Diaphragm, a sound generator, a hearing device and a method

Abstract

A diaphragm with a hinge portion and a drive portion and a plurality of oblong frame portions between the hinge portion and drive portion. The oblong frame portions are able to vibrate independently of each other and may have different resonance frequencies.

Claims

1. A diaphragm having a hinge portion and a drive portion and a longitudinal direction extending from the drive portion to the hinge portion, the diaphragm having a diaphragm length being a distance from the drive portion to the hinge portion, the diaphragm further comprising a plurality of distinct oblong diaphragm portions each having a length larger than 30% of the diaphragm length, the distinct oblong diaphragm portions being able to vibrate at least substantially independently of each other, the oblong diaphragm portions extending between the drive portion and hinge portion, wherein the plurality of distinct oblong diaphragm portions, when projected on to the plane of the diaphragm, do not contact one another during vibration of the diaphragm.

2. A diaphragm according to claim 1, wherein at least one of the distinct oblong diaphragm portions is directed transverse to the longitudinal direction.

3. A diaphragm according to claim 1, wherein at least one of the distinct oblong diaphragm portions is directed at least substantially along the longitudinal direction.

4. A diaphragm according to claim 1, wherein each of the plurality of distinct oblong diaphragm portions is connected to the drive portion at one end and to the hinge portion at an opposite end.

5. A diaphragm according to claim 1, wherein an oblong slit is provided between at least two of the distinct oblong diaphragm portions.

6. A diaphragm according to claim 5, wherein a resilient material covers the slit.

7. A diaphragm according to claim 1, wherein a resilient element is provided between at least two of the distinct oblong diaphragm portions.

8. A diaphragm according to claim 1, wherein at least two of the distinct oblong portions have one or more of: different width, different thickness, different density, different curvature, different bendability/stiffness and different resonance frequencies.

9. A diaphragm according to claim 1, further comprising an outer frame circumscribing, when projected onto the plane, the distinct oblong diaphragm portions and being connected to the oblong diaphragm portions only at the hinge portion.

10. A sound generator comprising a diaphragm according to claim 1, the diaphragm dividing an inner space of the sound generator into at least two compartments.

11. A hearing device comprising a sound generator according to claim 10.

12. A method of generating sound, the method comprising the steps of: providing a sound generator according to claim 10 and vibrating the drive portion.

13. A diaphragm according to claim 1, wherein each of the distinct oblong diaphragm portions is planar and provided in the plane.

14. A method of manufacturing a diaphragm, the method comprising: providing a sheet of metal, forming in the sheet a diaphragm with an outer diaphragm contour, the diaphragm having a hinge portion and a drive portion, the diaphragm defining a plane across the sheet, forming in the sheet and inside the outer diaphragm contour at least two distinct oblong diaphragm portions extending between the hinge portion of and the drive portion, each having a length of at least 30% of a distance between the hinge portion and the drive portion, by removing at least a portion of the sheet of metal between the oblong diaphragm portions, wherein the at least two distinct oblong diaphragm portions do not contact one another when projected on to the plane of the diaphragm such that any one the at least two distinct oblong diaphragm portions during vibration thereof can move out of the plane without contacting the other or others of the at least two distinct oblong diaphragm portions.

15. A method according to claim 14, wherein the step of forming the at least two distinct oblong diaphragm portions comprises providing the oblong diaphragm portions so as to not overlap when projected on to a plane of the diaphragm.

16. A diaphragm comprising: a central diaphragm portion having a hinge portion and a drive portion, an outer frame portion circumscribing, when projected on to a plane of the diaphragm, at least the drive portion of the central diaphragm portion, the outer frame portion being connected to the central diaphragm portion at the hinge portion, a plane layer of a resilient material extending from the outer frame portion to the central diaphragm portion, wherein the central diaphragm portion is made of a first material and the outer frame portion of a second material, the second material having a higher stiffness than the first material.

17. A method of manufacturing a diaphragm according to claim 16, the method comprising: providing a central diaphragm portion having a hinge portion and a drive portion, the central diaphragm portion being made of a first material, providing an outer frame portion of a second material, the second material having a higher stiffness than the first material, connecting the outer frame portion to the hinge portion so that the outer frame portion circumscribes, when projected on to a plane, at least the drive portion of the central diaphragm portion, and providing a plane layer of a resilient material extending from the outer frame portion to the central diaphragm portion.

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 prior art diaphragm having two stiffening portions,

(3) FIG. 2 illustrates a first embodiment of a diaphragm according to the invention,

(4) FIG. 3 illustrates a second embodiment of a diaphragm according to the invention connected to a drive unit,

(5) FIG. 4 illustrates the main components of a sound generator,

(6) FIG. 5 illustrates a cross section of the diaphragm of FIG. 2,

(7) FIG. 6 illustrates another type of diaphragm,

(8) FIG. 7 illustrates a cross section of the diaphragm of FIG. 6 and

(9) FIG. 8 illustrates a number of other shapes and positions of oblong portions.

DETAILED DESCRIPTION OF THE INVENTION

(10) In FIG. 1, a prior art diaphragm 10 is illustrated having a hinge portion 12, a drive portion 14 and two ridges 16 providing stiffness to the diaphragm 10.

(11) The operation of the diaphragm 10 is that a motor (not illustrated) will move the drive portion 14 up/down whereby the diaphragm 10 will rotate about the hinge portion 12 which is rotatably fastened to another element, typically a frame and/or the inner surface of a sound generator house.

(12) The ridges 16 impart a stiffness to the diaphragm so that the force applied to the drive portion will move all of the diaphragm. Naturally, the diaphragm will have one or more resonance frequencies defined by the diaphragm parameters.

(13) In FIG. 2, a diaphragm 20 according to the invention is illustrated. It is seen that the diaphragm 20 still has the hinge portion 22 and the drive portion 24 but that the vibrating portion between the hinge portion 22 and the drive portion 24 now has two oblong portions 26 and 26 divided by a slit 28.

(14) Driving the drive portion 24 up/down will still drive the portions 26/26 up/down, but as the portions 26/26 may have different resonance frequencies, the operation of the diaphragm 20 may be different than the prior art diaphragm.

(15) Vibrating a diaphragm will cause the generation of sound/vibration. The output intensity will depend on a number of factors, such as frequency and the resonance frequency/ies of the diaphragm. Generally, the output is higher at a resonance frequency.

(16) Providing a diaphragm with elements with different resonance frequencies allows the generation of a diaphragm with a better and/or more controllable output over the desired frequency spectrum. The oblong elements 26/26 may be tuned individually to better create the output desired. An oblong element may be tuned to have a resonance frequency at a frequency where the output would otherwise be lower than desired. Multiple oblong elements make it possible to provide multiple such local output increases in the output spectrum.

(17) Naturally, the portions 26/26 may be more than two portions and may be made of different materials and/or with different parameters, such as different thickness, width, density, material, curvature or the like. A portion 26/26 may be straight or curved (in a plane perpendicular to the longitudinal direction illustrated). A curved cross section may impart a higher rigidity of the portion 26/26.

(18) In FIG. 2, the diaphragm 20 comprises an outer frame 25 which may be fastened to or in an inner surface of a sound generator to fix the diaphragm 20 while allowing the portions 26/26 and 24 to vibrate around the hinge portion 22, which in this embodiment is formed by two bendable portions at the end of the portions 26/26 and simply created by forming a slit 22 between the portions. Another manner of providing a hinge portion would be to provide the frame and central portion as individual elements and connect these at the hinge portion by a resilient material, such as glue. The slit may, as described below, be covered in order to prevent air or sound passing through the slit.

(19) Usually, a resilient material is provided between the portions 26/26 themselves, i.e. in the slit 28, and between each portion 26/26 and the frame 25, i.e. in the opening or slit 25, in order to ensure an air tight diaphragm.

(20) As is usually the case in diaphragms where the space 25 between the frame and the movable portion of the diaphragm is to be sealed in a manner still allowing movement of the movable portion, it is desired that the portions 26/26 are movable relative to each other. Thus, if a material is provided in the slit 28, so as to seal this opening, it is desired that this material allows one portion 26 to move relative to the other portion 26.

(21) Suitable materials may be thin sheets of a resilient material, such as PU or PET. Alternatively, a gel may be provided to cover an area or slit. Naturally, any combination may be used, so that the slit(s) 28 between the oblong areas may be covered by a sheet, where the space 25 is covered by a gel, where both are covered by a gel, where both are covered by a sheet, or where the space 25 is covered by a sheet and the slit(s) 28 by a gel. In addition to that, a slit 22 may be covered by a gel or a sheet independently of how the slit(s) 28 and the space 25 is covered.

(22) In FIG. 3, a diaphragm 20 is illustrated having three portions 26/26/26 defining two slits 28/28 wherein a resilient material is provided for sealing those openings.

(23) In FIG. 3, a drive unit 30 is illustrated having an armature 32 connected to the drive portion 24 via a drive pin 34. In FIG. 3, the outer frame and housing etc. of a sound generator have been left out to better illustrate the driving of the diaphragm.

(24) In FIG. 4, a sound generator 40 is illustrated having the diaphragm 20, a drive unit generally illustrated at 46. As is usual, the diaphragm 20 divides an inner space of the housing into a back chamber 42 and a front chamber 44 having a sound outlet (not illustrated) from which sound may be output.

(25) FIG. 5 illustrates a cross section of the diaphragm 20 of FIG. 2 in a cross section along the line A of FIG. 2. In this cross section, the frame 25 is seen, as are the oblong portions 26/26 and the slit 28. Illustrated is also a layer 29 of a resilient material covering both the spaces between the frame and the portions 26/26 and the slit 28. Thus, an airtight diaphragm may be obtained while catering for the desired operation of the portions 26/26. An alternative to the layer 29 would be to provide this material only in the spaces between the frame and portions 26/26 and in the slit 28. This would make the portions 26/26 lighter but the manufacturing more complex.

(26) In FIG. 6, another type of diaphragm 40 is illustrated having a central portion 27, having a drive portion 24 and a hinge portion 22, is provided inside a frame 25 and where a resilient material 29 is provided in the space 25 between the central portion 27 and the frame 25 to seal that space. FIG. 7 illustrates a cross section of this diaphragm along the line B.

(27) The diaphragm is driven by moving the drive portion 24 up/down to have the central portion 27 rotate around the hinge portion 22 provided in this embodiment by two extending portions of the central portion 27 which have been attached to the frame 25.

(28) When applying the resilient material 29, it is desired that it is plane and not buckling, as a buckling material could create a range of problems. However, ensuring that the material is plane before attaching to the central portion 27 and the frame 25 will tend to stretch the material 29 and thus to, when applied, have the material 29 generate a biasing of the frame toward the central element 27. This may deform the frame 25, which is not desired.

(29) Thus, the frame 25 is made of a material which is stiffer than that of the central portion 27, which is typically Al or an alloy comprising Al.

(30) The frame 25 may be made of a stiffer material, such as copper, cobalt, iron, nickel, or alloys, such as steel, Nickel-Iron 50-50, Nickel-Iron 80-20, Brass, or metal matrix composite materials, such as an aluminium matrix with ceramic particles therein.

(31) The hinge portion 22 may be obtained by providing the central portion 27 with extending portions which are then fixed to the frame 25, such as by gluing/soldering/welding, or by providing a resilient material between the hinge portion of the central portion and the frame.

(32) Additional manners of providing and shaping the oblong portions are seen in FIG. 8, where, generally, slits 28 are provided as are the frame 25, the hinge portion 22 and the drive portion 24.

(33) In FIG. 8a), four slits 28 are provided effectively generating 6 oblong portions. The portions are attached at their ends to the remainder of the diaphragm. The ends of each oblong portion are attached at different distances to the drive and hinge portions.

(34) In FIG. 8b), again four slits are made parallel to the longitudinal axis, but now two slits are wider than the other two. Then, the widths of the oblong elements differ from the embodiment in FIG. 8a), as may the resonance frequencies.

(35) In FIG. 8c), the slits are not parallel to the longitudinal axis. The oblong elements thus have a wedged shape. This again tunes the vibrational behaviour and resonance frequency of the oblong portions.

(36) In FIG. 8d), four non-parallel slits are made forming more complex shapes of oblong elements which again may be dimensioned and tuned as desired.

(37) In FIG. 8e), the slit 28 is transverse to the longitudinal direction. Again, elements are formed which may be dimensioned and tuned as desired.

(38) In FIG. 8, different positions and shapes of a damping material 30 are illustrated. The damping material may be applied as a droplet, a line, a curve, a geometrical figure, such as a triangle, a square, a rectangle, a circle, an oval, or the like, open or filled with the damping material.

(39) The damping material may be provided at positions where it is desired to increase the mass or the stiffness of the diaphragm. The damping material may be provided on the resilient material 29, in the slits 28 or simply on the diaphragm, such as on an oblong element 26/26, or any combination thereof. In this situation, the diaphragm may comprise a frame 25 and need not have any slits 28.

(40) The damping material may be applied as a gel and subsequently cured, such as dried, heated, irradiated or the like.