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. 12, 1997
Filed:
Mar. 10, 1995
Mototaka Taneya, Nara, JP;
Tatsuya Morioka, Tenri, JP;
Hidenori Kawanishi, Nara, JP;
Atsushi Shimonaka, Nara-ken, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An optical data reading method and apparatus for photoelectrically converting reflection light of a laser beam radiated onto a recording medium and thereby reproducing digital data recorded in the recording medium, performing a coherent detection by photoelectrically converting a first laser beam having a light frequency .nu..sub.1 and a second laser beam having a light frequency .nu..sub.2, where .nu..sub.1 -.nu..sub.2 .gtoreq.R (R: rate of reading the digital data), in a state where wavefronts of the first and second laser beams are aligned with each other, detecting temporal changes of either an amplitude or a phase of a beat signal component of the first and second laser beams, having a frequency of (.nu..sub.1 -.nu..sub.2) and being included in an photoelectrically converted output, and reading the digital data recorded in the recording medium based on a result of detection.