Abstract: An on-vehicle camera lens glass material satisfies at least one of conditions in which a measurement result in water resistance based on a powder method prescribed by Japanese Optical Glass Industrial Standard is 1st Class, a measurement result in Knoop hardness based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 6th Class or higher, a measurement result in solarization based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 2% or less, and a measurement result in average linear expansion coefficient based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 100×10?7° C.?1 or less.

Abstract: An optical glass having high-refractivity and low-dispersion optical properties and having a low glass transition point so that a heat-treating furnace can be operated for a long period of time. The optical glass has a refractive index nd of at least 1.875, an Abbe's number vd of at least 39.5 and a glass transition point Tg of 700° C. or lower, and contains at least one of La2O3, Gd2O3, Y2O3 or Yb2O3 and at least one of ZrO2, Ta2O5 or Nb2O5, with a weight ratio of the total content of La2O3, Gd2O3, Y2O3 and Yb2O3 to the total content of SiO2 and B2O3 of from 3.2 to 5 and the weight ratio of the total content of ZrO2, Ta2O5 and Nb2O5 to the total content of SiO2 and B2O3 is from 1.1 to 1.5.

Abstract: Disclosed is an optical glass comprising, expressed as weight percentages, greater than or equal to 18 percent and less than 30 percent of SiO2, greater than or equal to 12 percent and less than 23 percent of BaO, 22 to 37 percent TiO2, greater than or equal to 7 percent and less than 16 percent Nb2O5, 5 to 20 percent of Na2O, 0 to 6 percent of K2O, 0 to 5 percent of CaO, 0 to 5 percent of SrO, 0 to 4 percent of ZrO2, 0 to 3 percent of Ta2O5, 0 to 1 percent of Sb2O5, and greater than or equal to 0 percent and less than 0.5 percent of P2O5, and by essentially not comprising PbO, As2O3, and F. The optical glass exhibits a refractive index (nd) greater than or equal to 1.80 and an Abbé number (vd) less than or equal to 30. A method of manufacturing a glass material for press molding is disclosed.

Abstract: Disclosed is an optical glass comprising, expressed as weight percentages, greater than or equal to 18 percent and less than 30 percent of SiO2, greater than or equal to 12 percent and less than 23 percent of BaO, 22 to 37 percent TiO2, greater than or equal to 7 percent and less than 16 percent Nb2O5, 5 to 20 percent of Na2O, 0 to 6 percent of K2O, 0 to 5 percent of CaO, 0 to 5 percent of SrO, 0 to 4 percent of ZrO2, 0 to 3 percent of Ta2O5, 0 to 1 percent of Sb2O5, and greater than or equal to 0 percent and less than 0.5 percent of P2O5, and by essentially not comprising PbO, As2O3, and F. The optical glass exhibits a refractive index (nd) greater than or equal to 1.80 and an Abbé number (vd) less than or equal to 30. A method of manufacturing a glass material for press molding is disclosed.

Abstract: An optical glass for a prism, which has high transmittance, high homogeneity and excellent thermal stability, and an optical part for a prism, which is formed of the optical glass, the optical glass being an optical glass (1) wherein the absolute value of K&Dgr;t represented by the relational expression (I), 1 K ⁢   ⁢ Δ ⁢   ⁢ t = [ ( specific ⁢   ⁢ heat × specific ⁢   ⁢ gravity ) / thermal ⁢   ⁢ conductivity ] × Young ' ⁢ s ⁢   ⁢ modulus × thermal ⁢   ⁢ expansion ⁢   ⁢ coefficient × ( 1 - Poisson ' ⁢ s ⁢   ⁢ ratio ) × photoelastic ⁢   ⁢ constant ( I )

Abstract: Disclosed is an optical glass comprising, expressed as weight percentages, greater than or equal to 18 percent and less than 30 percent of SiO2, greater than or equal to 12 percent and less than 23 percent of BaO, 22 to 37 percent TiO2, greater than or equal to 7 percent and less than 16 percent Nb2O5, 5 to 20 percent of Na2O, 0 to 6 percent of K2O, 0 to 5 percent of CaO, 0 to 5 percent of SrO, 0 to 4 percent of ZrO2, 0 to 3 percent of Ta2O5, 0 to 1 percent of Sb2O5, and greater than or equal to 0 percent and less than 0.5 percent of P2O5, and by essentially not comprising PbO, As2O3, and F. The optical glass exhibits a refractive index (nd) greater than or equal to 1.80 and an Abbé number (vd) less than or equal to 30. A method of manufacturing a glass material for press molding is disclosed.

Abstract: In a light polarization control element using a stress-optical coefficient glass, the stress-optical coefficient glass is substantially composed of a phosphorous acid glass containing 20 to 60 percent by weight of P.sub.2 O.sub.5 and 40 to 73 percent by weight of BaO and PbO.

Abstract: A highly reliable information recording medium capable of meeting a higher rotation speed of a drive device and a smaller thickness and a higher recording density of an information recording medium can be produced by using, as a substrate, chemically reinforced glass obtained from chemically reinforceable glass having an SiO.sub.2 --Al.sub.2 O.sub.3 --R.sub.2 O total content of more than 98% by weight and having a specific modulus of at least 30.times.10.sup.2.

Abstract: A near infrared absorption filter glass containing______________________________________ P.sub.2 O.sub.5 35.about.50% Li.sub.2 O 0.about.5% Na.sub.2 O 0.about.12% K.sub.2 O 0.about.20% Cs.sub.2 O 0.about.20% R.sub.2 O (in which R is an alkali metal) 1.5.about.20% ZnO 17.about.48% MgO 0.about.7% CaO 0.about.7% SrO 0.about.7% BaO 0.about.12% R'O (in which R' is an alkaline earth metal) 0.about.15% CuO 0.2.about.12% ______________________________________ in which % stands for % by weighthas excellent transmittance characteristics in the ultraviolet region over conventional phosphate-based glass, has glass stability and processability which enable the mass production, and further has sufficient weatherability.

Abstract: The optical glass of the present invention comprising SiO.sub.2, alkali metal oxides, P.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 has optical properties of 1.70 or more in refractive index nd and 30 or less in Abbe's number .nu.d and is superior in devitrification resistance and stability.