# US 9,521,492 B2 · Condenser microphone

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,521,492 B2
- Document ID: US9521492B2
- Status: Granted
- Kind: B2
- Application number: 14/699,545
- Filed: 2015-04-29
- Published: 2015-11-12
- Granted: 2016-12-13
- Earliest claimed: 2014-05-12
- Assignees: Kabushiki Kaisha Audio-Technica
- Applicants: Kabushiki Kaisha Audio-Technica
- Inventors: Shioto Okita
- Web page: https://patentgrep.com/patent/US9521492B2

## CPC

- H04R 19/016: {for microphones}
- H03F 3/185: with field-effect devices (H03F3/187 takes precedence)
- H03F 3/505: {with field-effect devices}
- H04R 1/08: Mouthpieces; {Microphones;} Attachments therefor
- H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F)
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)
- H03F: AMPLIFIERS

## Abstract

Provided is a condenser microphone having a plurality of condenser microphone units connected in series to improve output sensitivity, and a simplified circuit configuration. At least one of the preceding condenser microphone units, excepting a last condenser microphone unit, and an adjacent succeeding condenser microphone unit are directly connected to transmit an audio signal obtained from the at least one of the preceding condenser microphone units to the adjacent succeeding condenser microphone unit. An impedance converter using an active element is connected to the last condenser microphone unit, and the audio signals obtained from the condenser microphone units are added and output from the impedance converter using the active element.

## Claims

### Claim 1

A condenser microphone comprising:
a plurality of condenser microphone units each including a fixed electrode and a diaphragm disposed to oppose the fixed electrode; and
an impedance converter, wherein
the condenser microphone units are connected in series to be added in phase and output audio signals obtained from the condenser microphone units,
at least one of the preceding condenser microphone units, excepting a last condenser microphone unit, and an adjacent succeeding condenser microphone unit are directly connected to each other to transmit an audio signal obtained from the at least one of the preceding condenser microphone units to the adjacent succeeding condenser microphone unit,
the impedance converter using an active element is connected to the last condenser microphone unit, and
the audio signals obtained from the condenser microphone units are added and output from the impedance converter using the active element.

### Claim 2 (depends on 1)

The condenser microphone according to claim 1, wherein each of the condenser microphone units is an electret condenser microphone unit including a dielectric electret film on any one of the fixed electrode or the diaphragm.

### Claim 3 (depends on 1)

The condenser microphone according to claim 1, wherein a diaphragm of a first condenser microphone unit in the plurality of condenser microphone units is grounded and a fixed electrode opposed to the diaphragm of the first condenser microphone unit is directly connected to a diaphragm of a second condenser microphone unit in the plurality of condenser microphone units, and when the second condenser microphone unit is the last condenser microphone unit, the impedance converter is connected to a fixed electrode of the last condenser microphone unit.

### Claim 4 (depends on 1)

The condenser microphone according to claim 1, wherein the diaphragms of the plurality of condenser microphone units are disposed on the same plane.