GB1559519A

GB1559519A - Electrostatic loud-speakers

Info

Publication number: GB1559519A
Application number: GB4448076A
Authority: GB
Original assignee: Peters B G
Current assignee: Peters B G
Priority date: 1975-10-27
Filing date: 1976-10-26
Publication date: 1980-01-23
Also published as: FR2388449B1; DE2600742B2; FR2388449A1; NL7512512A; DE2600742C3; DE2600742A1

Description

(54) IMPROVEMENTS IN OR RELATING TO ELECTROSTATIC LOUDSPEAKERS (71) I, BERNARDUS GRADUS PETERS, of Apeldoorn, Netherlands, a citizen of the Netherlands, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement :- This invention relates to a method of manufacturing an electrostatic loudspeaker, and to a loudspeaker manufactured by such method.

According to this invention there is provided a method of manufacturing an electrostatic loudspeaker comprising a rigid frame supporting a planar diaphragm and two rigid apertured wall plates positioned one on each side of the diaphragm and spaced therefrom, there being an electrode mounted on the diaphragm and a further electrode mounted on one of the wall plates, the diaphragm being spaced from at least one wall plate by a plurality of resilient spacer bodies each engaged between the diaphragm and the wall plate, in which method the spacer bodies are each formed by injecting a flowable electrically insulting material into the space between the diaphragm and the wall plate at the required position, and then hardening the flowable material to form a resilient spacer body.

This invention will now be described by way of example with reference to the drawing, in which : Figure 1 is a plan view of an electrostatic loudspeaker manufactured by the method of this inventnon, with part broken away, Figure 2 is a section on the line II-II in Figure 1, and Figure 3 shows the part within the circle TII in Figure 2, to a larger scale.

The electrostatic loudspeaker 1 shown in the drawing is of known type, and comprises a diaphragm 2 supported by a rigid frame 3 which also supports two rigid apertured wall plates 4 having apertures 5 therein, the wall plates 4 being positioned one on each side of the diaphragm 2 and spaced therefrom as clearly shown in Figure 3. An electrode 6 having apertures aligned with the apertures 5 is mounted on each wall plate 4, the electrodes 6 having contact portions extending to the outer edge of the wall plates 4 for the connection of wires thereto as shown in Figure 1.

The diaphragm 2 also has contact portions which extend beyond the outer edge of the frame 3 for the connection of wires thereto, as also shown in Figure I.

Each wall plate 4 is also formed with three further apertures 7 which are smaller than the apertures 5, and the electrodes 6 are cut away around each of these apertures 7 as shown in Figure 1.

After the loudspeaker as thus far described has been assembled a flowable electrically insulating material is injected through each aperture 7 into the spaces between the diaphragm 2 and the wall plates 4 to form bodies 8, the flowable material subsequently being hardened to form resilient spacer bodies 8 serving to space the diaphragm 2 from the wall plates 4. Preferably the flowable material used is one which will adhere to the diaphragm 2 when in the hardened state.

The above described method of forming the spacer bodies 8 has the advantage that the bodies 8 are more easily located at the required positions than would be the case if pre-formed bodies where inserted during assembly of the loudspeaker. Further, the bodies 8 will be such that they will introduce no undesirable permanent stressing of the diaphragm 2, which could occur if preformed spacer bodies were used unless the pre-formed spacer bodies were made very accurately to the required size and manufacturing tolerances were very closely con trolled.

Claims

WHAT I CLAIM IS : 1. A method of manufacturing an electrostatic loudspeaker comprising a rigid frame supporting a planar diaphragm and two rigid apertured wall plates positioned one on each side of the diaphragm and spaced therefrom, there being an electrode mounted on the diaphragm and a further electrode mounted on one of the wall plates, the diaphragm being spaced from at least one wall plate by a plurality of resilient spacer bodies each engaged between the diaphragm and the wall plate, in which method the spacer bodies are each formed by injecting a flowable electrically insulating material into the space between the diaphragm and the wall plate at the required position, and then hardening the flowable material to form a resilient spacer body.
2. A method as claimed in Claim 1, in which the flowable material used is one which will adhere to the diaphragm when in the hardened state.
3. A method as claimed in Claim 1 or Claim 2, in which spacer bodies are formed between the diaphragm and each wall plate.
4. A method as claimed in any preceding claim, in which the flowable material is injected through holes in the wall plate or plates.
5. A method of manufacturing an electrostatic loudspeaker, substantially as hereinbefore described with reference to the drawing.
6. An electrostatic loudspeaker manufactured by a method as claimed in any preceding claim.