TWI743073B - Optical glass, preform and optical element - Google Patents

Abstract

The present invention obtains an _{optical glass whose refractive index (n d} ) and Abbe number (ν _d ) are in the required range and the partial dispersion ratio (θg, F) is small. The optical glass of the present invention contains 20.0-60.0% of SiO ₂ component and 15.0-50.0% of Nb ₂ O ₅ component based on the mass% of the oxide conversion composition. The partial dispersion ratio (θg, F) is equal to the Abbe number ( ν _d ) satisfy the relationship of (-0.00256×ν _d ＋0.637)≦(θg,F)≦(-0.00256×ν _d ＋0.684).

Description

Optical glass, preform and optical element

The invention relates to an optical glass, a preform and an optical element.

Optical systems such as digital cameras or camcorders include blurs called aberrations, although the blurs can vary in size. The aberrations are classified into monochromatic aberrations and chromatic aberrations. In particular, chromatic aberrations strongly depend on the material properties of the lens used in the optical system. Generally speaking, chromatic aberrations are corrected by combining a low-dispersion convex lens and a high-dispersion concave lens, but this combination can only correct aberrations in the red area and the green area, leaving aberrations in the blue area. The aberration of the blue area that has not been removed is called the secondary spectrum. In order to correct the secondary spectrum, it is necessary to perform an optical design that adds the g-line (435.835 nm) in the blue region. At this time, the partial dispersion ratio (θg, F) is used as an index of the optical characteristics that the optical design focuses on. In the above-mentioned optical system combining a low-dispersion lens and a high-dispersion lens, by using an optical material with a larger partial dispersion ratio (θg, F) for the lens on the low-dispersion side, and using a partial dispersion for the lens on the high-dispersion side An optical material with a smaller ratio (θg, F) can correct the secondary spectrum well. The partial dispersion ratio (θg, F) is represented by the following formula (1). θg，F=(n _g －n _F )/(n _F －n _C )・・・・・・・(1) In optical glass, the partial dispersion ratio (θg, F) representing the partial dispersion in the short wavelength region There is a roughly linear relationship with Abbe number (ν _{d ).} The straight line representing this relationship uses the partial dispersion ratio (θg, F) on the vertical axis and the Abbe number (ν _d ) on the horizontal axis. By drawing the partial dispersion ratio and Abbe of NSL7 and PBM2 The straight line that connects the two points of the number is called the normal line (refer to Figure 1). Although the standard glass that becomes the benchmark of the normal line varies with each optical glass manufacturer, each company defines it with roughly the same slope and intercept. (NSL7 and PBM2 are optical glasses manufactured by OHARA Co., Ltd. The Abbe number (ν _d ) of PBM2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν _d ) of NSL7 is 60.5. The partial dispersion ratio (θg, F) is 0.5436). In recent years, according to the requirements in optical design, as optical materials with a small partial dispersion ratio (θg, F), glass with an Abbe number (νd) of 30 or more and 47 or less has been used. _{Here, as conventional glasses having an Abbe number (ν d} ) of 30 or more and 47 or less, for example, optical glasses shown in Japanese Patent Documents 1 to 3 are known. On the other hand, in an optical material with a small partial dispersion ratio (θg, F), the components (Nb ₂ O ₅ component, B ₂ O ₃ component, Li ₂ O component) contained in order to obtain excellent optical properties, And there is a tendency for chemical durability to deteriorate. These optical glasses may have fog or interference film on the surface of the glass due to the polishing liquid, water vapor in the atmosphere, carbon dioxide, etc. during the processing or storage period. These phenomena are generally referred to as "whitening" and "bluish". It becomes a problem as a major defect when used as a lens. Furthermore, in recent years, automotive lenses, interchangeable lenses, etc., are often used in various environments, and there is a need for an optical glass that does not cause discoloration. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2002-029777 [Patent Document 2] Japanese Patent Laid-Open No. 2008-239478 [Patent Document 3] Japanese Patent Laid-Open No. 2003-054983 Bulletin

[Problems to be Solved by the Invention] However, the partial dispersion ratio of the glass disclosed in Patent Document 1 is not small, and it is not sufficient to be used as a lens for correcting the above-mentioned secondary spectrum. In addition, the glass disclosed in Patent Document 1 has a low transmittance, and therefore cannot be said to have sufficient optical properties. In addition, the glass disclosed in Patent Document 2 has a relatively small partial dispersion ratio, but has a large Abbe number. Therefore, a glass with a smaller Abbe number is sought. Furthermore, the stability of the glass is poor and the productivity is significantly reduced. In addition, although the glass disclosed in Patent Document 3 has a low glass transition point (Tg), the stability of the glass is poor, and the chemical durability, particularly the surface method weather resistance, is not sufficient. The present invention was completed in view of the above-mentioned problems, and its objective is to obtain _{an optical glass with a refractive index (n d} ) and Abbe number (ν _d ) within a required range and a small partial dispersion ratio (θg, F). In addition, the object of the present invention is to obtain an optical glass with good chemical durability, especially surface method weather resistance. [Technical Means to Solve the Problem] The inventors of the present invention have made great efforts to solve the above-mentioned problems. As a result, they have found that in a _{glass containing SiO 2} and Nb ₂ O ₅ , a high refractive index within the required range can be obtained. Or glass with low Abbe number (high dispersion) and low partial dispersion ratio until the present invention is completed. In addition, the present inventors have also discovered that in a _{glass containing SiO 2} and Nb ₂ O ₅ components, by containing K ₂ O as an essential component, it is possible to obtain good chemical durability, especially good weather resistance by the surface method. grass. (1) An optical glass containing 20.0-60.0% of SiO ₂ component and 10.0-50.0% of Nb ₂ O ₅ component in terms of mass% of oxide conversion composition, and the partial dispersion ratio (θg, F) is higher than that of A The number of shells (ν _d ) satisfies the relationship of (-0.00256×ν _d ＋0.637)≦(θg, F)≦(-0.00256×ν _d ＋0.684). (2) The optical glass as in (1), which contains 0 to 20.0% of ZrO ₂ component in terms of mass% of oxide conversion composition. (3) The optical glass of (1) or (2), which contains 0 to 15.0% of K ₂ O component in terms of mass% of oxide conversion composition. (4) The optical glass of any one of (1) to (3), whose surface method weather resistance is Grade 1 or 2. (5) The optical glass according to any one of (1) to (4), wherein the ZnO component is 0-25.0%, the Li ₂ O component is 0-20.0%, and the Na ₂ O component is 0-20.0%, B ₂ O ₃ component is 0-20.0%, TiO ₂ component is 0-15.0%, MgO component is 0-10.0%, CaO component is 0-10.0%, SrO component is 0-10.0 %, BaO component is 0～10.0%, La ₂ O ₃ component is 0～10.0%, Gd ₂ O ₃ component is 0～10.0%, Y ₂ O ₃ component is 0～10.0%, Yb ₂ O ₃ component is 0 ～10.0%, Ta ₂ O ₅ component is 0～10.0%, WO ₃ component is 0～10.0%, P ₂ O ₅ component is 0～10.0%, GeO ₂ component is 0～10.0%, Al ₂ O ₃ component is 0～10.0%, Ga ₂ O ₃ component is 0～10.0%, Bi ₂ O ₃ component is 0～10.0%, TeO ₂ component is 0～5.0%, SnO ₂ component is 0～5.0%, Sb ₂ O ₃ component is 0～5.0% It is 0～1.0%. (6) For the optical glass of any one of (1) to (5), the mass ratio (Li ₂ O + K ₂ O)/(ZrO ₂ + Li ₂ O) exceeds 0 and does not reach 2.5. (7) The optical glass according to any one of (1) to (6), wherein the sum of the content of the _{SiO 2} component and the Nb ₂ O _{5 component exceeds 50.0%.} (8) The optical glass according to any one of (1) to (7), wherein the Ln ₂ O ₃ component is calculated based on the mass% of the oxide (in the formula, Ln is selected from La, Gd, Y, Yb The mass sum of more than one species in the group of composition) is 0～15.0%; the mass sum of RO component (where R is selected from the group consisting of Mg, Ca, Sr, and Ba) is 0 ~30.0%; _{The total mass of the Rn 2} O component (where Rn is selected from one or more of the group consisting of Li, Na, and K) is 0 to 30.0%. (9) The optical glass according to any one of (1) to (8), which has a refractive index (n _d ) of 1.60 or more and 1.78 or less and an Abbe number (ν _d ) of 28 or more and 47 or less. (10) The optical glass according to any one of (1) to (9), wherein the wavelength (λ ₈₀ ) at which the spectral transmittance is shown as 80% is below 420 nm, and the wavelength at which the spectral transmittance is shown as 5% (λ ₅ ) Is 365 nm or less. (11) A preform used for grinding and/or precision press forming, comprising the optical glass of any one of (1) to (10). (12) An optical element comprising the optical glass of any one of (1) to (10). [Effects of the Invention] According to the present invention, it is possible to obtain a _{glass having a refractive index (n d} ) and Abbe number (ν _d ) in a desired range and having a low partial dispersion ratio. Furthermore, according to the present invention, it is possible to more economically obtain _{an optical glass whose refractive index (n d} ) and Abbe number (ν _d ) are within the required range and the opal whiteness or devitrification of the glass is reduced in the hot pressing step. Furthermore, according to the present invention, it is possible to obtain refractive index (n _d ) and Abbe number (ν _d ) within the required range and have high refractive index or low Abbe number (high dispersion) and low part within the required range. The glass of the dispersion ratio can obtain an optical glass with good chemical durability while keeping the partial dispersion ratio (θg, F) small.

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如該等表所示，本發明之實施例之光學玻璃之部分分散比(θg，F)與阿貝數(ν_d )滿足(-0.00256×ν_d ＋0.637)≦(θg，F)≦(-0.00256×ν_d ＋0.684)之關係，更詳細而言，滿足(-0.00256×ν_d ＋0.657)≦(θg，F)≦(-0.00256×ν_d ＋0.679)之關係。特別是，實施例(No.B1～No.B52、No.C1～C3)之光學玻璃滿足(-0.00256×ν_d ＋0.657)≦(θg，F)≦(-0.00256×ν_d ＋0.677)之關係。此處，關於本案實施例之玻璃之部分分散比(θg，F)與阿貝數(ν_d )之關係如圖2所示。 本發明之實施例之光學玻璃之折射率(n_d )均為1.60以上，更詳細而言為1.65以上，並且該折射率(n_d )為1.78以下，更詳細而言為1.76以下，為所需範圍內。特別是，實施例(No.A1～No.A28、No.C1～C3)之光學玻璃之折射率(n_d )為1.75以下，更詳細而言為1.73以下。 又，本發明之實施例之光學玻璃之阿貝數(ν_d )均為28以上，更詳細而言為30以上，為所需範圍內。又，本發明之實施例之光學玻璃之阿貝數(ν_d )為47以下，更詳細而言為46以下，為所需範圍內。特別是，實施例(No.A1～No.A28、No.C1～C3)之光學玻璃之阿貝數(ν_d )為43以下。 此外，本發明之實施例之光學玻璃之λ₈₀ (透過率80%時之波長)均為420 nm以下，更詳細而言為400 nm以下。特別是，實施例(No.A1～No.A28、No.C1～C3)之光學玻璃之λ₈₀ (透過率80%時之波長)為390 nm以下。 又，本發明實施例之光學玻璃之λ₅ (透過率5%時之波長)都為365 nm以下，更詳細而言，為345 nm以下，進而詳細地為340 nm以下。特別是，實施例(No.A1～No.A28、No.C1～C3)之光學玻璃之λ₅ (透過率5%時之波長)為335 nm以下。 由此可知，本發明之實施例之光學玻璃相對於可見光之透過率較高而不易著色。 此外，本發明之實施例(No.A1～No.A28、No.C1～C3)之光學玻璃之液相溫度為1200℃以下，更詳細而言為1110℃以下，進而詳細而言為1050℃以下。因此，該等光學玻璃不易引起因再加熱所導致之失透或乳白，故推測具有高再熱壓成形性。 又，本發明實施例(No.B1～No.B52、No.C1～C3)之光學玻璃之表面法耐候性為級1。 因此，明確可知，該等光學玻璃係表面法耐候性優異且不易產生所謂之變色之光學玻璃。 進而，使用本發明之實施例之光學玻璃而形成玻璃塊，對該玻璃塊進行研削及研磨，加工成透鏡及稜鏡之形狀。其結果能夠穩定地加工成各種透鏡及稜鏡之形狀。 再者，比較例(No.b)所記載之光學玻璃雖然滿足所需光學常數(n_d 、ν_d )，但由於部分分散比較大而異常分散性較小，並且透過率亦較差，化學耐久性亦較差，故無法獲得本案發明中作為目標的、折射率(n_d )及阿貝數(ν_d )處於所需之範圍內並且部分分散比(θg，F)較小且表面法耐候性良好之光學玻璃。 以上，基於例示之目的而對本發明進行詳細說明，但請理解本實施例始終僅為例示之目的，能夠由業者在不脫離本發明之思想及範圍之情況下完成多種改變。The optical glass of the present invention contains 20.0-60.0% of SiO ₂ component and 10.0-50.0% of Nb ₂ O ₅ component based on the mass% of oxide conversion composition, and the partial dispersion ratio (θg, F) is equal to the Abbe number ( ν _d ) satisfy the relationship of (-0.00256×ν _d ＋0.637)≦(θg,F)≦(-0.00256×ν _d ＋0.684). In the glass containing SiO ₂ component and Nb ₂ O ₅ component, a glass with high refractive index or low Abbe number (high dispersion) and low partial dispersion ratio within the required range can be obtained. Therefore, it is possible to obtain an optical glass that has the required high refractive index (n _d ) and low Abbe number (ν _d ) and has a small partial dispersion ratio (θg, F), which is useful for reducing the chromatic aberration of the optical system. In particular, the first optical glass contains 20.0-60.0% of SiO ₂ component, 20.0-45.0% of Nb ₂ O ₅ component, 1.0-20.0% of ZrO ₂ component, and has 1.60 or more The refractive index (n _d ) below 1.75 and the Abbe number (ν _d ) above 30 and 47 below, the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) satisfy (-0.00256×ν _d ＋0) .637)≦(θg,F)≦(-0.00256×ν _d ＋0.684). In the first optical glass, in a glass containing SiO ₂ component, Nb ₂ O ₅ component and ZrO ₂ component, a high refractive index or low Abbe number (high dispersion) and low partial dispersion ratio within the required range can be obtained Of glass. Therefore, it is possible to obtain an optical glass that has the required high refractive index (n _d ) and low Abbe number (ν _d ) and has a small partial dispersion ratio (θg, F), which is useful for reducing the chromatic aberration of the optical system. In addition, the second optical glass contains 20.0-60.0% of SiO ₂ component, 10.0-50.0% of Nb ₂ O ₅ component, and more than 0.1 to 15.0% of K ₂ O component in terms of mass% of oxide conversion composition. The dispersion ratio (θg, F) satisfies the relationship between (-0.00256×ν _d ＋0.637)≦(θg,F)≦(-0.00256×ν _{d ＋0.684) and the Abbe number (ν d} ). The surface Method weather resistance is level 1 or 2. In the second optical glass, in a glass containing SiO ₂ component, Nb ₂ O ₅ component, and K ₂ O component, a high refractive index or low Abbe number (high dispersion) and low partial dispersion within the required range can be obtained Compared with glass, especially by containing the K ₂ O component, the adjustment of the required optical constants becomes easier, and it is possible to reduce the occurrence of discoloration while keeping the partial dispersion ratio (θg, F) small. Therefore, it is possible to obtain the following optical glass, which has the required high refractive index (n _d ) and low Abbe number (ν _d ), and the partial dispersion ratio (θg, F) is small, which affects the chromatic aberration of the optical system Reduction is useful, and chemical durability, especially surface method weather resistance is good. Hereinafter, the embodiment of the optical glass of the present invention will be described in detail. The present invention is not limited to the following embodiments at all, and can be implemented with appropriate additions and changes within the scope of the object of the present invention. In addition, the description may be omitted as appropriate for the overlapping descriptions, but this does not limit the gist of the invention. [Glass component] The composition range of each component constituting the optical glass of the present invention will be described below. When there is no special description in this manual, the content of each component is expressed by mass% relative to the total mass of the glass in terms of all oxides. Here, the so-called "oxide conversion composition" is when it is assumed that the oxides, composite salts, metal fluorides, etc. used as the raw materials of the glass constituents of the present invention are all decomposed into oxides during melting. The total mass of oxides is set to 100% by mass, indicating the composition of each component contained in the glass. <Regarding essential components and optional components> The SiO ₂ component is an essential component that promotes stable glass formation and lowers the liquidus temperature, thereby reducing the devitrification (generation of crystals) which is undesirable as an optical glass. In particular, by making _{the content of the SiO 2} component 20.0% or more, it is possible to obtain a glass having excellent devitrification resistance without greatly increasing the partial dispersion ratio. In addition, it is possible to reduce devitrification or coloration during glass formation or reheating. Therefore, _{the content of the SiO 2} component is preferably 20.0%, more preferably 23.0%, still more preferably 25.0%, still more preferably 27.0%, still more preferably 30.0%, still more preferably 32.0% as the lower limit . On the other hand, by making _{the content of the SiO 2} component 60.0% or less, the refractive index is not easily lowered, so that the required high refractive index can be easily obtained, and the increase in the partial dispersion ratio can be suppressed. In addition, it is possible to suppress the decrease in the melting properties of the glass raw material by this. Therefore, _{the content of the SiO 2} component will be preferably 60.0%, more preferably 55.0%, still more preferably 50.0%, still more preferably 48.0%, still more preferably 47.0%, still more preferably 45.0%, and further It is preferably 44.0%, and more preferably 43.0% as the upper limit. As the SiO ₂ component, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like can be used as a raw material. The Nb ₂ O ₅ component is an essential component that can increase the refractive index, reduce the Abbe number and partial dispersion ratio, and improve the devitrification resistance. In particular, by setting _{the content of the Nb 2} O ₅ component to 10.0% or more, the refractive index can be increased and the optical constant can be adjusted to the target within the components within the scope of the present invention, thereby reducing the abnormal dispersibility. Therefore, _{the content of the Nb 2} O ₅ component is preferably 10.0%, more preferably 15.0%, still more preferably 20.0%, more preferably 22.0%, and still more preferably 23.0% as the lower limit. On the other hand, by making _{the content of the Nb 2} O ₅ component 50.0% or less, the material cost of the glass can be reduced. In addition, it is possible to suppress the increase in the melting temperature during glass production and reduce the devitrification caused by the excessive inclusion of the _{Nb 2} O _{5 component.} Furthermore, the chemical durability of the glass can also be deteriorated and improved. Therefore, _{the content of the Nb 2} O ₅ component will be preferably 50.0%, more preferably 45.0%, still more preferably 43.0%, still more preferably 41.5%, still more preferably 40.0%, still more preferably 35.0% , And more preferably 30.0% as the upper limit. For the Nb ₂ O ₅ component, Nb ₂ O ₅ or the like can be used as a raw material. The ZrO ₂ component is a component that can increase the refractive index and Abbe number of the glass, reduce the partial dispersion ratio, and improve the devitrification resistance when it contains more than 0%. It is an essential component especially in the first optical glass. In addition, by containing the ZrO ₂ component, it is possible to reduce devitrification or coloration during glass formation or reheating. Therefore, _{the content of the ZrO 2} component may also be preferably 1.0% or more, more preferably more than 1.0%, still more preferably more than 3.0%, and still more preferably more than 5.0%. On the other hand, by making _{the content of the ZrO 2} component 20.0% or less, devitrification can be reduced, and a more homogeneous glass can be easily obtained. Therefore, _{the content of the ZrO 2} component is preferably 20.0%, more preferably 18.0%, still more preferably 15.0%, still more preferably 13.0%, and still more preferably 10.0% as the upper limit. The ZrO ₂ component can use ZrO ₂ , ZrF _4, etc. as a raw material. The K ₂ O component is an optional component that can improve the solubility of the glass raw material and lower the liquidus temperature when the content exceeds 0%. Especially in the second optical glass, the K ₂ O component is an essential component that can improve the chemical durability. In particular, by containing the content of the K ₂ O component exceeding 0%, the discoloration in the glass can be effectively improved. Therefore, _{the content of the K 2} O component may preferably exceed 0%, more preferably exceed 0.1%, still more preferably exceed 0.3%, still more preferably exceed 0.5%, and still more preferably exceed 1.0%. On the other hand, by making _{the content of the K 2} O component 15.0% or less, the increase in the partial dispersion ratio can be suppressed, the devitrification can be reduced, and the chemical durability can be made difficult to deteriorate. Therefore, _{the content of the K 2} O component is preferably 15.0% or less, more preferably 10.0% or less, still more preferably less than 10.0%, still more preferably less than 8.0%, and still more preferably less than 5.0%. The K ₂ O component can use K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material. The ZnO component is an optional component that is inexpensive and can improve the devitrification resistance when it contains more than 0%, and can reduce the glass transition point. Therefore, the content of the ZnO component may also preferably exceed 0%, more preferably exceed 0.5%, and still more preferably exceed 1.0%. On the other hand, by making the content of the ZnO component 25.0% or less, devitrification or coloring during glass formation or reheating can be reduced, and chemical durability can be improved. Therefore, the content of the ZnO component is preferably 25.0% or less, more preferably 20.0% or less, still more preferably less than 18.0%, still more preferably less than 14.0%, still more preferably less than 13.0%, and more preferably It is less than 10.0%. The Li ₂ O component is an optional component that can reduce the partial dispersion ratio, improve the transmittance, lower the liquidus temperature, and improve the solubility of the glass raw material when the content exceeds 0%. Therefore, _{the content of the Li 2} O component may preferably exceed 0%, more preferably exceed 1.0%, still more preferably exceed 3.0%, and still more preferably exceed 5.0%. On the other hand, by making _{the content of the Li 2} O component 20.0% or less, the decrease in the refractive index can be suppressed, the chemical durability can be made difficult to deteriorate, and the devitrification caused by excessive content can be reduced. Therefore, _{the content of the Li 2} O component is preferably 20.0% or less, more preferably 15.0% or less, still more preferably 13.0% or less, still more preferably less than 10.0%, and still more preferably less than 8.0%. As the Li ₂ O component, Li ₂ CO ₃ , LiNO ₃ , LiF, etc. can be used as a raw material. The Na ₂ O component is an optional component that can reduce the partial dispersion ratio, lower the liquidus temperature, and improve the solubility of the glass raw material when the content exceeds 0%. Therefore, _{the content of the Na 2} O component may preferably exceed 0%, more preferably exceed 1.0%, still more preferably exceed 3.0%, and still more preferably exceed 5.0%. On the other hand, by making _{the content of the Na 2} O component 20.0% or less, the decrease in refractive index can be suppressed, the chemical durability can be made difficult to deteriorate, and the devitrification caused by excessive content can be reduced. Therefore, _{the content of the Na 2} O component is preferably 20.0% or less, more preferably 15.0% or less, still more preferably 13.0% or less, still more preferably less than 10.0%, and still more preferably less than 8.0%. For the Na ₂ O component, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like can be used as a raw material. The B ₂ O ₃ component is an optional component as follows: when it contains more than 0%, it can promote stable glass formation, and can lower the liquidus temperature, so it can improve the resistance to devitrification and improve the melting of the glass raw material sex. Therefore, _{the content of the B 2} O ₃ component may preferably exceed 0%, more preferably exceed 0.1%, still more preferably exceed 1.0%, still more preferably exceed 3.0%, and still more preferably exceed 5.0%. In particular, from the viewpoint of improving the resistance to devitrification and reducing the veins of molten glass formed at low temperature, it is more preferable to contain 3.0% or more of B ₂ O ₃ component, and it can also be more preferably 5.0% or more, and more preferably It is more than 7.0%. On the other hand, by making _{the content of the B 2} O ₃ component 20.0% or less, the decrease in refractive index can be suppressed, and the increase in the partial dispersion ratio can be suppressed. Furthermore, the deterioration of the chemical durability of the glass can also be improved. Therefore, _{the content of the B 2} O ₃ component is preferably 20.0%, more preferably 18.0%, still more preferably 15.0%, and still more preferably 12.0% as the upper limit. For the B ₂ O ₃ component, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ ·10H ₂ O, BPO _4, etc. can be used as raw materials. The TiO ₂ component is an optional component that increases the refractive index, decreases the Abbe number, and improves the resistance to devitrification when the content exceeds 0%. On the other hand, by making _{the content of the TiO 2} component 15.0% or less, the coloring of the glass can be reduced, and the internal transmittance can be improved. In addition, by this, the partial dispersion ratio is not easily increased, so that the required low partial dispersion ratio close to the normal line can be easily obtained. Therefore, _{the content of the TiO 2} component is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 5.0% or less, still more preferably less than 5.0%, still more preferably less than 3.0%, and more preferably It is 2.0% or less, more preferably less than 1.0%. In particular, from the viewpoint of reducing the abnormal dispersibility of the glass, it is preferable to not contain it substantially. As the TiO ₂ component, TiO ₂ or the like can be used as a raw material. The MgO component is any component that can lower the melting temperature of the glass when the content exceeds 0%. On the other hand, by making the content of the MgO component 10.0% or less, the decrease in refractive index can be suppressed and devitrification can be reduced. Therefore, the content of the MgO component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. The MgO component can use MgO, MgCO ₃ , MgF ₂ or the like as a raw material. The CaO component is an optional component that can reduce the material cost of the glass, reduce the Abbe number, reduce the devitrification, and improve the solubility of the glass raw material when it contains more than 0%. Therefore, the content of the CaO component may preferably exceed 0%, more preferably exceed 1.0%, and still more preferably exceed 2.0%. On the other hand, by making the content of the CaO component 10.0% or less, the decrease in refractive index, the increase in Abbe number, and the increase in partial dispersion ratio can be suppressed, and devitrification can be reduced. Therefore, the content of the CaO component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. CaO component can be used CaCO _3, CaF ₂ and the like as a raw material. The SrO component is an optional component that can increase the refractive index and increase the resistance to devitrification when it contains more than 0%. In particular, by making the content of the SrO component 10.0% or less, the deterioration of chemical durability can be suppressed. Therefore, the content of the SrO component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably 3.0% or less, still more preferably less than 3.0%, and still more preferably less than 1.0%. For the SrO component, Sr(NO ₃ ) ₂ , SrF ₂ or the like can be used as a raw material. The BaO component is an optional component as follows: when it contains more than 0%, it can increase the refractive index, reduce the partial dispersion ratio, improve the resistance to devitrification, and improve the solubility of the glass raw material, and compared with other alkaline earth components , Can reduce the material cost of glass. In particular, by making the content of the BaO component 10.0% or less, the decrease in refractive index, the increase in Abbe number, and the increase in partial dispersion ratio can be suppressed, and devitrification can be reduced. Therefore, the content of the BaO component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. The BaO component can use BaCO ₃ , Ba(NO ₃ ) ₂ and the like as a raw material. The La ₂ O ₃ component, the Gd ₂ O ₃ component, the Y ₂ O ₃ component, and the Yb ₂ O ₃ component are optional components that can increase the refractive index and reduce the partial dispersion ratio by containing at least one of more than 0%. In particular, by setting _{the content of each of the La 2} O ₃ component, Gd ₂ O ₃ component, Y ₂ O ₃ component, and Yb ₂ O ₃ component to 10.0% or less, the increase in Abbe number can be suppressed and devitrification can be reduced. And can reduce material costs. Therefore, _{the content of each of the La 2} O ₃ component, Gd ₂ O ₃ component, Y ₂ O ₃ component, and Yb ₂ O ₃ component is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0% as the upper limit. , And more preferably less than 1.0%. La ₂ O ₃ components, Gd ₂ O ₃ components, Y ₂ O ₃ components, and Yb ₂ O ₃ components can be used La ₂ O ₃ , La(NO ₃ ) ₃・XH ₂ O (X is any integer), Y ₂ O _3. YF ₃ , Gd ₂ O ₃ , GdF ₃ , Yb ₂ O ₃ and the like are used as raw materials. When the content of Ta ₂ O ₅ exceeds 0%, it is an optional component that increases the refractive index, reduces the Abbe number and partial dispersion ratio, and improves the resistance to devitrification. On the other hand, by making _{the content of Ta 2} O ₅ component 10.0% or less, the amount of Ta ₂ O ₅ component used as a rare mineral resource is reduced, and the glass becomes easier to melt at low temperature, so the production of glass can be reduced cost. In addition, it is possible to reduce the devitrification of the glass due to the excessive content of the _{Ta 2} O _{5 component.} Therefore, _{the content of the Ta 2} O ₅ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. Especially from the viewpoint of reducing the material cost of glass, the Ta ₂ O ₅ component may not be included. For the Ta ₂ O ₅ component, Ta ₂ O ₅ or the like can be used as a raw material. The WO ₃ component is an optional component that increases the refractive index and lowers the Abbe number when it contains more than 0%, improves the devitrification resistance, and can improve the meltability of the glass raw material. On the other hand, by making _{the content of the WO 3} component 10.0% or less, the partial dispersion ratio of the glass can not be easily increased, and the coloring of the glass can be reduced and the internal transmittance can be improved. Therefore, _{the content of the WO 3} component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. For the WO ₃ component, WO ₃ or the like can be used as a raw material. The P ₂ O ₅ component is an optional component that can improve the stability of the glass when the content exceeds 0%. On the other hand, by making _{the content of the P 2} O ₅ component 10.0% or less, it is possible to reduce the devitrification caused by the excessive inclusion of the _{P 2} O _{5 component.} Therefore, _{the content of the P 2} O ₅ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. The P ₂ O ₅ component can use Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , BPO ₄ , H ₃ PO _4, etc. as raw materials. The GeO ₂ component is an optional component that increases the refractive index and reduces devitrification when the content exceeds 0%. On the other hand, by making _{the content of the GeO 2} component 10.0% or less, _{the usage amount of the expensive GeO 2} component can be reduced, so that the material cost of the glass can be reduced. Therefore, _{the content of the GeO 2} component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. The GeO ₂ component can use GeO ₂ or the like as a raw material. The Al ₂ O ₃ component and the Ga ₂ O ₃ component are optional components that can improve chemical durability and increase resistance to devitrification when at least one of them exceeds 0%. On the other hand, by making _{the content of each of the Al 2} O ₃ component and the Ga ₂ O ₃ component 10.0% or less, it is possible to reduce the devitrification caused by the excessive inclusion of the _{Al 2} O ₃ component or the Ga ₂ O _{3 component.} Therefore, _{the content of each of the Al 2} O ₃ component and the Ga ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. The Al ₂ O ₃ component and the Ga ₂ O ₃ component can use Al ₂ O ₃ , Al(OH) ₃ , AlF ₃ , Ga ₂ O ₃ , Ga(OH) _3, etc. as raw materials. The Bi ₂ O ₃ component is an optional component that can increase the refractive index, lower the Abbe number, and lower the glass transition point when the content exceeds 0%. On the other hand, by making _{the content of the Bi 2} O ₃ component 10.0% or less, the partial dispersion ratio can be prevented from increasing easily, and the coloring of the glass can be reduced to increase the internal transmittance. Therefore, _{the content of the Bi 2} O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. For the Bi ₂ O ₃ component, Bi ₂ O ₃ or the like can be used as a raw material. The TeO ₂ component is an optional component that can increase the refractive index, reduce the partial dispersion ratio, and reduce the glass transition point when the content exceeds 0%. On the other hand, by making _{the content of the TeO 2} component 5.0% or less, the coloring of the glass can be reduced and the internal transmittance can be improved. In addition, by reducing _{the use of expensive TeO 2} components, glass with lower material cost can be obtained. Therefore, _{the content of the TeO 2} component is preferably 5.0% or less, more preferably less than 3.0%, and still more preferably less than 1.0%. For the TeO ₂ component, TeO ₂ or the like can be used as a raw material. The SnO ₂ component is an optional component that can clarify (defoam) the molten glass and increase the visible light transmittance of the glass when it contains more than 0%. On the other hand, by making _{the content of the SnO 2} component 1.0% or less, it is possible to make the coloring of the glass due to the reduction of the molten glass or the devitrification of the glass less likely to occur. In addition, since _{the alloying between the SnO 2} component and the melting equipment (especially noble metals such as Pt) is reduced, the life of the melting equipment can be increased. Therefore, _{the content of the SnO 2} component is preferably 1.0% or less, more preferably less than 0.5%, and still more preferably less than 0.1%. For the SnO ₂ component, SnO, SnO ₂ , SnF ₂ , SnF _4, etc. can be used as a raw material. The Sb ₂ O ₃ component is a component that promotes the defoaming of the glass and clarifies the glass when the content exceeds 0%, and is an optional component in the optical glass of the present invention. By making the content of Sb ₂ O ₃ relative to the total mass of the glass 1.0% or less, excessive foaming during glass melting can be prevented, and the Sb ₂ O ₃ component can be difficult to alloy with melting equipment (especially precious metals such as Pt) change. _{Therefore, the content rate of the Sb 2} O ₃ component relative to the total mass of the glass in the oxide conversion composition is preferably 1.0%, more preferably 0.8%, and still more preferably 0.6% as the upper limit. Here, especially from the viewpoint of easily obtaining optical glass with low exposure effect, _{the content of the Sb 2} O ₃ component in the total glass mass of the oxide-converted composition is preferably 0.5%, more preferably 0.3%, and further Preferably, it is 0.1% as the upper limit. In addition, the component for clarifying and defoaming glass is not limited to the above-mentioned Sb ₂ O ₃ component, and a well-known clarifier or defoamer in the field of glass manufacturing, or a combination thereof can be used. The ratio of the sum of the contents of the Li ₂ O component and the K ₂ O component to the sum of the contents of the _{ZrO 2} component and the Li _{2 O component is preferably more than 0 and less than 2.5.} In particular, by setting the mass ratio to exceed 0, devitrification and transmittance can be improved. Therefore, the lower _{limit of (Li 2} O+K ₂ O)/(ZrO ₂ +Li ₂ O) can preferably exceed 0, more preferably exceed 0.1, and still more preferably exceed 0.3. On the other hand, by setting the mass ratio to less than 2.5, it is possible to reduce the abnormal dispersion of the glass while maintaining the refractive index of the glass. Therefore, the _{upper limit of (Li 2} O+K ₂ O)/(ZrO ₂ ＋Li ₂ O) may also preferably be less than 2.5, more preferably less than 2.1, more preferably less than 2.0, and more preferably less than 1.5, more preferably less than 1.0, and still more preferably less than 0.5. The total (mass sum) of the SiO ₂ component and the Nb ₂ O _{5 component is preferably more than 50.0%.} Thereby, it is possible to obtain a glass that has excellent chemical durability, less abnormal dispersion, maintains a certain degree of viscosity, and has good moldability. Therefore, the mass sum may preferably exceed 50.0%, more preferably 53.0% or more, still more preferably 54.0% or more, and still more preferably 58.0% or more. On the other hand, the mass sum may also be preferably 90.0% or less, more preferably less than 85.0%, still more preferably less than 81.0%, and still more preferably less than 76.0%. The total content (mass sum) of the Ln ₂ O ₃ component (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is preferably 15.0% or less. Thereby, the devitrification of the glass can be reduced, the increase in the Abbe number can be suppressed, and the material cost of the glass can be reduced. Therefore, _{the mass sum of the Ln 2} O ₃ components is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 3.5%. By making _{the total content (mass sum) of the Rn 2} O component (in the formula, Rn is one or more selected from the group consisting of Li, Na, and K) more than 0%, the solubility of the glass raw material can be improved , And reduce the glass transfer point. Therefore, _{the content of the Rn 2} O component may also preferably exceed 0%, more preferably 5.0% or more, still more preferably more than 5.0%, still more preferably 8.0% or more, still more preferably 10.0% or more, and more It is preferably more than 10.0%, more preferably 12.0% or more, and still more preferably more than 13.0%. On the other hand, _{the total content (mass sum) of the Rn 2} O component (in the formula, Rn is one or more selected from the group consisting of Li, Na, and K) is preferably 30.0% or less. Thereby, the refractive index of the glass can be prevented from being lowered, and the devitrification of the glass can be reduced when the glass is formed. In addition, it can reinforce the viscosity in the glass and improve the formability. Therefore, _{the total content of the Rn 2} O components is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%, and still more preferably 17.0% as the upper limit. The total content (mass sum) of the RO component (in the formula, R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 30.0% or less. Thereby, it is possible to reduce the devitrification of the glass caused by the excessive inclusion of these components. Therefore, the mass sum of the RO component is preferably 30.0% or less, more preferably 25.0% or less, still more preferably 20.0% or less, still more preferably 15.0% or less, still more preferably less than 10.0%, and more preferably Less than 5.0%. On the other hand, the quality of the RO component and the viewpoint of improving the solubility of the glass raw material and reducing devitrification may also preferably exceed 0%, more preferably 1.0% or more, and even more preferably 2.0% or more. <About the components that should not be contained> Next, the components that should not be contained in the optical glass of the present invention and the components that are undesirable if contained. Other ingredients can be added as needed within the range that does not impair the characteristics of the glass of the present invention. However, in addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, Lu, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo and other transition metal components have even if singly or in combination Containing a small amount of each of them will also color the glass and absorb specific wavelengths in the visible region of the visible region. Therefore, especially in optical glass that uses wavelengths in the visible region, it is preferably not contained substantially. In addition, lead compounds such as PbO and _{arsenic compounds such as As 2} O ₃ are components that have a high environmental impact and are therefore preferably not contained substantially, that is, they are not contained except for unavoidable mixing. Furthermore, the components of Th, Cd, Tl, Os, Be, and Se have been used as hazardous chemicals in recent years, and their use has tended to be controlled. Not only the glass manufacturing steps, but also the processing steps, and the processing after productization are required Measures on environmental countermeasures. Therefore, when attaching importance to environmental impacts, it is preferable that these are not contained substantially. [Manufacturing method] The optical glass of the present invention is manufactured as follows, for example. That is, it is produced by the following steps: the above-mentioned raw materials are uniformly mixed in such a way that each component is within a specific content range, the produced mixture is put into a platinum crucible, a quartz crucible or an alumina crucible for rough melting, and then a gold Melt in the crucible, platinum crucible, platinum alloy crucible or iridium crucible in the temperature range of 1000～1400℃ for 3～5 hours, stir and homogenize for defoaming, etc., then cool to 900～1100℃, then perform fine stirring to Remove the veins, cast into the mold and slowly cool. <Physical properties> The optical glass of the present invention has a high refractive index and an Abbe number in a specific range. _{The refractive index (n d} ) of the optical glass of the present invention is preferably 1.60, more preferably 1.63, and even more preferably 1.65 as the lower limit. The upper limit of the refractive index is preferably 1.78, more preferably 1.77, still more preferably 1.76, still more preferably 1.75, still more preferably 1.73, and still more preferably 1.70. _{The Abbe number (ν d} ) of the optical glass of the present invention is preferably 28, more preferably 29, still more preferably 30, still more preferably 31, and still more preferably 33 as the lower limit. On the other hand, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 47, more preferably 45, still more preferably 43, still more preferably 42, further preferably 41, and still more preferably Is 40 as the upper limit. The optical glass of the present invention having such a refractive index and Abbe number is useful in optical design, and in particular, can achieve high imaging characteristics, etc., and can also achieve miniaturization of the optical system, so that the degree of freedom of optical design can be expanded. The optical glass of the present invention has a low partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention, and the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably between the Abbe number (ν _d ) Satisfy the relationship of (-0.00256×ν _d ＋0.637)≦(θg,F)≦(-0.00256×ν _d ＋0.684). Therefore, in the optical glass of the present invention, the partial dispersion ratio (θg, F) and Abbe number (ν _d ) preferably satisfy the relationship of θg, F≧(-0.00256×ν _d ＋0.637), and more preferably satisfy The relationship of θg, F≧(-0.00256×ν _d ＋0.647), and more preferably satisfies the relationship of θg, F≧(-0.00256×ν _d ＋0.657). On the other hand, in the optical glass of the present invention, the partial dispersion ratio (θg, F) and Abbe number (ν _d ) preferably satisfy the relationship of θg, F≦(-0.00256×ν _d ＋0.684), more preferably In order to satisfy the relationship of θg, F≦(-0.00256×ν _d ＋0.681), it is more preferable to satisfy the relationship of θg, F≦(-0.00256×ν _d ＋0.677). As a result, an optical glass with a low partial dispersion ratio (θg, F) can be obtained, so the optical element formed from the optical glass can help reduce the chromatic aberration of the optical system. Furthermore, especially in _{regions where the Abbe number (ν d} ) is small, the partial dispersion ratio (θg, F) of general glass is higher than the normal line. The abscissa takes the Abbe number (ν _d ) and the vertical When the axis takes the partial dispersion ratio (θg, F), _{the relationship between the partial dispersion ratio (θg, F) and Abbe number (ν d} ) of general glass is represented by a curve with a larger slope than the normal line. The above-mentioned partial dispersion ratio (θg, F) and Abbe's number (ν _d ) in the relational expressions indicate that the partial dispersion ratio (θg, F ) Smaller glass than ordinary glass. In the present invention, the weather resistance of the surface method is preferably grade 1 or grade 2, more preferably grade 1. Here, the so-called surface method weather resistance is performed using the following test method. Use a sample with a polished surface of 30 mm×30 mm×3 mm as a test piece, and place it in a constant temperature and humidity bath at 60°C with a relative humidity of 95% for 96 hours. Observe the polished surface with a 50-fold microscope to observe the discoloration state. The criterion is to observe the sample at 1500 lux with illuminance for 96 hours after no discoloration is found at level 1, and when observed at 100 lux, the discoloration is not found but can be detected at 1500 lux as level 2 , Set the person who can be found to be discolored when observed at 100 lux as level 3. In addition, for level 3, after re-placement in a constant temperature and humidity chamber at 50°C with a relative humidity of 85% for 6 hours, observe the polished surface with a 50-fold microscope, and set the color change that can be found by 1500 lux as level 4. If no discoloration is found, it will still be considered as level 3. In addition, in this specification, the term "surface method weather resistance" refers to the pros and cons of the discoloration state when used as a lens preform for a long time or when exposed to a certain period of time due to the storage environment of the optical glass. The optical glass of the present invention is preferably less colored. In particular, if the optical glass of the present invention is expressed in terms of the transmittance of the glass, the wavelength (λ ₈₀ ) that represents 80% of the spectral transmittance in a sample with a thickness of 10 mm is preferably 420 nm or less, more preferably 400 nm or less, More preferably, it is 380 nm or less. _{In addition, the wavelength (λ 5} ) at which the optical glass of the present invention has a spectral transmittance of 5% in a sample with a thickness of 10 mm is preferably 365 nm or less, more preferably 345 nm or less, and still more preferably 330 nm or less. As a result, the absorption end of the glass becomes near the ultraviolet region, and the transparency of the glass in the visible region is improved. Therefore, the optical glass can be preferably used as a material for optical elements such as lenses. In addition, the devitrification resistance of the optical glass of the present invention needs to be high. Thereby, the decrease in transmittance due to the crystallization of the glass during glass production can be suppressed, so the optical glass can be preferably used as an optical element that transmits visible light, such as a lens. In particular, the optical glass of the present invention preferably has a low liquidus temperature of 1200°C or less. More specifically, the liquidus temperature of the optical glass of the present invention is preferably 1200°C, more preferably 1150°C, more preferably 1100°C, more preferably 1050°C as the upper limit. As a result, even if the molten glass flows out at a lower temperature, the crystallization of the glass produced can be reduced, so the resistance to devitrification when the glass is formed from the molten state can be improved, and the optical characteristics of the optical element using the glass can be reduced The impact. On the other hand, the lower limit of the liquidus temperature of the optical glass of the present invention is not particularly limited. Most of the liquidus temperature of the glass obtained by the present invention is approximately 500°C or higher, specifically 550°C or higher, and more specifically 600°C above. Furthermore, the so-called "liquid phase temperature" in this manual means that a glass sample crushed into a granular shape with a diameter of about 2 mm is placed on a platinum plate and maintained in a furnace with a temperature gradient of 800°C to 1220°C. Take it out in minutes, and observe whether there are crystals in the glass using a microscope with a magnification of 80 times after cooling, thereby measuring the lowest temperature at which no crystals are found in the glass and no devitrification occurs. [Preform and Optical Element] A glass molded body can be produced from the produced optical glass using mold compression molding methods such as re-hot press molding or precision press molding. That is, a preform for press molding of a mold is produced from optical glass, and the preform is re-hot-pressed and then polished to produce a glass molded body, or, for example, a preform produced by grinding is precision-pressed Molding to produce a glass molded body. In addition, the means for producing the glass molded body is not limited to these means. The glass molded body produced in this manner is useful for various optical elements, and among them, it is particularly preferably used for optical elements such as lenses or ridges. Thereby, the bleeding caused by chromatic aberration in the transmitted light of the optical system provided with the optical element is reduced. Therefore, when the optical element is used in a camera, the photographic object can be expressed more accurately, and when the optical element is used in a projector, the desired image can be projected more brilliantly. [Example] The composition and refraction of the examples of the present invention (No.A1～No.A28, No.B1～No.B52, No.C1～C3) and comparative examples (No.a, No.b) Rate (n _d ), Abbe number (ν _d ), partial dispersion ratio (θg, F), spectral transmittance shown as 5% and 80% of wavelength (λ ₅ , λ ₈₀ ), liquidus temperature, surface method weather resistance The results of the properties are shown in Table 1 to Table 12. Here, the examples (No.A1～No.A28, No.C1～C3) may be examples of the first optical glass, and the examples (No.B1～No.B52, No.C1～C3) may also be This is an example of the second optical glass. Furthermore, the following examples are always for the purpose of illustration, and are not limited to these examples. The glasses of the examples and comparative examples are made in the following way: as the raw materials of each component, the corresponding oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric acid compounds, etc. are selected for general use. The high-purity raw materials of the optical glass are weighed and uniformly mixed in such a way as to become the composition ratio of each embodiment and comparative example shown in the table, and then put into a stone crucible (platinum can also be used according to the melting property of the glass Crucibles, alumina crucibles), according to the melting difficulty of the glass composition, melted in an electric furnace in the temperature range of 1100 to 1400°C for 0.5 to 5 hours, then moved to a platinum crucible to stir and homogenize for defoaming, etc., and then set the temperature It is lowered to 1000-1400°C and stirred and homogenized, then poured into a mold, and slowly cooled to produce glass. _{The refractive index (n d} ), Abbe number (ν _d ), and partial dispersion ratio (θg, F) of the glasses of the examples and comparative examples were measured based on the standard JOGIS01-2003 of the Optical Glass Industry Association of Japan. In addition, the glass used in this measurement is the one that has been processed in the annealing furnace with the slow cooling rate set to -25°C/hr. The surface method weather resistance of the examples and comparative examples was evaluated by the following method. Use a sample with a polished surface of 30 mm×30 mm×3 mm as a test piece, and place it in a constant temperature and humidity bath at 60°C with a relative humidity of 95% for 96 hours. Observe the polished surface with a 50-fold microscope to observe the discoloration state. The criterion is to observe the sample at 1500 lux with illuminance for 96 hours after no discoloration is found at level 1, and when observed at 100 lux, the discoloration is not found but can be detected at 1500 lux as level 2 , Set the person who can be found to be discolored when observed at 100 lux as level 3. In addition, for level 3, after re-placement in a constant temperature and humidity chamber at 50°C with a relative humidity of 85% for 6 hours, observe the polished surface with a 50-fold microscope, and set the color change that can be found by 1500 lux as level 4. If no discoloration is found, it will still be considered as level 3. The transmittance of the glass of the Examples and Comparative Examples was measured according to the standard JOGIS02 of the Optical Glass Industry Association of Japan. Furthermore, in the present invention, by measuring the transmittance of the glass, the presence or absence and degree of coloration of the glass are determined. Specifically, the opposing parallel polished product with a thickness of 10±0.1 mm is measured in accordance with JISZ8722, and the spectral transmittance of 200 to 800 nm is measured, and λ ₅ (wavelength when the transmittance is 5%) and λ ₈₀ (when the transmittance is 80%) are determined.的wavelength). The liquidus temperature of the Examples and Comparative Examples was obtained by placing the crushed glass samples on a platinum plate at 10 mm intervals, keeping them in a furnace with a temperature gradient of 800°C to 1200°C for 30 minutes, and then taking them out. After cooling, use a microscope with a magnification of 80 times to observe the presence or absence of crystals in the glass sample for measurement. At this time, the optical glass was pulverized into particles with a diameter of about 2 mm as a sample. [Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

As shown in the tables, the partial dispersion ratio (θg, F) and Abbe number (ν _d ) of the optical glass of the embodiment of the present invention satisfy (-0.00256×ν _d ＋0.637)≦(θg,F)≦ The relationship of (-0.00256×ν _d ＋0.684), more specifically, satisfies the relationship of (-0.00256×ν _d ＋0.657)≦(θg, F)≦(-0.00256×ν _d ＋0.679). In particular, the optical glass of the embodiment (No.B1～No.B52, No.C1～C3) satisfies (-0.00256×ν _d ＋0.657)≦(θg,F)≦(-0.00256×ν _d ＋0.677 ) Relationship. Here, the relationship between the partial dispersion ratio (θg, F) and Abbe number (ν _d ) of the glass in the examples of the present case is shown in FIG. 2. _{The refractive index (n d} ) of the optical glass of the embodiment of the present invention is 1.60 or more, more specifically, it is 1.65 or more, and the refractive index (n _d ) is 1.78 or less, more specifically, it is 1.76 or less. Need to be within range. _{In particular, the refractive index (n d} ) of the optical glass of the examples (No. A1 to No. A28, No. C1 to C3) is 1.75 or less, and more specifically, it is 1.73 or less. _{In addition, the Abbe number (ν d} ) of the optical glass of the embodiment of the present invention is 28 or more, more specifically, 30 or more, which is within the required range. _{In addition, the Abbe number (ν d} ) of the optical glass of the example of the present invention is 47 or less, more specifically, 46 or less, which is within a desired range. _{In particular, the Abbe number (ν d} ) of the optical glass of the examples (No. A1 to No. A28, No. C1 to C3) is 43 or less. _{In addition, the λ 80} (wavelength at a transmittance of 80%) of the optical glass of the embodiment of the present invention is 420 nm or less, more specifically, 400 nm or less. _{In particular, the λ 80} (wavelength at 80% transmittance) of the optical glass of the examples (No. A1 to No. A28, No. C1 to C3) is 390 nm or less. _{In addition, the λ 5} (wavelength at 5% transmittance) of the optical glass in the examples of the present invention is all 365 nm or less, more specifically, 345 nm or less, and more specifically, 340 nm or less. _{In particular, the λ 5} (wavelength at 5% transmittance) of the optical glass of the examples (No. A1 to No. A28, No. C1 to C3) is 335 nm or less. From this, it can be seen that the optical glass of the embodiment of the present invention has a relatively high transmittance with respect to visible light and is not easy to be colored. In addition, the liquidus temperature of the optical glass of the examples of the present invention (No.A1 to No.A28, No.C1 to C3) is 1200°C or less, more specifically, 1110°C or less, and more specifically, 1050°C the following. Therefore, these optical glasses are unlikely to cause devitrification or opalescence due to reheating, so it is presumed that they have high reheat press formability. In addition, the surface method weather resistance of the optical glass of the examples of the present invention (No. B1 to No. B52, No. C1 to C3) is level 1. Therefore, it is clearly understood that these optical glass-based surface methods are excellent in weather resistance and hardly produce so-called discoloration optical glass. Furthermore, the optical glass of the embodiment of the present invention is used to form a glass block, and the glass block is ground and polished to be processed into the shape of a lens and a rim. As a result, it can be stably processed into various lens and lens shapes. Furthermore, although the optical glass described in Comparative Example (No.b) satisfies the required optical constants (n _d , ν _d ), it has relatively large partial dispersion and low abnormal dispersion, and has poor transmittance, and is chemically durable. The performance is also poor, so it is impossible to obtain the refractive index (n _d ) and Abbe number (ν _d ) targeted by the invention in this case, and the partial dispersion ratio (θg, F) is small and the weather resistance of the surface method is small. Good optical glass. Above, the present invention has been described in detail based on the purpose of illustration, but please understand that this embodiment is always only for the purpose of illustration, and various changes can be made by the industry without departing from the spirit and scope of the present invention.

Fig. 1 is a diagram showing a normal line represented by the orthogonal coordinates of the partial dispersion ratio (θg, F) on the vertical axis and the Abbe number (ν _{d) on the horizontal axis.} Fig. 2 is a graph showing the relationship between the partial dispersion ratio (θg, F) and Abbe number (ν _d ) of the embodiment of this case.

Claims (9)

_{An optical glass containing 20.0-50.0% of SiO 2} component, 10.0-30.0% of Nb ₂ O ₅ component, 9.26% or more and 20.0% or less of B ₂ O ₃ component, based on the mass% of oxide conversion composition, 0~20.0% ZrO ₂ component, 0~15.0% K ₂ O component, 0~20.0% Li ₂ O component; the _{sum of the content of SiO 2} component and Nb ₂ O ₅ component exceeds 50.0% and is 61.39% or less , mass ratio of _{(Li 2 O + K 2 O} ) / (ZrO 2 + Li 2 O) of 0.55 or more and less than 1.0, the partial dispersion ratio (θg, F) between the number (ν _d) satisfy Abbe ( -0.00256×ν _d +0.637)≦(θg,F)≦(-0.00256×ν _d +0.684). Such as the optical glass of claim 1, its surface method weather resistance is grade 1 or 2. Such as the optical glass of claim 1 or 2, in which the ZnO content is 0-25.0%, the Na ₂ O content is 0 to 20.0%, the TiO ₂ content is 0 to 15.0%, and the MgO content is calculated based on the mass% of the oxide conversion composition. 0~10.0%, CaO composition is 0~10.0%, SrO composition is 0~10.0%, BaO composition is 0~10.0%, La ₂ O ₃ composition is 0~10.0%, Gd ₂ O ₃ composition is 0~10.0 %, Y ₂ O ₃ composition is 0~10.0%, Yb ₂ O ₃ composition is 0~10.0%, Ta ₂ O ₅ composition is 0~10.0%, WO ₃ composition is 0~10.0%, P ₂ O ₅ composition is 0~10.0%, GeO ₂ composition is 0~10.0%, Al ₂ O ₃ composition is 0~10.0%, Ga ₂ O ₃ composition is 0~10.0%, Bi ₂ O ₃ composition is 0~10.0%, TeO ₂ composition 0~5.0%, SnO ₂ composition is 0~5.0%, Sb ₂ O ₃ composition is 0~1.0%. Such as the optical glass of claim 1 or 2, in which the Ln ₂ O ₃ component is calculated on the basis of the mass% of the oxide (where Ln is selected from at least one of the group consisting of La, Gd, Y, and Yb) The sum of the mass is 0~15.0%; the RO component (in the formula, R is selected from more than one of the group consisting of Mg, Ca, Sr, Ba), the mass sum is 0~30.0%; the Rn ₂ O component ( In the formula, Rn is selected from one or more of the group consisting of Li, Na, and K. The mass sum is 0~30.0%. Such as the optical glass of claim 3, in which the mass of Ln ₂ O ₃ component (where Ln is selected from the group consisting of La, Gd, Y, and Yb) is based on the mass% of the oxide The sum is 0~15.0%; the mass sum of the RO component (where R is selected from the group consisting of Mg, Ca, Sr and Ba) is 0~30.0%; the Rn ₂ O component (where , Rn is selected from more than one of the group consisting of Li, Na, and K. The mass sum is 0~30.0%. Such as the optical glass of claim 1 or 2, which has a refractive index (n _d ) of 1.60 to 1.78 and an Abbe number (ν _d ) of 28 to 47. Such as the optical glass of claim 1 or 2, in which the wavelength (λ ₈₀ ) with a spectral transmittance of 80% is below 420 nm, and the wavelength (λ ₅ ) with a spectral transmittance of 5% is below 365 nm. A preform used for grinding and/or precision press forming, comprising the optical glass according to any one of claims 1 to 7. An optical element comprising the optical glass according to any one of claims 1 to 7.

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