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:
Dec. 14, 1999
Filed:
Jun. 05, 1995
Akira Miyagawa, Kanagawa, JP;
Hironori Fujita, Kanagawa, JP;
Sony Corporation, , JP;
Sony Chemicals Corp, , JP;
Abstract
A device for inspecting the surface of a disc-shaped recording medium is provided. The inspection device is capable of performing track control unaffected by the widths of the land and the groove in the radial direction of the recording medium in inspecting the entire surface of a data recording region of the recording medium. The device has a spindle motor 1, an optical pickup 2 and a thread motor 3. While an output signal is supplied from a spot size control section 4b within a signal detection unit 4, two sub-beams are radiated from the optical pickup for tracking control. These sub-beams are radiated to the vicinity of the boundary region between the land sandwiched between the grooves where the light volume of the reflected light of the radiated light is minimized.