Granted Patent
Utility
US 5,243,052 · App. 07/548,223
Mixed carbonate ester derivatives of quinophthalone dyes and their preparation
Inventors:
Lloyd D. Taylor, David P. Waller
Patented Case
View Patent ↗
Granted: Sep 7, 1993
Filed: Jun 29, 1990
Inventors
Lloyd D. Taylor
David P. Waller
Assignee (at issue)
Polaroid 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.