Granted Patent
Utility
US 4,567,382 · App. 06/598,682
Electret transducer and a method for manufacturing an assembly of backplate, electret foil and diaphragm plate
Inventor:
Aart Zeger van Halteren
Patented Case
View Patent ↗
Granted: Jan 28, 1986
Filed: Apr 10, 1984
Inventor
Aart Zeger van Halteren
Assignee (at issue)
Microtel, B.V.
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.