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:
Oct. 20, 1998
Filed:
Jul. 08, 1996
Applicant:
Inventors:
Amir Alon, Sunnyvale, CA (US);
Shlomo Shapira, Petach-Tikva, IL;
Assignee:
ZEN Research N.V., Curacao, AN;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369121 ; 369 4437 ; 369102 ; 369107 ; 369116 ;
Abstract
Methods and apparatus are provided for illuminating an optical disk in a multi-track optical disk reader. A laser beam is collimated and focused onto an area including multiple, adjacent data tracks on the optical disk. To minimize noise caused by interference resulting from the reflection of multiple beams from the optical disk the coherency of the laser beam is reduced. This is accomplished by one or more of the following techniques: passing the laser beam through a multi-mode optical fiber, combining laser beams from multiple independent laser sources, and modulating the laser operating current at high frequency.