Condenser microphone, microphone unit, and blood pressure gauge
First Claim
1. :
- A condenser microphone in which a diaphragm and a backplate are disposed as two opposing electrodes inside a housing having an opening for admitting sound waves in a front surface, whereinan aeration hole is formed in a wall portion that blocks off a back surface of said housing; and
a sound-absorbing filter having sound absorption characteristics with respect to a frequency band targeted for detection is disposed so as to cover said opening or aeration hole in one of the front surface or back surface of said housing.
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Accused Products
Abstract
The present invention provides a condenser microphone capable of detecting small sounds (e.g., Korotkoff sounds) with high sensitivity even in environments with variations in pressure, such as cuff pressure. A condenser microphone (10) is disposed as an acoustic sensor for detecting Korotkoff sounds in a communication space reachable by the internal pressure of the cuff of a blood pressure gauge. In the condenser microphone, a diaphragm (13) and a backplate 14) are disposed in the interior of a housing (11), an aeration hole (30) is formed in a wall (11B) that blocks off the housing back surface, and a sound-absorbing element (20) having sound absorption characteristics with respect to a frequency band targeted for detection is disposed on the front surface of a housing (11).
13 Citations
13 Claims
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1. :
- A condenser microphone in which a diaphragm and a backplate are disposed as two opposing electrodes inside a housing having an opening for admitting sound waves in a front surface, wherein
an aeration hole is formed in a wall portion that blocks off a back surface of said housing; and a sound-absorbing filter having sound absorption characteristics with respect to a frequency band targeted for detection is disposed so as to cover said opening or aeration hole in one of the front surface or back surface of said housing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13)
- A condenser microphone in which a diaphragm and a backplate are disposed as two opposing electrodes inside a housing having an opening for admitting sound waves in a front surface, wherein
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8. :
- A blood pressure gauge comprising;
a cuff that is wound around a blood pressure measure area; a pressurizing device for depressurizing said cuff; a conduit for communicating with said cuff; and an acoustic sensor for detecting the Korotkoff sounds transmitted through the air in said conduit, wherein the microphone unit according to 4 is used as said acoustic sensor; and the connection opening of said microphone unit is connected to an end portion of said conduit.
- A blood pressure gauge comprising;
Specification