Abstract: The invention provides an ultraviolet lithography method/system. The lithography method and system include providing a below 200 nm radiation source, providing a photolytically improved transmitting fused silica glass lithography optical element, transmitting below 200 nm photons through said photolytically improved transmitting fused silica glass lithography optical element to form a lithography pattern which is reduced and projected onto a radiation sensitive lithography printing medium to form a printed lithography pattern. Providing the photolytically improved transmitting fused silica glass lithography optical element includes providing a photolytically improved transmitting fused silica glass lithography optical element preform body and forming the photolytically improved transmitting fused silica glass lithography optical element preform into said lithography optical element.

Abstract: A method for making a polarizing glass article is provided. The method includes first providing a precursor glass containing metal-halide particles. The precursor glass may be encased in a gas-permeable medium. Then, form at least a first polarizing layer and a non-polarizing region in the precursor glass. Bond the polarizing layer to a substrate and removing the non-polarizing region to expose the polarizing layer. Then, separate the first polarizing layer from the substrate to produce an ultra-thin polarizing glass article measuring less than or equal to about 200 ?m in thickness. The method may further comprise cutting the polarizing layer into wafers.

Abstract: Problems the invention is to solve: An object of the present invention is to provide a method for producing a quartz glass crucible capable of pulling up a silicon single crystal at a highly improved yield, yet without generating oscillation at the surface of the melt on pulling up silicon single crystal, and free from generating dislocations due to the peeling off of quartz glass fractions.

Abstract: The invention provides coated optical lithography elements and methods of coating optical elements, and particularly optical photolithography elements for use in below 240 nm optical photolithography systems utilizing vacuum ultraviolet light (VUV) lithography wavelengths no greater than about 193 nm, such as VUV projection lithography systems utilizing wavelengths in the 193 nm or 157 nm region. The optical devices manipulate vacuum ultraviolet lithography light less than 250 nm utilizing a deposited silicon oxyfluoride film. The deposited silicon oxyfluoride optical coating assists in the manipulation of incident light and protects the underlying optical materials, layers, and surfaces.

Abstract: Disclosed are masks and mask blanks for photolithographic processes, photosensitive materials and fabrication method therefor. Photosensitive materials are used in the masks for recording permanent pattern features via UV exposure. The masks are advantageously phase-shifting, but can be gray-scale masks having index patterns with arbitrary distribution of refractive index and pattern dimension. The masks may have features above the surface formed from opaque or attenuating materials. Alumino-boro-germano-silicate glasses having a composition comprising, in terms of mole percentage, 1-6% of Al2O3, 10-36% of B2O3, 2-20% of GeO2, 40-80% of SiO2, 2-10% of R2O, where R is selected from Li, Na and K, and expressed in terms of weight percentage of the glass, 0-5% of F, can be used for the mask substrate.

Abstract: The subject of the invention is a process for treating a glass sheet which consists of a glass composition having a strain point above 540° C. and is intended for producing a display screen, the said process including at least one ion-exchange treatment on at least part of the surface of the glass sheet and a precontraction treatment.

Abstract: A process for producing fluorine-containing glass. An SiO2 soot is synthesized by hydrolyzing SiCl4. The soot is heated in a chlorine-compound-free atmosphere containing a fluorine compound gas to form a fluorine-containing silica glass. The glass contains not more than 10 ppm OH group, not more than 10 ppm Cl, and not less than 1,000 ppm F. The concentration ratio of F/Cl is 10,000 or more.

Abstract: A method for manufacturing a synthesized silica glass optical member, the method comprising: providing a porous silica glass body; heating the porous' silica glass body in an atmosphere containing hydrogen or oxygen, and sintering the porous silica glass body in an atmosphere containing fluorine compound. Furthermore, a synthesized silica glass optical member manufactured by the method.

Abstract: High purity silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed with the silicon oxyfluoride glass having a preferred fluorine content<0.5 weight percent. The inventive silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a “dry,” silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1×1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Abstract: The invention includes methods of making lithography photomask blanks. The invention also includes lithography photomask blanks and preforms for producing lithography photomask. The method of making a lithography photomask blank includes providing a soot deposition surface, producing SiO2 soot particles and projecting the SiO2 soot particles toward the soot deposition surface. The method includes successively depositing layers of the SiO2 soot particle on the deposition surface to form a coherent SiO2 porous glass preform body comprised of successive layers of the SiO2 soot particles and dehydrating the coherent SiO2 glass preform body to remove OH from the preform body. The SiO2 is exposed to and reacted with a fluorine containing compound and consolidated into a nonporous silicon oxyfluoride glass body with parallel layers of striae.

Abstract: The invention relates to a method for producing UV polarizers, according to which spheroid particles situated near the surface of the glass are incorporated into the support material (primarily standard float glass) in a novel arrangement. According to the method for producing UV polarizers, after the introduction of metal ions (e.g., silver ions) into the glass surface, a large size distribution of particles is achieved by multiple alternation of a heat treatment for separating out spherical metal particles, followed by the renewed introduction of metal ions and a subsequent heat treatment. A deformation of the glass produces spheroid particles of various sizes and different semi-axis relationships. The particles are characterized by their large size distribution and are deformed differently in relation to their spheroid shape. In this way UV polarizers are produced which have a wide absorption range since the absorption bands having different maximum positions overlap.

Abstract: Polarized glass articles having a wavelength range that is broadened for high contrast-ratio applications. A method that imparts to a glass article a high contrast ratio of at least 40 dB for use as dichroic glass polarizers over a wavelength range of 880 nm to 1,690 nm while keeping a high transmission value. The method comprises the step of heating the glass article at a temperature ranging from 400 to 450° C. in a reducing atmosphere for a period of time ranging from 12 to 30 hours. Preferably, the reducing atmosphere is hydrogen at atmospheric pressure.

Abstract: The present invention relates to a glass article for use as an optical waveguide fiber and more particularly to an optical waveguide fiber, the core of which is doped with a chalcogenide element to significantly increase the refractive index of the core. The subject of this invention is novel doped silica core compositions wherein a portion of the oxygen in the silica is replaced with either sulfur, selenium or tellurium using plasma enhanced chemical vapor deposition (PECVD). These compositions are designed to have higher refractive indices than silica, low coefficients of expansion, high optical transparency, and appropriate viscosity and softening points to make them ideal candidates for use as optical waveguide fibers.

Abstract: The present invention is directed to a method of making an ultra dry high purity, Cl-free, F doped fused silica glass. Silica powder or soot preforms are used to form a glass under conditions to provide a desired level of F doping while reducing the Cl and −OH concentrations to trace levels. The method includes providing a glass precursor in the from of a silica powder or soot preform. The powder is heated in a furnace. The powder is exposed to a F-species at a predetermined temperature and time sufficient to melt the powder and form a high purity fused silica glass in the bottom of said furnace.

Abstract: A crucible used in the growth of polycrystal silicon by a cast method comprises a crucible body for, when solid material silicon is melted, containing the melted material silicon, and a material holder provided on the crucible body, for holding further material silicon on the material silicon loaded into the crucible body.

Abstract: High purity silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed with the silicon oxyfluoride glass having a preferred fluorine content<0.5 weight percent. The inventive silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a “dry,” silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1×1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Abstract: An optical member manufacturing method of the present invention has a growth step of growing an ingot of a fluoride crystal, a plane orientation measurement step of measuring two ormore crystal plane orientations of the ingot, a cutout step of cutting out an optical material from the ingot along any one of the crystal plane orientations obtained in the plane orientation measurement step, and a machining step of performing predetermined machining processing on the optical material to obtain an optical member.

Abstract: There are provided a glass substrate for information recording media in which the undulations on the glass substrate surface are optimized, thus contributing to reduction of the flying height, and at the same time preventing the occurrence of head crashes and thermal asperity, and a method of manufacturing the glass substrate. At least one surface of a glass substrate is polished, and the polished at least one surface of the glass substrate is subjected to surface scrubbing using a sponge having an Asker C hardness of not less than 40 according to The Society of Rubber Industry, Japan SRIS 0101.

Abstract: A process for modifying the surface of a quartz glass crucible and a modified quartz glass crucible produced by the process, where the crucible has a transparent coated layer containing a crystallization accelerator on the surface. The process includes coating a mixed solution containing a metal salt and a partial hydrolyzate of alkoxysilane oligomer on the surface of the crucible and heating to obtain a quartz glass crucible having a transparent coated layer. The crystallization promoter contains a metal oxide or a metal carbonate dispersed in a silica matrix.

Abstract: A medium substrate comprising a borosilicate glass containing silica as a main component and having on the surface thereof a continuous texture derived from the porous structure, the medium substrate being used as a substrate in the production of a magnetic recording medium and other. The method for the production of the textured medium substrate is also disclosed, along with a magnetic recording medium using the medium substrate and a magnetic disk device.

Abstract: A photolithography apparatus has an exposure light source for emitting exposure light with a wavelength of 400 nm or less, a reticle with a pattern original image formed therein, an illumination optical system for illuminating the reticle with exposure light, a projection optical system for projecting the pattern image from the reticle onto a photosensitive plate and an alignment system for aligning the reticle and the photosensitive plate. At least some of the synthetic silica glass members composing the illumination optical system, the projection optical system and the reticle consist of synthetic silica glass members which, upon 1×104 pulse irradiation with an ArF excimer laser at an energy density from 0.1 &mgr;J/cm2·p to 200 mJ/cm2·p, have a loss factor no greater than 0.0050 cm−1 at 193.4 nm measured after irradiation, a hydrogen molecule concentration from 1×1016 molecules/cm3 to 2×1018 molecules/cm3 and a loss factor no greater than 0.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: A salt mixture used for chemical strengthening of data recording disks is subjected to sub-micron filtration prior to use to remove certain impurities. Preferably, glass disks are chemically strengthened by ion exchange in a bath of molten sodium nitrate and potassium nitrate. A salt fresh mixture is prepared by starting with high-grade bulk salt in the intended proportions, melting the salt, and filtering the salt in a stainless steel filter, which is preferably approximately 2 micron or smaller. Filtration removes trace amounts of certain contaminants. The salt mixture thus prepared is then used for chemical strengthening of disks in the conventional manner.

Abstract: Methods of improving the direct bonding of articles are disclosed. Lithium can be incorporated into the composition of one of the articles and/or lithium can be added to a bonding surface by ion exhchange, absorption, ion implantation, coating, or deposition. Bonding is achieved without use of adhesives or high temperature fusion. The invention is useful for bonding a wide variety of articles together such as optical components, optical fibers and articles having different coefficients of thermal expansion or refractive indices.

Abstract: The present invention provides a method for manufacturing an optical element to be used for an optical system and an optical instrument using the optical system, and a method for manufacturing a device using the optical instrument, wherein the optical element is manufactured by the steps including the steps for processing a high purity silica glass by lithography, and the hydrogen molecule content is adjusted after manufacturing the optical element.

Abstract: The invention relates to optical glass having improved initial transmittance, formed by subjecting the glass to a hydrogen and/or deuterium treatment at a temperature, and for a duration of time sufficient to diffuse the hydrogen and/or deuterium into the glass.

Abstract: A method for shifting the absorption peak wavelength in the wavelength range 900-1600 nm of an infrared radiation absorbing glass from less than 1100 nm to 1100 nm or longer without substantially changing the tint of the glass, comprising the step of irradiating with ultraviolet light of 400 nm or shorter at an energy density of 1.0×106 J/m2/hr or more to increase the content of FeO in the irradiated glass by reducing Fe (III) to Fe (II), the ultraviolet light irradiated glass thereby comprising 0.02 wt. % or more FeO in terms of Fe2O3. The glass to be irradiated comprises, in % by weight: 65 to 80% SiO2, 0 to 5% Al2O3, 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na2O, 0 to 5% K2O, 5 to 15% MgO+CaO, 10 to 20% Na2O+K2O, and 0 to 5% B2O3; 0.02% or more total iron oxide (T-Fe2O3) in terms of Fe2O3, 0 to 2.0% CeO2, 0 to 1.0% TiO2, 0 to 0.005% CoO, and 0 to 0.005% Se.

Abstract: A method for fabricating gradient-index rods and rod arrays. A central rod of optical glass having predetermined properties and predetermined outside dimensions is placed inside a tube of optical glass having predetermined properties and predetermined outside dimensions, to form an assembly. The inside dimensions of the tube are substantially equal to the outside dimensions of the rod. The tube is formed of a plurality of coaxial sleeves, the outside dimensions of each interior sleeve being substantially equal to the inside dimensions of the next adjacent sleeve, each sleeve having a selected refractive index so that, together with the tube, the refractive indices from the central rod through the outermost sleeve approximate the refractive index profile of the gradient-index rod to be fabricated. The central rod and sleeve material is selected so that their respective thermal indices of expansion are substantially equal.

Abstract: In a method of manufacturing a chemical reinforced glass substrate, consideration is previously made about a relationship between conditions of chemical reinforcement for a glass substrate and deformation caused by the chemical reinforcement at an edge portion of the glass substrate. The glass substrate is chemically reinforced on the basis of the relationship so that an edge profile is shaped into a desirable edge profile during the chemical reinforcement. The resultant chemical reinforced glass substrate is flat and smooth in a wide area and effective to improve a recording density and to avoid head crashes.

Abstract: A method for heat treating a synthetic quartz glass for optical use in a heating furnace, that comprises covering the surroundings of a synthetic quartz glass body with a SiO2 powder having a mean dissolved hydrogen molecule concentration of 1×1019 molecules/cm3 or higher, and then heat treating the body.

Abstract: There is disclosed second-order nonlinear glass material wherein a part having second-order nonlinearity contains Ge, H and OH and has second-order nonlinear optical constant d of 1 pm/V or more, and a method for producing second-order nonlinear glass material comprising treating a porous glass material containing Ge with hydrogen, sintering it and subjecting it to a ultraviolet poling treatment. There can be provided second-order nonlinear glass material having second-order nonlinearity which is a sufficiently high and has a sufficiently long lifetime for a practical purpose, in use of the glass material for optical functional elements or the like.

Abstract: A method for manufacturing an information recording medium glass substrate that prevents a glass plate from drying and prevents material from collecting on the surface when the glass plate is transferred. The method includes immersing the glass plate in a heated chemical strengthening liquid, washing the glass plate with warm water to remove adhered material from the surface of the glass plate, washing the glass plate to remove residual adhered material from the surface of the glass plate, and transferring the glass plate from a location at which the warm water washing is performed to a location at which the washing is performed by wetting or moistening the glass plate with liquid.

Abstract: A glass substrate for an information recording medium has an acid resistance represented by an etching rate of at most 45 nm/min. upon contact with a hydrofluoric acid having a temperature of 50° C. and a concentration of 0.1 weight %. The glass substrate has a recording surface having an average surface roughness Ra smaller than 0.3 nm.

Abstract: A method for heat treating a synthetic quartz glass for optical use in a heating furnace, that comprises covering the surroundings of a synthetic quartz glass body with a SiO2 powder having a mean dissolved hydrogen molecule concentration of 1×1019 molecules/cm3 or higher, and then heat treating the body.

Abstract: High purity direct deposit vitrified silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed. The inventive direct deposit vitrified silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a dry direct deposit vitrified silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive direct deposit vitrified silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1×1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Abstract: A method of producing a polarizing glass article that exhibits a broad band of high contrast polarizing properties in the infrared region of the radiation spectrum. The polarizing glass is phase-separated or exhibits photochromic properties based on silver, copper, or copper-cadmium halide crystals or a combination thereof, which are precipitated in the glass and having a size in the range of 200-5000 Å. The glass has a surface layer containing elongated silver, copper, or copper cadmium metal particles, or a mixture thereof. The method comprises subjecting the glass article to a time-temperature cycle in which the temperature is at least about 76° C. or greater above the glass softening point, in a step to thermally form and precipitate large halide crystals, and elongated metallic particles under a stress of not over about 3000 psi, preferably not over about 2675 psi.

Abstract: A process for producing a synthetic silica glass optical component which contains at least 1×1017 molecules/cm3 and has an OH concentration of at most 200 ppm and substantially no reduction type defects, by treating a synthetic silica glass having a hydrogen molecule content of less than 1×1017 molecules/cm3 at a temperature of from 300 to 600° C. in a hydrogen gas-containing atmosphere at a pressure of from 2 to 30 atms.

Abstract: In a method of manufacturing a glass substrate for an information recording medium including a step for chemically strengthening the glass substrate by contacting the glass substrate with chemical strengthening processing liquid containing chemical strengthening salt, concentration of Fe and Cr is 500 ppb or less in said chemical strengthening salt, respectively. The concentration may be detected by the use of an ICP (Inductively Coupled Plasma) emission spectrometry analyzing method or a fluorescent X-ray spectroscopy analyzing method.

Abstract: The present invention relates generally to UV (ultraviolet) photosensitive bulk glass, and particularly to batch meltable alkali boro-alumino-silicate and germanosilicate glasses. The photosensitive bulk glass of the invention exhibits photosensitivity to UV wavelengths below 300 nm.

Abstract: A method and plant for treating laminated glass having at least two glass sheets between which is arranged at least on intermediate sheet of non-glass material. The glass is attacked in a basic solution of fragmented laminated glass, so as to obtain an attack medium, wherein the fragments are disintegrated into non-laminated glass fragments and non-glass material, separating in a) the basic solution, b) the disintegrated non-laminated fragments and c) the disintegrated fragments of the non-glass material, and neutralizing the disintegrated fragments “b) and c)” before their subsequent recycling or upgrading.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: A synthetic glass member for use in excimer laser lithography, having superior homogeneity, high transmittance for ArF excimer laser beams and an excellent resistance against lasers is made from high purity synthetic quartz glass, and it is characterized in that layered structures, striae in three directions and internal strains are thermally and mechanically removed, the distribution of refractive index (&Dgr;n) in a plane orthogonal to the optical axis is up to about 1×10−6, the distribution of refractive index (&Dgr;n) in a plane parallel to the optical axis is up to about 5×10−6, the birefringence is up to about 2 nm/cm, the hydrogen molecule concentration is at least about 2×1017 molecules/cm3, and the internal transmittance is at least about 99.8% at a wavelength of 193.4 nm.

Abstract: High purity silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed with the silicon oxyfluoride glass having a preferred fluorine content<0.5 weight percent. The inventive silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a “dry,” silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1×1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Abstract: The invention provides coated optical lithography elements and methods of coating optical elements, and particularly optical photolithography elements for use in below 240 nm optical photolithography systems utilizing vacuum ultraviolet light (VUV) lithography wavelengths no greater than about 193 nm, such as VUV projection lithography systems utilizing wavelengths in the 193 nm or 157 nm region. The optical devices manipulate vacuum ultraviolet lithography light less than 250 nm utilizing a deposited silicon oxyfluoride film. The deposited silicon oxyfluoride optical coating assists in the manipulation of incident light and protects the underlying optical materials, layers, and surfaces.

Abstract: An apparatus is provided for making mirrors having enhanced reflective layer resistance to corrosion. The reflective layer of the mirror, typically silver, is contacted, preferably simultaneously, with a first solution containing a specific cation and a second solution containing a specific anion, or alkaline material which forms hydroxyl ions, the specific cation and specific anion or hydroxyl ion reacting to form a water insoluble precipitate on the silver surface. The mirror may then be painted to provide additional corrosion resistance to the mirror. The apparatus device for forming the precipitate eliminates the need for a device to form a copper layer on the silver surface and the device may be incorporated into existing mirror production lines as a replacement for the copper layering device. Also provided are mirrors made using the apparatus of the invention. A preferred cation containing solution contains tin (e.g., SnCl2) and a preferred anion containing solution contains hydroxyl ions (e.g, NaOH).

Abstract: Glass bottles having undergone high-frequency heat sealing, to depress the dispersion of sealing strength as low as possible and to improve the ease of both sealing and unsealing. A rough surface having minute unevenness is formed in the proximity of the apical part of the mouth of a glass bottle, wherein the apical part contacts with a sealing material. Since (1) a contact area between the sealing material and the glass surface decreases, and the quantity of heat taken by the glass from the sealing material decreases, (2) a bond area increases; and (3) an anchor effect is generated, the sealing strength increases, and simultaneously the dispersion of the sealing strength decreases.

Abstract: The invention is a method of retaining selenium in a lass containing selenium by including a manganese compound and not including nitrates or nitrites routinely used in the industry to retain selenium. Particularly, a preferred embodiment involves manufacturing a gray soda-lime-silica glass composition including selenium as a colorant, the components of the gray soda-lime-silica glass have colorants consisting essentially of: greater than 0.9 to 1.9 wt. % total iron oxide as Fe2O3; 0.10 to 1.00 wt. % manganese compound as MnO2; 0.0010 to 0.0060 wt. % selenium as Se; 0.002 to 0.025 wt. % cobalt oxide as Co, and 0 to 1.0 wt. % titanium oxide as TiO2 which are combined and melted to make the glass composition. The glass composition has at 4.0 mm. thickness: 10 to 55% light transmittance using Illuminant A, less than 25% ultra violet transmittance, and less than 50% infra red transmittance.

Abstract: A number of unique processes are disclosed for manufacture of sintered high-purity quartz glass products in which a shaped silica body or preform is made from an aqueous slurry of micronized silica particles by gel casting, slip casting or electrophoretic deposition. The silica particles may comprise a major portion by weight of crystalline silica. In one embodiment of the invention the sintered quartz glass is transparent, substantially bubble-free and suitable for scientific or optical uses. In another embodiment the porous silica preform is fired in steam to increase the hydroxyl content and then nitrided in a nitrogen-hydrogen reducing atmosphere. A minute amount of chemically-combined nitrogen in the high-purity quartz glass is sufficient to provide a tremendous improvement in physical properties and an incredible increase in the resistance to devitrification.

Abstract: A simple and economical method is described for compacting or shrinking flat glass panes. The method ensures high temperature homogeneity in the glass. First, the glass panes are cleaned and then a stack of glass panes to be treated is assembled without applying a release agent to any of the glass panes. Then the stack of glass panes is placed between ceramic panels made of silicon-infiltrated silicon carbide and this stack together with the ceramic panels is subjected to a heat treatment in a radiation furnace at temperatures ranging from 300° C. to 900° C. The ceramic panels have a thermal conductivity, which, in the region of the heat treatment temperature, is at least 5 times as large as that of the glass panes. The ratio of the total thickness of the ceramic panels to the height of the glass stack should be at least 1/&lgr;/40W/(mK), wherein &lgr; is the thermal conductivity of the ceramic panel at the temperatures of the heat treatment.

Abstract: An ophthalmic, protective, filter lens, and a method of producing such lens, the lens having a ratio of Z and Y tristimulus values between 0.25-0.40, a dominant wavelength between 570-580 nm. on a color mixture diagram, a sharp transmission drop between 450-500 nm. and a transmission not over 30% between 400-450 nm. The lens is produced by firing a silver halide-containing, photochromic glass lens in a hydrogen-containing atmosphere within a temperature range of 465° C. to 495° C. for less than 20 minutes.