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:
Mar. 20, 2001
Filed:
Mar. 19, 1998
Applicant:
Inventor:
Kenji Igarashi, Kanagawa-ken, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Primary Examiner:
Int. Cl.
CPC ...
G03C 5/00 ;
U.S. Cl.
CPC ...
G03C 5/00 ;
Abstract
When a laser beam is directed onto an optical head substrate (,) to allow it to form a spiral or concentric pit strings (P), the laser beam is so shot as to provide a path parallel to, or obliquely with respect to, the pit string (P). For example, the laser beam shot provides a circular arc path having a diameter corresponding to a sum of a radius r of the innermost side pit string {P(point B)} and a radius R of the outermost side pit string {P(point A)} on the optical disk substrate, the circular arc path contacting with the innermost side pit string and with the outermost side pit string on the optical disk substrate.