Granted Patent
Utility
US 4,340,306 · App. 06/117,855
Optical system for surface topography measurement
Inventor:
N. Balasubramanian
Patented Case
View Patent ↗
Granted: Jul 20, 1982
Filed: Feb 4, 1980
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.