Granted Patent
Utility
US 4,838,648 · App. 07/189,779
Thin film structure having magnetic and color shifting properties
Inventors:
Roger W. Phillips, Paul G. Coombs
Patented Case
View Patent ↗
Granted: Jun 13, 1989
Filed: May 3, 1988
Inventors
Roger W. Phillips
Paul G. Coombs
Assignee (at issue)
Optical Coating Laboratory, Inc.
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.