Abstract:
SiO2—TiO2 glasses having a low coefficient of thermal expansion are produced by a molding being produced that consists of SiO2 powder, SiO2—TiO2 powder or TiO2 powder and that contains by way of secondary component a titanium-containing component which is converted into amorphous TiO2.
Abstract:
Titania-containing silica glass bodies and extreme ultraviolet elements having low levels of striae are disclosed. Methods and apparatus for manufacturing and measuring striae in glass elements and extreme ultraviolet elements are also disclosed.
Abstract:
The present invention relates to a method for forming an optical device. The method includes providing a glass aggregate. Typically, the glass aggregate is a mixture of fine glass soot particles and coarser ground or milled glass powder. The glass particles are mixed with a liquid to form a slurry which is cast in a mold to form a porous pre-form. Subsequently, the porous pre-form is consolidated into a glass object by heating the pre-form at a relatively high temperature. The method of the present invention produces optical components having substantially no striae. As a result, scattering is substantially reduced when EUV light is reflected from a component produced from the optical blank.
Abstract:
A method for controlling the refractive index achieved using a fluorine dopant gas, wherein CF4 is employed as the dopant gas, and the soot preform is doped using the CF4 for a time and temperature sufficient to result in a decrease in fluorine dopant nearest the surface which is in contact with the CF4 gas.
Abstract:
Optical quality glass having a selected refractive index is produced by a two stage drying process. A gel is produced using sol-gel chemistry techniques and first dried by controlled evaporation until the gel volume reaches a pre-selected value. This pre-selected volume determines the density and refractive index of the finally dried gel. The gel is refilled with solvent in a saturated vapor environment, and then dried again by supercritical extraction of the solvent to form a glass. The glass has a refractive index less than the full density of glass, and the range of achievable refractive indices depends on the composition of the glass. Glasses having different refractive indices chosen from an uninterrupted range of values can be produced from a single precursor solution.
Abstract:
To inhibit, or at least sharply attenuate, fluorescence of a quartz-glass velope (10) surrounding a light source (11), such as a halogen incandescent lamp, a high-pressure discharge lamp, or the like, when the quartz glass is subjected to ultraviolet (UV) radiation from the light source, and has been doped with a UV radiation absorbing material, typically a cerium, or cerium-titanium doping, the quartz-glass envelope is additionally doped with barium and boron. The barium/boron in the doping is, preferably, present in quantities of between about 0.008 and 1.25%, by weight, with reference to the undoped quartz glass. Barium metaborate can be used, optionally together with praseodymium to attenuate the fluorescence. Preferably, barium and boron form a combined doping substance with cerium, in form of a cerium aluminate and metaborate, added to the starting material for the quartz glass, and before the quartz glass is fused from quartz sand or pulverized quartz crystal.
Abstract:
Ultraviolet (UV) radiation in the UV-C and UV-B bands, which is particularly dangerous, is absorbed and filtered by quartz glass doped with between 0.065% and 3.25%, and preferably between 0.065% and 1.3% by weight, of cerium metal, or cerium as such. Preferably, the cerium is added to quartz sand and/or rock crystal, in form of a fine-grained powder of up to 2 0 .mu.m grain size, in form of cerium aluminate (CeAlO.sub.3), present in up to about 5% by weight, and preferably up to about 2%, and melted together in a single step. The quartz glass so obtained is particularly suitable for a metal halide discharge lamp, e.g. as an outer envelope (1), or as the discharge vessel (27) itself, or for halogen incandescent lamps, to form the quartz-glass light bulb or an envelope therefor. A small quantity of titanium oxide, up to about 0.05%, may be added as a further doping agent to the melt to further improve the UV absorption in the B and C bands.
Abstract:
Fused quartz containing europium oxide, titanium dioxide and cerium oxide has been found to be effective for absorbing UV radiation while transmitting visible light radiation. Uses for this material include lamp envelopes and shrouds for halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation.
Abstract:
The method and apparatus for producing liquid silicon of high purity and for casting silicon. Hydrogen and a hydrogenated silane in gaseous state are mixed, preferably with a source of a small amount of oxygen, in a heated chamber producing the liquid silicon, with the exhaust gases bubbling out of the melt under a baffle. The chamber for the melt of liquid silicon preferably is lined with silicon dioxide. The liquid silicon may be used in making high purity vitreous silica and may be used in making castings of silicon. In making castings, the liquid silicon is accumulated in a second chamber and is periodically drawn from the second chamber into a third chamber which contains the mold for the casting.
Abstract:
The method and apparatus for producing liquid silicon of high purity and for casting silicon. Hydrogen and a hydrogenated silane in gaseous state are mixed, preferably with a source of a small amount of oxygen, in a heated chamber producing the liquid silicon, with the exhaust gases bubbling out of the melt under a baffle. The chamber for the melt of liquid silicon preferably is lined with silicon dioxide. The liquid silicon may be used in making high purity vitreous silica and may be used in making castings of silicon. In making castings, the liquid silicon is accumulated in a second chamber and is periodically drawn from the second chamber into a third chamber which contains the mold for the casting.