Halide glass and optical element

Abstract

Provided are a halide glass having dispersion characteristics comparable to that of fluorite, and an optical element. The halide glass comprises the following components in mole percent: 11%-40% of AlF3, 0.1%-20% of ScF3 and 10%-88.9% of (MgF2 + CaF2 + SrF2 + BaF2).

Description

Technical Field

[0001] This invention relates to halide glasses and optical components. Background Technology

[0002] In optical systems such as cameras, lenses made of low-dispersion materials are used to correct chromatic aberration. Fluorite is a typical example of a low-dispersion material.

[0003] On the other hand, fluorite lacks formability and processability, and manufacturing it into lenses requires a lot of time and cost. Therefore, as alternative materials to fluorite, halide glasses such as fluoride glasses and fluorophosphate glasses, which have Abbe numbers (νd) similar to fluorite, have been studied (Patent Document 1, Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-151493

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-023111 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In addition to its low dispersion, fluorite also exhibits a high partial dispersion ratio (abnormal partial dispersion). Therefore, halide glasses with dispersion characteristics comparable to fluorite have not yet been developed, and further research is needed.

[0010] In view of the above, the object of the present invention is to provide halide glasses and optical elements having dispersion characteristics comparable to fluorite.

[0011] Technical means for solving problems

[0012] Various methods for solving the above-mentioned technical problems in halide glasses and optical components are described.

[0013] The halide glass of Method 1 is characterized by containing, in molar percentage: AlF3 11%~40%, ScF3 0.1%~20%, and (MgF2+CaF2+SrF2+BaF2) 10%~88.9%.

[0014] The halide glass of method 2 preferably contains, in method 1, the following components in mol%: MgF2 0%~30%, CaF2 0%~30%, SrF2 0%~30%, and BaF2 0%~20%.

[0015] The halide glass of method 3 preferably contains 0% to 20% YF3 in method 1 or method 2, by mole%.

[0016] The preferred halide glass of Method 4 is that, in any of Methods 1 to 3, the molar ratio of ScF3 / (AlF3+YF3+ScF3) is 0.01 to 0.5.

[0017] The halide glass of method 5 is characterized by containing, in cation percent: Al 3+ 11%~60%, Sc 3+ 0.1%~20%, (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ 10%~88.9%, and contains F as anion%. - 70%~100%.

[0018] The preferred halide glass of method 6, in method 5, further contains (Cl) based on anion percentage. - +Br - +I - 0%~10%.

[0019] The halide glass of method 7 preferably contains, in method 5 or method 6, Mg, by cation percentage: 2+ 0%~30%, Ca 2+ 0%~30%, Sr 2+ 0%~30%, Ba 2+ 0%~20%.

[0020] The halide glass of method 8 preferably contains, in any of methods 5 to 7, Y, based on cation percent: 3+ 0%~20%.

[0021] The halide glass of Method 9 preferably contains, in any of Methods 5 to 8, less than 0.01% Ln (Ln is at least one selected from Cr, Ce, Nd, Yb, Er, Pr, Sm, Eu, Tb, Dy, Ho and Tm) in cation percent.

[0022] The halide glass of Method 10 preferably has an Abbe number (νd) of 85 to 110 in any of Methods 1 to 9.

[0023] The halide glass of Method 11 is preferably, in any of Methods 1 to 10, a partial dispersion ratio (θg, F) ​​of 0.516 to 0.580.

[0024] The optical element of method 12 is characterized in that it comprises a halide glass of any of methods 1 to 11.

[0025] Invention Effects

[0026] According to the present invention, it is possible to provide halide glasses and optical elements having dispersion characteristics comparable to fluorite. Detailed Implementation

[0027] (Halide glass A)

[0028] In one embodiment of the present invention, the halide glass is characterized by containing, in mole percent: AlF3 11%~40%, ScF3 0.1%~20%, and MgF2+CaF2+SrF2+BaF2 10%~88.9%. The reasons for limiting the content of each component as described above are explained below. It should be noted that in the description of the content of each component in halide glass A, the % expression indicates mole percent unless otherwise specified.

[0029] AlF3 is an essential component for improving stability against crystallization. The content of AlF3 is preferably 11% to 40%. More specifically, the lower limit of the AlF3 content is preferably 11% or more, 12% or more, 15% or more, or 20% or more, and particularly preferably 25% or more. The upper limit of the AlF3 content is preferably 40% or less, 35% or less, and particularly preferably 33% or less. If the AlF3 content is too low, crystallization is easily achieved. If the AlF3 content is too high, the partial dispersion ratio (θg, F) ​​is easily reduced.

[0030] ScF3 is an essential component that particularly facilitates an increase in the partial dispersion ratio (θg, F). The content of ScF3 is preferably 0.1% to 20%. More specifically, the lower limit of the ScF3 content is preferably 0.1% or more, 1% or more, 1.5% or more, 2% or more, and particularly preferably 5% or more. The upper limit of the ScF3 content is preferably 20% or less, and particularly preferably 19% or less. If the ScF3 content is too low, the partial dispersion ratio (θg, F) ​​tends to decrease. If the ScF3 content is too high, crystallization is likely to occur.

[0031] MgF2, CaF2, SrF2, and BaF2 are components that easily improve the stability of glass. The preferred content of MgF2+CaF2+SrF2+BaF2 is 10% to 88.9%. More specifically, the lower limit of the MgF2+CaF2+SrF2+BaF2 content is preferably 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more, and particularly preferably 45% or more. The upper limit of the MgF2+CaF2+SrF2+BaF2 content is preferably 88.9% or less, 88.8% or less, 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less, and particularly preferably 57.5% or less. If the MgF2+CaF2+SrF2+BaF2 content is too low, it is difficult to obtain the above-mentioned effects. If the content of MgF2+CaF2+SrF2+BaF2 is too high, the dispersion ratio (θg, F) ​​will tend to decrease. It should be noted that "MgF2+CaF2+SrF2+BaF2" refers to the total amount of MgF2, CaF2, SrF2, and BaF2. Furthermore, the preferred contents of each component (MgF2, CaF2, SrF2, and BaF2) are described below.

[0032] MgF2 is a component that reduces dispersion. The content of MgF2 is preferably 0% to 30%. More specifically, the lower limit of the MgF2 content is preferably 0% or more, 1% or more, 5% or more, or 10% or more, and particularly preferably 15% or more. The upper limit of the MgF2 content is preferably 30% or less, 28% or less, or 26% or less, and particularly preferably 24% or less. If the MgF2 content is too high, crystallization is likely to occur.

[0033] CaF2 is a component that easily improves the stability of glass. The preferred CaF2 content is 0% to 30%. More specifically, the lower limit of CaF2 content is preferably 0% or more, 1% or more, 5% or more, or 8% or more, and particularly preferably 10% or more. The upper limit of CaF2 content is preferably 30% or less, 27% or less, 25% or less, or 22% or less, and particularly preferably 20% or less. If the CaF2 content is too high, the Abbe number (νd) tends to increase. Furthermore, the partial dispersion ratio (θg, F) ​​tends to decrease.

[0034] SrF2 is a component that improves stability during glass transition. The content of SrF2 is preferably 0% to 30%. More specifically, the lower limit of the SrF2 content is preferably 0% or more, 1% or more, 5% or more, or 8% or more, and particularly preferably 10% or more. The upper limit of the SrF2 content is preferably 30% or less, 29% or less, 27% or less, 25% or less, or 23% or less, and particularly preferably 20% or less. If the content of SrF2 is too high, crystallization is likely to occur.

[0035] BaF2 is a component that improves stability during crystallization and readily increases the Abbe number (νd). The content of BaF2 is preferably 0% to 20%. More specifically, the lower limit of the BaF2 content is preferably 0% or more, 1% or more, or 3% or more, and particularly preferably 5% or more. The upper limit of the BaF2 content is preferably 20% or less, and particularly preferably 17% or less. If the BaF2 content is too high, the partial dispersion ratio (θg, F) ​​tends to decrease.

[0036] YF3 is a component that can improve the stability of crystallization. The content of YF3 is preferably 0% to 20%. More specifically, the lower limit of the YF3 content is preferably 0% or more, 0.1% or more, or 1% or more, and particularly preferably 3% or more. The upper limit of the YF3 content is preferably 20% or less, 19% or less, 15% or less, or 13% or less, and particularly preferably 11% or less. If the content of YF3 is too low, the partial dispersion ratio (θg, F) ​​is prone to decrease; if the content of YF3 is too high, crystallization is prone to occur.

[0037] The molar ratio ScF3 / (AlF3+YF3+ScF3) is preferably 0.01 to 0.5. More specifically, the upper limit of ScF3 / (AlF3+YF3+ScF3) is preferably 0.5 or less, 0.4 or less, and particularly preferably 0.3 or less. The lower limit of ScF3 / (AlF3+YF3+ScF3) is preferably 0.01 or more, and particularly preferably 0.1 or more. By satisfying the above values, the Abbe number (νd) can be easily increased. It should be noted that "ScF3 / (AlF3+YF3+ScF3)" refers to the value obtained by dividing the content of ScF3 by the total amount of AlF3, YF3, and ScF3.

[0038] The halide glass of the present invention may also contain other fluoride components. For example, it may also contain ZrF4, HfF4, GaF3, InF3, and ZnF2. More specifically, it may also contain ZrF4, HfF4, GaF3, InF3, and ZnF2 in an aggregate of 15% or less, 10% or less, and particularly 5% or less.

[0039] The halide glass of the present invention is preferably a so-called fluoride glass with fluoride as the main component. Of course, in addition to fluoride, the halide glass of the present invention may also contain any of the following components.

[0040] The halide glass of the present invention preferably contains chloride components such as AlCl3, YCl3, LaCl3, GdCl3, YbCl3, MgCl2, CaCl2, SrCl2, and BaCl2. The presence of chloride components easily improves the stability of the glass. More specifically, the upper limit of the total amount of chloride components is preferably 15% or less, 10% or less, and particularly preferably 5% or less. The lower limit of the total amount of chloride components is, for example, preferably 0% or more, 0.1% or more, and particularly preferably 0.5% or more. Furthermore, the content of each chloride component is preferably 15% or less, 10% or less, and particularly preferably 5% or less, and the lower limit of the content of each component can be, for example, 0% or more, 0.1% or more, and particularly preferably 0.5% or more. In addition, from the viewpoint of raw material cost, BaCl2 is preferably contained in the above-mentioned chloride components. For example, it is preferred to contain 0% to 15%, 0% to 10%, and particularly preferably 0.1% to 10% BaCl2.

[0041] The halide glass of the present invention preferably contains phosphate components such as Al(PO3)3, Mg(PO3)2, Ca(PO3)2, Sr(PO3)2, Ba(PO3)2, P2O5, and KPF6. The presence of phosphate components improves the stability of the glass. From the viewpoint of reliably enjoying the effects of the present invention, the total content of the aforementioned phosphate components is preferably 15% or less, 10% or less, and particularly preferably 5% or less. The lower limit of the total amount of phosphate components can be, for example, set to 0% or more, 0.1% or more, and particularly 0.5% or more.

[0042] (Halide Glass B)

[0043] In one embodiment of the invention, the halide glass is characterized by containing, in cation percent: Al 3+ 11%~60%, Sc 3+ 0.1%~20%, Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ 10%~88.9%, and contains F as anion%. - 70%~100%. The reasons for limiting the content of each component as described above are explained below. It should be noted that, unless otherwise specified, the % expression in the description of the content of each component in halide glass B represents cation % or anion %.

[0044] Al 3+ It is an essential component that can improve the stability of crystallization. Al 3+ The preferred content is 11% to 60%. More specifically, Al 3+The preferred lower limit of its content is 11% or more, 12% or more, 15% or more, or 20% or more, and particularly preferred to be 25% or more. 3+ The upper limit of its content is preferably below 60%, 55%, 50%, 45%, 40%, or 35%, and particularly preferably below 33%. If Al 3+ If the content of Al is too low, it is prone to crystallization. 3+ If the content of is too high, the partial dispersion ratio (θg, F) ​​is likely to decrease.

[0045] Sc 3+ It is an essential component that particularly readily increases the partial dispersion ratio (θg, F). Sc 3+ The preferred content is 0.1% to 20%. More specifically, Sc 3+ The preferred lower limit of its content is 0.1% or more, 1% or more, 1.5% or more, or 2% or more, and particularly preferred is 5% or more. Sc 3+ The upper limit of the content of [specific ingredient] is preferably 20% or less, particularly preferably 19% or less. If Sc 3+ If the content of Sc is too low, the partial dispersion ratio (θg, F) ​​is easily reduced. 3+ If the content is too high, it is prone to crystallization.

[0046] Mg 2+ Ca 2+ 、Sr 2+ and Ba 2+ It is a component that easily improves the stability of glass. Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The preferred content is 10% to 88.9%. More specifically, Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The preferred lower limit of its content is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more, and particularly preferred to be 45% or more. Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of its content is preferably below 88.9%, 88.8%, 80%, 75%, 70%, 65%, and 60%, and particularly preferably below 57.5%. If Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ If the content of Mg is too low, the above-mentioned effects will be difficult to achieve. 2+ +Ca 2++Sr 2+ +Ba 2+ Excessive Mg content can easily lead to a decrease in the partial dispersion ratio (θg, F). It should be noted that "Mg..." 2+ +Ca 2+ +Sr 2+ +Ba 2+ "Refers to Mg" 2+ Ca 2+ 、Sr 2+ and Ba 2+ The total amount. In addition, Mg 2+ Ca 2+ 、Sr 2+ and Ba 2+ The preferred amounts of each component are as follows.

[0047] Mg 2+ It is a component that reduces dispersion. Mg 2+ The preferred content is 0% to 30%. More specifically, Mg 2+ The lower limit of its content is preferably 0% or more, 1% or more, 5% or more, or 10% or more, and particularly preferably 15% or more. Mg 2+ The upper limit of its content is preferably 30% or less, 28% or less, or 26% or less, and particularly preferably 24% or less. If Mg 2+ If the content is too high, it is prone to crystallization.

[0048] Ca 2+ It is a component that easily improves the stability of glass. Ca 2+ The preferred content is 0% to 30%. More specifically, Ca... 2+ The lower limit of Ca content is preferably 0% or more, 1% or more, 5% or more, 8% or more, and particularly preferably 10% or more. 2+ The upper limit of the content is preferably below 30%, below 27%, below 25%, or below 22%, and particularly preferably below 20%. If Ca 2+ Excessive content of certain substances can easily lead to a higher Abbe number (νd). Additionally, the partial dispersion ratio (θg, F) ​​can easily decrease.

[0049] Sr 2+ It is a component that improves stability during vitrification. Sr 2+ The preferred content is 0% to 30%. More specifically, Sr 2+ The lower limit of its content is preferably 0% or more, 1% or more, 5% or more, or 8% or more, and particularly preferably 10% or more. Sr 2+ The upper limit of its content is preferably 30% or less, 29% or less, 27% or less, 25% or less, or 23% or less, and particularly preferably 20% or less. If Sr 2+ If the content is too high, it is prone to crystallization.

[0050] Ba 2+ It is a component that improves stability to crystallization and readily increases the Abbe number (νd). Ba 2+ The preferred content is 0% to 20%. More specifically, Ba 2+ The lower limit of its content is preferably 0% or more, 1% or more, or 3% or more, and particularly preferably 5% or more. Ba 2+ The upper limit of its content is preferably below 20%, particularly preferably below 17%. If Ba 2+ If the content of is too high, the partial dispersion ratio (θg, F) ​​is likely to decrease.

[0051] Y 3+ It is a component that can improve the stability of crystallization. Y 3+ The preferred content is 0% to 20%. More specifically, Y 3+ The lower limit of its content is preferably 0% or more, 0.1% or more, or 1% or more, and particularly preferably 3% or more. 3+ The upper limit of its content is preferably below 20%, below 19%, below 15%, below 13%, and particularly preferably below 11%. If Y 3+ If the content of Y is too low, the partial dispersion ratio (θg, F) ​​is easily reduced. 3+ If the content is too high, it is prone to crystallization.

[0052] Cation ratio Sc 3+ / (Al) 3+ +Y 3+ +Sc 3+ The preferred value is 0.01~0.5. More specifically, Sc 3+ / (Al) 3+ +Y 3+ +Sc 3+ The upper limit of ) is preferably 0.5 or less, and particularly preferably 0.3 or less. Sc 3+ / (Al) 3+ +Y 3+ +Sc 3+ The lower limit of ) is preferably 0.01 or higher, and particularly preferably 0.1 or higher. By satisfying the above values, it is easy to increase the Abbe number (νd). It should be noted that "Sc 3+ / (Al) 3+ +Y 3+ +Sc 3+ ")" refers to Sc 3+ The content divided by Al 3+ Y 3+ and Sc 3+ The value obtained from the total amount.

[0053] The halide glass of the present invention may also contain other cationic components. For example, it may contain Zr.4+ Hf 4+ Ga 3 + In 3+ and Zn 2+ At least one of the selected ingredients. For example, it may also contain less than 15%, less than 10%, and especially less than 5% Zr in total. 4+ Hf 4+ Ga 3+ In 3+ and Zn 2+ .

[0054] In the halide glass of the present invention, the content of Ln (Ln being at least one selected from Cr, Ce, Nd, Yb, Er, Pr, Sm, Eu, Tb, Dy, Ho, and Tm) is preferably less than 0.01%, less than 0.001%, and particularly preferably absent. When the content of these components is high, the glass is prone to devitrification. Furthermore, halide glasses exhibit coloration, which may make them difficult to use as a substitute for fluorite. Additionally, as the valence of Cr, trivalent (Cr... 3+ ), hexavalent (Cr) 6+ ), but not limited to this. As a valence of Ce, a trivalent (Ce) can be exemplified. 3+ ), tetravalent (Ce 4+ ), but not limited to this. As a valence of Nd, an example of trivalent (Nd) can be found. 3+ However, it is not limited to this. As a valence of Yb, an example of trivalent (Yb) can be given. 3+ ), but not limited to this. As a valence of Er, an example of a trivalent (Er) can be found. 3+ ), but not limited to this. As a valence of Pr, an example of trivalent (Pr) can be given. 3+ ), but not limited to this. As the valence of Sm, a trivalent (Sm) can be exemplified. 3+ However, it is not limited to this. As a valence of Eu, trivalent (Eu) can be exemplified. 3+ ), but not limited to this. As the price of Tb, an example of a 3-price (Tb) can be given. 3+ ), 4-valent (Tb 4+ ), but not limited to this. As a valence of Dy, an example of trivalent (Dy) can be found. 3+ (), but not limited to this. As a valence of Ho, an example of a trivalent (Ho) can be found. 3+ ), but not limited to this. As a valence of Tm, a trivalent valence (Tm) can be exemplified. 3+ (but not limited to this).

[0055] F - It is an essential component for forming the halide glass of this invention. F - The preferred content is 70% to 100%. More specifically, F -The lower limit of its content is preferably 70% or higher, 80% or higher, or 90% or higher, and particularly preferably 95% or higher. If F - If the content is too low, vitrification will be difficult. - The upper limit of its content is preferably below 100% or 99.9%, and particularly preferably below 99.6%. However, in order to contain F... - Other anionic components can also include F - The upper limit for its content is set below 95%, and especially below 90%.

[0056] The halide glass of the present invention may also contain the following anionic components.

[0057] Cl - ,Br - and I - Through F - Components that coexist in glass to enhance stability during crystallization. Cl - +Br - +I - The preferred content is 0% to 10%. - +Br - +I - The lower limit of its content is preferably 0% or more, 0.1% or more, or 0.2% or more, and particularly preferably 0.3% or more. Cl - +Br - +I - The upper limit of its content is preferably below 10%, below 6%, below 5%, and particularly preferably below 3%. If Cl - +Br - +I - Excessive Cl content can easily lead to problems such as glass devitrification, phase separation, and deterioration of weather resistance. It should be noted that "Cl..." - +Br - +I - "Indicates Cl - ,Br - and I - The total amount.

[0058] Cl - Through F - Components that coexist in glass and readily and significantly improve stability against crystallization. Cl - The preferred content is 0% to 10%. - The lower limit of its content is preferably 0% or more, 0.1% or more, or 0.2% or more, and particularly preferably 0.3% or more. Cl - The upper limit of its content is preferably below 10%, below 6%, below 5%, and particularly preferably below 3%. If Cl -Excessive content of certain substances can easily lead to problems such as glass devitrification, phase separation, and deterioration of weather resistance.

[0059] Br - Through F - Components that coexist in glass and readily improve stability against crystallization. Br - The preferred content is 0% to 10%. Br - The lower limit of its content is preferably 0% or more, 0.1% or more, or 0.2% or more, and particularly preferably 0.3% or more. Br - The upper limit of its content is preferably below 10%, below 6%, below 5%, and particularly preferably below 3%. If Br - Excessive content of certain substances can easily lead to problems such as glass devitrification, phase separation, and deterioration of weather resistance.

[0060] I - Through F - Components that coexist in glass and readily improve its stability during crystallization. - The preferred content is 0% to 10%. - The lower limit of its content is preferably 0% or more, 0.1% or more, or 0.2% or more, and particularly preferably 0.3% or more. - The upper limit of its content is preferably below 10%, below 6%, below 5%, and particularly preferably below 3%. If I - Excessive content of certain substances can easily lead to problems such as glass devitrification, phase separation, and deterioration of weather resistance.

[0061] The halide glasses A and B of the present invention, by satisfying the above-described composition, are able to possess dispersion characteristics comparable to fluorite. For example, the halide glasses of the present invention preferably have an Abbe number (vd) of 85 to 110 and a partial dispersion ratio (θg, F) ​​of 0.515 to 0.550.

[0062] The Abbe number (vd) is preferably 85 to 110. More specifically, the lower limit of the Abbe number (vd) is preferably 85 or more, 90 or more, 91 or more, or 93 or more, and particularly preferably 95 or more. The upper limit of the Abbe number (vd) is preferably 110 or less or 100 or less, and particularly preferably 99 or less. By having the above-mentioned Abbe number (vd), the halide glass of the present invention can be used as a substitute for fluorite.

[0063] The partial dispersion ratio (θg, F) ​​is preferably 0.516 to 0.580. More specifically, the lower limit of the partial dispersion ratio (θg, F) ​​is preferably 0.516 or more, 0.520 or more, or 0.525 or more, and particularly preferably 0.530 or more. The upper limit of the partial dispersion ratio (θg, F) ​​is preferably 0.580 or less, 0.550 or less, and particularly preferably 0.545 or less. By having the above-mentioned partial dispersion ratio (θg, F), the halide glass of the present invention exhibits exceptional partial dispersion comparable to fluorite. Therefore, it can be used as a substitute material for fluorite.

[0064] The refractive index (nd) of the halide glass of the present invention is preferably 1.39 to 1.5, and particularly preferably 1.40 to 1.45. Having the above-mentioned refractive index, the halide glass of the present invention is also suitable as a substitute for fluorite, which is comparable to fluorite in terms of refractive index.

[0065] The halide glass of the present invention is preferably used as an optical element. In other words, the optical element of the present invention is characterized by comprising the halide glass of the present invention described above. Examples of optical elements include optical lenses, prisms, filters, diffraction gratings, optical fibers, etc., with optical lenses being particularly preferred. As an optical lens, a special low-dispersion lens is preferred.

[0066] The halide glass of the present invention can be manufactured, for example, as follows.

[0067] First, the raw materials are weighed to obtain a raw material batch, which is then weighed to achieve the desired composition. Next, the raw material batch is placed into a crucible. Suitable crucibles include platinum crucibles, gold crucibles, and glassy carbon crucibles.

[0068] Next, the raw material batch is melted at approximately 900°C to 1100°C. The melting time can be set to, for example, 1 to 2 hours. Then, after the melt is rapidly cooled, it is slowly deformed near the glass transition temperature to obtain a halide glass.

[0069] Example

[0070] The present invention will now be described based on embodiments, but the present invention is not limited to these embodiments.

[0071] Tables 1 to 10 represent Examples 1 to 95 and Comparative Example 1 of the present invention.

[0072] [Table 1]

[0073]

[0074] [Table 2]

[0075]

[0076] [Table 3]

[0077]

[0078] [Table 4]

[0079]

[0080] [Table 5]

[0081]

[0082] [Table 6]

[0083]

[0084] [Table 7]

[0085]

[0086] [Table 8]

[0087]

[0088] [Table 9]

[0089]

[0090] [Table 10]

[0091]

[0092] The samples were prepared in the following order. First, the raw materials were weighed to obtain a batch of raw materials with the compositions described in Tables 1 to 10. Next, the batch of raw materials was placed in a crucible and melted at 900°C to 1100°C. The melt was then rapidly cooled to obtain the sample. The refractive index of the obtained sample was measured, and the Abbe number (νd) and partial dispersion ratio (θg, F) ​​were determined. The results of the refractive index (nd), Abbe number (νd), and partial dispersion ratio (θg, F) ​​are shown in Tables 1 to 10.

[0093] The refractive index was determined using the well-known V-block method. The measurement was performed using a Kalnew precision refractometer (Shimadzu Corporation, KPR-2000).

[0094] The Abbe number (νd) and partial dispersion ratio (θg, F) ​​are calculated using the measured values ​​of refractive indices nd (587.56 nm), nC (656.27 nm), nF (486.07 nm), and ng (435.83 nm) by the following formula.

[0095] νd = (nd-1) / (nF-nC)

[0096] θg, F=(ng-nF) / (nF-nC)

[0097] As shown in Tables 1 to 10, the refractive index (nd) of Examples 1 to 95 is 1.41 or higher, the Abbe number (vd) is 85 or higher, and the partial dispersion ratio (θg, F) ​​is 0.516 or higher. On the other hand, the partial dispersion ratio (θg, F) ​​of Comparative Example 1 is less than 0.516.

[0098] Industrial practicality

[0099] The halide glass of this invention can be used as optical components such as lenses, prisms, filters, diffraction gratings, and optical fibers. It is particularly suitable for use as a special low-dispersion lens.

Claims

1. A halide glass, characterized in that, It contains, in molar percentage: AlF3 11%~40%, ScF3 0.1%~20%, and (MgF2+CaF2+SrF2+BaF2) 10%~88.9%.

2. The halide glass as claimed in claim 1, wherein, It also contains, in molar percentage: MgF2 0%~30%, CaF2 0%~30%, SrF2 0%~30%, BaF2 0%~20%.

3. The halide glass according to claim 1 or 2, wherein, It also contains, in molar percentages: YF3 0%~20%.

4. The halide glass according to claim 1 or 2, wherein, In terms of molar ratio, ScF3 / (AlF3+YF3+ScF3) is 0.01~0.

5.

5. A halide glass, characterized in that, Contains Al (in cationic percentage) 3+ 11%~60%, Sc 3+ 0.1%~20%, (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ 10%~88.9%, and contains F as anion%. - 70%~100%.

6. The halide glass according to claim 5, wherein, It also contains, in terms of anion percentage: (Cl) - +Br - +I - 0%~10%.

7. The halide glass according to claim 5 or 6, wherein, It also contains, by cation percentage: Mg 2+ 0%~30%, Ca 2+ 0%~30%, Sr 2+ 0%~30%, Ba 2+ 0%~20%.

8. The halide glass according to claim 5 or 6, wherein, It also contains, in cation percent: Y 3+ 0%~20%.

9. The halide glass according to claim 5 or 6, wherein, It also contains less than 0.01% Ln, calculated as cations, wherein Ln is at least one selected from Cr, Ce, Nd, Yb, Er, Pr, Sm, Eu, Tb, Dy, Ho and Tm.

10. The halide glass according to claim 1 or 5, wherein, The Abbe number (vd) is 85-110.

11. The halide glass according to claim 1 or 5, wherein, The partial dispersion ratio (θg, F) ​​is 0.516~0.

580.

12. An optical element, characterized in that, It comprises the halide glass as described in claim 1 or 5.

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