Abstract: The lead-free, Li2O-free, CuO-free and preferably arsenic-free optical glass is suitable for applications in the fields of imaging, projection, telecommunications, optical communication technology and/or laser technology, and has a refractive index nd of 1.55?nd?1.60, an Abbe number Vd of 54?Vd?63 and a transformation temperature Tg?500° C. This optical glass has good production and processing properties and crystallization stability, and, at the same time, advantageously does not contain PbO and As2O3. These glasses contain, in percent by weight based on oxide content: P205, 43-56; ZnQ, 21-36; Al2O3, 0-6; Na2O, 0-16; K2O, 0-8; ?M2O ?16; MgO, 0-5; CaO, 0-5; BaO, 3-14; B2O3, 0-8; La2O3, 0-7. In addition, it may also contain standard refining agents.

Abstract: The invention relates to a meltdown device for the production of high-UV transmittive glass types, comprising a meltdown tank for a melt bath a feed opening for the supplying or laying-in of highly pure raw material for the melt bath a draw-off opening for the drawing-off of material melted in the melt tank a cover arranged above the melt tank, in which the infeed opening to the melt tank is arranged above the melt bath in the region of the cover the draw-off opening is arranged in the zone of the bottom of the melt tank a heating arrangement. The heating arrangement comprises heating elements, in particular electrodes that are arranged on the melt tank in the zone of the melt bath, as well as an agitating arrangement for stirring of the melt bath and uniform intermixing and sub-mixing into the melt of material from the mixture lying on the melt surface.

Abstract: The lead-free and arsenic-free optical glass has a refractive index nd of 1.84?nd?1.96 and an Abbé number ?d of 27??d?36, with good chemical resistance, excellent crystallization resistance and the following composition (in % by weight based on oxide): SiO2, 1 to 8, B2O3, 13 to 19.5, La2O3, 34 to 50; MgO, 0 to 6, CaO, 0 to 6, BaO, 0 to 6, ZnO, 0 to 9 with ?MO, 1 to 10; and TiO2, 4 to 15, ZrO2, 0 to 11, Nb2O5, 6 to 14.5. In addition, the glass according to the invention, as well as having a maximum alkali metal oxide content of 10% by weight, may also contain standard refining agents other than arsenic. The glass according to the invention is used in imaging, projection, telecommunications, optical communication and/or laser technology.

Abstract: A process for producing a borate-containing, low-alkali material is provided. The process includes induction-heating a boron-containing melting material directly in an appliance using an alternating electromagnetic field. The, melting material as a constituent includes at least one metal oxide, the metal ions of which have a valency of at least two, in a quantitative proportion of at least 25 mol %, and in which the ratio of the molar substance quantities of silicon dioxide to borate in the melting material is less than or equal to 0.5.

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: 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.

Abstract: A glass with high internal transmission as well as low tendency to radiation-caused physical compaction and low tendency to solarization, comprising 18 to 31% by weight of SiO2, 0 to 7% by weight of Na2O3, 0 to 7% by weight of K2O, 65 to 84% by weight of PbO, 0.001 to 1% by weight of As2O3+As2O5, which is characterized by a content of 0 to 5000 ppm of Sb2O3 0 to 500 ppm of TiO2 0 to 100 ppm of CuO 0 to 1000 ppm of F. The ?(As2O3, As2O5, Sb2O3, F)?20 ppm and the ratio of As(III)/As(V) is at least 0.5. Such a glass is suitable for the use as optical element.

Abstract: The lead-free, preferably lithium-free, optical glass is useful in imaging, projection, telecommunications, optical communication and/or laser technology, particularly for making precise-pressed optical elements. It has a refractive index nd of 1.50 to 1.57, an Abbé number ?d of 61 to 70. It also has a low transformation temperature of about or below 400° C., good production and processing properties and crystallization resistance. It has a composition, in percent by weight, based on oxide content of P2O5, 40 to 60; Al2O3, 1 to 20; B2O3, 0 to <5; Na2O, 0 to 30; K2O, 0 to 30; Li2O, 0 to <1; ?M2O, >15 to 40; BaO, 1 to 20; ZnO, 1 to 20; SrO, 0 to 5; CaO, 0 to 5; MgO, 0 to 5; and ?MO, 5 to 25. In addition, it may contain standard refining agents, although it is preferably free of arsenic and fluorine.

Abstract: The invention relates to optical glasses that are composed as follows: 5-35% by weight of SiO2, 55-88% by weight of PbO; 0-10% by weight of B2O3; 0-5% by weight of Na2O, 0-5% by weight of K2O; 0-10% by weight of TiO2, 0-10% by weight of ZrO2; 0-10% by weight of La2O3; 0-10% by weight of BaO; 0-10% by weight of ZnO, with the proviso that S(Na2O; K2O): 0=x=8 and S(TiO2; ZrO2; La2O3; ZnO; BaO): x=15. The glasses are particularly suitable for LCD projection purposes, especially rLCD projectors. The inventive glasses are glasses from the heavy flint-glass and lanthane heavy flint glass type and have a stress-optical coefficient approaching zero while having a good chemical resistance and sufficient Knoop hardness and are characterized by excellent melting and workability properties. They are therefore suitable for use in fields of application that benefit from low stress-optical effects.

Abstract: A short optical glass is disclosed which is particularly suited for the applications imaging, projection, telecommunication, optical information technology and/or laser technology, also particularly suited for fiber applications (light guides or imaging guides). Preferably, the glass has a refractive index of 1.54≦nd≦1.62 and an Abbe coefficient of 48≦vd=57. It further has good attenuating and ion exchange characteristics, good chemical stability and good crystallization stability. The glass comprises 35 to 50 wt.-% SiO2, 0.1 to 6 wt.-% B2O3, 0.1 to 7 wt.-% Al2O3, 0.1 to 4 wt.-% P2O5, 4 to 24 wt.-% R2O (alkali oxides), 6 to 14.5 wt.-% BaO, 0 to 12 wt.-% other RO (alkaline earth oxides), 14 to 25 wt.-% ZnO, 0 to 5 wt.-% La2O3, 0 to 10 wt.-% ZrO2, wherein R2O is an alkali oxide, RO is an alkaline earth oxide other than BaO, wherein Li2O is 6 wt.

Abstract: A short optical glass is disclosed which does not comprise any silver, copper, thallium, lead or boron and is particularly suited for the application imaging, projection, telecommunication, optical information technology, and/or laser technology, also particularly suited for fiber applications (light guides or imaging guides). Preferably the glass has a refractive index of 1.55≦nd≦1.65 and an Abbe coefficient of 48≦vd≦57 and also has good attenuating and ion exchange characteristics, good chemical stability and good crystallization stability. The glass comprises 35 to <50 wt.-% SiO2; 1 to 10 wt.-% Al2O3; 5 to 15 wt.-% Na2O+K2O+CS2O+Li2O; 20 to 30 wt.-% BaO; 0 to 15 wt.-% ZnO; 0 to 10 wt.-% La2O3; 0 to 10 wt.-% ZrO2; 0 to 6 wt.-% P2O5; 0 to 8 wt.-% MgO+CaO+SrO; 0 to 3 wt.-% of other oxides, and Cs2O<1, Li2O<1, and TiO2<1 wt.-%.

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: 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 ≦vd≦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): 1 SiO2 53-58 B2O3 11-15 Al2O3 16-20 Na2O  0-13 K2O  0-13 &Sgr;M2O  9-13 F 0.

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: The lead-free and preferably arsenic-free optical glass is suitable for applications in the fields of imaging, projection, telecommunications, optical communication technology and/or laser technology, and has a refractive index nd of 1.55≦nd≦1.60, an Abbe number vd of 54≦vd≦63 and a transformation temperature Tg≦500° C. This optical glass has good production and processing properties and crystallization stability, and, at the same time, advantageously does not contain PbO and As2O3. These glasses contain, in percent by weight based on oxide content: P2O5, 43-56; ZnO, 21-36; Al2O3, 0-6; Na2O, 0-16; K2O, 0-8; &Sgr;M2O≦16; MgO, 0-5; CaO, 0-5; BaO, 3-14; B2O3, 0-8; La2O3, 0-7. In addition, it may also contain standard refining agents.

Abstract: The invention relates to a borosilicate glass containing zinc oxide, which has the following composition (oxide-based in wt. %): 58-67% SiO2, 1-5% B2O3, 0-5% Al2O3, 8-17% Na2O, 0-12% K2O, 3-12% MgO, 0-12% CaO, 2-8% ZnO, 1-5% TiO2. The glass is particularly suitable for use as a hard disk substrate.

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: 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 and preferably arsenic-free optical glass has a refractive index nd of 1.84≦nd≦1.96 and an Abbé number &ngr;d of 27≦&ngr;d≦36, with good chemical resistance, excellent crystallization resistance and the following composition (in % by weight based on oxide): SiO2, 1 to 8, B2O3, 13 to 19.5, La2O3, 34 to 50; MgO, 0 to 6, CaO, 0 to 6, BaO, 0 to 6, ZnO, 0 to 9 with &Sgr; MO, 1 to 10; and TiO2, 4 to 15, ZrO2, 0 to 11, Nb2O5, 6 to 14.5. In addition, the glass according to the invention, as well as having a maximum alkali metal oxide content of 10% by weight, may also contain standard refining agents, although arsenic is not preferred. The glass according to the invention is used in imaging, projection, telecommunications, optical communication and/or laser technology.

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.