Abstract: A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 ?m. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

Abstract: A synthetic quartz glass lid is provided comprising a synthetic quartz glass and an adhesive formed on a periphery of a main surface of the window member. Further, an optical device package is provided comprising a box-shaped receptacle having an open upper end, an optical device received in the receptacle, and a window member of synthetic quartz glass bonded to the upper end of the receptacle with an adhesive. The adhesive is a low-melting metallic glass consisting of Te, Ag and at least one element selected from W, V, P, Ba, and Zr.

Abstract: Synthetic quartz glass substrates are prepared by furnishing a synthetic quartz glass block, coating two opposed surfaces of the glass block with a liquid having a transmittance of at least 99.0%/mm at a birefringence measuring wavelength, measuring a birefringence of the glass block by directing light thereacross, determining a slice thickness on the basis of the birefringence measurement and the dimensions of the substrate, and slicing the glass block at the determined slice thickness.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating an arbitrary surface and an opposite surface of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring the birefringence of the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable or unacceptable group, based on the measured birefringence value.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating two opposite surfaces of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring a birefringence distribution on the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable group or unacceptable group, based on the measured birefringence distribution.

Abstract: A synthetic quartz glass cavity member (1) is bonded to a substrate (6) having an optical device (7) mounted thereon such that the device may be accommodated in the cavity member. The cavity member (1) has an inside surface consisting of a top surface (2a) opposed to the device (7) and a side surface (3a). The top surface (2a) is a mirror surface and the side surface (3a) is a rough surface.

Abstract: A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 ?m. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

Abstract: A polishing composition comprising a colloidal dispersion of spherical silica particles and associated silica particles as abrasive is provided. When used in the step of polishing synthetic quartz glass substrates, the polishing composition ensures a higher polishing rate than conventional colloidal silica and is effective for preventing any microscopic defects on the substrate surface, thus providing the substrate with a high smoothness. The polishing composition can be used as the ceria replacement polishing composition for polishing a lapped surface.

Abstract: Proposed herein is a method for producing substrates, particularly those of synthetic quartz glass, while saving the substrate surface from killer defects without resorting to any large-scale apparatus and precision polishing plate, thereby reducing defects and improving yields more than in production with conventional facilities. The method for producing substrates by polishing, includes steps of placing substrate stocks individually in work holes formed in a carrier on a lower polishing plate, bringing an upper polishing plate into contact with the surface of the substrate stocks, with the surface of the substrate stocks being coated with an impact-absorbing liquid and the lower polishing plate being rotated, and rotating the upper and lower polishing plates, with the surface of the substrate stocks being accompanied by a polishing slurry.

Abstract: A substrate is prepared by polishing a surface of the substrate using a polishing pad while feeding a slurry. The polishing pad has a porous nap layer which comes in contact with the substrate surface and is made of a base resin comprising at least three resins, typically an ether resin, ester resin, and polycarbonate resin. The polished substrate has a highly flat surface with a minimal number of defects.

Abstract: A synthetic quartz glass lid for use in optical device packages is prepared by furnishing a synthetic quartz glass lid precursor comprising a synthetic quartz glass substrate (1) and a metal or metal compound film (2), and forming a metal base adhesive layer (3) on the metal or metal compound film (2). The metal or metal compound film contains Ag, Bi, and at least one element selected from P, Sb, Sn and In.

Abstract: In polishing of synthetic quartz glass substrates, a polishing slurry is used comprising (i) an oligopeptide comprising recurring units of pentapeptide: -[valine-proline-glycine-valine-glycine]- and having a molecular weight of 800-150,000 or a copolymer of the pentapeptide with another monomer, and (ii) a colloidal solution.

Abstract: Disclosed is a polishing agent for synthetic quartz glass substrates, which is characterized by containing a colloidal solution of a colloidal silica or the like having a colloid concentration of 20-50% by mass, and a polycarboxylic acid polymer, an acidic amino acid, a phenol or a glycosaminoglycan.

Abstract: A rectangular glass substrate has a front surface, a back surface, four side surfaces, and eight chamfered surfaces, and a thickness of at least 6 mm. A first curved surface along the edge line between the front surface and the chamfered surface disposed adjacent thereto has an average gradient of up to 25% in a range from the front surface to a position of 50 ?m below the front surface when the substrate is rested horizontal with the front surface facing upward. A second curved surface along the edge line between at least one of four side surfaces and the chamfered surface disposed adjacent to the front surface has an average gradient of at least 30% in a range from the at least one side surface to a position of 50 ?m below the at least one side surface when the substrate is rested horizontal with the at least one side surface facing upward.

Abstract: A synthetic quartz glass lid is provided comprising a synthetic quartz glass and an adhesive formed on a periphery of a main surface of the window member. Further, an optical device package is provided comprising a box-shaped receptacle having an open upper end, an optical device received in the receptacle, and a window member of synthetic quartz glass bonded to the upper end of the receptacle with an adhesive. The adhesive is a low-melting metallic glass consisting of Te, Ag and at least one element selected from W, V, P, Ba, and Zr.

Abstract: Synthetic quartz glass substrates are prepared by furnishing a synthetic quartz glass block, coating two opposed surfaces of the glass block with a liquid having a transmittance of at least 99.0%/mm at a birefringence measuring wavelength, measuring a birefringence of the glass block by directing light thereacross, determining a slice thickness on the basis of the birefringence measurement and the dimensions of the substrate, and slicing the glass block at the determined slice thickness.

Abstract: A synthetic quartz glass substrate is prepared by immersing a starting substrate in an aqueous solution of a nonionic surfactant and precision polishing the substrate with a colloidal silica water dispersion. A synthetic quartz glass substrate having a few defects and low surface roughness is obtained while the polishing rate is improved and the polishing time is reduced.

Abstract: A rough surface of a starting synthetic quartz glass substrate is polished to a mirror finish, using a polishing slurry containing tetragonal or cubic zirconia.

Abstract: A synthetic quartz glass substrate has a surface of 6 inch squares including a central surface area of 132 mm squares. The central surface area of 132 mm squares has a flatness of up to 50 nm. A frame region obtained by subtracting the central surface area of 132 mm squares from the central surface area of 148 mm squares has a flatness of up to 150 nm.

Abstract: A synthetic quartz glass substrate is prepared by furnishing a synthetic quartz glass block, coating two opposite surfaces of the block with a liquid having a transmittance of at least 99.0%/mm at the wavelength of birefringence measurement, measuring a birefringence distribution on the block by letting light enter one coated surface and exit the other coated surface, and sorting the block to an acceptable group or unacceptable group, based on the measured birefringence distribution.