TWI659004B - Optical glass, preforms and optical components - Google Patents

Abstract

The present invention provides an optical glass that can more inexpensively obtain a preform having a refractive index (n _d ) and an Abbe number (ν _d ) within a required range, and which is easy to perform precision compression molding and has high devitrification resistance. , Preforms and optical components. The optical glass of the present invention contains B ₂ O ₃ component in an amount of 10.0% or more and 50.0% or less, and La ₂ O ₃ component in a range of 5.0% or more and 30.0% or less, and has a refractive index (n _d ) of 1.80 or more. Abbe number (ν _d ) of 30 or more and 45 or less.

Description

Optical glass, preforms and optical components

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

In recent years, the digitization or high-definition of equipment using optical systems has been rapidly developed. In the field of various optical equipment such as photographic equipment such as digital cameras or video cameras, image playback (projection) equipment such as projectors and projection televisions, Reducing the number of lenses or optical elements used in the optical system to make the overall optical system lighter and smaller has become more demanding. Among the optical glasses used in the production of optical elements, in particular, it is possible to reduce the weight and size of the entire optical system, have a refractive index (n _d ) of 1.80 or more, and an Abbe number (ν _d ) of 30 or more and 45 or less. The demand for high-refractive-index, low-dispersion glass that can be precision-molded has increased significantly. As such a high-refractive-index low-dispersion glass, the glass composition represented by the glass of patent documents 1-4 is known. [Prior Art Literature] [Patent Literature] [Patent Literature 1] Japanese Patent Laid-Open No. 06-305769 [Patent Literature 2] Japanese Patent Laid-Open No. 2006-137662 [Patent Literature 3] Japanese Patent Laid-Open No. 2006-240889 Gazette [Patent Document 4] Japanese Patent Laid-Open No. 2008-201661

[Problems to be Solved by the Invention] The lenses used in the optical system include spherical lenses and aspherical lenses. If aspheric lenses are used, the number of optical elements can be reduced. In addition, it is known that various optical elements other than a lens include a surface having a complicated shape. However, if it is desired to use the previous grinding and grinding steps to obtain aspheric surfaces or surfaces with complex shapes, the cost is high and complicated operating steps are required. Therefore, the current mainstream method is a method of obtaining the shape of an optical element by directly pressing and forming a preform obtained from a preform or a glass brick using an ultra-precision processing mold, that is, a method of performing precision compression molding. Furthermore, in addition to a method of precision press-molding a pre-formed material, it is also known to reheat a blank or glass brick made of a glass material to form (reheat press molding), and to grind and grind the obtained glass formed body method. As a method for manufacturing a preform used for such precision press molding or reheat press molding, there are a method of directly manufacturing molten glass by a dropping method, or reheat pressing or grinding of glass bricks into a ball shape and obtaining the same. Grinding method for processed products. In order to obtain an optical element by forming a molten glass into a desired shape, any method is required to facilitate precision press molding and to prevent devitrification of the formed glass. In addition, in order to reduce the material cost of optical glass, it is expected that the raw material cost of each component constituting the optical glass is as low as possible. In addition, in order to reduce the manufacturing cost of optical glass, it is expected that the melting property of the raw material is high, that is, it is melted at a lower temperature. However, it is difficult to say that the glass compositions described in Patent Documents 1 to 4 are sufficient to meet the above-mentioned requirements. The present invention has been made in view of the above problems, and its purpose is to obtain the refractive index (n _d ) and Abbe number (ν _d ) within a desired range more inexpensively, and it is easy to perform precision compression molding and devitrification resistance is relatively low. Tall preform. [Technical means to solve the problem] In order to solve the above problems, the present inventors and the like have made repeated efforts in experimental research and found that the refractive index (n _d ) can be obtained in glass containing a B ₂ O ₃ component and a La ₂ O ₃ component. And the Abbe number (ν _d ) is within the required range, and the optical glass which is easy to be precision-molded is formed, thereby completing the present invention. In particular, the inventors have found that the Gd ₂ O ₃ component and the Ta ₂ O ₅ component of the refractive index (n _d ) and Abbe number (ν _d ) are within the required ranges and the material cost is higher. Optical glass with reduced content and easy precision molding. In addition, the inventors have found that the refractive index (n _d ) and Abbe number (ν _d ) can be obtained within a desired range, and a material having a low material cost among components that contribute to high refractive index and high dispersion can be obtained. Optical glass with Y ₂ O ₃ component and easy precision molding. Specifically, the present invention provides the following. (1) An optical glass containing, in mole%, a B ₂ O ₃ component of 10.0% to 50.0%, a La ₂ O ₃ component of 5.0% to 30.0%, and a refractive index of 1.80 or more (n _d ), Which has an Abbe number (ν _d ) of 30 or more and 45 or less. (2) The optical glass according to (1), wherein the content of the Y ₂ O ₃ component is 20.0% or less in mole%. (3) The optical glass according to (1) or (2), which contains a Y ₂ O ₃ component in a molar ratio of more than 0% to 20.0%. (4) The optical glass according to any one of (1) to (3), wherein the content of the Y ₂ O ₃ component is 10.0% or less in mole%. (5) The optical glass according to any one of (1) to (4), wherein the Gd ₂ O ₃ component is 0 to 10.0%, the Yb ₂ O ₃ component is 0 to 10.0%, and _{The 2} O ₃ component is 0 to 10.0%. (6) The optical glass according to any one of (1) to (5), wherein the content of the Ta ₂ O ₅ component is 10.0% or less in mole%. (7) The optical glass according to any one of (1) to (6), wherein Mohr and (Gd ₂ O ₃ + Yb ₂ O ₃ + Ta ₂ O ₅ ) are 10.0% or less. (8) The optical glass according to any one of (1) to (7), in which the mole and (Gd ₂ O ₃ + Ta ₂ O ₅ ) are less than 5.0%. (9) The optical glass according to any one of (1) to (8), wherein the content of the Ta ₂ O ₅ component is less than 1.0% in mole%. (10) The optical glass according to any one of (1) to (9), wherein the content of the Gd ₂ O ₃ component is less than 1.0% in mole%. (11) The optical glass according to any one of (1) to (10), wherein the Ln ₂ O ₃ component (wherein Ln is one selected from the group consisting of La, Gd, Y, Yb, and Lu The Mohr sum is 10.0% or more and 40.0% or less. (12) The optical glass according to any one of (1) to (11), which contains two or more components of the Ln ₂ O ₃ component. (13) The optical glass according to any one of (1) to (12), wherein the TiO ₂ component is 0 to 20.0% and the Nb ₂ O ₅ component is 0 to 10.0% in mole%. (14) The optical glass according to any one of (1) to (13), wherein the content of the WO ₃ component is 20.0% or less in mole%. (15) The optical glass according to any one of (1) to (14), which contains at least 1.0% and less than 20.0% of the WO ₃ component in mol%. (16) The optical glass according to any one of (1) to (15), wherein Mohr and (TiO ₂ + WO ₃ + Nb ₂ O ₅ ) are 1.0 to 30.0%. (17) The optical glass according to any one of (1) to (16), which contains a ZnO component in an amount of 10.0% to 38.0% in mole%. (18) The optical glass according to any one of (1) to (17), wherein the content of the ZrO ₂ component is 10.0% or less in mole%. (19) The optical glass according to any one of (1) to (18), wherein the content of the SiO ₂ component is 15.0% or less in mole%. (20) The optical glass according to any one of (1) to (19), wherein the content of the Li ₂ O component is 8.0% or less in mole%. (21) The optical glass according to any one of (1) to (20), wherein the Na ₂ O component is 0 to 15.0%, the K ₂ O component is 0 to 10.0%, and Cs ₂ O is expressed in mole%. The composition is 0 to 10.0%. (22) The optical glass according to any one of (1) to (21), wherein the Rn ₂ O component (wherein, Rn is one or more selected from the group consisting of Li, Na, K, and Cs) Moire sum is below 20.0%. (23) The optical glass according to any one of (1) to (22), wherein the MgO component is 0 to 10.0%, the CaO component is 0 to 10.0%, and the SrO component is 0 to 10.0% in mole%. The BaO component is 0 to 10.0%. (24) The optical glass according to any one of (1) to (23), wherein the component RO (in the formula, R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) The sum is 11.0% or less. (25) The optical glass according to any one of (1) to (24), wherein in terms of mole%, the GeO ₂ component is 0 to 10.0%, the P ₂ O ₅ component is 0 to 10.0%, and Bi ₂ O ₃ components are 0 to 15.0%, TeO ₂ components are 0 to 15.0%, Al ₂ O ₃ components are 0 to 15.0%, Ga ₂ O ₃ components are 0 to 15.0%, and Sb ₂ O ₃ components are 0 to 1.0%. In addition, the content of the fluorine compound in which one or two or more of the oxides of each of the above elements is partially or completely replaced is 0 to 15.0 mol%. (26) The optical glass according to any one of (1) to (25), which has a refractive index (n _d ) of 1.80 or more and 1.95 or less, and an Abbe number (ν _d ) of 30 or more and 45 or less . (27) The optical glass according to any one of (1) to (26), wherein the glass transition point (Tg) exceeds 580 ° C and is 630 ° C or lower. (28) The optical glass according to any one of (1) to (27), which has a liquidus temperature of 1100 ° C or lower. (29) A preform comprising the optical glass according to any one of (1) to (28). (30) An optical element produced by press-molding the preform according to (29). (31) An optical element using the optical glass according to any one of (1) to (28) as a base material. (32) An optical device including the optical element according to (30). (33) An optical device comprising the optical element according to (31). [Effects of the Invention] According to the present invention, it is possible to more inexpensively obtain a refractive index (n _d ) and an Abbe number (ν _d ) within a desired range, and it is easy to perform precision compression molding and have high devitrification resistance. Forming material.

The optical glass of the present invention contains B in mole% ₂ O ₃ 10.0% to 50.0%, La ₂ O ₃ 5.0% to 30.0% of the component, and a refractive index (n of 1.80 or more) _d ), With an Abbe number of 30 or more and 45 or less (ν _d ). In particular, the first optical glass contains B in mole% ₂ O ₃ 10.0% to 50.0%, La ₂ O ₃ Ingredients 5.0% to 30.0%, Mor and (Gd ₂ O ₃ ＋ Ta ₂ O ₅ ) Is less than 5.0%, and has a refractive index (n of 1.80 or more) _d ), With an Abbe number of 30 or more and 45 or less (ν _d ). The second optical glass contains B in mol%. ₂ O ₃ 10.0% to 50.0%, La ₂ O ₃ 5.0% to 30.0%, Y ₂ O ₃ The composition exceeds 0% to 20.0% and has a refractive index (n of 1.80 or more) _d ), With an Abbe number of 30 or more and 45 or less (ν _d ). Especially the first optical glass can reduce Gd ₂ O ₃ Composition and Ta ₂ O ₅ The content of ingredients reduces the material cost of glass. On the other hand, especially the second optical glass, by containing Y ₂ O ₃ Ingredients and reduce the material cost of glass. And, with B ₂ O ₃ Composition and La ₂ O ₃ The component is used as a basis, and has a refractive index (n of 1.80 to 1.95) _d ) And Abbe's number (ν) from 30 to 45 _d ), And the liquidus temperature becomes easy to decrease. The inventor of the present case found that by having a refractive index (n of 1.80 or more and 1.95 or less) _d ) And Abbe's number (ν) from 30 to 45 _d ) Glass, lower Gd with higher material cost ₂ O ₃ Composition and Ta ₂ O ₅ The content of the ingredients, and the low-cost Y contained in the ingredients that contribute to the high refractive index and high dispersion ₂ O ₃ And adjust the content of each component, so that compared with optical glass with a lower glass transition point, devitrification during glass production can be reduced, thereby making it easier to press-form glass. According to the above, the obtainable refractive index (n _d ) And Abbe number (ν _d ) An optical glass of a preform that is easily within a required range and is easily press-molded and has high devitrification resistance. Hereinafter, embodiments of the optical glass of the present invention will be described in detail. The present invention is not limited in any way by the following embodiments, and can be implemented by appropriately changing within the scope of the object of the present invention. In addition, there are overlaps in the description, and the description may be omitted as appropriate, but the gist of the invention is not limited. [Glass component] The composition range of each component which comprises the optical glass of this invention is demonstrated below. In this specification, when there is no special regulation regarding the content of each component, all are expressed in mole% with respect to the total mass of the glass in terms of oxide conversion composition. Here, the "oxide conversion composition" refers to the case where the oxide, the composite salt, and the metal fluoride which are assumed to be used as raw materials of the glass constituents of the present invention are all decomposed during melting and converted into oxides. The total mass of the substance is set to 100 mol%, which indicates the composition of each component contained in the glass. <About essential components and optional components> In the optical glass of the present invention containing a large amount of rare earth oxides, B ₂ O ₃ The component is an essential component as a glass-forming oxide. Especially by making B ₂ O ₃ The content of the ingredients is 10.0% or more, which can improve the devitrification resistance of the glass and increase the Abbe number of the glass. Therefore, B ₂ O ₃ The content of the ingredients is preferably 10.0% as the lower limit, more preferably 15.0% as the lower limit, still more preferably 20.0% as the lower limit, and even more preferably 25.0% as the lower limit. On the other hand, by making B ₂ O ₃ The content of the component is 50.0% or less, a larger refractive index can be easily obtained, and deterioration in chemical durability can be suppressed. Therefore, B ₂ O ₃ The content of the component is preferably 50.0% as the upper limit, more preferably 45.0% as the upper limit, and still more preferably 40.0% as the upper limit. About B ₂ O ₃ Ingredients, can use H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ 10H ₂ O, BPO ₄ And so on as raw materials. La ₂ O ₃ The composition is an essential component that increases the refractive index of glass and increases the Abbe number of glass. So La ₂ O ₃ The content of the ingredients is preferably 5.0% as the lower limit, more preferably 10.0% as the lower limit, and even more preferably 13.0% as the lower limit. On the other hand, by making La ₂ O ₃ The content of the component is 30.0% or less to improve the stability of the glass, thereby reducing devitrification. So La ₂ O ₃ The content of the component relative to the total mass of the glass in terms of oxide conversion is preferably 30.0% as the upper limit, more preferably 25.0% as the upper limit, still more preferably 20.0% as the upper limit, and even more preferably 17.0% as Ceiling. About La ₂ O ₃ Ingredients, can use La ₂ O ₃ , La (NO ₃ ) ₃ · XH ₂ O (X is an arbitrary integer) or the like is used as a raw material. Y ₂ O ₃ A component is an arbitrary component which can maintain a high refractive index and a high Abbe number while suppressing the material cost of glass when it contains more than 0%, and can reduce the specific gravity of glass more than other rare earth components. Especially in the second optical glass, Y ₂ O ₃ Ingredients are essential ingredients. Therefore, Y ₂ O ₃ The content of the component is preferably more than 0% as the lower limit, more preferably 0.5% as the lower limit, further preferably 1.0% as the lower limit, even more preferably 2.0% as the lower limit, and even more preferably 3.0% as the lower limit . On the other hand, by making Y ₂ O ₃ The content of the component is 20.0% or less, which can suppress the decrease in the refractive index of the glass and improve the devitrification resistance of the glass. Therefore, Y ₂ O ₃ The content of the components is preferably 20.0% as the upper limit, more preferably 10.0% as the upper limit, still more preferably 8.0% as the upper limit, and even more preferably 6.0% as the upper limit. About Y ₂ O ₃ Ingredients, use Y ₂ O ₃ , YF ₃ And so on as raw materials. Gd ₂ O ₃ The component is an arbitrary component that can increase the refractive index of glass and increase the Abbe number when the content exceeds 0%. On the other hand, by making rare earth elements, particularly expensive Gd, ₂ O ₃ The composition is less than 10.0%, which reduces the material cost of glass, so that optical glass can be produced more inexpensively. In addition, this can prevent the Abbe number of the glass from increasing excessively. Therefore, Gd ₂ O ₃ The content of each component is preferably set to less than 10.0%, more preferably set to less than 5.0%, further preferably set to less than 1.0%, still more preferably set to less than 0.5%, and even more preferably It is set to less than 0.3%, and more preferably set to less than 0.1%. About Gd ₂ O ₃ Ingredients, Gd can be used ₂ O ₃ GdF ₃ And so on as raw materials. Yb ₂ O ₃ Ingredients and Lu ₂ O ₃ The component is an arbitrary component that can increase the refractive index of glass and increase the Abbe number when the content exceeds 0%. On the other hand, by making Yb ₂ O ₃ Ingredients and Lu ₂ O ₃ The content of the components is 10.0% or less, which can reduce the material cost of the glass, so that optical glass can be manufactured more inexpensively. In addition, the devitrification resistance of glass can be improved by this. Therefore, Yb ₂ O ₃ Ingredients and Lu ₂ O ₃ The content of the ingredients is preferably 10.0% as the upper limit, more preferably 5.0% as the upper limit, still more preferably 3.0% as the upper limit, still more preferably 1.0% as the upper limit, and still more preferably 0.1% as Ceiling. From the viewpoint of reducing material cost, Yb may not be contained ₂ O ₃ Ingredients and Lu ₂ O ₃ ingredient. About Yb ₂ O ₃ Ingredients and Lu ₂ O ₃ Ingredients, use Yb ₂ O ₃ Lu ₂ O ₃ And so on as raw materials. Ta ₂ O ₅ The component is an arbitrary component which can increase the refractive index of glass and can improve devitrification resistance when it contains more than 0%. On the other hand, by making expensive Ta ₂ O ₅ The composition is less than 10.0%, which can reduce the material cost of glass, so it can make optical glass cheaper. In addition, the melting temperature of the raw material is thereby lowered, thereby reducing the energy required for the melting of the raw material, so the manufacturing cost of the optical glass can also be reduced. Therefore, Ta ₂ O ₅ The content of the components is preferably less than 10.0%, more preferably less than 5.0%, even more preferably less than 1.0%, still more preferably 0.7% or less, and even more preferably 0.4% or less, more preferably 0.3% or less, still more preferably 0.2% or less, still more preferably 0.1% or less. About Ta ₂ O ₅ Composition, Ta can be used ₂ O ₅ And so on as raw materials. Gd ₂ O ₃ Composition, Yb ₂ O ₃ Composition and Ta ₂ O ₅ The sum of the contents of the components is preferably 10.0% or less. Thereby, the content of these expensive components can be reduced, and the material cost of glass can be suppressed. Therefore, Mor and (Gd ₂ O ₃ ＋ Yb ₂ O ₃ ＋ Ta ₂ O ₅ ) Is preferably 10.0% as the upper limit, more preferably 7.0% as the upper limit, still more preferably 5.0% as the upper limit, still more preferably 3.5% as the upper limit, still more preferably 2.0% as the upper limit, further The upper limit is preferably 1.0%, and the lower limit is more preferably 0.5%. Gd ₂ O ₃ Composition and Ta ₂ O ₅ The total amount of the components is preferably less than 5.0%. Thereby, the content of these expensive components can be reduced, and the material cost of glass can be suppressed. Therefore, Mor and (Gd ₂ O ₃ ＋ Ta ₂ O ₅ ) Is preferably not more than 5.0%, more preferably not more than 3.5%, even more preferably not more than 1.0%, and even more preferably not more than 0.5%. Ln ₂ O ₃ The sum (molar sum) of the content of the components (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, Yb, Lu) is preferably 10.0% or more and 40.0% or less. In particular, by making the sum of 10.0% or more, both the refractive index and the Abbe number of the glass can be improved, so that a glass having the required refractive index and the Abbe number can be easily obtained. Therefore, Ln ₂ O ₃ The Mohr sum of the ingredients is preferably 10.0% as the lower limit, more preferably 15.0% as the lower limit, still more preferably 16.0% as the lower limit, even more preferably 17.0% as the lower limit, and even more preferably 18.0% as Lower limit. On the other hand, since the liquidus temperature of the glass is lowered by making the sum to 40.0% or less, the devitrification of the glass can be reduced. Therefore, Ln ₂ O ₃ The molar sum of the ingredients is preferably 40.0% as the upper limit, more preferably 30.0% as the upper limit, still more preferably 25.0% as the upper limit, and even more preferably 22.0% as the upper limit. The optical glass of the present invention preferably contains the above-mentioned Ln ₂ O ₃ Two or more of the ingredients. As a result, the liquidus temperature of the glass becomes lower, and a glass with higher devitrification resistance can be obtained. In terms of the ease of lowering the liquidus temperature of the glass and the production of inexpensive optical glass, it is particularly preferred to contain La ₂ O ₃ Composition and Y ₂ O ₃ Two or more ingredients as Ln ₂ O ₃ ingredient. TiO ₂ The component is an arbitrary component that can increase the refractive index and Abbe number of the glass when the content exceeds 0%, and can increase the devitrification resistance by lowering the liquidus temperature of the glass. On the other hand, by making TiO ₂ The content of the ingredients is less than 20.0%, which can reduce the cause of TiO ₂ The devitrification caused by the excessive content of the component can suppress the decrease of the transmittance of the glass to visible light (especially the wavelength below 500 nm). Therefore, TiO ₂ The content of the components is preferably 20.0% as the upper limit, more preferably 15.0% as the upper limit, still more preferably 12.0% as the upper limit, and even more preferably 10.0% as the upper limit. About TiO ₂ Composition, TiO can be used ₂ And so on as raw materials. Nb ₂ O ₅ The component is an arbitrary component which can increase the refractive index of glass and reduce the Abbe number when it contains more than 0%, and can reduce the devitrification resistance by lowering the liquidus temperature of the glass. On the other hand, by making Nb ₂ O ₅ The content of the ingredients is 10.0% or less, which can reduce the cause of Nb ₂ O ₅ The devitrification caused by the excessive content of the component can suppress the decrease of the transmittance of the glass to visible light (especially the wavelength below 500 nm). Therefore, Nb ₂ O ₅ The content of the components is preferably 10.0% as the upper limit, more preferably 8.0% as the upper limit, still more preferably 6.0% as the upper limit, and even more preferably 5.0% as the upper limit. About Nb ₂ O ₅ Composition, use Nb ₂ O ₅ And so on as raw materials. WO ₃ The component is an arbitrary component which can reduce the coloration of glass caused by other high refractive index components, increase the refractive index, reduce the glass transition point, and improve the devitrification resistance of the glass when it contains more than 0%. Therefore, WO ₃ The content of the component is preferably more than 0%, more preferably more than 0.3%, still more preferably more than 0.5%, and even more preferably more than 1.0%. On the other hand, by making WO ₃ The content of ingredients is less than 20.0%, which can reduce ₃ The coloration of the glass caused by the composition increases the visible light transmittance. Therefore, WO ₃ The content of the components is preferably 20.0% or less as the upper limit, more preferably 17.0% or less as the upper limit, still more preferably 15.0% or less as the upper limit, and even more preferably 13.0% or less as the upper limit. About WO ₃ Ingredients, can use WO ₃ And so on as raw materials. TiO ₂ Ingredients, WO ₃ Composition and Nb ₂ O ₅ Molar sum of the components is preferably 1.0% or more and 30.0% or less. In particular, even if Ta is reduced by 1.0% or more, ₂ O ₅ The components and the like can also obtain the required optical constants, so it is possible to produce the optical glass with the required optical characteristics more inexpensively. Therefore, Moore and (TiO ₂ + WO ₃ ＋ Nb ₂ O ₅ ) Is preferably 1.0% as the lower limit, more preferably 2.5% as the lower limit, and still more preferably 5.0% as the lower limit. On the other hand, by making the Mohr sum to 30.0% or less, an increase in the liquidus temperature caused by an excessive content of these components can be suppressed, so that devitrification of the optical glass can be reduced. Therefore, Moore and (TiO ₂ + WO ₃ ＋ Nb ₂ O ₅ ) Is preferably 30.0% as the upper limit, more preferably 25.0% as the upper limit, and even more preferably 20.0% as the upper limit. A ZnO component is an arbitrary component which reduces a glass transition point and improves chemical durability when it contains more than 0%. Therefore, the content of the ZnO component is preferably set to more than 0%, and more preferably, the lower limit is 10.0%, further preferably the lower limit is 12.0%, further preferably the lower limit is 15.0%, and even more preferably The lower limit is 20.0%, and even more preferably the lower limit is 24.0%. On the other hand, when the content of the ZnO component is 38.0% or less, the liquidus temperature can be reduced, and devitrification due to excessive reduction of the glass transition point can be reduced. Therefore, the content of the ZnO component is preferably 38.0% as the upper limit, more preferably 36.0% as the upper limit, and even more preferably 35.0% as the upper limit. Regarding the ZnO component, ZnO and ZnF can be used ₂ And so on as raw materials. ZrO ₂ A component is an arbitrary component which raises the refractive index and Abbe number of glass, and improves devitrification resistance when it contains more than 0%. Therefore, ZrO ₂ The content of the components is preferably more than 0%, more preferably more than 0.5%, and even more preferably more than 0.8%. On the other hand, by making ZrO ₂ The content of ingredients is 10.0% or less, which can reduce the cause of ZrO ₂ Devitrification caused by excessive content of ingredients. Therefore, ZrO ₂ The content of the components is preferably 10.0% as the upper limit, more preferably 8.0% as the upper limit, and even more preferably 5.0% as the upper limit. About ZrO ₂ Composition, use ZrO ₂ , ZrF ₄ And so on as raw materials. SiO ₂ A component is an arbitrary component which improves the viscosity of a molten glass, reduces the color of glass, and can improve devitrification resistance when it contains more than 0%. Therefore, SiO ₂ The content of the ingredients is preferably more than 0% as the lower limit, more preferably 1.0% as the lower limit, still more preferably 3.0% as the lower limit, and even more preferably 4.0% as the lower limit. On the other hand, by making SiO ₂ The content of the component is 15.0% or less, which can suppress an increase in the glass transition point and can suppress a decrease in the refractive index. Therefore, SiO ₂ The content of the ingredients is preferably 15.0% as the upper limit, more preferably 12.0% as the upper limit, still more preferably 10.0% as the upper limit, and even more preferably 9.0% as the upper limit. About SiO ₂ Composition, SiO can be used ₂ K ₂ SiF ₆ , Na ₂ SiF ₆ And so on as raw materials. Li ₂ The O component is an optional component that can reduce the glass transition point when the content is more than 0%. On the other hand, by making Li ₂ The content of the O component is 8.0% or less, which can reduce the liquidus temperature of the glass and reduce devitrification, thereby improving chemical durability. So Li ₂ The content of the O component is preferably 8.0% or less, more preferably 4.0% or less, still more preferably 2.0% or less, and still more preferably 1.0% or less. About Li ₂ O component, Li can be used ₂ CO ₃ LiNO ₃ Li ₂ CO ₃ And so on as raw materials. Na ₂ O component, K ₂ O composition and Cs ₂ The O component is an arbitrary component which improves the melting property of glass, the glass transition point, and the devitrification resistance when it contains more than 0%. On the other hand, by making Na ₂ The content of O component is 15.0% or less and / or K ₂ O composition and Cs ₂ Each content of the O component is 10.0% or less, it is difficult to reduce the refractive index of the glass, and the devitrification of the glass can be reduced. So Na ₂ The content of the O component is preferably 15.0% as the upper limit, more preferably 10.0% as the upper limit, still more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. Again, K ₂ O composition and Cs ₂ The content of the O component is preferably 10.0% as the upper limit, more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. About Na ₂ O component, K ₂ O composition and Cs ₂ O component, can use Na ₂ CO ₃ NaNO ₃ , NaF, Na ₂ SiF ₆ K ₂ CO ₃ KNO ₃ , KF, KHF ₂ K ₂ SiF ₆ , Cs ₂ CO ₃ CsNO ₃ And so on as raw materials. Rn ₂ The sum (mole sum) of the content of the O component (where Rn is one or more selected from the group consisting of Li, Na, and K) is preferably 20.0% or less. This makes it difficult to reduce the refractive index of the glass and reduces the devitrification of the glass. Therefore, Rn ₂ The Mo content of the O component is preferably 20.0% as the upper limit, more preferably 10.0% as the upper limit, still more preferably 5.0% as the upper limit, still more preferably 3.5% as the upper limit, and even more preferably 1.7. % Is the upper limit. The MgO component, the CaO component, the SrO component, and the BaO component are arbitrary components that can adjust the refractive index, meltability, and devitrification resistance of the glass when the content exceeds 0%. On the other hand, by setting the contents of each of the MgO component, CaO component, SrO component, and BaO component to 10.0% or less, the required refractive index can be easily obtained, and the loss of glass caused by excessive content of these components can be reduced through. Therefore, the respective contents of the MgO component, the CaO component, the SrO component, and the BaO component are preferably 10.0% as the upper limit, more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. For MgO component, CaO component, SrO component, and BaO component, MgCO can be used ₃ , MgF ₂ CaCO ₃ CaF ₂ , Sr (NO ₃ ) ₂ , SrF ₂ BaCO ₃ , Ba (NO ₃ ) ₂ BaF ₂ And so on as raw materials. The sum (molar sum) of the content 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 11.0% or less. Thereby, a desired high refractive index can be easily obtained. Therefore, the molar sum of the RO component is preferably 11.0% as the upper limit, more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. GeO ₂ The component is an arbitrary component which can increase the refractive index of glass and can improve devitrification resistance when it contains more than 0%. However, due to GeO ₂ The price of raw materials is high, so if its content is large, the production cost will increase, so it will offset the reduction of Gd ₂ O ₃ Composition or Ta ₂ O ₅ Ingredients and other effects. Therefore, GeO ₂ The content of the ingredients is preferably 10.0% as the upper limit, more preferably 5.0% as the upper limit, still more preferably 3.0% as the upper limit, still more preferably 1.0% as the upper limit, and even more preferably 0.1% as the upper limit. From the viewpoint of reducing material costs, GeO may not be contained ₂ ingredient. About GeO ₂ Composition, GeO can be used ₂ And so on as raw materials. P ₂ O ₅ A component is an arbitrary component which can reduce the liquidus temperature of glass, and improves devitrification resistance when it contains more than 0%. On the other hand, by making P ₂ O ₅ The content of the component is 10.0% or less, which can suppress the reduction of the chemical durability of the glass, especially the water resistance. Therefore, P ₂ O ₅ The content of the components is preferably 10.0% as the upper limit, more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. About P ₂ O ₅ Ingredients: Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ And so on as raw materials. Bi ₂ O ₃ A component is an arbitrary component which can raise a refractive index and can reduce a glass transition point when it contains more than 0%. On the other hand, by making Bi ₂ O ₃ The content of the component is 15.0% or less, which can reduce the liquidus temperature of the glass and improve the devitrification resistance. Therefore, Bi ₂ O ₃ The content of the components is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less. About Bi ₂ O ₃ Composition, Bi can be used ₂ O ₃ And so on as raw materials. TeO ₂ A component is an arbitrary component which can raise a refractive index and can reduce a glass transition point when it contains more than 0%. On the other hand, when melting glass raw materials in a crucible made of platinum or a part in contact with molten glass is a melting tank formed of platinum, TeO ₂ May be problematic with platinum alloying. So TeO ₂ The content of the components is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less. About TeO ₂ Ingredients, TeO can be used ₂ And so on as raw materials. Al ₂ O ₃ Composition and Ga ₂ O ₃ A component is an arbitrary component which improves the chemical durability of glass, and the devitrification resistance of a molten glass when it contains more than 0%. On the other hand, by making Al ₂ O ₃ Composition and Ga ₂ O ₃ The content of each component is 15.0% or less, which can reduce the liquidus temperature of the glass and improve the devitrification resistance. Therefore, Al ₂ O ₃ Composition and Ga ₂ O ₃ The content of each component is preferably 15.0% as the upper limit, more preferably 10.0% as the upper limit, still more preferably 5.0% as the upper limit, and even more preferably 3.0% as the upper limit. About Al ₂ O ₃ Composition and Ga ₂ O ₃ Composition, Al can be used ₂ O ₃ , Al (OH) ₃ , AlF ₃ Ga ₂ O ₃ , Ga (OH) ₃ And so on as raw materials. SnO ₂ A component is an arbitrary component which can reduce the oxidation of a molten glass and clarify when it contains more than 0%, and can improve the visible light transmittance of glass. On the other hand, by making SnO ₂ The content of the ingredients is 1.0% or less, which can reduce the color of the glass or the devitrification of the glass caused by the reduction of the molten glass. In addition, it can reduce SnO ₂ The alloying of the components with the melting equipment (especially noble metals such as Pt) allows the long life of the melting equipment. Therefore, SnO ₂ The content of the components is preferably 1.0% or less, more preferably 0.5% or less, and still more preferably 0.1% or less. About SnO ₂ Composition, SnO, SnO can be used ₂ , SnF ₂ , SnF ₄ And so on as raw materials. Sb ₂ O ₃ A component is an arbitrary component which can defoam a molten glass when it contains more than 0%. On the other hand, if Sb ₂ O ₃ If the amount is too large, the transmittance in the short wavelength region of the visible light region is deteriorated. Therefore, Sb ₂ O ₃ The content of the components is preferably 1.0% as the upper limit, more preferably 0.7% as the upper limit, and still more preferably 0.5% as the upper limit. About Sb ₂ O ₃ Ingredients, use Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ 5H ₂ O and the like are used as raw materials. In addition, the component which clarifies and defoams glass is not limited to the above-mentioned Sb ₂ O ₃ As the component, a clarifier, a defoaming agent, or a combination thereof known in the field of glass production can be used. The F component is an arbitrary component that can increase the Abbe number of the glass, reduce the glass transition point, and improve devitrification resistance when the content is more than 0%. However, if the content of the F component, that is, the total amount of the fluoride in which one or two or more of the oxides of the above-mentioned elements are partially or completely replaced by F, exceeds 15.0%, the volatile content of the F component will increase, so It becomes difficult to obtain a stable optical constant, and it becomes difficult to obtain a homogeneous glass. Therefore, the content of the F component is preferably 15.0% as the upper limit, more preferably 10.0% as the upper limit, and most preferably 5.0% as the upper limit. Regarding the F component, for example, by using ZrF ₄ , AlF ₃ , NaF, CaF ₂ Etc. are contained in glass as a raw material. <About the component which should not be contained> Next, the component which should not be contained in the optical glass of this invention, and the component which is inferior in content are demonstrated. Other components may be added as needed within a 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, and Lu, each of the transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo has a small amount, respectively. When it is contained or contained in a small amount in a complex form, the glass may also be colored, and absorb the specific wavelength in the visible region. Therefore, it is preferable that it is substantially not contained in the optical glass using the wavelength in the visible region. In addition, lead compounds such as PbO and As ₂ O ₃ The arsenic compound is a component having a high environmental load, and therefore it is preferably not substantially contained, that is, it does not contain the above components except for inevitable mixing. Furthermore, the components of Th, Cd, Tl, Os, Be, and Se have tended to inhibit their use as harmful chemical materials in recent years. The environment must be adopted not only in the glass manufacturing steps, but also in the processing steps and post-productive treatment. Measures. Therefore, when it is important to take environmental impact into consideration, it is preferable not to include these substances in substance. Regarding the glass composition of the present invention, its composition is expressed in mole% relative to the total mass of the glass in terms of oxide conversion, so it is not directly expressed as mass%. In the present invention, it exists in satisfying the requirements The composition represented by mass% of each component in the glass composition of each characteristic has the following values in terms of an oxide conversion composition. B ₂ O ₃ 5.0 ~ 30.0% by mass, La ₂ O ₃ Ingredients 10.0 to 60.0% by mass, and Y ₂ O ₃ Component 0 to 40.0% by mass Gd ₂ O ₃ Component 0 to 30.0% by mass Yb ₂ O ₃ Ingredients 0 to 20.0% by mass Lu ₂ O ₃ Ingredients 0 to 20.0% by mass Ta ₂ O ₅ Component 0 to 30.0% by mass TiO ₂ 0 to 15.0% by mass of Nb ₂ O ₅ Ingredients 0 to 20.0% by mass WO ₃ Component 0 to 40.0% by mass ZnO component 0 to 25.0% by mass ZrO ₂ Component 0 to 10.0% by mass SiO ₂ Ingredients 0 to 8.0% by mass Li ₂ O component 0 to 2.0% by mass Na ₂ O component 0 to 10.0% by mass K ₂ O component 0 ～ 8.0% by mass Cs ₂ O component 0 to 15.0% by mass MgO component 0 to 3.0% by mass CaO component 0 to 5.0% by mass SrO component 0 to 8.0% by mass BaO component 0 to 10.0% by mass GeO ₂ Ingredients 0 to 12.0% by mass P ₂ O ₅ Component 0 to 10.0% by mass Bi ₂ O ₃ Component 0 to 40.0% by mass TeO ₂ Component 0 to 15.0% by mass Al ₂ O ₃ Component 0 to 12.0% by mass Ga ₂ O ₃ Component 0 to 20.0% by mass Sb ₂ O ₃ 0 to 3.0% by mass of the total amount of F and a fluoride partially or completely replacing one or two or more of the oxides of each of the above elements, 0 to 3.0% by mass, especially those present in the first optical glass The composition of the component represented by mass% is roughly the following value in terms of oxide conversion composition. B ₂ O ₃ Ingredients 5.0 to 30.0% by mass, and La ₂ O ₃ Ingredients 10.0 to 60.0% by mass, and Y ₂ O ₃ Component 0 to 20.0% by mass Gd ₂ O ₃ Component 0 to 3.0% by mass Yb ₂ O ₃ Ingredients 0 to 20.0% by mass Lu ₂ O ₃ Ingredients 0 to 20.0% by mass Ta ₂ O ₅ Component 0 to 4.0% by mass TiO ₂ 0 to 15.0% by mass of Nb ₂ O ₅ Ingredients 0 to 20.0% by mass WO ₃ Component 0 to 40.0% by mass ZnO component 0 to 25.0% by mass ZrO ₂ Component 0 to 10.0% by mass SiO ₂ Ingredients 0 to 8.0% by mass Li ₂ O component 0 to 2.0% by mass Na ₂ O component 0 to 10.0% by mass K ₂ O component 0 ～ 8.0% by mass Cs ₂ O component 0 to 15.0% by mass MgO component 0 to 3.0% by mass CaO component 0 to 5.0% by mass SrO component 0 to 8.0% by mass BaO component 0 to 10.0% by mass GeO ₂ Ingredients 0 to 12.0% by mass P ₂ O ₅ Component 0 to 10.0% by mass Bi ₂ O ₃ Component 0 to 40.0% by mass TeO ₂ Component 0 to 15.0% by mass Al ₂ O ₃ Component 0 to 12.0% by mass Ga ₂ O ₃ Component 0 to 20.0% by mass Sb ₂ O ₃ 0 to 3.0% by mass of the total amount of F and fluorinated compounds in which one or two or more of the oxides of each of the above elements are partially or completely replaced by F are 0 to 3.0% by mass On the other hand, they are present in the second optical glass The composition of each component represented by mass% is roughly the following value in terms of oxide conversion composition. B ₂ O ₃ 5.0 ~ 30.0% by mass, La ₂ O ₃ Ingredients 10.0 to 60.0% by mass, and Y ₂ O ₃ The composition exceeds 0% by mass to 40.0% by mass and Gd ₂ O ₃ Component 0 to 30.0% by mass Yb ₂ O ₃ Ingredients 0 to 20.0% by mass Lu ₂ O ₃ Ingredients 0 to 20.0% by mass Ta ₂ O ₅ Component 0 to 30.0% by mass TiO ₂ 0 to 15.0% by mass of Nb ₂ O ₅ Ingredients 0 to 20.0% by mass WO ₃ Component 0 to 40.0% by mass ZnO component 0 to 25.0% by mass ZrO ₂ Component 0 to 10.0% by mass SiO ₂ Ingredients 0 to 8.0% by mass Li ₂ O component 0 to 2.0% by mass Na ₂ O component 0 to 10.0% by mass K ₂ O component 0 ～ 8.0% by mass Cs ₂ O component 0 to 15.0% by mass MgO component 0 to 3.0% by mass CaO component 0 to 5.0% by mass SrO component 0 to 8.0% by mass BaO component 0 to 10.0% by mass GeO ₂ Ingredients 0 to 12.0% by mass P ₂ O ₅ Component 0 to 10.0% by mass Bi ₂ O ₃ Component 0 to 40.0% by mass TeO ₂ Component 0 to 15.0% by mass Al ₂ O ₃ Component 0 to 12.0% by mass Ga ₂ O ₃ Component 0 to 20.0% by mass Sb ₂ O ₃ The total amount of 0 to 3.0% by mass of the component F and the fluoride in which one or two or more of the oxides of each of the above elements are partially or completely replaced is 0 to 3.0% by mass. [Production method] The optical glass of the present invention is, for example, Make it as follows. That is, the above raw materials are uniformly mixed so that each component is within a specific content range, and the prepared mixture is put into a platinum crucible. According to the ease of melting of the glass composition, an electric furnace is used at a temperature of 1100-1500 ° C The range is melted for 2 to 5 hours, stirred and homogenized, and then lowered to an appropriate temperature, and then casted into a mold and slowly cooled to produce it. [Physical properties] The optical glass of the present invention preferably has a high refractive index and a high Abbe number (low dispersion). In particular, the refractive index (n _d ) Is preferably 1.80 as the lower limit, more preferably 1.81 as the lower limit, and still more preferably 1.82 as the lower limit. The refractive index (n _d ) Is preferably 1.95 as the upper limit, more preferably 1.93 as the upper limit, and even more preferably 1.92 as the upper limit. The Abbe number of the optical glass of the present invention (ν _d ) Is preferably 30 as the lower limit, more preferably 32 as the lower limit, and even more preferably 33 as the lower limit. The Abbe number (ν _d ) Is preferably 45 as the upper limit, more preferably 43 as the upper limit, and even more preferably 41 as the upper limit. By having such a high refractive index, a large amount of light refraction can be obtained even if the thickness of the optical element is reduced. In addition, by having such a low dispersion, even if it is a single lens, the focus shift (chromatic aberration) caused by the wavelength of light is reduced. In addition, by having such a low dispersion, for example, when it is combined with an optical element having a high dispersion (low Abbe number), higher imaging characteristics can be achieved. Therefore, the optical glass of the present invention is more useful in optical design, in particular, it is possible to achieve higher imaging characteristics and the like, and to miniaturize the optical system, thereby expanding the degree of freedom in optical design. The optical glass of the present invention preferably has a high transmittance of visible light, especially a light having a short wavelength side in the visible light, thereby reducing coloration. In particular, the 10-mm-thick sample of the optical glass of the present invention showed the shortest wavelength (λ ₇₀ ) Is preferably 450 nm as the upper limit, more preferably 420 nm as the upper limit, and still more preferably 400 nm as the upper limit. In addition, the 10 mm-thick sample of the optical glass of the present invention showed the shortest wavelength (λ ₅ ) Is preferably 400 nm as the upper limit, more preferably 380 nm as the upper limit, and still more preferably 360 nm as the upper limit. With these, the absorption end of the glass is located in the vicinity of the ultraviolet region to improve the transparency of the glass to visible light. Therefore, the optical glass can be preferably used for an optical element such as a lens that transmits light. The optical glass of the present invention preferably has high devitrification resistance, and more specifically, has a lower liquidus temperature. That is, the liquidus temperature of the optical glass of the present invention is preferably 1100 ° C as the upper limit, more preferably 1080 ° C as the upper limit, and even more preferably 1060 ° C as the upper limit. Thereby, even if the molten glass flows out at a lower temperature, the crystallization of the produced glass will be reduced, so the devitrification when the glass is formed from the molten state can be reduced, thereby reducing the optical characteristics of the optical element using the glass The impact. In addition, the temperature range in which the preform can be stably produced is widened. Therefore, even if the melting temperature of the glass is reduced, the preform can be formed, thereby suppressing the energy consumed during the formation of the preform. On the other hand, the lower limit of the liquidus temperature of the optical glass of the present invention is not particularly limited, but the liquidus temperature of the glass obtained by the present invention is usually about 800 ° C or higher, and more specifically 850 ° C or higher. Specifically, it is 900 ° C or higher. In addition, the "liquid phase temperature" in the present specification means a temperature in which a glass sample in the form of 30 cc of glass flakes is placed in a platinum crucible with a capacity of 50 ml, and is completely melted at 1250 ° C. , Cool down to a specific temperature and keep it for 12 hours, take it out of the furnace and immediately observe whether there is crystal on the glass surface and glass after cooling. At this time, no minimum temperature of crystal was found. Here, the specific temperature at the time of temperature reduction is a temperature per 10 ° C between 1180 ° C and 800 ° C. The optical glass of the present invention preferably has a glass transition point (Tg) exceeding 580 ° C and below 630 ° C. In particular, by having an optical glass having a glass transition point exceeding 580 ° C, the refractive index (n _d ) And Abbe's number (ν) from 30 to 45 _d High-refractive index and low-dispersion optical glass also makes it difficult to crystallize the glass, so it can reduce devitrification during glass production, and thereby obtain glass that can be easily pressed and formed. In particular, as the glass having a higher refractive index and a larger Abbe number tends to crystallize the glass, the effect obtained by setting the glass transition point to a temperature range exceeding 580 ° C is more significant. Therefore, the glass transition point of the optical glass of the present invention is preferably set to exceed 580 ° C, more preferably set to exceed 590 ° C, and even more preferably set to exceed 600 ° C. On the other hand, since the glass is softened at a lower temperature by making the optical glass have a glass transition point of 630 ° C. or lower, the glass can be easily press-formed at a lower temperature. In addition, it is also possible to reduce the oxidation of the press-molded mold and achieve a longer life of the mold. Therefore, the glass transition point of the optical glass of the present invention is preferably 630 ° C as the upper limit, more preferably 625 ° C as the upper limit, and even more preferably 620 ° C as the upper limit. Furthermore, even if the glass transition point exceeds 580 ° C, the use of a molding machine or a mold as shown in, for example, Japanese Patent Laid-Open No. 2007-186384 can reduce the damage to the surface of the pressing mold, thereby improving the mold material. Because of its durability, precision press molding of optical glass with a glass transition point exceeding 580 ° C is generally performed. The optical glass of the present invention preferably has a small specific gravity. More specifically, the specific gravity of the optical glass of the present invention is 5.50 [g / cm ³ ]the following. As a result, the quality of the optical element or the optical equipment using the optical element is reduced, which can contribute to the weight reduction of the optical equipment. Therefore, the specific gravity of the optical glass of the present invention is preferably 5.50 as the upper limit, more preferably 5.40 as the upper limit, and even more preferably 5.30 as the upper limit. Moreover, the specific gravity of the optical glass of this invention is about 3.00 or more in many cases, More specifically, it is 3.50 or more, More specifically, it is 4.00 or more. The specific gravity of the optical glass of the present invention is measured based on the specification of the Japan Optical Glass Industry Association JOGIS05-1975 "Method for Measuring Specific Gravity of Optical Glass". [Preform material and optical element] A glass molded body can be produced from the produced optical glass using a method such as reheat press forming or precision press forming. That is, a preform for press molding can be made from optical glass, and the preform can be reheated and press-formed, followed by a grinding process to produce a glass formed body, or a preform produced by grinding processing can be used. A preform formed by a known float-forming process or the like is subjected to precision press molding to produce a glass formed body. In addition, the method of manufacturing a glass forming body is not limited to these methods. Thus, the optical glass of the present invention can be used for various optical elements and optical designs. Among them, it is particularly preferable to form a preform from the optical glass of the present invention, and use the preform to perform reheat press molding or precision press molding to produce optical elements such as lenses or cymbals. As a result, a preform having a large diameter can be formed, so that it is possible to increase the size of an optical element and to realize high-definition and high-precision imaging characteristics and projection characteristics when used in optical equipment such as a camera or a projector. [Examples] The compositions of the examples (No. A1 to No. A75, No. B1 to No. B71) and the comparative example (No. a) of the present invention, and the refractive index of these glasses (n _d ), Abbe number (ν _d ), Glass transition point (Tg), liquidus temperature, and spectral transmittance show wavelengths of 5% and 70% (λ ₅ , Λ ₇₀ ) And specific gravity results are shown in Tables 1 to 20. Here, Examples (No. A1 to No. A75) are examples of the first optical glass, and Examples (No. B1 to No. B71) are examples of the second optical glass. In addition, the following examples are for illustration purposes only and are not limited to these examples. The glass of the examples and comparative examples of the present invention are selected from oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphate compounds, etc., which are equivalent to the respective raw materials of the components. The purity raw materials were weighed so as to become the composition ratios of the respective examples shown in the table and mixed uniformly, and then put into a platinum crucible. According to the ease of melting of the glass composition, the electric furnace was used at 1100 to 1500 ° C. It is melted in a temperature range of 2 to 5 hours, and then stirred and homogenized, and then cast into a mold or the like, and then slowly cooled to produce it. Here, the refractive index (n _d ) And Abbe number (ν _d ) Is measured based on the specifications of the Japan Optical Glass Industry Association JOGIS01-2003. Here, the refractive index (n _d ), Abbe number (ν _d ) Is obtained by measuring a glass obtained by setting the slow cooling temperature drop rate to -25 ° C / hr. In addition, the glass transition point (Tg) of the glass of an Example and a comparative example was calculated | required by performing the measurement using the horizontal expansion measuring device. Here, when a sample is used for measurement, f4.8 mm and a length of 50 to 55 mm are used, and the heating rate is set to 4 ° C / min. In addition, the transmittances of the glasses of the examples and comparative examples were measured according to the specifications of the Japan Optical Glass Industry Association JOGIS02. In addition, in the present invention, the presence or absence of the color of the glass is determined by measuring the transmittance of the glass. Specifically, for a parallel polished product with a thickness of 10 ± 0.1 mm, the spectral transmittance of 200 to 800 nm was measured in accordance with JIS Z8722 to obtain λ. ₅ (Wavelength at 5% transmittance), λ ₇₀ (Wavelength at 70% transmittance). Moreover, the liquidus temperature of the glass of the Example and the comparative example was calculated | required as follows: 30 cc glass frit glass samples were put in the platinum crucible with a capacity of 50 ml, and it melted completely at 1250 degreeC. State, lower the temperature to any temperature set between 1180 ° C and 800 ° C and set it at 10 ° C for 12 hours. After taking it out of the furnace and cooling it, immediately observe the glass surface and crystals in the glass. temperature. Moreover, the specific gravity of the glass of an Example and a comparative example was measured based on the Japan Optical Glass Industry Association specification JOGIS05-1975 "The measuring method of the specific gravity of an optical glass." [Table 1] [Table 2] [table 3] [Table 4] [table 5] [TABLE 6] [TABLE 7] [TABLE 8] [TABLE 9] [TABLE 10] [TABLE 11] [TABLE 12] [TABLE 13] [TABLE 14] [Table 15] [TABLE 16] [TABLE 17] [TABLE 18] [TABLE 19] [TABLE 20] As shown in the table, the optical glass according to the embodiment of the present invention can reduce Gd, which has a high material cost. ₂ O ₃ Composition or Ta ₂ O ₅ The content of the ingredients can therefore be obtained more cheaply. In particular, the optical glass of the examples (No.A1 to No.A75) of the present invention ₂ O ₃ ＋ Ta ₂ O ₅ ) Is less than 5.0%, and more specifically, it is less than 0.3%, so it can be obtained more cheaply. In addition, the optical glass according to the embodiment (No. B1 to No. B71) of the present invention contains Y, which has a low material cost, ₂ O ₃ The composition exceeds 0%, more specifically 3.0% or more, which can reduce the high Gd of material cost ₂ O ₃ Composition or Ta ₂ O ₅ Content of ingredients. In more detail, since Mor and (Gd ₂ O ₃ ＋ Ta ₂ O ₅ ) Is reduced to less than 5.0%, and more specifically to less than 0.3%, so that an optical glass having a required optical constant can be obtained more inexpensively. On the other hand, the glass of the comparative example does not contain Y, which has a low material cost. ₂ O ₃ Composition, Mor and (Gd ₂ O ₃ ＋ Ta ₂ O ₅ ) Is 16.455% and contains a large amount of Gd ₂ O ₃ Or Ta ₂ O ₅ Therefore, the cost of materials becomes higher. The glass transition point (Tg) of the optical glass according to the embodiment of the present invention exceeds 580 ° C. and is 630 ° C. or lower, more specifically, 583 ° C. or higher and 630 ° C. or lower within a desired range. On the other hand, the glass transition point (Tg) of the glass of the comparative example exceeds 630 ° C. In addition, the liquidus temperature of the optical glass according to the embodiment of the present invention is all 1100 ° C. or less and within a desired range. On the other hand, the liquidus temperature of the glass of the comparative example exceeds 1100 ° C. Therefore, it is clearly known that even if the optical glass according to the embodiment of the present invention contains Y, which has a low material cost among components that contribute to high refractive index and high dispersion, ₂ O ₃ In the case of ingredients or not using Gd ₂ O ₃ Composition or Ta ₂ O ₅ In the case of a component having a high material cost such as a component, the devitrification at the time of glass production can be reduced more than the optical glass having a lower glass transition point than the glass of the comparative example. Moreover, λ of the optical glass according to the embodiment of the present invention ₇₀ (Wavelength at 70% transmittance) are all 450 nm or less, and more specifically 440 nm or less. Moreover, λ of the optical glass according to the embodiment of the present invention ₅ (Wavelength at 5% transmittance) are all 400 nm or less, and more specifically 370 nm or less. Therefore, it is clearly known that the optical glass of the embodiment of the present invention has a high transmittance at a visible short wavelength and is difficult to be colored. In addition, the refractive index (n _d ) Are all 1.80 or more, more specifically 1.81 or more, and the refractive index (n _d ) Is 1.95 or less, and more specifically 1.92 or less, so that it is within a desired range. In addition, the Abbe number (ν of the optical glass of the embodiment of the present invention _d ) Are all 30 or more, more specifically 33 or more, and the Abbe number (ν _d ) Is 45 or less, and more specifically 43 or less, so that it is within a desired range. The specific gravity of the optical glass in the examples of the present invention is 5.50 or less, and more specifically 5.21 or less. Therefore, it is clearly known that the specific gravity of the optical glass of the embodiment of the present invention is relatively small. Therefore, it is clearly known that the refractive index (n _d ) And Abbe number (ν _d ) Is within the required range, and it can be seen that the transmittance at short wavelengths is high, the devitrification resistance is high, it is easy to perform press molding by softening by heating, and the specific gravity is small. Furthermore, the optical glass according to the embodiment of the present invention was used for reheat press molding, followed by grinding and polishing to be processed into the shapes of lenses and cymbals. In addition, the optical glass according to the embodiment of the present invention is used to form a preform for precision press molding, and the preform for precision press molding is precision pressed into a shape of a lens and a cymbal. In any case, the glass after heating and softening does not cause problems such as milk whitening and devitrification, so that it can be stably processed into various lens and cymbal shapes. In the above, the present invention has been described in detail for the purpose of illustration, but it should be understood that this embodiment is only for the purpose of illustration, and the industry can make many changes without departing from the spirit and scope of the present invention.

Claims (11)

An optical glass containing B ₂ O ₃ component in an amount of 10.0% to 50.0%, La ₂ O ₃ component in a range of 5.0% to 30.0%, and a Gd ₂ O ₃ component content of less than 1.0%, The content of Li ₂ O component is less than 1.0%, the content of Y ₂ O ₃ component is 0 to 20.0%, the content of Yb ₂ O ₃ component is 0 to 10.0%, and the content of Lu ₂ O ₃ component is 0 to 10.0%. The content of the Ta ₂ O ₅ component is 0 to 10.0%, the content of the TiO ₂ component is 0 to 20.0%, the content of the Nb ₂ O ₅ component is 0 to 10.0%, the content of the WO ₃ component is 0 to 20.0%, and the content of ZnO is The content is 0 to 38.0%, the content of ZrO ₂ is 0 to 10.0%, the content of SiO ₂ is 0 to 15.0%, the content of Na ₂ O is 0 to 15.0%, and the content of K ₂ O is 0 ~ 10.0%, Cs ₂ O content is 0 ~ 10.0%, MgO content is 0 ~ 10.0%, CaO content is 0 ~ 10.0%, SrO content is 0 ~ 10.0%, BaO content 0 to 10.0%, GeO ₂ content is 0 to 10.0%, P ₂ O ₅ content is 0 to 10.0%, Bi ₂ O ₃ content is 0 to 15.0%, and TeO ₂ content is 0. ~ 15.0%, content of Al ₂ O ₃ component is 0 ~ 15.0%, content of Ga ₂ O ₃ component is 0 ~ 15.0%, content of Sb ₂ O ₃ component is 0 ~ 1.0%, the content of fluoride in terms of F which partially or completely replaces one or two or more of the oxides of the above elements is 0 ~ 15.0 mole%, and the above-mentioned optical glass has a refractive index of 1.80 or more ( n _d ) and has an Abbe number (ν _d ) of 30 or more and 45 or less. For example, the optical glass of claim 1, wherein the molar sum (Gd ₂ O ₃ + Yb ₂ O ₃ + Ta ₂ O ₅ ) is 10.0% or less. For example, the optical glass of claim 1, wherein the molar sum (Gd ₂ O ₃ + Ta ₂ O ₅ ) is less than 5.0%. For example, the optical glass of claim 1, wherein the molar 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, Yb, and Lu) is 10.0% or more and 40.0 % Or less, the molar sum of the Rn ₂ O component (where Rn is one or more selected from the group consisting of Li, Na, K, and Cs) is 20.0% or less, and the RO component (where R is selected from the group consisting of The molar sum of one or more of the group consisting of Mg, Ca, Sr, and Ba) is 11.0% or less. For example, the optical glass of claim 1 contains two or more of the above-mentioned components of Ln ₂ O ₃ (wherein, Ln is one or more selected from the group consisting of La, Gd, Y, Yb, and Lu) . For example, the optical glass of claim 1, wherein the molar sum (TiO ₂ + WO ₃ + Nb ₂ O ₅ ) is 1.0 to 30.0%. For example, the optical glass of claim 1 has a refractive index (n _d ) of 1.80 or more and 1.95 or less, an Abbe number (ν _d ) of 30 or more and 45 or less, and a liquid phase temperature of 1100 ° C. or less. The optical glass of claim 1, wherein the glass transition point (Tg) exceeds 580 ° C and is 630 ° C or lower. A preform comprising the optical glass according to any one of claims 1 to 8. An optical element using the optical glass according to any one of claims 1 to 8 as a base material. An optical device comprising an optical element as claimed in claim 10.