Granted Patent
Utility
US 6,775,065 · App. 09/970,697
Diffraction element and optical pickup device
Inventors:
Kenichi Hayashi, Tadashi Takeda
Patented Case
View Patent ↗
Granted: Aug 10, 2004
Filed: Oct 5, 2001
Inventors
Kenichi Hayashi
Tadashi Takeda
Assignee (at issue)
Kabushiki Kaisha Sankyo Seiki Seisakusho
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.