DE3007773A1 - Speech capsule for telephone handset - includes perforated discs with embossed circular slots of specified size to reduce oscillation - Google Patents

Abstract

The electroacoustic transducer used as the speech capsule for a telephone handset includes a damping system to prevent mechanical overloading. The capsule has a transducer plate with a piezoceramic coating, mounted between plates with holes through them. The cover plate also has speech openings. The perforated plates are of thin material and the openings which reduce the excess oscillation are formed by six narrow circular slots (22). Further holes (23) are included in the sloping surface of the dished part, which terminates in an external flange. The surface area of the openings is between 3 and 5 sq.cm. e.g. 3.6 sq.cm. and they are formed by embossing. These slots are in the central region, and their width is between 50 and 100 microns, typically 80 microns.

Description

Electroacoustic converter

The invention relates to an electroacoustic transducer with a transducer plate arranged in a housing, through which the volume in the housing is divided into an anteroom and a pressure room, furthermore with one, the anteroom sealing, provided with sound passage openings, with between Socket and transducer plate a partition plate having sound passage openings is arranged and one having sound passage openings closing the socket Objection.

For the frequency profile of the transmission transmission rate of speech capsules an admissibility area is prescribed in the field of telephony technology, within which the relevant data may move.

It should be noted that the frequency profile of the transmission transmission rate is not determined by the transmission behavior of the converter alone, but also by installing the transducer in a handset body, for example. There the design of the vestibule in front of the capsule in the handset and the voice of the Handset are usually largely fixed, corrections must be made to the frequency response on the capsule itself.

For the purpose of increasing the sensitivity, one now has the resonance frequencies placed in such a way that the resonance exaggeration formed by the fundamental oscillation is approximately in the middle of the transmission range common in telephony technology. These Excessive elevation is attenuated in the usual way with absorption resonators. Next to This increase in resonance of the fundamental oscillation creates further resonances that must be attenuated by additional measures. Here in particular is the one by one Partial oscillation marked in the node circle as well as the antechamber resonance. Both of these produce undesirable excesses in sensitivity, which can be reduced are.

It has been suggested to replace these cusps with one in the Dismantle the anteroom inserted damping disk made of foam or the like. Large variations in the damping properties of the materials and the risk However, the deflection due to mechanical stress on the adjacent parts make extremely careful manufacturing and testing are required.

It is the object of the present invention to provide additional components such as Damping washers to dampen the above-mentioned excessive sensitivity avoid.

The object is achieved according to the invention in that to reduce the increased sensitivity in the vestibule (vestibule resonance) the sound passage openings the socket are enlarged, the wall thickness of the socket being small and that the sensitivity exaggeration caused by the converter plate the harmonic, in particular that indicated by a circle of nodes fourth partial oscillation can be reduced by narrow slots in the partition plate.

Such measures ensure that the reproducibility this converter is given in a simple way at any time.

Advantageous designs are described in the subclaims as well as in the following description explained in more detail.

The invention is explained in more detail below with reference to three figures.

1 shows an electroacoustic transducer in a simplified section Representation, FIG. 2 a partition plate in plan view and FIG. 3 a part of a socket on average.

In a housing 1, a carrier 2 is initially arranged, the absorption resonators 3, 4 has.

Furthermore, there is a converter plate clamped in bearing bodies 5, 6 7 arranged, which is provided with a piezoceramic layer, not shown. A partition plate 8 is provided in front of the transducer plate and has a plurality of sound passage openings 9 has. This is followed by the one provided with several sound passage openings 10 Version 11. The housing 1 is through the sound passage openings 12 having Objection 13 closed.

In Fig. 2, the partition plate 8 is shown in more detail.

This has sound passage openings 14 arranged in a circle to 19, the sound passage openings each through annular slots 20, 21 are formed.

The essential parts of the socket are shown in FIG. Here Particularly noteworthy is the embossing 22 in the middle area of the frame, which has a large opening area. Several holes (hole 23 shown) the lateral slope of the Sockets are used for additional enlargement the opening area. The wall thickness 24 is chosen so that it is just big enough that the stability of the socket is not impaired.

5 claims 3 figures

Claims (5)

Claims Electroacoustic transducer with one in a housing arranged converter plate, through which the volume in the housing in an anteroom and a back room is divided, furthermore with one, which closes the anteroom, socket provided with sound passage openings, with between socket and transducer plate a partition plate having sound passage openings is arranged and one the opening having sound passage openings, d a -d It is not stated that it is used to reduce the increase in sensitivity In the vestibule (vestibule resonance) the sound passage openings of the socket are enlarged are formed, the wall thickness of the socket is small and that by the Transducer plate caused excessive sensitivity of the harmonics, in particular the fourth partial oscillation marked by a nodal circle narrow slots in the partition plate can be reduced. 2. Converter according to claim 1, d a d u r c h g e -k e n n z e i c h n e t that the area of the sound passage openings of the socket is about 3 to 5 cm2, in particular 3.6 cm2. 3. Converter according to claim 1 and 2, d a d u r c h g e -k e n n z e i c h n e t that the required area by embossing in the central area of the Version is formed. 4. Converter according to claim 1, d a d u r c h g e -k e n n z e i c h n e t that the slots have a width of approximately 50 to 100 pin, in particular 80 μm. 5. Converter according to claim 4, d a d u r c h g e - k It is noted that the slots are annular and in 6 areas are distributed over the surface of the partition plate.