Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% of less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.

Abstract: A sheet-metal rocker arm formed by the steps of punch-pressing a sheet of metal member to form a blank having a predetermined shape and a through-hole, of subjecting the blank to a bending process based on pressing to form a pair of substantially parallel side wall sections and a connection section for connecting the widthwise edges of the both side wall sections and to form at least one pair of circular holes in the both side wall sections at locations in alignment, of deforming the middle of the connection section in the thickness direction to form an engagement portion on one side of the connection section such that the engagement portion is recessed from the other portion of the connection section, and of forming on the other side of the connection section a bulge section, trapezoidal in cross section, which protrudes in an embanked-shape as the engagement portion is formed, whereby the widthwise edges of the middle of the bulge section corresponding to the top edge of the trapezoidal shape exist on the w

Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.

Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.