Abstract: Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %?B3+?50 cat %, 15 cat %?La3+?35 cat %, 20 cat %?Nb5+?50 cat %, and 15 cat %?Ti4+?25 cat %.

Abstract: An optical glass includes La3+, Zn2+, Nb5+, and Ti4+ as a cation configuring glass. La3+, Zn2+, Nb5+, and Ti4+ which satisfy 10 cat %?La3+?20 cat %, 10 cat %?Zn2+?60 cat %, 20 cat %?Nb5+?60 cat %, and 0 cat %?Ti4+?40 cat % expressed by cation %.

Abstract: Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %?B3+?50 cat %, 15 cat %?La3+?35 cat %, 20 cat %?Nb5+?50 cat %, and 15 cat %?Ti4+?25 cat %.

Abstract: An optical glass includes La3+, Zn2+, Nb5+, and Ti4+ as a cation configuring glass. La3+, Zn2+, Nb5+, and Ti4+ which satisfy 10 cat %?La3+?20 cat %, 10 cat %?Zn2+?60 cat %, 20 cat %?Nb5+?60 cat %, and 0 cat %?Ti4+?40 cat % expressed by cation %.

Abstract: [Problem] To provide an online learning system in which learning outcome content output by learners is used without modification as teaching content for other learners, and teaching content is developed and improved in an autonomous manner without management by a system administrator. [Solution] In this invention, video/audio content materials (referred to herein as “video/audio clips”) of small units having a certain significance and typically having a length from several seconds to several tens of seconds are used as learning/teaching content, and video/audio clips of images and recordings of learners themselves implementing learning content are collected. The video/audio clips are used not only as material for measuring the degree of learning achieved, but also as learning/teaching content.

Abstract: An optical glass including B3+, La3+ and Nb5+ as cationic components constituting the glass, wherein the optical glass satisfies the following expressions represented in cation percentages: 10 cat. %?B3+?50 cat. %; 40 cat. %?La3+?65 cat. %; 0 cat. %?Nb5+?40 cat. %; 80 cat. %?(total amount of B3++La3++Nb5+)?100 cat. %; and 0 cat. %?Si4+?10 cat. %; 0 cat. %?Ge4+?5 cat. %; 0 cat. %?Mg2+?5 cat. %; 0 cat. %?Ba2+?10 cat. %; 0 cat. %?Ca2+?10 cat. %; 0 cat. %?Sr2+?10 cat. %; 0 cat. %?Zn2+?20 cat. %; 0 cat. %?W6+?5 cat. %; 0 cat. %?Zr4+?5 cat. %; 0 cat. %?Ti4+?5 cat. %; 0 cat. %?Bi3+?5 cat. %; 0 cat. %?Ta5+?10 cat. %; 0 cat. %?(total amount of Y3++Gd3+)?20 cat. %; and 0 cat. %?(total amount of Yb3++Lu3+)?10 cat. %.

Abstract: An optical glass including B3+, La3+ and Nb5+ as cationic components constituting the glass, wherein the optical glass satisfies the following expressions represented in cation percentages: 10 cat. %?B3+?50 cat. %; 40 cat. %?La3+?65 cat. %; 0 cat. %?Nb5+?40 cat. %; 80 cat. %?(total amount of B3++La3++Nb5+)?100 cat. %; and 0 cat. %?Si4+?10 cat. %; 0 cat. %?Ge4+?5 cat. %; 0 cat. %?Mg2+?5 cat. %; 0 cat. %?Ba2+?10 cat. %; 0 cat. %?Ca2+?10 cat. %; 0 cat. %?Sr2+?10 cat. %; 0 cat. %?Zn2+?20 cat. %; 0 cat. %?W6+?5 cat. %; 0 cat. %?Zr4+?5 cat. %; 0 cat. %?Ti4+?5 cat. %; 0 cat. %?Bi3+?5 cat. %; 0 cat. %?Ta5+?10 cat. %; 0 cat. %?(total amount of Y3++Gd3+)?20 cat. %; and 0 cat. %?(total amount of Yb3++Lu3+)?10 cat. %.

Abstract: Provided is an optical glass having homogeneous optical characteristics such that striae and devitrification hardly occur at the time of producing a gob. The optical glass includes cationic components having the following composition, provided that a total of the cationic components is 95 cat %, and has a refractive index (nd) of 1.6 or more and less than 1.7 and an Abbe number (vd) of 50 or more and 56 or less, Si4+ 3 cat % or more and 13 cat % or less B3+ 40 cat % or more and 55 cat % or less La3+ 4 cat % or more and 9 cat % or less Ca2+ 6 cat % or more and 12 cat % or less Li+ 11 cat % or more and 18 cat % or less Zn2+ 6 cat % or more and 12 cat % or less Zr4+ 1 cat % or more and 4 cat % or less provided that Si4+/B3+ is 0.05 or more and 0.3 or less, and Li+/Zn2+ is 1.3 or more and 2.0 or less.

Abstract: An optical element comprising a vacuum-sintered body comprising a plurality of particles each having a two-layer structure comprising a ceramic particle and a coating layer, wherein the ceramic particle comprises LnxAlyO[x+y]×1.5, where Ln represents a rare-earth element, x represents 1?x?10, and y represents 1?y?5, and has an average particle diameter of 1 ?m or more and 10 ?m or less, and wherein the coating layer comprises a ceramic having a lower sintering temperature than a sintering temperature of the ceramic particle.

Abstract: An optical element is formed by vacuum-sintering a molded body of ceramic particles having an average particle diameter of 1 ?m or more and 10 ?m or less and including LnxAlyO[x+y]×1.5 (Ln represents a rare-earth element, 1?x?10, and 1?y?5). Ln preferably includes at least one kind selected from La, Gd, Yb, and Lu. The optical element preferably has a refractive index of 1.85 or more and 2.06 or less, and an Abbe number of 48 or more and 65 or less. The obtained optical element has optical properties of high refractive index and low dispersibility.

Abstract: An optical element is formed by vacuum-sintering a molded body of ceramic particles having an average particle diameter of 1 ?m or more and 10 ?m or less and including LnxAlyO[x+y]×1.5 (Ln represents a rare-earth element, 1?x?10, and 1?y?5). Ln preferably includes at least one kind selected from La, Gd, Yb, and Lu. The optical element preferably has a refractive index of 1.85 or more and 2.06 ?m or less, and an Abbe number of 48 or more and 65 or less. The obtained optical element has optical properties of high refractive index and low dispersibility.

Abstract: Provided is an optical element, which is formed by vacuum-sintering a molded body of ceramic particles having an average particle diameter of 1 ?m or more and 10 ?m or less and including LnxAlyO|x+y|×1.5 (Ln represents a rare-earth element, x represents 1?x?10, and y represents 1?y?5). Ln preferably includes at least one kind selected from La, Gd, Yb, and Lu. The optical element preferably has a refractive index of 1.85 or more and 2.06 ?m or less, and an Abbe number of 48 or more and 65 or less. The optical element having optical properties of high refractive index and low dispersibility is obtained.

Abstract: Provided is an optical glass having homogeneous optical characteristics such that striae and devitrification hardly occur at the time of producing a gob. The optical glass includes cationic components having the following composition, provided that a total of the cationic components is 95 cat %, and has a refractive index (nd) of 1.6 or more and less than 1.7 and an Abbe number (vd) of 50 or more and 56 or less, Si4+ 3 cat % or more and 13 cat % or less B3+ 40 cat % or more and 55 cat % or less La3+ 4 cat % or more and 9 cat % or less Ca2+ 6 cat % or more and 12 cat % or less Li+ 11 cat % or more and 18 cat % or less Zn2+ 6 cat % or more and 12 cat % or less Zr4+ 1 cat % or more and 4 cat % or less provided that Si4+/B3+ is 0.05 or more and 0.3 or less, and Li+/Zn2+ is 1.3 or more and 2.0 or less.

Abstract: Provided is an optical element, which is formed by vacuum-sintering a molded body of ceramic particles having an average particle diameter of 1 ?m or more and 10 ?m or less and including LnxAlyO[x+y]×1.5 (Ln represents a rare-earth element, x represents 1?x?10, and y represents 1?y?5). Ln preferably includes at least one kind selected from La, Gd, Yb, and Lu. The optical element preferably has a refractive index of 1.85 or more and 2.06 ?m or less, and an Abbe number of 48 or more and 65 or less. The optical element having optical properties of high refractive index and low dispersibility is obtained.

Abstract: An optical glass having a remarkably high refractive index and excellent stability can be give without being based on PbO, and the optical glass contains, as essential components, at least one oxide selected from La2O3, Gd2O3, Y2O3, Yb2O3, TiO2, Nb2O5 or WO3, at least one oxide selected from MgO, CaO, SrO or BaO and B2O3 and optionally containing SiO2, wherein on the basis of mass, the total content of B2O3 and SiO2 is from 1 to 25%, the ratio of (B2O3+SiO2)/(La2O3+Gd2O3+Y2O3+Yb2O3+TiO2+Nb2O5+WO3) is from 0.05 to 0.3 and the ratio of (MgO+CaO+SrO+BaO)/(La2O3+Gd2O3+Y2O3+Yb2O3+TiO2+Nb2O5+WO3) is from 0.1 to 0.4, the optical glass having a refractive index (nd) of 2.000 or more and an Abbe's number (vd) of 27 or less.

Abstract: An optical glass having a high light transmittance, a high refractive index and excellent production stability, which contains at least one of CaO and SrO together with SiO2, B2O3, La2O3, Nb2O5, TiO2 and BaO, having a composition that substantially contains, by weight %, 1 to 18% of SiO2, 3 to 24% of B2O3, provided that the ratio of content of B2O3 to the content of SiO2 (B2O3/SiO2) is over 1, 10 to 50% of La2O3, 1 to 30% of Nb2O5, 1 to 30% of TiO2, over 6% but not more than 25% of BaO, less than 7% of CaO, 6% or less of SrO, 0 to 13% of MgO, provided that the total content of BaO, CaO, SrO and MgO is 40% or less, 0 to 15% of ZnO, 0 to 15% of ZrO2, 0 to 10% of Al2O3, 0 to 20% of Gd2O3, 0% or more but less than 2% of Y2O3, 0 to 5% of Yb2O3, 0 to 18% of Ta2O5, 0 to 20% of Bi2O3, 0 to 10% of GeO2, 0% or more but less than 2% of Sb2O3, and 0% or more but less than 2% of SnO2, and having a refractive index (nd) of over 1.8, Abbe's number (?d) of 28 to 40 and a density of 4.2 g/cm3 or more.

Abstract: An optical glass whose refractive index is high and whose coloring is decreased comprising, by weight %, 2 to 45% of B2O3, 0 to 30% of SiO2 provided that the content of B2O3>the content of SiO2, 10 to 50% of La2O3, 0 to 30% of TiO2, 0 to 15% of ZnO, 0 to 15% of ZrO2, 0 to 35% of Nb2O5, 0 to 35% of BaO, 0 to 5% of SrO, 0% or more but less than 8% of CaO, 0% or more but less than 13% of MgO, provided that the total content of BaO, SrO, CaO and MgO is 0 to 40%, 0 to 20% of Gd2O3, 0 to 15% of Y2O3, 0 to 18% of Ta2O5, 0% or more but less than 0.5% of WO3, 0% or more but less than 1.5% of a total of Na2O, K2O and Li2O, 0 to 10% of GeO2, 0 to 20% of Bi2O3, 0 to 10% of Yb2O3, 0 to 10% of Al2O3, 0% or more but less than 2% of Sb2O3 and 0 to 1% of SnO2.

Abstract: An optical glass whose refractive index is high and whose coloring is decreased comprising, by weight %, 2 to 45% of B2O3, 0 to 30% of SiO2 provided that the content of B2O3>the content of SiO2, 10 to 50% of La2O3, 0 to 30 % of TiO2, 0 to 15% of ZnO, 0 to 15% of ZrO2, 0 to 35% of Nb2O5, 0 to 35% of BaO, 0 to 5% of SrO, 0% or more but less than 8% of CaO, 0% or more but less than 13% of MgO, provided that the total content of BaO, SrO, CaO and MgO is 0 to 40%, 0 to 20% of Gd2O3, 0 to 15% of Y2O3, 0 to 18% of Ta2O5, 0% or more but less than 0.5% of WO3, 0% or more but less than 1.5% of a total of Na2O, K2O and Li2O, 0 to 10% of GeO2, 0 to 20% of Bi2O3, 0 to 10% of Yb2O3, 0 to 10% of Al2O3, 0% or more but less than 2% of Sb2O3 and 0 to 1% of SnO2.

Abstract: An optical glass having a remarkably high refractive index and excellent stability can be give without being based on PbO, and the optical glass contains, as essential components, at least one oxide selected from La2O3, Gd2O3, Y2O3, Yb2O3, TiO2, Nb2O5 or WO3, at least one oxide selected from MgO, CaO, SrO or BaO and B2O3 and optionally containing SiO2, wherein on the basis of mass, the total content of B2O3 and SiO2 is from 1 to 25%, the ratio of (B2O3+SiO2)/(La2O3+Gd2O3+Y2O3+Yb2O3+TiO2+Nb2O5+WO3) is from 0.05 to 0.3 and the ratio of (MgO+CaO+SrO+BaO)/(La2O3+Gd2O3+Y2O3+Yb2O3+TiO2+Nb2O5+WO3) is from 0.1 to 0.4, the optical glass having a refractive index (nd) of 2.000 or more and an Abbe's number (vd) of 27 or less.

Abstract: An optical glass having a high light transmittance, a high refractive index and excellent production stability, which contains at least one of CaO and SrO together with SiO2, B2O3, La2O3, Nb2O5, TiO2 and BaO, having a composition that substantially contains, by weight %, 1 to 18% of SiO2, 3 to 24% of B2O3, provided that the ratio of content of B2O3 to the content of SiO2 (B2O3/SiO2) is over 1, 10 to 50% of La2O3, 1 to 30% of Nb2O5, 1 to 30% of TiO2, over 6% but not more than 25% of BaO, less than 7% of CaO, 6% or less of SrO, 0 to 13% of MgO, provided that the total content of BaO, CaO, SrO and MgO is 40% or less, 0 to 15% of ZnO, 0 to 15% of ZrO2, 0 to 10% of Al2O3, 0 to 20% of Gd2O3, 0% or more but less than 2% of Y2O3, 0 to 5% of Yb2O3, 0 to 18% of Ta2O5, 0 to 20% of Bi2O3, 0 to 10% of GeO2, 0% or more but less than 2% of Sb2O3, and 0% or more but less than 2% of SnO2, and having a refractive index (nd) of over 1.8, Abbe's number (?d) of 28 to 40 and a density of 4.2 g/cm3 or more.