Sealed microphone assembly

• US 5,365,595 A
• Filed: 02/19/1993
• Issued: 11/15/1994
• Est. Priority Date: 02/19/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Li, Richard C.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): TRAN, SINH N
• Application Number:
  US08/019,800
• Time in Patent Office: 634 Days
• Field of Search: 381/168, 381/169, 381/173, 381/174, 381/176, 381/177, 381/179, 381/91, 381/189, 381/159, 455/128, 379/175, 367/141
• US Class Current: 381/360
• CPC Class Codes: H04R 1/086 Protective screens, e.g. all weather or wind screens

Abstract

A sealed microphone assembly is disclosed including a microphone (120), a microphone housing (110) having a cavity (116) being resonant at an audio frequency range, and a sealing membrane (130). The sealing membrane 130 covers the cavity 116, thereby making the microphone assembly (100) fully sealed. The attenuation caused by sealing the microphone assembly (100) is compensated by the resonant characteristic of the cavity (116). The cavity (116) also includes one or more apertures (112) for creating a bandpass response.

Claims

1. A waterproof microphone assembly for operating within an audio frequency range, comprising:

a microphone having a sensitivity;

a microphone housing including (a) an acoustically resonant cavity within the audio frequency range, wherein said acoustically resonant cavity is formed to include a backside upon which a microphone is centrally positioned, (b) a first selectively shaped aperture for producing an acoustic bandpass response within the audio frequency range and (c) a second selectively shaped aperture, wherein said first selectively shaped aperture and said second selectively shaped aperture are formed on said backside, and said first selectively shaped aperture and said second selectively shaped aperture are being symmetrically positioned with respect to said microphone; and

a sealing membrane covering said acoustically resonant cavity to render the microphone assembly waterproof while substantially maintaining the sensitivity of the microphone.

2. The microphone assembly of claim 1, wherein said acoustic bandpass response has a bandwidth within 300 Hz to 3 KHz range.

3. A radio comprising:

a transmitter for transmitting a communication signal including a modulator for modulating an audio signal within an audio frequency range;

a waterproof microphone assembly for operating within an audio frequency range, comprising;

a microphone having a sensitivity;

a microphone housing including (a) an acoustically resonant cavity within the audio frequency range, wherein said acoustically resonant cavity is formed to include a backside upon which a microphone is centrally positioned, (b) a first selectively shaped aperture for producing an acoustic bandpass response within the audio frequency range and (c) a second selectively shaped aperture, wherein said first selectively shaped aperture and said second selectively shaped aperture are formed on said backside, and said first selectively shaped aperture and said second selectively shaped aperture are being symmetrically positioned with respect to said microphone; and

a sealing membrane covering said acoustically resonant cavity to render the microphone assembly waterproof while substantially maintaining the sensitivity of the microphone.

4. The microphone assembly of claim 3, wherein said acoustic bandpass response has a bandwidth within 300 Hz to 3 KHz range.