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:
Feb. 01, 2000
Filed:
May. 27, 1998
Johannes H Spruit, Eindhoven, NL;
Johan P Duchateau, Wellen, BE;
U.S. Philips Corporation, New York, NY (US);
Abstract
An optical recording medium having a recording layer with grooves that define recording tracks. The structure of unwritten tracks enable a scanning device to derive a radial tracking error signal using the push-pull method. The structure of the written tracks enable the scanning device to derive a radial tracking error signal using the high-frequency phase-detection method. The width of the groove is in the range from 0.3 to 0.6 time the wavelength over the numerical aperture for scanning the recording medium. The depth of the groove is in the range from 1/24 to 1/7 times the wavelength for scanning the recording medium. The phase difference between a radiation beam reflected from a track at a mark and a radiation beam reflected from that track in a region between written marks is in the range from 0.4 to 2.0 radians.