Granted Patent
Utility
US 5,659,531 · App. 08/606,272
Optical head device and birefringent diffraction grating polarizer and polarizing hologram element used therein
Inventors:
Yuzo Ono, Akitomo Oba
Patented Case
View Patent ↗
Granted: Aug 19, 1997
Filed: Feb 23, 1996
Inventors
Yuzo Ono
Akitomo Oba
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.