Granted Patent
Utility
US 4,387,994 · App. 06/399,520
Optical system for surface topography measurement
Inventor:
N. Balasubramanian
Patented Case
View Patent ↗
Granted: Jun 14, 1983
Filed: Jul 19, 1982
Inventor
N. Balasubramanian
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.