The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 08, 2005
Filed:
Mar. 24, 2004
Hirokazu Tajima, Osaka, JP;
Tamaki Horisaka, Osaka, JP;
Hirokazu Tajima, Osaka, JP;
Tamaki Horisaka, Osaka, JP;
Hoya Corporation, , JP;
Abstract
A glass substrate for a data recording medium is manufactured by using a tabular carrier with circular holes formed therein, housing disk-shaped glass workpieces in the circular holes of this carrier, sliding polishing pads over the surface of the carrier and the principal surfaces of the glass workpieces and polishing the glass workpieces until the height (NRa) of micro-waviness on the principal surfaces of the glass workpieces is reduced to a predetermined value or less. The height (NRa) of micro-waviness of the principal surfaces is a value dependent on the surface roughness of the polishing pad and the surface roughness of this polishing pad is a value dependent on the surface roughness of the carrier. A glass substrate for a data recording medium is manufactured by reducing the surface roughness (Ra) of the carrier to 0.08 μm or less and polishing the glass workpieces until the height (NRa) of micro-waviness on the principal surfaces measured using a three-dimensional surface structure analysis microscope whose measuring wavelength (λ) is set to 0.2 to 1.4 mm is reduced to 0.12 nm or less.