole percentages, 1) Ca ２＋ / Sr ２＋ The ratio is 0.6 to 1.6, preferably Ca ２＋ / Sr ２＋ The ratio is 0.7 to 1.4, and more preferably Ca ２＋ / Sr ２＋ The fact that it is between 0.75 and 1.35, 2) Y ３＋ +La ３＋ +Gd ３＋ The percentage is 1.5 to 7%, preferably Y ３＋ +La ３＋ +Gd ３＋ The percentage is 2-6%, and more preferably Y ３＋ +La ３＋ +Gd ３＋ The percentage is 2.5-4.5%, 3) Y ３＋ / (La ３＋ +Gd ３＋ ) is 1.0 or more, preferably Y ３＋ / (La ３＋ +Gd ３＋ ) is 2.0 or higher, more preferably Y ３＋ / (La ３＋ +Gd ３＋ ) is between 2.0 and 15.0, 4) Li ＋ / Mg ２＋ The ratio is 0.28 to 0.8, preferably Li ＋ / Mg ２＋ The ratio is 0.3 to 0.75, and more preferably Li ＋ / Mg ２＋ The fact that it is between 0.32 and 0.7, 5) Li ＋ / (Li ＋ +Na ＋ ) is 0.5 or more, preferably Li ＋ / (Li ＋ +Na ＋ ) is 0.6 or more, more preferably Li ＋ / (Li ＋ +Na ＋ ) is 0.75 or higher, and one or more of the following five conditions are met. A fluorophosphate optical glass according to any one of claims 1 to 3.

5. The above components are expressed in mole percentages as follows: ２－ / P ５＋ The ratio is 2.5 to 3.5, preferably O ２－ / P ５＋ The ratio is 2.5 to 3.25, and more preferably O ２－ / P ５＋ The value is between 2.5 and 3.

0. A fluorophosphate optical glass according to any one of claims 1 to 3.

6. When the above components are expressed in mole percentages, Al ３＋ : 33 - 41%, preferably Al ３＋ : 36 - 40%, and / or Mg ２＋ : 4 - 9%, preferably Mg ２＋ : 5 - 8%, and / or Ca ２＋ : 16 - 25%, preferably Ca ２＋ : 17 - 23%, and / or Sr ２＋ : 16 - 28%, preferably Sr ２＋ : 17 - 26%, and / or Ba ２＋ : 2 - 8%, preferably Ba ２＋ : 3 - 6%, and / or Y ３＋ : 1.5 - 5%, preferably Y ３＋ : 2 - 4%, and / or Li ＋ : 2.5 - 5.5%, preferably Li ＋ : 3 - 5%, and / or P ５＋ : 2 - 8.5%, preferably P ５＋ : 3 - 8%, and / or La ３＋ : 0.2 - 2.5%, preferably La ３＋ : 0.3 - 2%, and / or Gd ３＋ : 0.1 - 2.5%, preferably Gd ３＋ : 0.2 - 2%, and / or Na ＋ : 0.3 - 2%, preferably Na ＋ : is 0.4 - 1%. A fluorophosphate optical glass according to any one of claims 1 to 3.

7. When the above components are expressed in mole percentages, O ２－ : 4 to 18%, preferably O ２－ : 7 to 16%, and / or F － : 82 to 96%, preferably F － : 84 to 93%, A fluorophosphate optical glass according to any one of claims 1 to 3.

8. The above components are expressed in mole percentages as follows: Cl － : Further containing 0-0.5%, and / or K ＋ It does not contain and / or Zr ４＋ It does not contain and / or Zn ２＋ It does not contain and / or Be ２＋ It does not contain and / or Pb ２＋ It does not contain and / or Tl ＋ It does not contain and / or Rb ＋ It does not contain and / or Cs ＋ Does not contain The fluorophosphate optical glass according to claim 1 or 2.

9. Refractive index n ｄ It is between 1.4200 and 1.4350, and the Abbe number ν ｄ n is 95 to 99, preferably the refractive index n ｄ and the Abbe number ν ｄ In the diagram of the optical glass region, it is located in the region enclosed by lines connecting four points: a point with a refractive index of 1.4255 and an Abbe number of 96.10, a point with a refractive index of 1.4335 and an Abbe number of 96.80, a point with a refractive index of 1.4330 and an Abbe number of 97.55, and a point with a refractive index of 1.4317 and an Abbe number of 98.

20. A fluorophosphate optical glass according to any one of claims 1 to 3.

10. (T ｘ -T ｇ ) / (T ｍ -T ｇ ) is 0.36 or more, preferably 0.40 or more, and in the formula, the T ｇ This is the temperature at the junction between the lowest endothermic peak and the baseline in the differential thermal analysis curve, and the T ｘ This is the temperature corresponding to the peak position of the lowest crystallization exothermic peak in the differential thermal analysis curve, and T ｍ This is the temperature at which the temperature in the differential thermal analysis curve corresponds to the peak position of the highest crystallization exothermic peak, and / or water resistance D ｗ It is grade 3 or higher, preferably grade 2 or higher, and / or acid-resistant D Ａ It is level 4 or higher, preferably level 3 or higher. A fluorophosphate optical glass according to any one of claims 1 to 3.

11. Made from fluorophosphate optical glass according to any one of claims 1 to 10, An optical preform characterized by the following features.

12. Manufactured from fluorophosphate optical glass according to any one of claims 1 to 10 or optical preform according to claim 11, An optical element characterized by the following features.

Images