Granted Patent
Utility
US 6,472,766 · App. 09/755,438
Step mask
Inventor:
Guangming Xiao
Patented Case
View Patent ↗
Granted: Oct 29, 2002
Filed: Jan 5, 2001
Inventor
Guangming Xiao
Assignee (at issue)
PHOTRONICS, 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.