Abstract: The invention provides a polishing pad by which optical materials such as lenses, reflecting mirrors etc., or materials requiring a high degree of surface planarity, as in the polishing of silicone wafers, glass substrates or aluminum substrates for hard disks, or general metal polishing, can be flattened with stability and high polishing efficiency. The invention also provides a polishing pad for semiconductor wafers, which is superior in planarizing characteristic, is free from scratches and can be produced at low cost. There is provided a polishing pad which is free from dechucking error so that neither damage to wafers nor decrease in operating efficiency occurs. There is provided a polishing pad which is satisfactory in planarity, within wafer uniformity, and polishing rate and produces less change in polishing rate. There is provided a polishing pad which can make planarity improvement and scratch decrease compatible.

Abstract: The invention provides a polishing pad by which optical materials such as lenses, reflecting mirrors etc., or materials requiring a high degree of surface planarity, as in the polishing of silicone wafers, glass substrates or aluminum substrates for hard disks, or general metal polishing, can be flattened with stability and high polishing efficiency. The invention also provides a polishing pad for semiconductor wafers, which is superior in planarizing characteristic, is free from scratches and can be produced at low cost. There is provided a polishing pad which is free from dechucking error so that neither damage to wafers nor decrease in operating efficiency occurs. There is provided a polishing pad which is satisfactory in planarity, within wafer uniformity, and polishing rate and produces less change in polishing rate. There is provided a polishing pad which can make planarity improvement and scratch decrease compatible.

Abstract: A highly pure hexagonal boron nitride single crystal not influenced by impurities and capable of high-luminance short wave ultraviolet light emission reflecting inherent characteristics is provided; a high-luminance ultraviolet light emitting element is provided by using the above single crystal; and utilizing the above element, a simple compact low-cost long-lived far ultraviolet solid-state laser and far ultraviolet solid-state light emitting apparatus are provided. A highly pure hexagonal boron nitride single crystal having a single light emission peak in the far ultraviolet region of up to a wavelength of 235 nm is produced by melting said boron nitride crystal as raw material in the presence of a highly pure solvent under high-temperature and high-pressure, followed by crystallization. A light emitting element or a light emitting layer comprised of the obtained crystal is excited with electron beams, and the thus generated far ultraviolet light resonated or without resonation is taken out.

Abstract: A method of producing a polishing pad having a polishing layer is characterized in that the polishing layer is produced by a photolithographic method including: forming a sheet molding from a curing composition containing at least an initiator and an energy ray-reactive compound to be cured with energy rays; exposing the sheet molding to energy rays to induce modification thereof, to change the solubility of the sheet molding in a solvent; and developing the sheet molding after irradiation with energy rays, to partially remove the curing composition with a solvent thereby forming a concave and convex pattern at least one surface.

Abstract: A polishing pad includes at least a polishing layer and a cushion layer and is characterized in that the difference in hardness in Shore D hardness between the polishing layer and the cushion layer is 3 or more.

Abstract: A polishing pad includes a polishing layer having abrasive grains dispersed in a resin and is characterized in that the resin is a resin containing ionic groups in the range of 20 to 1500 eq/ton.

Abstract: An objective lens is configured of a first crown-glass lens and a second flint-glass lens, whereby it can exhibit substantially identical optical properties at a plurality of recording/reproducing light source wavelengths, particularly, in both 650 nm and 405 nm wavelength bands. Also, by maximizing the difference in glass transition point between the first and second lenses, one of the first and second lenses having a higher glass transition point is molded first, to allow that first molded lens to serve as a mold tool for molding the other lens. This dispenses with the steps of aligning and adhesive bonding the two lenses, whereby this objective lens can be used at a plurality of wavelengths as a single objective lens, and thus an information recording/reproducing apparatus can be of a simple configuration.

Abstract: A polishing pad enabling a highly precise optical endpoint sensing during the polishing process and thus having excellent polishing characteristics (such as surface uniformity and in-plane uniformity) is disclosed. A polishing pad enabling to obtain the polishing profile of a large area of a wafer is also disclosed. A polishing pad of a first invention comprises a light-transmitting region having a transmittance of not less than 50% over the wavelength range of 400 to 700 nm. A polishing pad of a second invention comprises a light-transmitting region having a thickness of 0.5 to 4 mm and a transmittance of not less than 80% over the wavelength range of 600 to 700 nm. A polishing pad of a third invention comprises a light-transmitting region arranged between the central portion and the peripheral portion of the polishing pad and having a length (D) in the diametrical direction which is three times or more longer than the length (L) in the circumferential direction.

Abstract: The invention provides a polishing pad by which optical materials such as lenses, reflecting mirrors etc., or materials requiring a high degree of surface planarity, as in the polishing of silicone wafers, glass substrates or aluminum substrates for hard disks, or general metal polishing, can be flattened with stability and high polishing efficiency. The invention also provides a polishing pad for semiconductor wafers, which is superior in planarizing characteristic, is free from scratches and can be produced at low cost. There is provided a polishing pad which is free from dechucking error so that neither damage to wafers nor decrease in operating efficiency occurs. There is provided a polishing pad which is satisfactory in planarity, within wafer uniformity, and polishing rate and produces less change in polishing rate. There is provided a polishing pad which can make planarity improvement and scratch decrease compatible.

Abstract: A polyurethane composition containing solid beads dispersed therein, characterized in that the polyurethane is a microcellular polyurethane foam and the composition has a storage modulus of elasticity at 40° C. of 270 MPa or more as measured by means of a dynamic elasticity measuring device: and a polyurethane composition containing solid beads dispersed therein, characterized in that the solid beads are capable of swelling with or being soluble in an aqueous medium. The former composition has excellent flattening capability, and the latter composition can provide a polished surface which combines good flatness and good uniformity and can also reduce scratches on the surface.

Abstract: The polishing pad of this invention is a polishing pad effecting stable planarizing processing, at high polishing rate, materials requiring surface flatness at high level, such as a silicon wafer for semiconductor devices, a magnetic disk, an optical lens etc. This invention provides a polishing pad which can be subjected to surface processing to form a sheet or grooves, is excellent in thickness accuracy, attains a high polishing rate, achieves a uniform polishing rate, and also provides a polishing pad which is free of quality variations resulting from an individual variation, easily enables a change the surface patterns, enables fine surface pattern, is compatible with various materials to be polished, is free of burrs upon forming the pattern. This invention provides a polishing pad which can have abrasive grains mixed at very high density without using slurry, and generates few scratches by preventing aggregation of abrasive grains dispersed therein.

Abstract: An objective lens is configured of a first crown-glass lens and a second flint-glass lens, whereby it can exhibit substantially identical optical properties at a plurality of recording/reproducing light source wavelengths, particularly, in both 650 nm and 405 nm wavelength bands. Also, by maximizing the difference in glass transition point between the first and second lenses, one of the first and second lenses having a higher glass transition point is molded first, to allow that first molded lens to serve as a mold tool for molding the other lens. This dispenses with the steps of aligning and adhesive bonding the two lenses, whereby this objective lens can be used at a plurality of wavelengths as a single objective lens, and thus an information recording/reproducing apparatus can be of a simple configuration.

Abstract: An optical lens composed of a transparent material, wherein one surface thereof on a light source side is a convex aspherical surface of rotation symmetry defined by a function relative to the radial distance from an optical axis. The aspherical surface is shaped to be a curved one without any stepped region with regard to the radial direction in the defined area, and has a portion where the derivatives of the function are discontinuous at a predetermined radial position. Although not equipped with an iris diaphragm, this optical lens is capable of eliminating an incident light beam outside the optical effective surface thereof without deteriorating the optical characteristics.

Abstract: The improved silver halide photographic material comprises a support having an antistatic coating thereon that contains a water-soluble conductive polymer, hydrophobic polymer particles and a curing agent which is a bifunctional ethylene oxide type curing agent that is to be cured by exposure to electron beams or X-rays. This silver halide photographic material may contain a tetrazolium compound or a hydrazine compound in order to prevent desensitization due to aging. At least one hydrophilic colloidal layer may be provided on the antistatic coating, which colloidal layer contains an epoxy curing agent having a hydroxy group.