Sound generator, a shielding and a spout

Abstract

A sound generator including a housing having a first wall portion with a housing opening, a shielding element covering at least a portion of the first wall portion and having a shield opening, where the shielding element covers a portion of the first wall portion.

Claims

1. A sound generator comprising: a housing having a first, plane, wall portion with a housing opening, a shielding element, for shielding against electrical and/or magnetic fields, covering at least a portion of the first wall portion and having a shield opening, the shielding element being positioned adjacent to the first wall portion, where: a sound outlet formed by an overlap, when projected on to a plane of the first wall portion, of an outline of the housing opening and an outline of the shield opening, the shield opening has, when projected on to the plane, an area being no more than 150% of an area of the sound outlet.

2. A sound generator according to claim 1, further comprising a spout having a first opening and a second opening, the first opening being positioned so as to receive sound from the sound outlet, wherein the shield opening has a cross sectional area, when projected on to the plane, of no more than 50% of a cross sectional area of the second opening projected onto the plane.

3. A sound generator according to claim 2, wherein the spout portion is tube-shaped.

4. A sound generator according to claim 2, wherein the spout portion has a length of at least 0.5 mm.

5. A sound generator according to claim 2, wherein the shielding element comprises an end element comprising the shield opening and positioned between the first wall portion and the spout.

6. A sound generator according to claim 2, wherein the spout is made of a shielding material.

7. A sound generator according to claim 6, wherein the spout comprises a waist part between the first wall portion and the spout portion, the waist having an opening forming the shield opening.

8. A sound generator according to claim 2, wherein the shielding element comprises the spout.

9. A spout unit for use in the sound generator according to claim 2, the spout unit comprising: a spout channel extending along a longitudinal axis and having a first opening and a second opening and a shielding element positioned at the first opening, shielding element having a shield opening having a cross sectional area, when projected on to a plane perpendicular to the longitudinal direction, of no more than 50% of a cross sectional area of the second opening when projected onto the plane.

10. A spout unit for use in the sound generator according to claim 2, the spout unit comprising: a spout extending along a longitudinal axis and having a first portion and a spout portion, the spout portion being configured to be attached to a sound guide and having an inner contour, and a shielding element comprising a shield opening opening into the spout, the shield opening having a cross sectional area, when projected on to a plane perpendicular to the longitudinal axis, being no more than 50% of a cross sectional area of the inner contour projected onto the plane.

11. A sound generator according to claim 1, wherein the shield opening is slit-shaped.

12. A sound generator according to claim 1, wherein the shielding element comprises an end element comprising the shield opening and positioned inside the housing.

13. A sound generator according to claim 1, wherein the housing opening is oblong.

14. A shielding element for use in the sound generator according to claim 1, the shielding element being configured to be positioned adjacently to the first wall portion.

15. A shielding element according to claim 14, wherein the shielding element is configured to be positioned inside the housing.

16. A sound generator comprising: a housing having a first wall portion with a housing opening, a spout having a first opening and a second opening, the first opening being positioned so as to receive sound from the sound outlet, wherein the shield opening has a cross sectional area, when projected on to a plane of the first wall portion, of no more than 50% of a cross sectional area of the second opening projected onto the plane and a shielding element covering at least a portion of the first wall portion and having a shield opening, the shielding element being positioned adjacent to the first wall portion, where: a sound outlet formed by an overlap, when projected on to the plane, of an outline of the housing opening and an outline of the shield opening, the shield opening has, when projected on to the plane, an area being no more than 150% of an area of the sound outlet and the shielding element comprises an end element comprising the shield opening and positioned between the first wall portion and the spout.

17. A sound generator comprising: a housing having a first wall portion with a housing opening, a spout having a first opening and a second opening, the first opening being positioned so as to receive sound from the sound outlet, wherein the shield opening has a cross sectional area, when projected on to a plane of the first wall portion, of no more than 50% of a cross sectional area of the second opening projected onto the plane and a shielding element covering at least a portion of the first wall portion and having a shield opening, the shielding element being positioned adjacent to the first wall portion, where: a sound outlet formed by an overlap, when projected on to the plane, of an outline of the housing opening and an outline of the shield opening, the shield opening has, when projected on to the plane, an area being no more than 150% of an area of the sound outlet and the spout is made of a shielding material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, preferred embodiments will be described with reference to the drawing, wherein:

(2) FIG. 1 illustrates a first embodiment of a sound generator according to the invention,

(3) FIG. 2 illustrates second embodiment of a sound generator according to the invention,

(4) FIG. 3 illustrates a third embodiment of a sound generator according to the invention,

(5) FIG. 4 illustrates a fourth embodiment of a sound generator according to the invention,

(6) FIG. 5 illustrates a standard receiver with a shielded spout, and

(7) FIG. 6 illustrates a fifth embodiment of a sound generator according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) In FIG. 1, a sound generator 10 is illustrated comprising an outer shielding housing 20 and a sound generator 30 provided therein. Naturally, the housing 32 of the generator 30 could be made of the shielding material, but that is often not desired.

(9) The sound generator housing 32 has a housing opening 34, in a first wall portion 21, and a sound generating motor (not illustrated) usually comprising a magnet system, a coil and a membrane moved by the magnet/coil, such as via an armature, when the coil is supplied with a current. Sound generated in the housing 32 is output via the opening 34. In order to supply the motor, terminals 36 are provided on the outer side of the housing 32, and an opening 38 is provided for wires connecting the terminals 36 to the motor.

(10) The shielding housing 20 has a shield opening 22 through which sound exiting the housing opening 34 may exit the generator 10. The openings 22 and 34 together form a sound output.

(11) The shielding housing 20 also comprises an opening 24 for allowing power/signal supply to the terminals 36 of the sound generator.

(12) Optimal shielding of the sound generator 30 is desired in order to not have magnetic or electric fields from the generator 30 influence other components in the vicinity. In one example, the generator 10 is provided in a hearing aid housing or hearable housing together with sensitive elements, such a coils or the like. In such situations, it is desired to provide the shielding on or around the sound generator and not those elements.

(13) The openings 22 and 34 are oblong. The shape of the openings may be selected based on a number of factors such as a shape of the sound generator chamber from which the sound is to be output.

(14) In many embodiments, a diaphragm, indicated by the dashed line 33, of the sound generator divides the inner space of the housing 30 into two chambers, a front chamber (above the diaphragm) and a back chamber (below the diaphragm). When the front chamber has a low height, the shape and dimensions of the opening 34 has corresponding limitations. As the sound intensity output naturally depends on the size of the opening, a larger opening and thus a larger sound output intensity may be achieved by making the opening 34 oblong with a largest dimension parallel to the diaphragm plane.

(15) The overall sound output of the generator 10 will be the overlap between the opening 34 and the opening 22. Thus, in order to have both a large sound output intensity and a good shielding, it is preferred that the shapes and positions of the openings 34 and 22 are about the same. A larger opening 22 may not increase the sound output intensity, if the opening 34 (projected on to a plane of the surface in which the opening is present) lies within the opening 22. However, that could reduce the shielding of the generator 10.

(16) In the same manner, a larger opening 34 may not increase the sound output intensity, if the opening 22 (projected on to a plane of the surface in which the opening is present) lies within the opening 34. However, that would not affect the shielding of the generator 10 to any substantial degree.

(17) FIG. 2 illustrates a particular manner of obtaining the shielding housing 20, i.e. providing it as two parts, 24 and 26, inside which the generator 30 may be provided. The two parts may be assembled so form the final shielding housing 20.

(18) FIG. 3 illustrates and embodiment 11 where the same elements have the same numbers as in FIG. 1 with the exception that in FIG. 3, a back portion of the shielding housing 20 has not been illustrated and that the openings 34/22 are positioned centrally on the left housing and shielding walls.

(19) In FIG. 3, the generator 11 has a spout 40 into which sound from the openings 34/22 is output. The spout has an input opening 42 and an output opening 44 and a sound channel there between along a longitudinal axis (hatched line).

(20) Often, spouts are provided to facilitate connecting the generator 11 to sound guides, such as tubes/channels which may be connected to the spout by providing the spout at least partly within the tube/channel to form a sound proof connection between the generator 11 and the tube/channel.

(21) Often, at least the outermost (leftmost) portion of the spout has a well defined cross section (being tubular with the same, often circular, cross section along the portion) so that it may be attached to the sound tube/channel. However, as may be seen in FIG. 4, other portions, such as the innermost (rightmost) portion, may have other shapes.

(22) Often, the spout 40 is formed integrally with the generator housing, such as the housing 20 or the housing 30. Alternatively, the spout may be attached thereto and may thus have, at the input end 42, a surface configured to conform to the generator housing and which may be attached thereto, such as by gluing, welding, snap fitting or the like.

(23) The spout 40 may be made of a shielding material, but this it not required, as the shielding extends to within the opening 42 in FIG. 3. Thus, the fact that the shielding extends to, when projected on to a plane of the left wall portion of the housing 20 or the housing 30, within the inner circumference of at least the opening 44 of the spout, the shielding housing 20 itself provides an improved shielding, even if the spout itself is not shielding.

(24) In FIG. 4, a generator 12 is illustrated seen from the side. In this embodiment, the spout 41 is integral with the shield housing 20 and has a waist 48 close to the housing wall. This waist thus defines the shield opening. The shield housing 20 is, in this embodiment, open at the opposite end of the spout. This is merely a design choice. In an alternative, the shield housing may cover only the front surface 21 of the generator if desired.

(25) In FIG. 5, a generator 12 is seen comprising (disassembled), to the right, a sound generator with a first wall portion 21 and a slit-shaped housing opening 34 and, to the left and seen from the front, a spout 40 comprising a tube-shaped portion 40 and a shielding portion 20 with a slit-shaped shield opening 22.

(26) It is noted that the shielding portion 20 is configured to shield all of the first wall portion 21 in the same manner as the shielding in e.g. FIG. 1. Thus, the sound generator 12 may be a standard unshielded generator. The shielding portion 20 may extend even farther, such as when bent and also extending along at least a portion of the length of the generator 12 so as to also shield part of (or all of) the side portions of the generator.

(27) Clearly, the tube-shaped portion 40 may also be shielding. Then, the portion of the shielding 20 inside the tube-shaped portion 40 may be replaced by a non-shielding materialor no material at all. This shielded tube-shaped portion 40 may then the slit-shaped opening 22 at its far end or have the waist 48 to increase its shielding.

(28) In FIG. 6, a generator 13 is seen having an alternative shape and position of the shielding, where a back shielding portion 201 is provided within which the generator 30 is positioned. However, the back portion 201 is open at the front, left, side of the housing 32, where the housing opening 34 is positioned. To shield also the front side, a shielding end element 202 is provided wherein the shield opening 22 is provided. The element 202 is provided inside the generator housing 32.

(29) In general, the shield may be made of a metal, such as mu-metal 80-20. The shielding effect naturally depends not only on the size(s) of the opening(s) 22/24 but also the thickness of the shielding material. For miniature generators, a thickness of about 0.130 mm is preferred with a housing thickness of about 140 m.

(30) The desired attenuation is 3 dB or more, and the minimum thickness for usual mu-metal materials is about 50 m, but primarily due to thinner layers being difficult to handle.

(31) The present sound generator 10, 11, 12, 13 may be used in e.g. a hearing aid, hearable, personal hearable, ear phone or the like and thus preferably is a so-called miniature receiver.