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. 16, 2003
Filed:
Jun. 27, 2001
Hideaki Yamada, Suwa, JP;
Hiroyasu Kaseya, Suwa, JP;
Seiko Epson Corporation, , JP;
Abstract
A processing method of a master for optical disk by a laser processing to form grooves, prepit groups on a groove track and prepit groups on a land track in a high quality and in a good balance. On an optical course of a laser beam for forming the prepit groups, an optical deflector is provided. Also, the laser beam is positioned to shoot on the center of the groove track and the land track. The deflector deflects the laser beam in the same amount of deflection to the opposite direction to form each of the prepit groups. Further, a difference in diffraction efficiencies by a difference in the deflection directions is corrected by controlling the laser power independently from each other.