Granted Patent
Utility
US 6,282,164 · App. 09/177,578
Optical head having a phase-shifting diffraction grating
Inventor:
Ryuichi Katayama
Patented Case
View Patent ↗
Granted: Aug 28, 2001
Filed: Oct 23, 1998
Inventor
Ryuichi Katayama
Assignee (at issue)
NEC CORPORATION
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.