DE971443C - Tweeter with solid dielectric - Google Patents

Description

ISSUED JANUARY 29, 1959

L 19743 VIIIaJ21 a *

The invention relates to a high-frequency capacitor loudspeaker with a solid dielectric which the foil rests loosely on a perforated sheet.

Broadcast receivers are often used to transmit the broadest possible audio frequency band special loudspeakers intended for the reproduction of high frequencies. Additional speakers make the device more expensive and there is therefore a desire to To create tweeters that are relatively easy to manufacture, without the simple arrangement however, the playback quality is lower.

The invention solves this problem in a particularly advantageous manner.

It is known to use condenser speakers as tweeters. Such Loudspeakers require relatively few parts per se, but they require special fittings, suspensions or tensions, which make the arrangement relatively cumbersome and require special skills and abilities to assemble.

For example, foils metallized on one side are used in known tweeter condenser loudspeakers which this layer forms one electrode with

80 »714/6

With the help of a special ring clamped and as Counter electrode uses a perforated plate over which the membrane is stretched.

In other known arrangements which use a perforated plate with foil, with the help Such a special ring clamped a gauze and the film with the help of this gauze pressed or stretched against the perforated sheet, whereby the tensile stress on the film in part

ίο is reduced.

It is now also known to place the film loosely on a perforated plate or, on the other hand, the membrane film to press against the perforated fixed electrode with the help of an elastic body,

that they are pressed on only by the elastic body, but not by the electrostatic forces will. Finally, it is also known not to tighten diaphragms. These well-known proposals however, it is in no way indicative of the nature of the

To remove bracket. The invention now eliminates the above-mentioned deficiencies and consists in that the film is held by an elastic body in such a way on the perforated plate that the elastic body only the necessary

Contact pressure is generated at the contact point, but the pressure on the film is practically due to the electrostatic Forces takes place. The pressure of the elastic body is only applied to the Contact, but it is practically not used for holding

tion of the membrane. The contact between the elastic base and the film is not enough in order to achieve the desired efficiency of the loudspeaker. So only causes the power on the DC voltage an application of the

Foil on the surface of the perforated sheet. On the other hand, if the pressure were to be effected through the base let it and make it so large that the film fits evenly, as is the case with part of the above known arrangements · the case

is, the efficiency of the loudspeaker would decrease considerably because of the movements the membrane now also larger parts of the base would have to be moved. According to the invention therefore the pressure is only applied on the

contact point of the supply line made strong. The elastic body can consist of a cushion, z. B. felt, corrugated paper, ribbed rubber or a material with rubber-like · Eigenr stocks, exist. It can be useful that

Train the counter electrode as a protective hood at the same time.

In the case of the arrangement according to the invention, there is thus no need for any use of a tensioning device the film to be inserted only loosely, and

it is applied pressure using the electrostatic forces that exist between the two Electrodes occur, causes. The elastic body only serves as a counter-surface to prevent that the membrane is caused by external forces,

which are directed away from the perforated plate, loosens. This body becomes without any lateral tension only placed on the metallized side of the membrane. As the amplitudes of the higher tones are only small, the unevenness of the perforated sheet is sufficient on one side, for the free vibrations of the membranes. On the other hand, the hairs allow the Pad or the elastic body the execution of vibrations in the other direction. '

The invention is explained in more detail with reference to the drawing, which shows an exemplary embodiment explained.

Fig. Ι is a cross-sectional view of an inventive Embodiment;

FIGS. 2 and 3 show further exemplary embodiments in the same view as FIG.

The housing 1 (Fig. 1) is approximately U-shaped and continues to form both the counter electrode and the perforated plate at the same time. After On the open side, the housing or perforated plate 1 is covered by an insulating plate 2. On the flat On the side of the perforated plate is the insulating film 3, which is on the side facing away from the perforated plate Side is metallized on one side. This metallized layer is denoted by 4. One feed line 6 leads, e.g. B. coming from a rivet, to the metallized layer 4. To prevent a Short circuit between the counter electrode and the metallized layer is an insulating strip 5 placed in the area of the supply line between counterelectrode and film 3. The overview parts 1 to 7 are drawn with a greater distance from each other. Actually lie But of course they are close to each other. With the help of the pad 7, the z. B. made of felt can, the lead 6 is pressed against the metal layer and the film is held in place. the between the perforated plate 1 and the metallized layer 4 occurring electrostatic forces suffice to press the insulating film 3 against the perforated plate and, on the other hand, to swing freely allow. As can be seen, the structure of the arrangement is extremely simple, since without any Bracing all parts only need to be placed one on top of the other.

In Fig. 2, the pad 7 consists of corrugated paper, while according to FIG. 3 it is made of rib rubber consists. Incidentally, in these figures are the parts which are already. described in Fig. 1 have been provided with the same reference numerals.

Claims (3)

PATENT CLAIMS: ι. High-frequency capacitor loudspeaker with a solid dielectric, in which the film is loosely attached rests on a perforated plate, characterized in that the film is replaced by an elastic Body is held on the perforated plate in such a way that the elastic body only generates the required contact pressure at the contact point, but the pressure of the Foil is practically done by the electrostatic forces. 2. Loudspeaker according to claim i, characterized characterized in that the elastic body consists of a pad. 3. Loudspeaker according to claim 1 or 2, characterized in that the elastic body Made of felt, corrugated paper, ribbed rubber or material with rubber-like properties consists. References considered: British Patent Nos. 318876, 326 131; French patent specification No. 879 857. 1 sheet of drawings © 609 710/234 11.56 (809 714/6 1.59)