Granted Patent
Utility
US 6,778,475 · App. 10/294,943
Optical detector, optical pickup and optical information reproducing apparatus using optical pickup for detecting at least three light beams separated from one or more light sources
Inventors:
Katsuhiko Izumi, Kunikazu Ohnishi, Kenichi Shimada, Masayuki Inoue, Shinji Fujita
Patented Case
View Patent ↗
Granted: Aug 17, 2004
Filed: Nov 15, 2002
Inventors
Katsuhiko Izumi
Kunikazu Ohnishi
Kenichi Shimada
Masayuki Inoue
Shinji Fujita
Assignees (at issue)
HITACHI, LTD.
HITACHI MEDIA ELECTRONICS CO., LTD.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.