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US 4,063,050 AGranted
Acoustic transducer with improved electret assembly
AssigneeIndustrial Research Products, Inc.
InventorsElmer V. Carlson, Mead C. Killion
Life of this patent
Estimating the term…
Abstract
The present invention relates to an acoustic transducer including an improved electret assembly mounted in an improved case and having an electronic amplifier circuit comprising FET transistors. The electronic circuit further includes means for protecting the FET transistors against current surges.
Claims10
An acoustical transducer, comprising, in combination, a case having a bottom and side walls;
- an electret assembly including a diaphragm having a central vibratable plate-like portion and a relatively flexible surround on the periphery of the plate-like portion, a backplate having apertures extending therethrough, protrusions on one surface of the backplate, and an electret film formed on the surface of the backplate having the protrusions, the electret film cooperating with the diaphragm to develop a signal;
- and, spaced support posts on the interior surface of the bottom of the case and selectively aligned with protrusions on the surface of the backplate for supporting the electret assembly in the case and for forming an acoustical chamber between the electret assembly and the interior surface of the bottom of said case.
Dependencies are inferred from the claim text.