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:
Sep. 11, 2001
Filed:
Jan. 12, 1999
Mark E. McDonald, Mountain View, CA (US);
Robert R. McLeod, Morgan Hill, CA (US);
Siros Technologies, Inc., San Jose, CA (US);
Abstract
An improved focus error signal generator device and an optical data delivery and detection system including an optical lens disposed in the path of a return read beam and a birefringent plate disposed in the path of the return beam of light after the optical lens, wherein the birefringent plate provides for a first and second focal plane of corresponding first and second polarization. A pinhole is disposed in the path of the return read beam after the birefringent plate and in close proximity to first and second focal planes. A polarizing beam splitter is positioned after the second focal plane and serves to split the return read beam into two light beams of first and second polarization. First and second detectors are disposed in the path of corresponding first and second polarization light beams. The detectors are connected to the inputs of an electrical differencing circuit that has an output to an optical head servo system.