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US3930128A Expired / Lapsed US ⏱️ 0.0 years remaining

Electret diaphragm microphone with means to corrugate the diaphragm when in an overstressed condition

Assignee: AKG Acoustics GmbH
•
Filing: 1974-06-12
•
Granted: 1975-12-30
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Expires: 1994-06-12
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Abstract

Abstract A condenser microphone comprises two electrodes spaced from each other by a small distance, of which one electrode is a diaphragm responsive to sound waves and the other electrode is formed with raised pin-like portions or projections projecting into the interspace between the electrodes, toward the diaphragm. The raised portions extend through only a part of the interspace so that a free space is left permitting unimpeded oscillation of the diaphragm in response to normal sound waves. The raised portions act as stops determining the maximum amplitude so that if the sound waves are abnormally strong, the diaphragm is deflected only up to contact with the end faces of the raised portions thus remaining spaced from the main surface of the opposite electrode. The electrostatic attractive forces are thereby limited and do not prevent the diaphragm from further free oscillation. To further reduce the electrostatic forces in the extreme position of the diaphragm, the end faces of the raised portions against which the diaphragm may apply are concave or electrically nonconductive. The electrodes preferably comprise an electretic material.

Inventors

  • 👤 Werner Fidi
  • 👤 Herbert Piribauer

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 05:03
CPC Classifications
H; H04; H04R; H04R19/00

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 73 words
A condenser microphone, comprising an electrode having a surface, an electret diaphragm at a spaced location from said surface, and means for corrugating said diaphragm in the event said diaphragm becomes overstressed, comprising at least one pinlike projection extending outwardly from said surface in normally spaced relation to said electrode, the space between said pinlike projection and said diaphragm being unimpeded to permit oscillation of said diaphragm in response to normal sound waves.
Claim 2
Dependent Claim 73 words
A condenser microphone, comprising an electrode having a surface, an electret diaphragm at a spaced location from said surface, and means for corrugating said diaphragm in the event said diaphragm becomes overstressed, comprising at least one pinlike projection extending outwardly from said surface in normally spaced relation to said electrode, the space between said pinlike projection and said diaphragm being unimpeded to permit oscillation of said diaphragm in response to normal sound waves.
Claim 3
Dependent Claim 133 words
A condenser microphone comprising a mount, a first electrode connected to said mount and having an upper surface, and a second electrode in the form of an electretifiable foil diaphragm connected to said mount and having a lower surface facing said upper surface of said electrode and spaced therefrom by a small distance, and means for corrugating said diaphragm in the event said diaphragm becomes overstressed, comprising a plurality of pin-like raised projections projecting from and distributed over said upper surface of said first electrode and having end faces turned to said lower surface of said diaphragm and spaced therefrom by a free distance so that a free space adjacent said diaphragm is provided between said end faces and said diaphragm permitting unimpeded oscillations of the latter in response to normal sound waves.
Claim 4
Dependent Claim 133 words
A condenser microphone comprising a mount, a first electrode connected to said mount and having an upper surface, and a second electrode in the form of an electretifiable foil diaphragm connected to said mount and having a lower surface facing said upper surface of said electrode and spaced therefrom by a small distance, and means for corrugating said diaphragm in the event said diaphragm becomes overstressed, comprising a plurality of pin-like raised projections projecting from and distributed over said upper surface of said first electrode and having end faces turned to said lower surface of said diaphragm and spaced therefrom by a free distance so that a free space adjacent said diaphragm is provided between said end faces and said diaphragm permitting unimpeded oscillations of the latter in response to normal sound waves.
Claim 5
Dependent Claim 40 words
A condenser microphone, according to claim 2, wherein said free distance between said end faces and said diaphragm is approximately one-third of said small distance separating said upper surface of said first electrode from said lower surface of said diaphragm.
Claim 6
Dependent Claim 17 words
A condenser microphone, according to claim 2, wherein said end faces of said raised portions are concaved.
Claim 7
Dependent Claim 18 words
A condenser microphone, according to claim 2, wherein said end faces of said raised portions are electrically non-conductive.
Claim 8
Dependent Claim 18 words
A condenser microphone, according to claim 2, wherein said raised projections have the form of upright cylindrical bodies.

References Cited (Backward Citations)

US3418436A Cited
US3328653A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-12-29 1979-06-30 1979-12-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-12-29 1983-06-30 1983-12-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-12-29 1987-06-30 1987-12-30 $7700.00 Window Closed / Lapsed

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