The present invention is concerned with a glass substrate for a magnetic disk, and were especially, it relates to a magnetic disk with a surface which has no chemical strengthening layer.
Moreover, the present invention relates to a magnetic disk whose surface roughness in an information recording portion thereof is sufficiently small, and a glass substrate for use in magnetic disk and magnetic disk that are suitable for a high density recording with high reliability. The present invention also relates to the process of manufacturing a glass substrate and a magnetic disk device.
Texturing of a glass substrate of a magnetic disk by using a laser has been attempted recently. While this method involves a technique used on metal substrates, such as Ni—P, this technique also maybe applied to glass. As described in Patent pre-publication 7-182655 and Patent prepublication 9-138942, laser texturing techniques using an ultraviolet light laser of 266 nm or a carbon dioxide laser that has a long wavelength of 10.6 μm have been used for ordinary glass having a transparency to light in the range from infrared to near ultraviolet.
In the above-described glass system, the substrate is reinforced by a chemical strengthening layer, and it is also known that texture formation maybe easily performed by compression of the substrate surface. (Ref. A. C. Tam et. al., IEEE(1997)).
USPTO Backgrounds
USPTO Backgrounds