Electrical audio signal processing systems and devices – Hearing aids – electrical – Specified casing or housing
Reexamination Certificate
2002-06-28
2004-04-20
Le, Huyen (Department: 2643)
Electrical audio signal processing systems and devices
Hearing aids, electrical
Specified casing or housing
C381S313000
Reexamination Certificate
active
06724903
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a hearing aid to be worn behind the ear having a hearing aid housing, and a microphone that is arranged in the hearing aid housing and that has a microphone housing.
2. Description of the Prior Art
Particular attention is paid to miniaturization in the development of hearing aids. In particular, the microphones play an important part in modern hearing aids since a number of microphones often must be integrated in a hearing aid in the case of directional microphone arrangement. Moreover, the position of the microphones often is prescribed for acoustic reasons, so that the limits of miniaturization often are reached as a result of the arrangement of the microphones and the design of the hearing aides being prescribed.
Known microphones have a microphone body that is connected to a nozzle-shaped component for sound admission. This sound entry nozzle is introduced into a corresponding receptacle in the hearing aid housing. The sound entry nozzle—for acoustic and mechanical reasons—usually leads directly through the housing surface to the sound entry aperture in the hearing aid housing.
German Utility Model 296 21 611 discloses a microphone for an electrical hearing aid that is provided with a sound entry nozzle.
German Translation 689 14 083 discloses a hearing aid with whistling suppression. To this end, the hearing aid has a further microphone, in addition to a first microphone, that is sensitive only for near sound and is coupled to a second input of the amplifier. Both microphones are coupled to the allocated inputs of the amplifier that, given supply of the output signals of both microphones to the appertaining inputs of the amplifier, the amplifier delivers nearly no output signal insofar as the output signals of the two microphones are caused by near sound.
German PS 198 52 758 discloses a hearing aid device to be worn behind the ear that has a microphone system connected to an amplifier circuit. The pick-up characteristic of the microphone system can be modified by means of a carrier for the microphone system that is pivotable relative to the vertical and/or rotatable relative to the horizontal and is arranged in or at the hearing device, this carrier having at least one microphone and two sound entry apertures.
Further, WO 00/49836 discloses a microphone for arrangement in a hearing aid, the microphone having three sound entry apertures that are all arranged in a common plane.
SUMMARY OF THE INVENTION
An object of the present invention is to improve the arrangement of a microphone with a microphone housing in a hearing aid to be worn behind the ear.
In a hearing aid to be worn behind the ear that has a hearing aid housing and a microphone arranged in the hearing aid housing, the microphone having a microphone housing, this object is achieved by the hearing aid housing having a respective sound entry apertures in opposite sides with respective sound entry nozzles, each with a sound entry aperture, arranged at two opposite sides of the microphone housing. The sound entry nozzles project into the sound entry apertures of the hearing aid housing, and, when the hearing aid is worn, the sound entry aperture of one sound entry nozzle is arranged approximately distally from the head of the hearing aid wearer and the sound entry aperture of the other sound entry nozzle is approximately arranged proximally relative to the head of the hearing aid wearer.
In a simple way, the hearing aid fashioned according to the invention enables the arrangement of lateral sound entry apertures in the hearing aid housing. Due to the small structure of the microphone as well as the elimination of additional sound conducting channels between the microphone and the sound entry aperture in the hearing aid housing, the accommodation of the microphone is possible in the middle as well as at an end within the hearing aid housing. In contrast to microphones previously employed, which have a one-sided admission of the acoustic signals into the frontal volume of the microphone lying directly at the microphone membrane, the inventive arrangement has a microphone with two sound entry nozzles. These are arranged at two opposite microphone sides and likewise provide the incoming acoustic signals with access to the frontal microphone volume.
Microphones with sound entry nozzles lying opposite one another can be integrated in a simple way in the hearing aid housing and allow double-sided sound entry with minimal space requirements. The total cross-section of the sound entry area required for physical reasons thus is distributed between the two sound entry nozzles (i.e., they each provide a portion of that area), as a result of which these nozzles can be made comparatively small. The acoustic channels between the lateral sound entry apertures in the hearing aid housing and the microphone membrane are extremely short and are implemented in a simple way in the microphone of the invention, having an advantageous influence on the acoustic properties. Further, the sound entry nozzles in the microphone of the invention can simultaneously serve as structure for fastening the microphone in the hearing aid. Further fastening structure can be eliminated as a result. In the microphone of the invention, thus, acoustic as well as design rules are taken into consideration.
In a preferred embodiment of the invention, the sound entry nozzles of the microphone as well as the sound entry apertures are arranged in opposite sides of the hearing aid housing on a shared symmetry axis. As a result of the symmetrical structure of the microphone housing achieved in this way, the installation as well as the alignment in the hearing aid housing are simplified. Further, moisture or dirt entering through one sound entry aperture can emerge or, if necessary, be blown out through the opposite sound entry aperture.
As a result of the arrangement of a number of microphones in the hearing aid as well as a suitable electrical interconnection, a directional microphone system can be realized. All microphones in this system preferably are designed according to the invention. The simple, space-saving accommodation of a microphone of the invention in the housing of the hearing aid facilitates the accommodation of a number of such microphones within one microphone housing.
Another possibility for realizing a directional microphone is to modify an individual microphone of the invention so that it exhibits a directional effect. To this end, the microphone has several pairs of sound entry nozzles, with the sound entry nozzles in each pair arranged at two opposite sides of the microphone housing and discharging into a chamber at one side of a microphone membrane. The sound entry nozzles of each pair are introduced into respective sound entry apertures at opposite sides of the hearing aid housing. The sound entry aperture of one sound entry nozzle of a pair is arranged distally from the head and the sound entry aperture of the other sound entry nozzle of a pair is arranged approximately proximally relative to the head when the hearing aid is worn. In this way, a differential microphone that exhibits a directional characteristic can be formed with one microphone of the invention having at least two pairs of sound entry nozzles.
REFERENCES:
patent: 5003606 (1991-03-01), Bordewijk
patent: 296 21 611 (1997-04-01), None
patent: 198 52 758 (2001-05-01), None
patent: WO 00/49836 (2000-08-01), None
Le Huyen
Schiff & Hardin LLP
Siemens Audiologische Technik GmbH
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