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:
Aug. 31, 1999
Filed:
Apr. 09, 1997
Applicant:
Inventors:
Hiromichi Kobori, Yokohama, JP;
Kazuo Watabe, Kawasaki, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369124 ; 369 4441 ; 3692754 ;
Abstract
An optical information recording medium comprises tracks having information recorded thereon as a mark portion where information is readable by irradiation of a light beam and a non-mark portion, wherein a first track whose optical phase difference between the mark portion and the non-mark portion is about .lambda. (1/4+k/2) and a second track whose optical phase difference between the mark portion and the non-mark portion is about .lambda. (1/8+m/4)(k and m are integers of 0 or more) are alternatively arranged when a wavelength of the optical beam is set to .lambda..