JPS6221320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improved vibrating membrane disposed in a so-called ribbon type electroacoustic transducer (speaker, microphone, etc.).

First, before explaining the present invention, a brief description will be given of this type of electroacoustic transducer related to the applicant's earlier application (Japanese Patent Application No. 53-60842). FIG. 1 is a vertical cross-sectional view of the main part showing one example. 1 and 2 in the figure
are the first, symmetrically arranged polarities in the same direction,
A second magnet, 3 and 4 are first and second magnetic pole plates provided on the N-pole faces of both magnets, 5 is a yoke joined across the S-pole face, and 6 is integral with this yoke in a predetermined manner. shows a center pole with a height of
As is clear from the illustration, the first and second magnets 1,
2 maintains a certain distance on both sides of the center pole 6, and the first and second magnetic pole plates 3 and 4 on the N-pole side extend inward from each magnet and are spaced apart from each other by a certain distance. A magnetic field is formed between the first and second magnetic pole plates 3 and 4 and the center pole 6, respectively.

In this example, the inner surfaces of the overhanging parts of the first magnetic pole plate 3 and the second magnetic pole plate 4,
That is, the portions corresponding to the corner positions of the left and right magnets 1 and 2 are formed into symmetrical L-shaped notches 7,
A ribbon body 8 (this is a general term including a vibrating membrane in which a conductor is formed on a film, its fixing plate, etc., which will be described below) is disposed within these notches 7. As shown in FIG.
0 is formed, and an electrically insulating film 11 such as Mylar film or polyamide film is adhesively stretched over one surface of the fixing plate 9. Further, a metal layer such as aluminum is deposited on the upper surface of the film 11 by lamination or vapor deposition.
This is subjected to photoetching to form a conductor 12 (12a, 12b are forward and reverse paths for signal current) in an elliptical spiral pattern to form a vibrating membrane. 1
3a and 13b are terminals for connecting lead wires to both ends of the conductor.

As shown in FIG. 1 and described above, such a ribbon body 8 is disposed between the first and second magnetic pole plates 3, 4 and the center pole 6, and a length of the vibrating membrane is placed in each of the above-mentioned magnetic fields. Forward and reverse paths 12 of circular spiral conductor 12
When a and 12b are positioned respectively and an audio signal is applied to the conductor 12, the vibrating membrane is driven by a well-known principle and vibrates, converting the electrical signal into sound (air vibration). Further, by vibrating the diaphragm with sound, electrical signals are extracted from the terminals 13a and 13b of the conductor 12. Incidentally, it is better to understand that this example is a case of a speaker, and the details of such an electroacoustic transducer are described in the above-mentioned earlier application.

By the way, there is a big problem when manufacturing the ribbon body 8 in the illustrated apparatus. That is, when the film 11 is adhesively stretched on the fixing plate 9, its thickness is extremely thin, and its positioning and
Since fixation is difficult, the tension in each part of the film 11 may become uneven. In this case, the portion of the punched hole 10 that becomes the vibrating portion is likely to stretch, sag, wrinkle, etc., and this will adversely affect the acoustic characteristics.

The present invention has been made in view of the above matters,
By applying a metal layer to the ends of the diaphragm that is adhesively stretched to the fixed plate 9, the rigidity of the ends is increased.
The problem lies in the fact that the drawbacks of the conventional technology cannot be overcome.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 5.

In FIG. 3A, reference numeral 11 indicates a film made of the above-mentioned material, and reference numeral 14 indicates a metal layer deposited on its upper surface by lamination or vapor deposition. Under this state, photoetching is performed on the metal layer 14, and then The point that the diaphragm is adhesively stretched over the surface of the fixed plate 9 in Figure B is the same as before. Note that a punch hole 10 is formed in the fixed plate 9 in advance. However, in the case of this example, the initial contour dimensions of the fixed plate 9 and the diaphragm are larger than those of the final ribbon body 8 (FIG. 2).

FIG. 4 is a plan view when an etched vibrating membrane is stretched over the fixed plate 9. In this figure, the inner contour part except the shaded area is punched out,
Finally, it is used as a ribbon body 8. This fourth
It goes without saying that the important point in the figure is the etching pattern of the metal layer 14. That is, in the case of the present invention, an oblong spiral conductor 12 is formed on the metal layer 14 on the film 11 by etching, and at the same time, the left and right ends in the longitudinal direction and both sides in the width direction of the ribbon body 8 are etched. In addition, the film holding parts 14a, 14
b, 14c, and 14d are formed, respectively, to increase the rigidity of the end and side portions. Each holding part 14a
~14d are electrically insulated from each other by the slit 15, and the inner edge thereof is connected to the hole 10 of the fixing plate 9.
It is designed to surround the Therefore, when the diaphragm is adhesively stretched on the surface of the fixed plate 9 (this is not shown, but see FIG. 2), the highly rigid film holding part 1 is
Since the vibrating membrane is held with uniform tension at each part by 4a to 14d, the above-mentioned conventional problems are almost eliminated.

It goes without saying that the conductor 12 on the vibrating membrane surface and the terminals 13a and 13b formed at both ends of the conductor are formed as patterns insulated from the left and right holding parts 14a and 14b, respectively. FIG. 5 is an enlarged view of the holding portion 14a, and the reference numerals of each part are the same as in FIG. 4.

As explained above, in the present invention, a conductor layer that is electrically insulated from the conductor that is attached to the diaphragm for electroacoustic conversion is attached to the periphery of the diaphragm. Increases rigidity. Therefore, it becomes easy to adhesively stretch the vibrating membrane to the fixed plate.
Moreover, thereby, it is possible to provide an electroacoustic transducer with improved conversion characteristics and with no variation in quality.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part showing an example of an electroacoustic transducer to which the present invention can be applied, FIG. 2 is a perspective view showing a ribbon body thereof, and FIGS. 3 to 5 are for explaining the present invention. FIG. In the figure, 1 and 2 are first and second magnets, 3 and 4 are first and second magnetic pole plates, 5 is a yoke, 6 is a center pole, 8 is a ribbon body, 9 is a fixed plate, 1
0 is a punch hole, 11 is a film, 12 is a conductor, 13
a and 13b are terminals, 14 is a metal layer, 14a, 1
4b, 14c and 14d are film holding parts; 15
indicates a slit.

Claims (1)

[Claims] 1. A conductor through which an audio signal current flows is adhered to the surface of a vibrating membrane, and an electric conductor in which electroacoustic conversion is performed in response to magnetic flux interlinking with the conductor and the audio signal current. An electroacoustic transducer characterized in that, in the diaphragm of the acoustic transducer, a conductor layer electrically insulated from the conductor is attached to the periphery of the diaphragm to increase the rigidity of the periphery. vibrating membrane.