Microphone
US4850016A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1988 |
| Grant date | Jul 18, 1989 |
| Priority date | — |
| Expiry date | Jan 29, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R1/222
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A noise cancelling microphone for location inside an apertured mouthpiece region of a telephone handset comprises a housing with a face for securement in contact with the inside of the mouthpiece region. A cavity accommodates a vibratable diaphragm. A first sound path is provided to a front surface of the diaphragm by way of an opening in a central region of the face of the housing and apertures in a central portion of the mouthpiece region of the handset. A second sound path, physically separated from the first, is provided to a rear surface of the diaphragm by way of an opening in an outer region of the face of the housing and apertures in an outer portion of the mouthpiece region. The separated sound paths are extended by securing an upstanding member, such as a hollow truncated cone, externally on the mouthpiece region to separate the central and outer apertures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.