GB2068681A - Improvements in or relating to earphones - Google Patents

Abstract

An earphone comprises a sound-transmitting protective cap (2) covering the diaphragm of the electro-acoustic transducer of the earphone. A support member (4) provided with a soft sound-transmitting covering (6) projects from part of the protective cap or a corresponding part of the casing or transducer of the earphone, which support member (4) in use of the earphone engages in the external ear of the user to support the earphone in a position adjacent the ear. The support member (4) is so constituted that sound is omnidirectionally transmitted thereby but not substantially reflected therefrom. <IMAGE>

Description

SPECIFICATION Improvements in or relating to earphones THIS INVENTION relates to an earphone having a support member for holding the earphone to the ear, the support member being constituted as a projection on a protective cap which covers the diaphragm of an electroacoustic transducer of the earphone or on a corresponding part of the casing or transducer of the earphone, the support member having a soft (compressible) sound-transmitting covering.

Earphones having support members of the above-mentioned kind are known and have been suggested, for example, in Austrian Patent Specification No. 325693 and in German Offenlegungsschrift No.2353708. In both these examples the support member is a rigid body of revolution which projects like a pin or peg and which is pierced along its longitudinal axis, or is in the form a tube, so as to be able to transmit sound. Austrian Patent Specification No.325693 further discloses the suggestion of forming the support member as a solid member and of transmitting the sound pastthe exterior of the support member.

The disadvantage of the known support members in the form of tubular sound guides is that they cause resonances which impair the quality of reproduction of the associated electroacoustic transducer.

Also, sound reflections from the known support members occur very near the external auditory meatus and disturb directional and distance listening in stereophonic reproductions by impairing the acoustic properties of the cavum conchae and the external ear.

It is an object of the present invention to provide an earphone having a support member which is free from the disadvantages of the known constructions.

Accordingly, the present invention provides an earphone having a support member for engaging in the external ear of a user to support the earphone in a position adjacent the ear, the support member being in the form of a projection on a protective cap which covers the diaphragm of an electroacoustic transducer of the earphone or on a corresponding part of the casing or transducer of the earphone, in which earphone the support member is so constituted that sound is omnidirectionally transmitted thereby and not significantly reflected thereby.

A support member in accordance with the invention has no acoustic effect, causing neither appreciable damping nor sound reflection. Consequently, there is no impairing of the resonance characteristics of the cavum conchae or the reflection properties of the external ear, and therefore of the ear resonances important for spatial listening. The support member, particularly if used in association with porous (open-celled) pads of foam material, is likely to be advantageous in creating a sound impression corresponding to that obtained naturally, i.e. heard without earphones; since porous foam material or the like does not cause acoustic disturbances of the sound field either in the cavum conchae or in the external ear.Consequently, the support member of an earphone embodying the invention makes it possible, in association with the known use of foam material or the like between the ear and the support member, to use at least the inner zone of the external ear to form ear resonances, so that the signals radiated by the transducer diaphragm and incident on the tympanic membrane experience substantially the same natural linear distortions as occur when sounds are heard naturally.

The invention provides substantial improvements even with the smaller type of diaphragm, that is, diaphragms smaller than the external ear, since the sound waves are first reflected in the outer regions of the external ear and can then return to the central region thereof, which is of advantage in creating the impression of spatial listening.

So that the support member may engage softly in the cavum conchae before the auditory meatus, a thin layer of a foam material or a textiel fabric is used.

The support member of an earphone embodying the invention may take various forms. In the cheapest and simplest construction, the support member takes the form of a tube of plastics material, the surface of which is formed with a plurality of perforations, such that adjacent perforations are separated by a web of plastics material that is narrow relative to the dimensions of the perforations.

To prevent a build-up of heat in the ear when an earphone embodying the invention is used, it is advantageous for the support memberto be made of a material which is a good heat conductor. There can be considered more particularly for this purpose metals, e.g. a wire mesh shaped to form the support memberwhich can, if required, be unitary with the protective cap covering the transducer diaphragm.

This construction not only allows very good heat removal but is also fairly cheap to produce.

Alternatively, the support member may be formed from a bunch of U-shaped metal wires, the ends of which are anchored to the protective cap, casing part ortransducerpart.

The support member can also take the form of a substantially semi-cylindrical tubular member of perforate metal sheet which, like the bunch of wires or metal mesh, helps to remove the heat building up in the foam material or the like within the external ear, thus making wearing of the earphone more pleasant.

The support member of an earphone embodying the invention can be produced at a much reduced cost if made of a hard foam material and integral with the protective cap which engages by friction on the side of the transducer adjacent to the ear in use.

The support member can therefore be exchanged whenever required, which is, for hygienic reasons, a useful feature when the earphone is to be used by more than one person.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a diagrammatic sectional view of an earphone embodying the invention, the elec troacoustictransducer not being shown; FIGURE 2 is a diagrammatic cross-sectional view of another embodiment of an earphone in accor dance with the invention, without its transducer; FIGURE 3 shows in cross-section the protective cap and support member of an earphone embodying the invention, wherein the support member is formed from a wire mesh; FIGURE 4 is an axonometric view of the protective cap and support member of an earphone embodying the invention, wherein the support member is formed from a bunch of U-shaped wires;; FIGURE 5 is a similarviewto Figure4showing a support member formed by a substantially semicylindrical perforated tube; FIGURE 6 shows in cross-section a protective cap and support member made of a hard foam material; and FIGURE 7 illustrates the engagement in the cavum conchae of the support of an earphone embodying the invention.

Referring now to Figure 1 there can be seen a boxlike earphone 1. The side of the earphone which in use is adjacent to the ear, i.e., the side associated with the diaphragm of the electroacoustic transducer, (not shown) receives a protective cap 2 formed with orifices or apertures 3 large enough to offer substantially no resistance to the transmission of sound. The cap 2 can be made of metal or of some other solid substance such as a plastics material. A support member 4 projects preferably centrally, from the cap 2. If the construction is made of plastics material the support member4 can be formed unitary with the protective cap 2.The support member 4, which in use of the earphone is just engaged in the cavum conchae of the external ear before the external auditory meatus, substantially resembles a tube lar member, the surface ofwhich is formed with substantial perforations 5, such that adjacent perforations are separated by a web of plastics material which is narrow relative to the dimensions of the perforations. Clearly, a structure of this kind has zero acoustic effect and can be regarded just as a support or carrier for a foam-material cap or covering 6 which also has zero acoustic effect.

The plastics support member4 shown in Figure 2 also has zero acoustic effect. In this case the perforations 5 take the form of longitudinally extending slots separated from one another by narrow webs parallel to the axis of the support member. The covering 6 (shown in broken lines) on the support member, is preferably made of porous foam material. The covering 6 can also coverthe protective cap 2 and, if required, to some extent the side parts of the earphone 1.

The insert of foam material between the external ear and the earphone may cause excessive heat to evolve during use within the external ear to an extent which the user may find unpleasant. To obviate or at least to reduce any such build-up of heat, the sup port member may be made of metal and a variety of constructions are possible. For instance, Figure 3 shows a support member4formed as unitary member of wire mesh with the cap 2, which must be able to transmit sound. Figure 4 shows in axonometric view a support member comprising a bunch of substantially U-shaped wires, the free ends ofwhich are anchored in the protective cap 2. If the cap 2 is made of plastics material, the wire ends can be moulded into the cap 2 during the manufacture thereof so as to be unitary with the cap 2.In the case of a metal cap 2 the wire ends can be secured by being pressed into welded, or possibly soldered to the cap. Figure 5 shows a metal support member prepared from a metal sheet having numerous perforations and bent to form a substantially semicylindrical member. To improve retention of the earphone in the ear, the semi-cylindrical member 4 can be subdivided into two portions, one portion 4a having a smaller radius of curvature than the other portion 40. When the conventional cap 6 offoam material is pushed over the support member, the resulting product resembles a button which readily engages in the external earwhen the earphone is used.

Rigid foam materials are known which have good dimensional stability and through which numerous continuous- passages of relatively large cross-section extend. Consequently, such materials can be regarded as having zero acoustic effect in a sound field. A foam material ofthis kind can therefore be used to form the support member of an earphone embodying the invention shown in Figure 6. Conveniently, the support member 4 is unitary with the protective cap 2, in which case a single working step suffices to produce both the support member 4 and the protective caps 2. This has the advantage of being the cheapest form of support member, but has the disadvantage of unsatisfactory heat removal. One possible way of improving heat removal is by metallization of the surface of the support member.

Figure 7 shows how the omnidirectionally soundtransmitting support member 4 of an earphone embodying the invention engages in the cavum conchae 8 of a human ear 7. For the sake of clarity in the illustration the electro-acoustic transducer associated with the support member 4 is not shown.

Earphones embodying the invention can be used with advantage for lightweight twin headphones in which the headband passes below the chin or in the neck region of the user. Known headphones in which this form of support can be used require a relatively substantial pressure to be supplied by the band between the earphones to ensure that the headphones do not drop off the ear under the force of gravity and to ensurethatthe band does not take up an undesirable position. In the case of headphones employing earphones embodying the invention having the conventional pad of foam material, a relatively slight pressure applied by the band is sufficient to produce such a reliable engagement between the external ear and the earphones that, in contrast to the known constructions, using the earphones with a stethoscope band or neck band inconveniences the user very little.

Claims (10)

1. An earphone having a support memberfor engaging in the external ear of a userto supportthe earphone in a position adjacent the ear, the support member being in the form of a projection on a protective cap which covers the diaphragm of an electroacoustic transducer of the earphone or on a cor responding part of the casing or transducer of the earphone, in which earphone the support member is so constituted that sound is omnidirectionally transmitted thereby and not significantly reflected thereby.

2. An earphone according to claim 1, wherein the support member is formed from a tube, the surface of which is formed with a plurality of perforations such that adjacent perforations are separated by a web of material which is narrow relative to the dimensions of the perforations.

3. An earphone according to claim 2, wherein the support member is formed from a tube made of plastics material.

4. An earphone according to claim 1, wherein the support member is made of a material which is a good heat conductor, such as a metal.

5. An earphone according to claim 1 or 4, wherein the support member is made from wire mesh.

6. An earphone according to claim 1 or 4, wherein the support member comprises a bunch of U-shaped members, the ends of which are anchored to the protective cap, casing or transducer.

7. An earphone according to claims 1 or 4, wherein the support mbmer is formed from perforate metal sheet bent into a substantially semicylindrical shape.

8. An earphone according to any preceding claim, wherein the support member is a unitary part of the protective cap.

9. An earphone substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

10. Any novel feature or combination of features herein disclosed.