Hosiden Corporation

Hiroshi Yamagata

Kensuke Nakanishi

Kazuo Ono

Hiroyuki Harano

Ryuji Awamura

Toshiro Izuchi

Tsuyoshi Baba

Naosuke Fukada

Hideki Kozawa

Hironori Saeki

A unidirectional microphone includes: a case having a shape of a bottomed cylinder and including a sound hole in a bottom thereof; a ring-shaped diaphragm fixed to the bottom in the case; a vibrating membrane stretched on the diaphragm; a backplate which has a shape of a bottomed cylinder and is housed in the case in a nested manner such that an air gap to serve as a sound propagation path is formed between the backplate and an inner surface of the case, the backplate including an aperture serving as a sound propagation path in a side face thereof; a spacer positioned between the diaphragm and the backplate to fix the diaphragm and the backplate, and including a notch serving as a sound propagation path in a portion thereof; and a base plate covering a top opening of the case and including a hole serving as a sound propagation path.

Unidirectional microphone

A microphone capable of canceling vibration noise caused by mechanical vibration is provided with, in capsules, a pair of diaphragms and a pair of back plates opposite to the respective diaphragms. A printed circuit board is disposed at the middle of capsules. A pair of diaphragms is disposed close and opposite to the surfaces of the printed circuit board with the printed circuit board disposed therebetween. The difference in distance from a vibration source to the two diaphragms is made small. The microphone has a high canceling effect for canceling vibration noise caused by mechanical vibration.

Microphone

A unidirectional microphone includes a cylindrical capsule, a front plate blocking one end of the cylindrical capsule, a front plate sound hole formed in the front plate, a vibrating membrane and a first rear pole plate that are housed in the cylindrical capsule and form capacitance, a substrate blocking another open end of the capsule, and a rear plate sound hole formed in the substrate. The front plate sound hole and the rear plate sound hole are placed on mutually opposite sides of a central axis of the capsule so as to be offset relative to the central axis. The directional axis can be significantly offset relative to the central axis of the microphone using the microphone alone.

There is provided a condenser microphone that has improved portability and that can be realized at low costs. The condenser microphone includes, as all being accommodated within a cylindrical housing, a capacitor including a diaphragm electrode and a fixed electrode, a signal processing circuit board disposed at one opening of the cylindrical housing and having a converter circuit for converting a change in capacitance of the capacitor which has occurred in association with vibration of the diaphragm electrode into an electric signal and outputting this electric signal, a gate ring disposed between the capacitor and the signal processing circuit board for establishing electric conduction therebetween, a switch circuit board disposed at the other opening of the cylindrical housing and having a switch for controlling operation of the converter circuit, and a drain ring disposed between the switch circuit board and the signal processing circuit board for transmitting a switch signal according to an operation of the switch to the signal processing circuit board.

Condenser microphone

Affixed in intimate contact to the inside surface of a front boardof a conductive capsuleprovided with a receiving sound apertureis a conductive back electrode board provided with air vent apertureswhich are positioned not in alignment with the receiving sound aperture, these aperturesandbeing connected by a slitA polarized FEP filmwhich is an electret film is disposed on the surface of the back electrode boardopposite from the front board 10, and a conductive diaphragmis disposed on the surface of the FEPopposite from the back electrode boardwith a spacerinterposed therebetween which extends around the outer periphery of the opposite surface of the FEPThese component parts are accommodate in the capsuleto constitute an electret condenser microphone which is capable of suppressing sensitivity degradation due to ingress of grit from the outside to the electret film.

Growing community of inventors

Fukuoka, Japan

Hiroshi Yamagata