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. 25, 2012
Filed:
Sep. 09, 2008
Takashi Kikukawa, Tokyo, JP;
Kazushi Tanaka, Tokyo, JP;
Takashi Kikukawa, Tokyo, JP;
Kazushi Tanaka, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
An optical reading system is provided to improve read signal quality with increasing its linear recording density. An optical recording medium in which the distance from a light incident surface to an information recording layer is less than 100 μm is irradiated with a laser beam through an objective lens and information stored in the information recording layer is read by means of a PRML detection method. At this time, the constraint length n in the PRML detection method is set to an integer which satisfies 0.5×(λ/NA)/(LV/f)−1<n<0.5×(λ/NA)/(LV/f)+1, wherein λ represents the wavelength of the laser beam, NA represents the numerical aperture of the objective lens, LV represents the linear velocity of the optical recording medium when recording, and f represents a channel bit frequency when recording.