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: Provided are an amorphous polyamide resin composition having high transparency, and is excellent in heat resistance and stiffness, and a molded product thereof. The glass filler contains, expressed in terms of oxides by mass %, 68 to 74% of silicon dioxide (SiO2), 2 to 5% of aluminum oxide (Al2O3), 2 to 5% of boron oxide (B2O3), 2 to 10% of calcium oxide (CaO), 0 to 5% of zinc oxide (ZnO), 0 to 5% of strontium oxide (SrO), 0 to 1% of barium oxide (BaO), 1 to 5% of magnesium oxide (MgO), 0 to 5% of lithium oxide (Li2O), 5 to 12% of sodium oxide (Na2O), and 0 to 10% of potassium oxide (K2O), where a total amount of lithium oxide (Li2O), sodium oxide (Na2O), and potassium oxide (K2O) is 8 to 12%.

Abstract: Disclosed is a glass composition having a stable quality, which can be easily obtained. This glass composition can be used as a glass filler to be blended into a polycarbonate resin, and enables to reduce the load imposed on a glass manufacturing apparatus. Specifically, this glass composition contains, in mass %, 50?SiO2?60, 8?Al2O3?15, 0?MgO?10, 5?CaO<21, 0<SrO+BaO?25, 10<MgO+SrO+BaO?30, 0?Li2O+Na2O+K2O<2, 2<TiO2?10 and 0?ZrO2<2 and does not substantially contain B2O3, F, and ZnO.

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: An optical glass has optical constants represented by a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (?d) of 65 to 74, has excellent hot preform shapeability, low softenability and excellent climate resistance, and comprises, by mol %, 45 to 65% of P2O5, 8 to 19% of Al2O3, 5 to 30% of MgO, 1 to 25% of a total of Li2O, Na2O and K2O, 0 to 16% of B2O3, 0 to 25% of ZnO, 0 to 25% of CaO, 0 to 25% of SrO, 0 to 30% of BaO, 0 to 10% of La2O3, 0 to 10% of Gd2O3, 0 to 10% of Y2O3, 0 to 10% of Yb2O3 and 0 to 10% of Lu2O3, and the total content of the above components of the optical glass is at least 95%.

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 ?d 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: An optical glass comprising in mass %: P2O5 25%-less than 45% B2O3 6-20% BaO 24%-less than 40% ZnO 3-14% MgO 0-15% CaO 0-15% SrO 0-15% Li2O 0-5% Na2O 0-5% K2O 0-5% WO3 0-5% and Al2O3 0-5%. The optical glass should preferably contain 0.1-5% WO3, 3.6-15% MgO, 0.1-5% Li2O+Na2O+K2O, 0—less than 0.5% and Sb2O3+As2O3 with the mass ratio of ZnO/BaO being 0.12—less than 0.50. The optical glass should preferably have refractive index (nd) within a range from 1.54 to 1.65 and Abbe number (?d) within a range exceeding 57 up to 69 and liquid phase temperature within a range from 870° C. to 930° C. There is provided an optical glass having high resistance to devitrification and medium refractive index and low dispersion characteristics which is free of ingredients such as Ta2O5 having a high cost of raw material and therefore can be manufactured at a relatively low cost of raw materials.

Abstract: An optical glass taking account of meltability and the moldability of a preform, having optical constants including a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe's number (?d) of over 55 but not more than 65, having the property of softening at a low temperature and being suitable as a glass for precision press-molding, the optical glass including an optical glass containing B2O3, SiO2, La2O3, Gd2O3, an alkali metal oxide and an alkaline earth metal oxide as essential components, having a B2O3 and SiO2 total content of 52% by weight or more and having an SiO2/B2O3 content ratio of from 0.38 to 1.2, and an optical glass wherein the relationship of the refractive index (nd) and the Abbe's number (?d) satisfies the equation (1), ?d>260?126×nd.

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: The present invention relates to lead and arsenic free optical glasses, used for the application areas imaging, digital projection, photolithography, laser technology, wafer/chip technology as well as telecommunication, optical communications engineering, optics, illumination and in the automotive sector. The glasses have a refraction power of from 1.73?nd?1.82 and an Abbé value of 43?vd?53 with good chemical consistency and excellent crystallisation stability with the following composition (in weight-%): SiO2 0.1-5.5 B2O3 27-35 La2O3 42-48 BaO 0-5 ZnO 0.5-5?? Y2O3 ?6-12 TiO2 0-4 ZrO2 ?4-10 Nb2O5 0-5 WO3 ?0-5.

Abstract: An optical glass has optical constants which are an refractive index (nd) of 1.70–1.75 and an Abbe number (vd) of 45.0–54.0; a glass transformation temperature (Tg) of 500–580° C. The glass has the following composition in mass percent of: SiO2 more than 5–15%; B2O3 20-less than 30%; a total amount of SiO2+B2O3 more than 25–40%; La2O3 more than 21-less than 30%; Y2O3 more than 5–15%; Gd2O3 0-less than 10%; ZrO2 1–8%; Nb2O5 0.1–5%; Ta2O5 more than 5–12%; a total amount of ZrO2+Nb2O5+Ta2O5 7–20%; ZnO 0–10%; CaO 0–10%; SrO 0–5%; BaO 0–10%; a total amount of ZnO+CaO+SrO+BaO 5–15%; Li2O 1–8%; Sb2O3 0–1%; and As2O3 0–1%. The glass is substantially free of Yb2O3 and Al2O3. Devitrification is not generated when the optical glass is kept at a temperature of 920° C. for two hours.

Abstract: An optical glass having a refractive index (nd) of 1.57 to 1.67, an Abbe's number (?d) of 55 to 65 and a glass transition temperature (Tg) of 560° C. or lower and having a low-temperature softening property and excellent climate resistance or a haze value of 3% or less, or an optical glass comprising, by mol %, 22 to 40% of B2O3, 12 to 40% of SiO2, 2 to 20% of Li2O, 5 to 15% of CaO, 2 to 14% of ZnO, 0.5 to 4% of La2O3, 0 to 3% of Gd2O3, 0 to 3% of Y2O3, the total content of La2O3, Gd2O3 and Y2O3 being at least 1%, 0 to 5% of Al2O3, 0 to 3% of ZrO2 and 0 to 5% of BaO, the total content of the above components being more than 96%, and having a refractive index (nd) of 1.57 to 1.67 and an Abbe's number (?d) of 55 to 65.

Abstract: There is provided an optical glass suitable for mold pressing having optical constants of a refractive index (nd) within a range from 1.60 to 1.69 and Abbe number (?d) within a range from 35 to 45, having a glass transition point (Tg) within a range from 300° C. to 500° C., being free from devitrification when the optical glass is held at a temperature which is higher by 100° C. than the glass transition point (Tg) for 30 minutes, comprising in mass % on oxide basis: SiO2 20–less than 40% B2O3 5–20% Al2O3 0–5% ZrO2 more than 3%–15% Nb2O5 10–30% MgO + CaO 0–less than 5% in which MgO 0–less than 5% CaO 0–less than 5% SrO 0–10% BaO 0–10% ZnO 0–18% Li2O more than 5%–15% Na2O 1–10% K2O 1–10% Sb2O3 0–1%, and being free from La2O3, TiO2, Ta2O5 and PbO.

Abstract: Zinc-containing optical glass materials with a refractive index nd between 1.52 and 1.66, an Abbe number ?d of between 35 and 54 and a composition (in % by weight based on oxide) of: SiO2 38–58, ZnO 0.3–42, PbO 0–<30, ZnO+PbO 20–55, Li2O 0–<3, Na2O 0–14, K2O 0–12, Li2O+Na2O+K2O ?2, F 0–3, MgO 0–6, CaO 0–<5, SrO 0–6, BaO 0–<0.9, B2O3 0–<1, Al2O3 0–<1.5 and ZrO2 0–<2 and, if appropriate, refining agents in the customary amounts.

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: The present invention relates to preferably lead-free and arsenic-free optical glasses, having a refractive index of 1.48?nd?1.56, an Abbe number of 64??d?72, a low transformation temperature (Tg?500° C.) and good ion exchange properties, as well as good chemical resistance and crystallization stability, and comprising the following composition (in % by weight): SiO2 53-58 B2O3 11-15 Al2O3 16-20 Na2O ?0-13 K2O ?0-13 ?M2O ?9-13 F 0.5-4?? The glass may additionally contain standard refining agents. The invention also relates to the use of the optical glasses according to the invention in the application areas of imaging, projection, telecommunications, optical communication technology and/or laser technology.

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 having a positive anomalous dispersion comprises, in mass %, SiO2 40-60% B2O3 3-9% TiO2 ?3-15% Nb2O5 0.1-5.0% Al2O3 ?3-15% WO3 0.5-5.0% MgO 0-3% CaO 0-3% SrO 0-3% BaO 0-3% K2O exceeding 10% and up to 21% Na2O ?0-10% Sb2O3 0-1% and a fluoride or fluorides of a metal element or elements ??3-10%, contained in the above metal oxides, a total amount of F contained in the fluoride or fluorides is free of PbO and As2O3 except for unavoidable mixing of these compounds as impurities, has optical constants of a refractive index (nd) within the range from 1.48 to less than 1.55 and an Abbe number (?d) within the range from 45 to 55, and has an anomalous dispersion (??g,F) of +0.0010 or over.

Abstract: An optical glass which is free of PbO which causes environmental pollution and also is free of expensive Ta2O5 and Nb2O5 comprises, in mass %, SiO2 40-60% B2O3 1 to less than 5% Al2O3 0-3% TiO2 15.5-19%?? ZrO2 0-1% WO3 0-5% ZnO 0-5% CaO 0-4% SrO 0-10% BaO 10.5-20%?? Na2O + K2O 11-20% in which Na2O 0-9% and K2O ?6-20% a refining agent 0-1% and has optical constants of a refractive index (nd) within a range from 1.55 to less than 1.67 and an Abbe number (?d) within a range from 30 to 45.

Abstract: The optical glass of the present invention comprises a composition in terms of weight ratio within the range of 0 to 14.8 wt % of SiO2, 30 to 60 wt % of B2O3, 0 to 17.5 wt % of Al2O3, 0 to 0.4 wt % of Li2O, 0 to 3 wt % of Na2O, 0 to 3 wt % of K2O, 0 to 5 wt % of MgO, 0 to 30 wt % of CaO, 0 to 30 wt % of SrO, 0 to 35 wt % of BaO, where RO (MgO+CaO+SrO+BaO) is 8 to 35 wt %, 0 to 20 wt % of ZnO, 0 to 6.5 wt % of La2O3, 0 to 15 wt % of Gd2O3, 0 to 15 wt % of Y2O3, 0 to 10 wt % of Ta2O3, 0 to 9.5 wt % of ZrO2, 0 to 1 wt % of As2O3, and 0 to 0.5 wt % of Sb2O3; and has a refractive index (nd) of 1.52 to 1.65, an Abbe number (vd) of 55 to 61, and an 80% transmission wavelength (at a thickness of 10 mm including no reflection loss) of 330 nm or shorter.

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: Optical glasses and optical articles comprised of the optical glass are disclosed. One of which comprises, by means of weight percentages, more than 32 percent and not more than 45 percent P2O5, more than 0.5 percent and not more than 6 percent Li2O, more than 5 percent and not more than 22 percent Na2O, 6-30 percent Nb2O5, 0.5-10 percent B2O3, 0-35 percent WO3, 0-14 percent K2O, and 10-24 percent Na2O+K2O, and the total of all the above components is not less than 80 percent.

Abstract: The lead-free optical glasses have an index of refraction (nd) between 1.49 and 1.55 and an Abbé number (&ngr;d) between 47 and 59. They contain (in percent by weight on an oxide basis) 60 to 70, SiO2; 0.3 to 5, Al2O3; 16 to 25, Na2O; 0 to 9, TiO2; 0 to 7, advantageously 0.1 to 2, ZrO2; 0 to <0.5, Nb2O5; 0 to 7, Ta2O5 and 0 to 3, F. The lead-free optical glass is advantageously free of arsenic oxide, except for impurities, and contains antimony oxide as a fining agent.

Abstract: An optical glass for precision press molding that has desired optical constants, a low glass transformation point (Tg), and a devitrification temperature that is lower than a temperature of a glass melt, at which a viscosity suitable for forming of a preform material is obtained, is provided. The optical glass for precision press molding has a lanthanum borosilicate system glass having optical constants of refractive index (nd) within a range from 1.65 to 1.73 and Abbe number (&ngr;d) within a range from 50 to 60, a Tg within a range of 480-580° C. The optical glass for precision press molding has a devitrification temperature that is lower than a temperature of the glass melt when the glass melt has a viscosity &eegr; (poise) of log &eegr;=2.5. The optical glass for precision press molding has a specific composition range of SiO2—B2O3—La2O3—Y2O3—Ta2O5—CaO—Li2O system composition.

Abstract: There is provided an optical glass suitable for mold pressing having optical constants of a refractive index (nd) within a range from 1.60 to 1.69 and Abbe number (&ngr;d) within a range from 35 to 45, having a glass transition point (Tg) within a range from 400° C. to 500° C., being free from devitrification when the optical glass is held at a temperature which is higher by 100° C. than the glass transition point (Tg) for 30 minutes, and comprising in mass % on oxide basis: SiO2 20-less than 40% B2O3  5-20% Al2O3  0-5% ZrO2 more than 3%-15% Nb2O5 10-30% MgO + CaO  0-less than 5% in which MgO  0-less than 5% CaO  0-less than 5% SrO  0-10% BaO  0-10% ZnO  0-18% Li2O  1-15% Na2O  1-10% K2O  1-10% Sb2O3  0-1%.

Abstract: The optical glass has an index of refraction (nd) greater than or equal to 1.70, an Abbé number (&ngr;d) greater than or equal to 35 and a density (&rgr;) less than or equal to 4.5 g/cm3. Optical elements made with this optical glass are especially desirable in optical data transfer applications, particularly in read-write devices with movable read-write heads. The glass compositions required to make optical glass with these properties are described.

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: The invention relates to lead-free optical glasses which have refractive indices nd of between 1.65 and 1.80 and Abbe numbers &ngr;d of between 21 and 33 and possess the following composition (in % by weight, based on oxide) SiO2 27-40; B2O3 0-<0.5; Al2O3 0-6; Na2O 7-18; K2O 1-10; BaO 1-10; SrO 0-3; CaO 0.5-5; MgO 0-3; with BaO+SrO+CaO+MgO<15; TiO2 21-37; ZrO2 0-7; Nb2O5 5-17; WO3 0.1-7.

Abstract: The lead-free optical light flint glass material has a refractive index nd between 1.54 and 1.61 and an Abbe number &ngr;d of between 38 and 45. It has a composition, based on oxide content, of SiO2 from 52 to 62% by weight, Al2O3 from 3 to 8% by weight, Na2O from 7 to 14% by weight, K2O from 8 to 14% by weight, TiO2 from 13 to 18% by weight, ZrO2 from 0 to 5% by weight, with at least one refining agent, if needed, in an amount suitable for the purposes of refining; and with the proviso that a sum total of Na2O and K2O present is greater than 18% by weight.

Abstract: An optical glass has optical constants which are an refractive index (nd) of 1.70-1.75 and an Abbe number (&ngr;d) of 45.0-54.0; a glass transformation temperature (Tg) of 500-580° C. The glass has the following composition in mass percent of: SiO2 more than 5 to 15%; B2O3 20 to less than 30%; a total amount of SiO2+B2O3 more than 25 to 40%; La2O3 more than 21 to less than 30%; Y2O3 more than 5 to 15%; Gd2O3 0 to less than 10%; ZrO2 1-8%; Nb2O5 0.1-5%; Ta2O5 more than 5 to 12%; a total amount of ZrO2+Nb2O5+Ta2O5 7-20%; ZnO 0-10%; CaO 0-10%; SrO 0-5%; BaO 0-10%; a total amount of ZnO+CaO+SrO+BaO 5-15%; Li2O 1-8%; Sb2O3 0-1%; and As2O3 0-1%. Devitrification is not generated when the optical glass is kept at a temperature of 920° C. for two hours.

Abstract: The lead-free optical glasses have an index of refraction (nd) between 1.49 and 1.55 and an Abbé number (&ngr;d) between 47 and 59. They contain (in percent by weight on an oxide basis) 60 to 70, SiO2; 0.3 to 5, Al2O3; 16 to 25, Na2O; 0 to 9, TiO2; 0 to 7, advantageously 0.1 to 2, ZrO2; 0 to <0.5, Nb2O5; 0 to 7, Ta2O5 and 0 to 3, F. The lead-free optical glass is advantageously free of arsenic oxide, except for impurities, and contains antimony oxide as a fining agent.

Abstract: There is provided an optical glass suitable for mold pressing having optical constants of a refractive index (nd) within a range from 1.60 to 1.69 and Abbe number (&ngr;d) within a range from 35 to 45, having a glass transition point (Tg) within a range from 400° C. to 500° C., being free from devitrification when the optical glass is held at a temperature which is higher by 100° C. than the glass transition point (Tg) for 30 minutes, and comprising in mass % on oxide basis: 1 SiO2 20 - less than 40% B2O3  5-20% Al2O3  0-5% ZrO2 more than 3%-15% Nb2O5 10-30% MgO + CaO  0 - less than 5% in which MgO  0 - less than 5% CaO  0 - less than 5% SrO  0-10% BaO  0-10% ZnO  0-18% Li2O  1-15% Na2O  1-10% K2O  1-10% Sb2O3  0-1%.

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 object of the present invention is colorless inorganic glasses, as well as products manufactured from said glasses. Said glasses are of the type containing copper halides or copper cadmium halides and having a sharp optical absorption cutoff between 370 nm and 425 nm essentially having the composition below, expressed in cationic percentages: 23-73% SiO2 15-45% B2O3  0-24% Al2O3  0-12% Li2O  0-20% Na2O  0-12% K2O 0-5% CaO + BaO + SrO 0.125-1%    Cu2O 0-1% CdO 0-5% ZrO2 with   0-1.75% Cl 0.

Abstract: A reduced glare window glass, suitable for use in glass window, containing Neodymium Oxide, a rare earth compound. The Neodymium Oxide filters out the yellow light of the spectrum, thereby providing improved vision. Incorporation of yellow light in the light spectrum desaturates colors and reduces contrast. Improvement in contrast and a reduction in glare permits, for example, one to use this window glass in a building to reduce glare without the expense of blinds or curtains that are normally used to reduce glare. Additionally, the light transmittance is kept high, as high as 61.81 percent with a Neodymium Oxide doping of the glass in the amount of at least 0.0244 grams per square centimeter. This glass can be used for multiple layers of glass in assembled glazing.

Abstract: When a glass melt of an optical glass having a refractive index (nd) of at least 1.7 and an Abbe number (&ngr;d) of 28 to 41 is flowed down from a flow pipe made of Pt or a Pt alloy to form glass gobs continuously, there is caused a problem that the glass gobs have striae or that the weight variability among the glass gobs is large, and the problem can be overcome by the use of an optical glass comprising silicon oxide and boron oxide, the ratio of a content of the silicon oxide to a content of the boron oxide being greater than 0.78, the optical glass having a contact angle of at least 40° to Pt or a Pt alloy at a predetermined temperature equivalent to, or higher than, its liquidus temperature or in a predetermined temperature range whose lower limit is equivalent to, or higher than, the liquidus temperature and having a sag temperature Ts of 580° C. or lower.

Abstract: The invention relates to lead-free optical glasses having a refractive index nd of from 1.52 to 1.58, an Abbe number vd of from 50 to 57 and a negative partial dispersion &Dgr;Pg,F of <−0.0090, having a composition (in % by weight, based on oxide) of SiO2>15-25; B2O3 45-55; Al2O3 8-13; CaO 2-8; ZnO 0-5; with CaO+ZnO 2-10; Li2O 0-4; Na2O 0-4; K2O 0-4; with Li2O+Na2O+K2O 3-8; La2O3 0-14; Nb2O5 0-4.8; Ta2O5>10-17; with Ta2O5+Nb2O5>10-17; SnO2 0-2; ZrO2 0-7; with Ta2O5+ZrO2>10-<18.

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 relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO2 29-35, B2O3 0.5-5, Li2O 0.5-3, Na2O 4-8, K2O 0-2, PbO 28-40, BaO 4-14, La2O3 4-12, TiO2 3-8, ZnO 0-8, ZrO2 0-4, Nb2O5 0-5, with: Li2O+Na2O+K2O 5.5-9; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.

Abstract: The object of the present invention is a novel inorganic glass, which is capable of being strengthened by ionic exchange, and which has a refractive index of between 1.67 and 1.72; said novel glass strengthened on the surface thereof; its method of strengthening; and the corresponding ophthalmic lenses. Said novel glass has the following composition, expressed in wt. % of oxides: SiO2 33-37 B2O3 7.5-13  with SiO2 + B2O3 44-48 Li2O 5-8 Na2O >2.5-7.5   K2O 0-2 with Li2O + Na2O + K2O <14 CaO   0-<8 Al2O3 0-6 Nb2O5  8-13 ZrO2 4-6 TiO2  5-10 La2O3 12-19 SrO 2-4 As2O3 and/or Sb2O3   0-0.8 (refining agents).

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: The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO2 27-36 B2O3 0-9 Li2O 1-5 Na2O 1-7 K2O 0-7 CaO 0-7 BaO  4-13 ZnO 0-8 La2O3  4-15 PbO  4-27 TiO2  7-18 ZrO2 0-9 Nb2O5 0-8 with: Li2O + Na2O + K2O  6-15 SiO2 + TiO2 + ZrO2 42-55 PbO + TiO2 + ZrO2 + Nb2O5 29-40; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.

Abstract: In optical glass, P.sub.2 O.sub.5, TiO.sub.2, and Li.sub.2 O are included as essential components together with at least one divalent component, such as ZnO, MgO, and CaO. Such essential component are mixed together to accomplish a sag point not higher than 450.degree. C. and a specific gravity not heavier than 3.0. The optical glass also has water durability not greater than 0.3.

Abstract: The invention concerns glasses characterized by the fact that they have a refractive index higher than 1.740; a dilatation coefficient .alpha., between 25 and 300.degree. C., between 65 and 70.times.10.sup.-7 /.degree.C.; and a Littleton point not exceeding 635.degree. C. but higher than 600.degree. C.; they have the following composition, expressed in weight percent of oxides:______________________________________ SiO.sub.2 23-32.0 Al.sub.2 O.sub.3 1.5-5.0 B.sub.2 O.sub.3 5-9.0 PbO 43-54.0 Li.sub.2 O 0-0.5 Na.sub.2 O 0-1.0 K.sub.2 O 0-1.0 with Li.sub.2 O + Na.sub.2 O + K.sub.2 O <1.0 BaO + SrO 4-9.0 TiO.sub.2 0-4.0 ZrO.sub.2 0-2.0 La.sub.2 O.sub.3 0-3.0 Nb.sub.2 O.sub.5 0-3.0 As.sub.2 O.sub.3 0-0.3 Sb.sub.2 O.sub.3 0-0.4 with ZrO.sub.2 + La.sub.2 O.sub.3 + Nb.sub.2 O.sub.5 1.5-4.0 ______________________________________Use for the production of segments to be used in the manufacture of multifocal lenses, particularly photochromic.

Abstract: An optical glass has a large negative anomalous dispersion value and optical constants of refractive index (nd) within a range of 1.65-1.80 and Abbe number (.nu.d) within a range of 28-42. The optical glass includes, as its essential ingredients, in weight percent, 20-50% SiO.sub.2, 6-20% B.sub.2 O.sub.3 where SiO.sub.2 /B.sub.2 O.sub.3 .ltoreq.6, 0.5-15% ZrO.sub.2 and 31-50% Nb.sub.2 O.sub.5.

Abstract: The preparation of objects, in particular optical components and/or devices, is described using, as precursors of optical materials, amorphous monolithic aerogels for high-precision mechanical machining.

Abstract: The invention relates to glasses which absorb UV radiation and which have the following composition, in wt. %: SiO.sub.2 30-52; ZnO 0-8; B.sub.2 O.sub.3 12-22; PbO 0-2; ZrO.sub.2 5-14; Y.sub.2 O.sub.3 0-15; Al.sub.2 O.sub.3 0-12; La.sub.2 O.sub.3 5-25; Li.sub.2 O 1.5-3.5; TiO.sub.2 0-2; Na.sub.2 O 0-6; HfO.sub.2 0-2; K.sub.2 O 2-9; Nb.sub.2 O.sub.5 0-2; MgO 0-5; Ta.sub.2 O.sub.5 0-2; CaO 0-5; MoO.sub.3 0-2; SrO 0-9; WO.sub.3 0-2; BaO 0-14; SnO 0-4; Sb.sub.2 O.sub.3 0-4; SnO.sub.2 0-4; AS.sub.2 O.sub.3 0-4; CdO 0-1; CuO 0.15-1; F 0-2; Cl 0-3; Br 0-3; I 0-2 with the following conditions: Li.sub.2 O+Na.sub.2 O+K.sub.2 O (X.sub.2 O) 7-14; MgO+CaO+SrO+BaO (XO) 12-20; ZrO.sub.2 +Al.sub.2 O.sub.3 <15; F+Cl+Br+I 0.2-4.0; TiO.sub.2 +PbO+Nb.sub.2 O.sub.5 .ltoreq.2; AS.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +SnO.sub.2 +SnO 0.05-4.0 and a ratio R=(M.sub.2 O+2MO-Al.sub.2 O.sub.3 -ZrO.sub.2)/B.sub.2 O.sub.3 where M.sub.

Abstract: A mold has a moling surface of a material containing silicon carbide and/or silicon nitride as a main component and a carbon thin film formed on the molding surface to prevent fusion sticking. A glass substance which has a sag point not higher than 565.degree. C. and a predetermined composition free from arsenic oxide is introduced into the mold. The glass substance is press-formed in a heated and softened condition into a glass optical element of high precision.