Telephone handset including directional microphone module

• US 5,216,711 A
• Filed: 08/07/1991
• Issued: 06/01/1993
• Est. Priority Date: 08/07/1990
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Takagi, Hisamitsu, Tomura, Masashi
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Le, Huyen D.
• Application Number:
  US07/741,632
• Time in Patent Office: 664 Days
• Field of Search: 379/433, 379/428, 379/429, 379/440, 381/155, 381/169
• US Class Current: 379/433.03
• CPC Class Codes: H04M 1/03 Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
• CPC Class Codes: H04M 1/19 Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor circuit arrangements for preventing eavesdropping H04M1/68; telephone cabinets E04H1/14
• CPC Class Codes: H04R 1/38 in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone

Abstract

A telephone handset favorably fabricated in a compact size and yet providing a good S/N characteristic of the transmitter portion thereof. The telephone handset has a directional microphone module in its transmitter portion. The directional microphone module comprises a directional microphone having a first and a second sound collector provided on the upper side and the under side thereof and a bush formed of an elastic material having its peripheral wall receiving the directional microphone in such a manner that the outer peripheral surface of the directional microphone is tightly fit to the inner surface of the peripheral wall. The telephone handset is formed of a front case and a rear case to be put together. In the interior of the front case, there is defined a microphone module receiving portion by a rib and the inner wall surface thereof and the microphone module is received therein.

Claims

1. A directional microphone module for use in a telephone handset, comprising:

a directional microphone having first and second sides, an outer peripheral surface, and first and second sound collecting holes provided in proximity to the first side and second side, respectively; and

a housing formed of an elastic material having a peripheral wall for receiving said directional microphone so that the outer peripheral surface of said directional microphone is tightly fit to an inner surface of said peripheral wall, said housing defining a space at a position opposing said second sound collecting hole, said housing having a first opening formed at a position opposing said first sound collecting hole, a second opening communicating with said space formed in the peripheral wall thereof, and a flange integrally formed substantially around an entirety of its end portion opposite to the end portion where said first opening is formed, the flange being for securing said housing between first and second portions of the telephone handset.

2. A directional microphone module according to claim 1, wherein the peripheral wall of said housing includes a thin-walled portion and a thick-walled portion with a step formed therebetween, and said microphone is supported at the second side on said step.

3. A directional microphone module according to claim 2, wherein said elastic material is rubber.

4. A telephone handset incorporating a directional microphone module, said directional microphone module including a directional microphone having first and second sides, an outer peripheral surface, and first and second sound collecting holes provided in proximity to the first side and the second side, respectively and a housing formed of an elastic material having a peripheral wall for receiving said directional microphone so that the outer peripheral surface of said directional microphone is tightly fit to an inner surface of said peripheral wall, said housing defining a space at a position opposing said second sound collecting hole, said housing having a first opening formed at a position opposing said first sound collecting hole, a second opening communicating with said space formed in the peripheral wall thereof, and a flange integrally formed at its end portion opposite to the end portion where said first opening is formed, said telephone handset comprising:

a front case having an inner wall surface, and a first rib integrally projected from the inner wall surface, said first rib and the inner wall surface defining a receiving portion for receiving said directional microphone module, said front case having a third and a fourth opening formed at positions respectively opposing said first and second openings when said directional microphone module is received in said receiving portion; and

a rear case having a second rib integrally formed therewith at a position opposing said first rib,

said directional microphone module adapted such that, when said front case and said rear case are joined, said flange is held between said first rib and said second rib of said front case and said rear case, respectively, thereby fixing said directional microphone module to said front case and said rear case.