Abstract: Provided is a high-strength crystallized glass or substrate having a high visible light transmittance and a good color balance, which is suitable for use in protecting members of portable electronic devices, optical devices and the like. Provided is a crystallized glass comprising, in terms of mol % on an oxide basis: an SiO2 component of 30.0% or more and 70.0% or less, an Al2O3 component of 8.0% or more and 25.0%, an Na2O component of 0% or more and 25.0% or less, an MgO component of 0% or more and 25.0% or less, a ZnO component of 0% or more and 30.0% or less and a TiO2 component of 0% or more and 10.0% or less, the molar ratio [Al2O3/(MgO+ZnO)] having a value of 0.5 or more and 2.0 or less, and comprising one or more selected from RAl2O4, RTi2O5, R2TiO4, R2SiO4, RAl2Si2O8 and R2Al4Si5O18 as a crystal phase.

Abstract: Provided are an optical glass that has optical properties including a medium refractive index and low dispersion and that has good chemical durability and a low specific gravity, and a preform material and an optical element that use the optical glass. The optical glass contains a SiO2 component: 0% or more and less than 30.0%; 8.0% to 30.0% of an Al2O3 component; less than 20.0% of an RO component (where R represents at least one selected from the group consisting of Zn, Mg, Ca, Sr, and Ba) in terms of a mass sum; and 10.0% to 55.0% of an Ln2O3 component (where Ln represents at least one selected from the group consisting of La, Gd, Y, and Lu) in terms of a mass sum. A mass ratio (SiO2+Al2O3)/B2O3 is 0.3 to 10.0, and the optical glass has a refractive index (nd) of 1.58 or more and 1.80 or less and an Abbe number (?d) of 35 or more and 65 or less.

Abstract: Provided is a high-strength crystallized glass or substrate having a high visible light transmittance and a good color balance, which is suitable for use in protecting members of portable electronic devices, optical devices and the like. Provided is a crystallized glass comprising, in terms of mol % on an oxide basis: an SiO2 component of 30.0% or more and 70.0% or less, an Al2O3 component of 8.0% or more and 25.0%, an Na2O component of 0% or more and 25.0% or less, an MgO component of 0% or more and 25.0% or less, a ZnO component of 0% or more and 30.0% or less and a TiO2 component of 0% or more and 10.0% or less, the molar ratio [Al2O3/(MgO+ZnO)] having a value of 0.5 or more and 2.0 or less, and comprising one or more selected from RAl2O4, RTi2O5, R2TiO4, R2SiO4, RAl2Si2O8 and R2Al4Si5O18 as a crystal phase.

Abstract: Provided is a high-strength crystallized glass or substrate having a high visible light transmittance and a good color balance, which is suitable for use in protecting members of portable electronic devices, optical devices and the like. Provided is a crystallized glass comprising, in terms of mol % on an oxide basis: an SiO2 component of 30.0% or more and 70.0% or less, an Al2O3 component of 8.0% or more and 25.0%, an Na2O component of 0% or more and 25.0% or less, an MgO component of 0% or more and 25.0% or less, a ZnO component of 0% or more and 30.0% or less and a TiO2 component of 0% or more and 10.0% or less, the molar ratio [Al2O3/(MgO+ZnO)] having a value of 0.5 or more and 2.0 or less, and comprising one or more selected from RAl2O4, RTi2O5, R2TiO4, R2SiO4, RAl2Si2O8 and R2Al4Si5O18 as a crystal phase.

Abstract: Provided is a high-strength crystallized glass or substrate having a high visible light transmittance and a good color balance, which is suitable for use in protecting members of portable electronic devices, optical devices and the like. Provided is a crystallized glass comprising, in terms of mol % on an oxide basis: an SiO2 component of 30.0% or more and 70.0% or less, an Al2O3 component of 8.0% or more and 25.0%, an Na2O component of 0% or more and 25.0% or less, an MgO component of 0% or more and 25.0% or less, a ZnO component of 0% or more and 30.0% or less and a TiO2 component of 0% or more and 10.0% or less, the molar ratio [Al2O3/(MgO+ZnO)] having a value of 0.5 or more and 2.0 or less, and comprising one or more selected from RAl2O4, RTi2O5, R2TiO4, R2SiO4, RAl2Si2O8 and R2Al4Si5O18 as a crystal phase.

Abstract: It is an object of the present invention to provide a crystallized glass which has various properties required for employing the substrate for information recording medium of the next generation, and also has significantly low specific gravity; and a crystallized glass substrate for information recording medium. A crystallized glass containing, as a crystal phase, one or more selected from RAl2O4 and R2TiO4 (wherein R is one or more selected from Mg and Fe), the crystallized glass comprising the components of SiO2 of 50% to 70%, Al2O3 of 10% to 26%, TiO2 of 1 to 15%, MgO of 2.5% to 25%, FeO of 0% to 8%, and ZnO of 0% to less than 2%, expressed in terms of mass percentage on an oxide basis, wherein the value of (Al2O3+MgO)/SiO2 is 0.30 or more and 0.65 or less, and a specific gravity is less than 2.63.

Abstract: It is an object of the present invention to provide a crystallized glass which has various properties required for employing the substrate for information recording medium of the next generation, and also has significantly low specific gravity; and a crystallized glass substrate for information recording medium. A crystallized glass containing, as a crystal phase, one or more selected from RAl2O4 and R2TiO4 (wherein R is one or more selected from Mg and Fe), the crystallized glass comprising the components of SiO2 of 50% to 70%, Al2O3 of 10% to 26%, TiO2 of 1 to 15%, MgO of 2.5% to 25%, FeO of 0% to 8%, and ZnO of 0% to less than 2%, expressed in terms of mass percentage on an oxide basis, wherein the value of (Al2O3+MgO)/SiO2 is 0.30 or more and 0.65 or less, and a specific gravity is less than 2.63.

Abstract: Provided is an optical glass having optical constants, a refractive index (nd) of more than 1.9 and an Abbe number (?d) of not more than 38, having a small partial dispersion ratio and capable of being produced from inexpensive materials. The optical glass has a partial dispersion ratio (?g, F) of at most 0.615, and contains, as indispensable ingredients, B2O3, La2O3, TiO2, Nb2O5 and Ta2O5, wherein the ratio, as % by mass, of TiO2/Nb2O5 is at most 0.26 and GeO2/Nb2O5 is at most 0.38. The optical glass contains, in terms of % by mass, the following ingredients: B2O3 ??5 to 22%, La2O3 ??15 to 50%, TiO2 0.01 to 15%, Nb2O5 ??5 to 40%, and Ta2O5 ?0.1 to 25%, and SiO2 0 to 10% and/or GeO2 0 to 10% and/or Al2O3 0 to 10% and/or Gd2O3 0 to 16% and/or ZrO2 0 to 15% and/or WO3 0 to 22% and/or Sb2O3 0 to 1%.

Abstract: Provided is an optical glass having optical constants, a refractive index (nd) of more than 1.9 and an Abbe number (?d) of not more than 38, having a small partial dispersion ratio and capable of being produced from inexpensive materials. The optical glass has a partial dispersion ratio (?g, F) of at most 0.615, and contains, as indispensable ingredients, B203, La2O3, TiO2, Nb2O5 and Ta2O5, wherein the ratio, as % by mass, of TiO2/Nb2O5 is at most 0.26 and GeO2/Nb2O5 is at most 0.38. The optical glass contains, in terms of % by mass, the following ingredients: B2O3 ??5 to 22%, La2O3 ??15 to 50%, TiO2 0.01 to 15%, Nb2O5 ??5 to 40%, and Ta2O5 ?0.1 to 25%, and SiO2 0 to 10% and/or GeO2 0 to 10% and/or Al2O3 0 to 10% and/or Gd2O3 0 to 16% and/or ZrO2 0 to 15% and/or WO3 0 to 22% and/or Sb2O3 0 to 1%.