Abstract: A transparent glass-ceramic composition including: of the formula Ta2-xAlxO5-x where x is less than 1; of the formula AlTaO4; of the formula AlPO4; a mixture of AlTaO4 and AlPO4; or a mixture of the formula Ta2-xAlxO5-x, AlTaO4, and AlPO4. Also disclosed are transparent glass-ceramic compositions including, for example, a dopant as defined herein, or a supplemental metal oxide or metalloid oxide of MxOy, MxM?xOy, or a mixture thereof such as oxides of Nb, Ti, W, B, or Ga, as defined herein. Also disclosed are methods of making the disclosed transparent glass-ceramic compositions, and optical articles, optical components, and optical apparatus thereof.

Abstract: Provided is a light guide plate for an image display device which uses lead-free glass, has excellent color reproducibility and a light weight, and may obtain a wide viewing angle. A light guide plate for an image display device, which guides image light inputted from an image display element and outputs the image light toward a user's pupil, is configured to be made of lead-free glass having a refractive index of 1.8 or more with respect to a wavelength of the image light, and to have internal transmittance of 0.6 or more with respect to a wavelength of 400 nm when a plate thickness is 10 mm.

Abstract: An aspect of the present invention relates to an optical glass, which comprises, denoted as weight percent, 2 to 37 percent of SiO2, 0 to 25 percent of B2O3, 0 to 10 percent of GeO2, 18 to 55 percent of a combined content of Li2O, Na2O, K2O, CaO, SrO, and BaO, and 27 to 55 percent of a combined content of TiO2, Nb2O5, and WO3, wherein the weight ratio of SiO2 content relative to a combined content of SiO2 and B2O3 ranges from 0.1 to 1, a weight ratio of the Li2O content to a combined content of Li2O, Na2O, K2O, CaO, SrO, and BaO ranges from 0 to 0.4, and a weight ratio of TiO2 content relative to a combined content of TiO2, Nb2O5, and WO3 ranges from 0.35 to 1, with a refractive index nd of 1.860 to 1.990 and an Abbé number ?d of 21 to 29.

Abstract: An optical glass having ultrahigh refractive index and high dispersion characteristics in the form of a refractive index nd exceeding 2.05 and an Abbe number vd of 18.5 or lower and of permitting the stable production of high-quality glass from a glass melt; and a glass material for press molding and an optical element comprised of the optical glass. The optical glass is in the form of an oxide glass and comprises, denoted as cationic percentages: 16 to 35% of P5+, 14 to 35% of Bi3+, 10 to 33% of Nb5+, 0 to 18% of Ti4+, and 0 to 20% of W6+; the total content of Bi3+, Nb5+, Ti4+, and W6+ being 55% or higher; the refractive index and exceeding 2.05; and the Abbe number vd being 18.5 or lower.

Abstract: Disclosed is a glass material for press forming providing an optical element having a sufficient optical performance without surface cracks, cloudiness, scratches, and the like even when the glass material contains a highly reactive component. Also disclosed are an optical element having a sufficient optical performance without surface cracks, cloudiness, scratches, and the like and a method for manufacturing the same. Specifically disclosed is a glass material for press forming which comprises a core portion composed of multicomponent optical glass and a surface glass layer covering at least a region serving as an optical functional surface of the core portion. The surface glass layer contains more than 90 mass % of SiO2, and the thickness of the layer is less than five nanometers. Also specifically disclosed is a method for manufacturing a glass optical element by heating the glass material and by press forming the softened glass material using a forming die.

Abstract: A lens formed of a high-refractivity low-dispersion glass and free of fogging and scorching on its optical-function surface, which is obtained by precision press-molding of an optical glass having a refractive index (nd) of over 1.83, an Abbe's number (?d) of 40 or more and a glass transition temperature (Tg) of 640° C. or lower and containing no Li2O and has one form of a meniscus form, a biconcave form or a plano-concave form.

Abstract: Disclosed is a glass composition which can be suitably used as a glass filler to be blended into a polycarbonate resin. This glass composition contains, in mass %, 50?SiO2?60, 8?Al2O3?15, 0?MgO?10, 10?CaO?30, 0?Li2O+Na2O+K2O<2, and 5<TiO2?10, and does not substantially contain B2O3, F, ZnO, SrO, BaO and ZrO2.

Abstract: An optical glass having a refractive index (nd) within a range from 1.825 to 1.870, an Abbe number (?d) within a range from 22 to less than 27, a transformation temperature (Tg) within a range from 530° C. to 585° C. and an mean coefficient of linear thermal expansion (?) within a range from 80×10?7° C.?1 to 103×10?7° C.?1, comprising SiO2, TiO2, Nb2O5 and Li2O and being substantially free of a Pb compound.

Abstract: An optical glass having refractive index (nd) exceeding 1.85, Abbe number (?d) of 36 or over, comprising SiO2, B2O3, La2O3, Gd2O3, Ta2O5 and Li2O as essential components, being free of Pb and As components, and having glass transition temperature (Tg) of 630° C. or below.

Abstract: The refractive, transmissive or diffractive optical elements are made from a ceramic containing one or more oxides of the type X2O3, which is transmissive for visible light and/or for infrared radiation and which has a cubic crystal structure analogous to that of Y2O3. In preferred embodiments X is Y, Sc, In, or a lanthanide element, namely La to Lu, and in particular is Lu, Yb, Gd, or La. Also mixtures of oxides of the type X2O3 with oxides having different stoichiometries, such as HfO2 and/or ZrO2, may be present, as long as the cubic structure of the ceramic is maintained.

Abstract: An optical glass comprising SiO2, B2O3 and La2O3 and one or more oxides selected from the group consisting of ZrO2, Nb2O5 and Ta2O5, having a refractive index of 1.83 or over and an Abbe number of 35 or over and being free of F.

Abstract: An optical glass that has high-refractivity and high-dispersion properties, that is less colored and that is suitable for a shapable glass material for press-shaping and various optical elements, the optical glass containing, as glass components and by mass %, 10 to 32% of P2O5, 27 to 65% of Nb2O5, 10 to 30% of BaO, 0 to 12% of B2O3, more than 0% but not more than 20% of TiO2, more than 0% but not more than 10% of total of Li2O, Na2O and K2O, and more than 0% but not more than 1%, based on the total content of the said glass components, of Sb2O3, and having a light transmittance that is 50% at a wavelength of 420 nm or shorter.

Abstract: Disclosed is an optical glass having high-refractivity and high-dispersion properties and having little coloring, said glass containing P2O5, Nb2O5 and TiO2 as glass components, containing Sb2O3 in an amount of over 0% by weight but not more than 1% by weight based on the total content of the glass components excluding Sb2O3, having a refractive index (nd) of 1.91 or more and an Abbe's number (?d) of 21 or less and having a light transmittance that comes to be 70% at a wavelength of 500 nm or less.

Abstract: Optical glasses are described, which are useful for imaging, sensors, microscopy, medical technology, digital protection, photolithography, laser technology, wafer/chip technology, as well as telecommunication, optical communications engineering and optics/lighting in the automotive sector, with a refractive index of 1.80?nd?1.95 and an Abbe value from 19??d?28 with excellent chemical resistance and stability to crystallization. These optical glasses have a composition, in weight. % based on oxide content, of: P2O5, 14-35; Nb2O5, 45-50; Li2O, 0-4; Na2O, 0-4; K2O, 0.5-5; BaO, 17-23; ZnO, 0.1-5; TiO2, 1-<5; ZrO2, 0-6; and Sb2O3, 0.1-2.

Abstract: This disclosure relates to oxide materials, as well as related articles, systems and methods.

Abstract: An optical glass suitable for precision mold pressing has a refractive index (nd) of 1.88 or over and an Abbe number (? d) within a range from 22 to 28, comprises, in mass %, SiO2 15-25%? B2O3 0-5%? La2O3 0-5%? TiO2 5-15% ZrO2 0-10% Nb2O5 more than 30% and less than 50% WO3 0-5%? CaO 0-10% BaO 0-10% Li2O 3-12% Na2O 0-10% K2O 0-10% Bi2O3 0-15% Ta2O5 0-7%? and has a glass transition point (Tg) within a range from 500° C. to 580° C. The optical glass preferably has a yield point (At) within a range from 550° C. to 640° C.

Abstract: The present invention provides a high refractive index, high dispersion optical glass for precision molding, being free from harmful materials causing environmental problems, such as lead oxide, etc., and having a low yield temperature, a refractive index (nd) of at least 1.83 and an Abbe number (?d) of at most 26.0 and further providing a low softening property as well as an improved mass production property with less coloration, which is represented in terms of for making up the glass, by the following chemical composition (wt %): P2O5 15 to 29% B2O3 ?0 to 2% GeO2 ?0 to 14% Sum of P2O5 + B2O3 + GeO2 20 to 35% Li2O ?0 to 5% Na2O ?3 to 14% K2O ?0 to 9% Sum of Li2O + Na2O + K2O ?5 to 15% Nb2O5 ?2 to less than 22% Bi2O3 34 to 60% WO3 ?0 to 5% BaO ?0 to 5% In2O3 ??0 to 7%.

Abstract: The present invention relates to optical glass having a high refractive index, high dispersion, and a low glass transition temperature; a preform comprised of the optical glass for precision press-molding and a method of manufacturing the same; and an optical element comprised of the optical glass and a method of manufacturing the same.

Abstract: An optical glass comprises, in mass percent, 15–35% of P2O5, 40–60% of Nb2O5, 0.5% to less than 15% of Na2O and 3% to less than 25% of BaO, has a ratio in mass % of (BaO+Nb2O5)/{(TiO2+WO3)×3+Bi2O3+Nb2O5}>1.0; is free of Pb and As; and has a refractive index (nd) within a range from 1.78 to 1.90 and an Abbe number (?d) within a range from 18 to 27.

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 consists essentially, expressed in term of weight percent, of: P2O5: 20.0 to 30.0%, B2O3: 0.5 to 10.0%, Nb2O5: 5.0 to 50.0%, WO3: 15.0 to 27.0%, Bi2O3: 0.1 to 3.0%, ZnO: 1.0 to 7.0%, Li2O: 0 to 8.0%, Na2O: 0 to 15.0%, K2O: 0 to 15.0%, and Li2O+Na2O+K2O: 5.0 to 20.0%.

Abstract: An optical glass includes SiO2; PbO; B2O3; not less than 0.1 mass % of TeO2; and not less than 0.4 mass % of Li2O.

Abstract: An optical glass that substantially does not contain any Ta2O5 and has high-refractivity low-dispersion optical properties and various optical parts made of such optical glass are provided stably at a low cost, and an optical part made thereof is provided, the optical glass having a glass composition comprising, by weight %, 0 to 7% of SiO2, 18 to 30% of B2O3, provided that the total content of SiO2 and B2O3 is 23 to 35%, 2 to 10% of ZnO, 30 to 50% of La2O3, 0 to 20% of Gd2O3, 0 to 20% of Y2O3, provided that the total content of La2O3, Gd2O3 and Y2O3 is 45 to 60%, 3 to 8% of ZrO2 and 3 to 12% of Nb2O5, the total content of these components being at least 95% by weight, the optical glass having a refractive index [nd] and an Abbe's number [&ngr;d] which satisfy specified relational expressions.

Abstract: Provided is an optical glass that has high-refractivity and high-dispersion properties and can give preforms for press-molding, which are excellent in shapability at high temperatures and suitable for precision press-molding.

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: Transparent solid, fused microspheres are provided. In one embodiment, the microspheres contain alumina, zirconia, and silica in a total content of at least about 70% by weight, based on the total weight of the solid, fused microspheres, wherein the total content of alumina and zirconia is greater than the content of silica, and further wherein the microspheres have an index of refraction of at least about 1.6 and are useful as lens elements.

Abstract: An optical glass comprises the following composition in mass percent of: SiO2 18-29%; PbO 68-78%; and TeO2 0.1-3.5%; wherein the glass has optical constants which are a refractive index (nd) having a range of 1.75 to 1.87 and an Abbe number (&ngr;b) having a range of 21 to 28; and a wavelength of a light transmitted through the glass having a thickness of 10±0.1 mm at a transmittance of 80% by including a reflection loss, is not more than 420 nm.

Abstract: The invention can relate to essentially lead-free optical glasses having a refractive index nd of from about 1.65 to about 1.87 and an Abbe number &ngr;d of from about 27 to about 43 and a composition (in % by weight, based on oxide) of SiO2 about 10-about 25, B2O3>about 10-about 25, Na2O about 2.5-about 10, K2O 0-about 3, CaO about 0.5-about 5, BaO about 15-about 30, ZnO about 5-about 15, TiO2 about 6-about 15, ZrO2 about 0.5-about 8, Y2O3 about 0.1-about 2, La2O3 about 0.5-about 8, Nb2O5 about 6-about 12, with La2O3+Nb2O5≦about 17,Ta2O5 0-about 1, and Gd2O3 0-about 1.

Abstract: The present invention provides an optical glass for precision molding, having excellent properties, i.e. yield temperature (At) of at most 550° C., refractive index (nd) of at least 1.83 and Abbe number (&ngr;d) of at most 26.0 and further providing a low softening property as well as an improved mass production property with less coloration, which is represented, in term of atoms for making up the glass, by the following chemical composition (wt %) P2O5 14.0 to 31.0% B2O3   0 to 5.0% GeO2   0 to 14.0% Sum of P2O5 + B2O3 + GeO2 14.0 to 35.0% Li2O   0 to 6.0% Na2O  2.5 to 14.0% Sum of Li2O + Na2O  2.5 to 15.0% Nb2O5 22.0 to 50.0% WO3   0 to 30.0% Bi2O3  5.0 to 36.0% BaO   0 to 22.0%.

Abstract: An optical glass having properties of a high refractive index and low dispersion and having both a low sag temperature Ts and a low liquidus temperature L.T., is provided. The optical glass comprises, by % by weight, 25 to 42% of B2O3, 14 to 30% of La2O3, 2 to 13% of Y2O3, 2 to 20 of SiO2, greater than 2% and 9% or less of Li2O, 0.5 to 20% of CaO, 2 to 20% of ZnO, 0 to 8% of Gd2O3, 0 to 8% of ZrO2, Gd2O3+ZrO2 being 0.5 to 12%, the total content thereof being at least 90%, and optionally contains 0 to 5% of Na2O, 0 to 5% of K2O, 0 to 5% of MgO, 0 to 5% of SrO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 5% of Ta2O, 0 to 5% of Al2O3, 0 to 5% of Yb2O3, 0 to 5% of Nb2O5, 0 to 2% of As2O3 and 0 to 2% of Sb2O3.

Abstract: A lead-free glass, which is suitable for use as imitation lead crystal tableware and decorative crystal glassware, has a chemical composition as a percentage by weight within the following range: silica 50-58 zirconium oxide 0-5 potash (K2O) 0-13, e.g. 0-12 yttrium oxide 0-5 soda (Na2O) 0-9 alumina 0-3 lithium oxide 0-4 tin oxide 0-5 calcium oxide 0-3 lanthanum oxide 0-9 magnesium oxide 0-4 niobium oxide 0-9 boric anhydride (B2O3) 0-2 bismuth oxide 0-13, e.g. 0-12 zinc oxide 16-30 germanium oxide 0-5 barium oxide 0-13, e.g. 0-12 antimony oxide 0-1 titanium oxide 0-6.

Abstract: Ophthalmic and optical glasses have a composition in weight percent of 4.5-9.5% SiO2, 10-19.5% B2O3, 0-3% Al2O3, 0-5% GeO2, 18—less than 23% La2O3, 0.3—less than 2% Gd2O3, 5.5-13.5% TiO2, 0-7.5% ZrO2, 15-21% Nb2O5, 0-1.5% Ta2O5, 0.3-5% WO3, with the proviso that (Ta2O5+WO3)/B2O3 is 0.5 or below in the ration terms of weight, 2.1-10% ZnO, 0-5% MgO, 7-12.5% CaO, 0-5% SrO, 0-4% BaO, ≧0.1% Li2O+Na2O+K2O in which 0-1% Li2O, 0-1% Na2O and 0-1% K2O, 0-0.5% As2O3 and 0-0.5% Sb2O3 and have a specific gravity of 4.1 or below, and optical constants of a refractive index (nd) exceeding 1.88 and up to 1.93 and an Abbe number j(&ngr; d) within a range from 28 to 31. A preferable range of Nb2O5 is 15.5—less than 20.5% and a more preferable range of Nb2O5 is less 15.5-20%.

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: The invention relates to a glass of high refractive index suitable for the close-vision part of multifocal, in particular phototropic multifocal, spectacle lenses. The glass has a composition (in % by weight, based on oxide) of:SiO.sub.2 28-40; B.sub.2 O.sub.3 0-8.5; Li.sub.2 O 0-1; Na.sub.2 O 0-2.5; K.sub.2 O 0-5; CaO 0-6; SrO 0-6; BaO 6-12; ZnO 9-16; PbO 32-40; TiO.sub.2 0.3-7; ZrO.sub.2 0.4-5; .SIGMA. Li.sub.2 O+Na.sub.2 O+K.sub.2 O 0-5, anda refractive index n.sub.e of 1.66-1.81, an expansion coefficient .alpha..sub.20-300 of 5.7-6.8.times.10.sup.-6 K.sup.-1, a softening point of 650.degree.-700.degree. C. and a glass transition temperature Tg of 520.degree.-560.degree. C.

Abstract: The present invention relates generally to a novel and unique class of gly materials and methods of making such materials in which substantially all of the anions are nitride ions, in contrast to the oxide ions of conventional optical glasses, or the fluoride ions of the more recently discovered fluoride optical glasses. The chemical nature of these new glasses dispose the glassy materials to a remarkable combination of desirable properties, including, but not limited to, high hardness, high refractive index and high softening temperature.

Abstract: An optical crown glass having a negative anomalous partial dispersion .DELTA.P.sub.g,F, a refractive index n.sub.d of greater than 1.52, an Abbe number .nu..sub.d of greater than 57, and a high UV transmission has a composition (in % by weight) 40-72 B.sub.2 O.sub.3, 9-31 Al.sub.2 O.sub.3, 0-15 SiO.sub.2, 0.1-0.5 H.sub.2 O, 0-12 Li.sub.2 O, wherein the total of R.sub.2 O (R=Li, Na, K, Rb, Cs) is 0-20 and the total of MO (M=Mg, Ca, Sr, Ba) is 0-30, and wherein the total of R.sub.2 O and MO is greater than 5, and the molar ratio between Al.sub.2 O.sub.3 and B.sub.2 O.sub.3 is 0.2-0.3 and the molar ratio between (R.sub.2 O+MO) and B.sub.2 O.sub.3 is 0.1-0.4.

Abstract: This invention relates to glasses exhibiting refractive indices higher than 1.880, Abbe numbers of at least 29, densities lower than 4.1, good chemical durability and stability against devitrification, and an integrated transmission over the range of 380-800 nm at a thickness of 10 mm greater than 79%, the glasses consisting essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ SiO.sub.2 5-8 B.sub.2 O.sub.3 15-21 ZrO.sub.2 3-10 TiO.sub.2 7-17 Nb.sub.2 O.sub.5 20.5-26 ZrO.sub.2 + TiO.sub.2 + Nb.sub.2 O.sub.5 29-45 La.sub.2 O.sub.3 19-32 Y.sub.2 O.sub.3 0-9 CaO 8-16 SrO 0-5 BaO 0-5 MgO 0-5 CaO + SrO + BaO + MgO 8-16 ZnO 0-5 Li.sub.2 O 0-2 Na.sub.2 O 0-2 K.sub.2 O 0-2 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-2.

Abstract: A method of making a yellow, transparent tempered glass and the product so made that comprises adding a certain quantity of CeO2 and TiO2 to the glass composition prior to a rapid cooling of the composition. Each additive is in the amount of about 1% to 6% and together they produce a yellow color. Also, at the same time, from 1% to 5% of BaO or PbO is added as an additive for enhancing the transparency and refractive index of the glass. The resulting yellow transparent tempered glass is especially suited for use in a reflecting roadstud and used for separating the traffic lanes on roads.

Abstract: This invention relates to the production of glasses exhibiting a refractive index between about 1.66-1.81, a softening point between about 625.degree.-675.degree. C., a strain point between about 455.degree.-490.degree. C., a linear coefficeint of thermal expansion (25.degree.-300.degree. C.) between about 53-65.times.10.sup.-7 /.degree.C., and good chemical durability which consist essentially, in weight percent, of:______________________________________ SiO.sub.2 24-42 Li.sub.2 O 0.2 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-3.5 Al.sub.2 O.sub.3 3-7.5 Na.sub.2 O 0-2 ZrO.sub.2 0-2.5 B.sub.2 O.sub.3 2-7.5 K.sub.2 O 0-3 TiO.sub.2 0-8 PbO 35-57 La.sub.2 O.sub.3 0-8 La.sub.2 O.sub.3 + ZrO.sub.2 4-12.sub.

Abstract: A chemically resistant glass which can be produced at relatively low melting temperatures and has anomalous negative partial dispersion P.sub.g,F, a refractive index n.sub.d of from 1.73 to 1.83 and an Abbe coefficient v.sub.d of from 31 to 38 preferably contains (in % by weight, based on oxides):______________________________________ 0-4 SiO.sub.2 + GeO.sub.2 0-2 GeO.sub.2 0-10 MgO 26-33 B.sub.2 O.sub.3 0-1 Li.sub.2 O 0-16 CaO 19-50 PbO 0-1 Na.sub.2 O 0-16 BaO 1-6 ZrO.sub.2 0-1 K.sub.2 O 0-16 SrO 4-16 Ta.sub.2 O.sub.5 0-2 .SIGMA. alkaline earth 0-6 Al.sub.2 O.sub.3 metal oxides 0-16 ZnO 0-4 TiO.sub.2 1.5-20 .SIGMA. alkaline earth metal oxides + ZnO 0-1 WO.sub.3 0-11 La.sub.2 O.sub.3 0-7 Nb.sub.2 O.sub.5 0-5.5 Y.sub.2 O.sub.3 0-5.5 Gd.sub.2 O.sub.3 4-11 .SIGMA. La.sub.2 O.sub.3 + Y.sub.2 O.sub.3 + Gd.sub.2 O.sub.3 ______________________________________with the proviso that the .SIGMA.(SiO.sub.2 +GeO.sub.2 +B.sub.2 O.sub.3)/.SIGMA.(ta.sub.2 O.sub.5 +ZrO.sub.2 +HfO.sub.2) ratio is less than 5 and the PbO/.

Abstract: Solid, transparent, non-vitreous, zirconia and zirconia-silica ceramic microspheres, useful as lens elements in retroreflective pavement markings. The microspheres are characterized by:(a) containing at least one additive metal oxide selected from alumina, magnesia, yttria and mixtures thereof;(b) an index of refraction greater than 1.6; and(c) being virtually free of cracks.These microspheres are formed by a sol-gel technique of extractive gelation (extracting carboxylic acid away from zirconyl carboxylate) of a sol in liquid medium such as hot peanut oil. The microspheres of this ceramic composition have been made with relatively large diameters, (e.g. 200-1000 micrometers) making them quite useful as lens elements in pavement marking sheet materials.

Abstract: This invention is concerned with a glass for optical and/or ophthalmic applications having an index of refraction between about 1.78-1.82, an Abbe number greater or equal to 31, and a density less than about 3.80 g/cm.sup.3 consisting essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ SiO.sub.2 15-30 CaO 15-28 B.sub.2 O.sub.3 2-17 SrO 0-11 SiO.sub.2 + B.sub.2 O.sub.3 24-36 BaO 0-11 Al.sub.2 O.sub.3 0-6.5 MgO + CaO + 16-33 SrO + BaO Li.sub.2 O 0-5 ZnO 0-11 Na.sub.2 O 0-5 La.sub.2 O.sub.3 16-30 K.sub.2 O 0-5 ZrO.sub.2 0-10 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-6 Nb.sub.2 O.sub.5 5-26 MgO 0-6 TiO.sub.2 0-14.

Abstract: A highly refractive optical glass (n.sub.d .gtoreq.1.83) with high dispersion (v.sub.d .ltoreq.25) and very good chemical stability at relatively low density (.delta..ltoreq.3.5 g/cm.sup.3) consists of (in weight percent) SiO.sub.2 19-25, Na.sub.2 O 7-10, K.sub.2 O 4-7, Cs.sub.2 O 0-12, Cao 0.5-2.0, BaO 9-15, TiO.sub.2 25-30, ZrO.sub.2 0-6, Nb.sub.2 O.sub.5 16-20, WO.sub.3 0-3, with Nb.sub.2 O.sub.5 :TiO.sub.2 =0.6-0.71.

Abstract: An Ophthalmic and optical glass which is a B.sub.2 O.sub.3 - SiO.sub.2 - Li.sub.2 O - CaO - La.sub.2 O.sub.3 - TiO.sub.2 - ZrO.sub.2 -Nb.sub.2 O.sub.5 system in which relatively large amounts of B.sub.2 O.sub.3 and La.sub.2 O.sub.3 ingredients coexist has improved resistivity to devitrification while maintaining desirable optical constants, i.e., a refractive index (.eta.d) in the range of 1.75 to 1.84, Abbe number (.nu.d) in the range of 33 to 40 and specific gravity of 4.0 or less. Besides, the range of content of the Li.sub.2 O ingredient which is effective for the chemical strengthening treatment can be enlarged by this system of glass.

Abstract: High PbO-content glass in the optical range of flint and heavy flint glasses from the system SiO.sub.2 --PbO--M.sub.2 O wherein M.sub.2 O=alkali metal oxides, said glass having a minimum PbO content of 30 wt. % and a minimum M.sub.2 O content of 0.5 wt. %, are provided with enhanced chemical stability without loss of the desired optical position by replacing a portion of the SiO.sub.2 and PbO such that the glass contains 1.5-6 wt. % (TiO.sub.2 +ZrO.sub.2) and the ratio of TiO.sub.2 :ZrO.sub.2 is about 0.3-2.0.

Abstract: A glass for an eye glass lens comprising a SiO.sub.2 (or B.sub.2 O.sub.3)-CaO-Nb.sub.2 O.sub.5 system as a basic system and having a refractive index of 1.79 or more, an Abbe number of 32 to 38 and a specific gravity of less than 3.6 is disclosed.

Abstract: Optical glass with refractive indicies.gtoreq.1.90, Abbe numbers.gtoreq.25 consisting essentially of, in weight percent; 0-10 SiO.sub.2, 2-20 B.sub.2 O.sub.3, 0-2 Al.sub.2 O.sub.3, the sum of SiO.sub.2, B.sub.2 O.sub.3, and Al.sub.2 O.sub.3 being 7.5-25, 1-16 TiO.sub.2, 0-10 ZrO.sub.2, 35-55 La.sub.2 O.sub.3, 0.5-10 Y.sub.2 O.sub.5, 0.5-15 Nb.sub.2 O.sub.5, 0-10 Gd.sub.2 O.sub.3, 0-15 Ta.sub.2 O.sub.5, 0-3 P.sub.2 O.sub.5 wherein the ratio of SiO.sub.2 to B.sub.2 O.sub.3 is between 0.1 and 1.6, and the sum of Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5 is from 9 to 20%.

Abstract: An optical glass with the familiar optical position of n.sub.d >1.70 and v.sub.d >22, which differs from the familiar optical glasses of the optical position due to its lower density and good chemical stability, and is composed of (in percent by weight): SiO.sub.2 25-42, TiO.sub.2 15-35, B.sub.2 O.sub.3 0.5-7, BaO 3-13, CaO 1-3, Nb.sub.2 O.sub.5 1-20, GeO.sub.2 0-2, Al.sub.2 O.sub.3 0-4, Na.sub.2 O 7.5-15, Li.sub.2 O 0-9, K.sub.2 O 2-10, SrO 0-6, ZnO 0-5, ZrO.sub.2 0-3, and WO.sub.3 0-3.

Abstract: A thallium-containing optical glass composition which contains the following oxides in the indicated proportions in mole %:______________________________________ SiO.sub.2 35-80 Tl.sub.2 O 4-26 Tl.sub.2 O + R.sub.2 O 8-42 (in which R is an alkali metal) ZnO 6-26 ZrO.sub.2 0-2 Al.sub.2 O.sub.3 0-8 SnO and/or SnO.sub.2 0-5 B.sub.2 O.sub.3 0-less than 10 ______________________________________and satisfies the following relations:O.ltoreq.K.sub.2 O.ltoreq.104.ltoreq.Na.sub.2 O+Li.sub.2 O.ltoreq.260.1.ltoreq.ZrO.sub.2 +Al.sub.2 O.sub.3 +SnO and/or SnO.sub.2 .ltoreq.

Abstract: This invention is directed to the preparation of glasses in the PbO--Ga.sub.2 O.sub.3 field exhibiting good infrared transmitting characteristics out to wavelengths of 8 microns. The binary glasses consist essentially, by weight, of about 15-28% Ga.sub.2 O.sub.3 and 72-85% PbO. However, the preferred glasses contain up to 85% Bi.sub.2 O.sub.3 and consist essentially as included within the area generally encompassed by the curve in FIG. 2.