Producing a molded body made of opaque quartz glass includes providing SiO.sub.2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO.sub.2, forming a slurry containing a suspension liquid and the SiO.sub.2 grains and which has a total solids content, wet grinding the SiO.sub.2 grains in the slurry so as to form ground SiO.sub.2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO.sub.2 grains takes place at least temporarily in the presence of SiO.sub.2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO.sub.2 nanoparticles and after the wet grinding.

The present invention relates to a silica glass including bublles in the number of 1×10.sup.7/cm.sup.3 to 1×10.sup.15/cm.sup.3 and having a density of 0.5 g/cm.sup.3 to 1.95 g/cm.sup.3. The present invention also relates to a method for producing a silica glass, including: a step of depositing SiO.sub.2 fine particles generated by flame hydrolysis of a silicon compound, to obtain a silica glass porous body; a step of heating and sintering the silica glass porous body in an inert gas atmosphere, to obtain a silica glass dense body; and a step of performing a foaming treatment to heat the silica glass dense body under a reduced pressure condition.

A method for manufacturing a large sized opaque quartz glass ingot having excellent heat ray shielding and light blocking properties without using a foaming agent. The obtained opaque quartz glass has small diameter spherical bubbles and a preferable mechanical strength. Silica powder is dispersed in water to form a slurry having a silica powder concentration of 45 to 75 wt % and the average particle size of the silica powder is adjusted to 8 μm or less and the standard deviation of the particle size is adjusted to 6 μm or more by wet pulverization. The slurry is sprayed for forming granules of the silica powder. An opaque quartz glass ingot with a small bubble diameter and high mechanical strength is obtained by melting the granulated silica powder.

An alkali-free glass substrate contains, as represented by mass % based on oxides: 54% to 68% of SiO.sub.2; 10% to 25% of Al.sub.2O.sub.3; 0.1% to 5.5% of B.sub.2O.sub.3; and 8% to 26% of MgO+CaO+SrO+BaO. The alkali-free glass substrate has β-OH of 0.15 mm.sup.−1 to 0.35 mm.sup.−1, and a Cl content of 0.15 to 0.3 mass %. A bubble growth index I of the alkali-free glass substrate given by the following formula is 320 or more: I=590.5×[β-OH]+874.1×[Cl]−5.7×[B.sub.2O.sub.3]−33.3. In the formula, [β-OH] is β-OH of the alkali-free glass substrate in mm.sup.−1, [Cl] is the Cl content of the alkali-free glass substrate in mass %, and [B.sub.2O.sub.3] is a B.sub.2O.sub.3 content of the alkali-free glass substrate in mass %.

Provided is a silica glass member for hermetic sealing of an ultraviolet SMD LED element to be suitably used for hermetic sealing of, and as a transmission window material for, a surface mount-type package (SMD) having an ultraviolet LED mounted thereon and configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm. The silica glass member for hermetic sealing includes a silica glass substrate, which is homogeneously and integrally formed without an internal boundary, wherein the silica glass substrate has: a first surface on an inside opposed to an SMD LED element; and a second surface on an outside corresponding to the first surface, wherein an outer peripheral portion of the first surface has formed therein a substrate joining plain surface for joining to the container outer periphery joining plain surface, and wherein the second surface on the outside corresponding to the first surface has formed therein a lens-like convex portion configured to process emitted light from the ultraviolet SMD LED element.

A diffuser material of synthetically produced, pore-containing quartz glass and a method for the manufacture of a molded body consisting fully or in part thereof. The diffuser material has a chemical purity of at least 99.9% SiO.sub.2, a cristobalite content of not more than 1%, and a density in the range of 2.0 to 2.18 g/cm.sup.3. Starting therefrom, to indicate a diffuser material which is improved with respect to diffuse reflectivity with Lambertian behavior over a wide wavelength range, high material homogeneity and UV radiation resistance, the quartz glass has a hydroxyl group content in the range of at least 200 wt. ppm and at least 80% of the pores have a maximum pore dimension of less than 20 μm.

A glass tube for sealing a metal includes a glass that contains, in terms of mass %, 50% or more of SiO.sub.2+B.sub.2O.sub.3, 0% to 10% of Al.sub.2O.sub.3, 3% to 20% of RO (R is an alkaline earth metal), and 11% to 22% of R′.sub.2O (R′ is an alkali metal), and that has 10 μl/g or less of an amount of CO.sub.2 emitted when heated from a room temperature to 1100° C.

Provided is a silica glass member for hermetic sealing of an ultraviolet SMD LED element to be suitably used for hermetic sealing of, and as a transmission window material for, a surface mount-type package (SMD) having an ultraviolet LED mounted thereon and configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm. The silica glass member for hermetic sealing includes a silica glass substrate, which is homogeneously and integrally formed without an internal boundary, wherein the silica glass substrate has: a first surface on an inside opposed to an SMD LED element; and a second surface on an outside corresponding to the first surface, wherein an outer peripheral portion of the first surface has formed therein a substrate joining plain surface for joining to the container outer periphery joining plain surface, and wherein the second surface on the outside corresponding to the first surface has formed therein a lens-like convex portion configured to process emitted light from the ultraviolet SMD LED element.

Provided is a silica glass member for hermetic sealing of an ultraviolet SMD LED element to be suitably used for hermetic sealing of, and as a transmission window material for, a surface mount-type package (SMD) having an ultraviolet LED mounted thereon and configured to emit ultraviolet light in a wavelength range of from 200 nm to 350 nm. The silica glass member for hermetic sealing includes a silica glass substrate, which is homogeneously and integrally formed without an internal boundary, wherein the silica glass substrate has: a first surface on an inside opposed to an SMD LED element; and a second surface on an outside corresponding to the first surface, wherein an outer peripheral portion of the first surface has formed therein a substrate joining plain surface for joining to the container outer periphery joining plain surface, and wherein the second surface on the outside corresponding to the first surface has formed therein a lens-like convex portion configured to process emitted light from the ultraviolet SMD LED element.

A body, such as a lamp body, includes a tubular element. At least one conductor is introduced into the tubular element and a glass material surrounds the conductor. The glass material forms a seal between the tubular element and the conductor. The glass material includes a sintered glass, such as a sintered glass ring, and may completely surround the conductor.