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:
Jun. 15, 2010
Filed:
Jun. 19, 2007
Jun Sumioka, Kawasaki, JP;
Masakuni Yamamoto, Yamato, JP;
Kaoru Okamoto, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical information reproducing method of reproducing multivalued information recorded on a track of an optical information medium having a recording/reproducing region, which has virtual cells arranged thereon at regular spacings. The multivalued information is recorded thereon by changing a length of an information pit in a track direction or an area of the information pit in a cell with the use of a light spot. The multivalued information is reproduced by detecting the level of a multistage reproduced signal from the information pit. The method includes sampling a reproduced signal in the multivalued information recorded in one cell with an M-value (M<N), which is arranged at each of the plurality of cells recorded with an N-value (N≧3) on the track, and detecting a cell center value. A phase error for producing a reproduction clock is obtained on the basis of the detected cell center value, a previously derived ideal value of the cell center value, and a previously derived gradient of the reproduced signal in the vicinity of the ideal value of the cell center value.