DYNAMIC LOUDSPEAKER DRIVER, LOUDSPEAKER AND MOBILE DEVICE COMPRISING A LOUDSPEAKER

Abstract

The invention relates to a dynamic loudspeaker driver which comprises a magnet-system, a membrane and a voice coil. The membrane comprises a semi-rigid diaphragm and a flexible annulus surrounding the diaphragm. The diaphragm is movably mounted with respect to the magnet-system by means of the annulus and comprises a substrate which comprises a first surface and a second surface being opposite to the first surface, a first layer attached to and continuously covering the first surface, and a second layer attached to and covering the second surface. The second layer comprises a plurality of holes having a predefined pattern. The voice coil is attached to the diaphragm and is operatively coupled with the magnet-system.

Claims

1. A dynamic loudspeaker driver, comprising a magnet-system; a membrane which comprises a semi-rigid diaphragm and a flexible annulus surrounding the diaphragm, the diaphragm being movably mounted with respect to the magnet-system by means of the annulus and comprising a substrate which comprises a first surface and a second surface being opposite to the first surface, a first layer attached to and continuously covering the first surface, and a second layer attached to and covering the second surface, the second layer comprising a plurality of holes having a predefined pattern; and a voice coil attached to the diaphragm and operatively coupled with the magnet-system.

2. The dynamic loudspeaker driver of claim 1, wherein the second surface of the diaphragm faces towards the magnet-system.

3. The dynamic loudspeaker driver of claim 1, wherein the diaphragm is a flat diaphragm and the second layer has a flat surface.

4. The dynamic loudspeaker driver of claim 3, wherein the flat surface has an area less than 2 cm.sup.2, is circular, is oval, or is rectangular.

5. The dynamic loudspeaker driver of claim 3, wherein the flat surface has a center and at least two of the holes of the plurality of holes are arranged symmetrically with respect to the center of the flat surface, and/or wherein at least some of the holes of the plurality of holes are arranged along the perimeter of a two dimensional shape.

6. The dynamic loudspeaker driver of claim 3, wherein the holes of the plurality of holes are arranged along the perimeters of a plurality of non-intersecting two dimensional shapes.

7. The dynamic loudspeaker driver of claim 6, wherein the holes of the plurality of holes are arranged along the perimeters of a plurality of two dimensional shapes arranged concentrically with respect to a common center.

8. The dynamic loudspeaker driver of claim 5, wherein the two dimensional shapes are taken from a group consisting of a circle, an ellipse and a rectangle.

9. The dynamic loudspeaker driver of claim 5, wherein the flat surface has a center which is the common center such that the at least two dimensional shapes are arranged concentrically with respect to the center of the flat surface.

10. The dynamic loudspeaker driver of claim 5, wherein the holes are arranged along the relevant perimeters such that holes of two subsequent two dimensional shapes do not overlap or at least only partially overlap in radial direction with respect to the common center.

11. The dynamic loudspeaker driver of claim 1, wherein the holes are symmetrical with respect to the common center.

12. The dynamic loudspeaker driver of claim 5, wherein the two dimensional shapes comprise an inner circle having an inner radius and at least two outer circles having respective outer radii arranged concentrically with respect to the common center.

13. The dynamic loudspeaker driver of claim 12, wherein, beginning from the inner circle, the radius of a subsequent outer circle increases by a constant value.

14. The dynamic loudspeaker driver of claim 1, wherein the plurality of holes is a plurality of slit-shaped holes.

15. The dynamic loudspeaker driver of claim 14, wherein the slit-shaped holes have a width of less than 100 m.

16. The dynamic loudspeaker driver of claim 1, wherein the substrate is made from a foamed plastics, or the first and second layers are made from aluminum, and/or wherein the plurality of holes is applied to the second layer by means of laser cutting.

17. A loudspeaker, comprising an enclosure and the dynamic loudspeaker driver of claim 1 mounted in the enclosure.

18. A mobile device comprising the loudspeaker of claim 17.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a top view of a mobile phone;

[0034] FIG. 2 and FIG. 3 are each a loudspeaker of the mobile phone;

[0035] FIG. 4 is a side and sectional view of a dynamic loudspeaker driver of the loudspeaker;

[0036] FIG. 5 is a top view of the dynamic loudspeaker driver;

[0037] FIG. 6 is a diaphragm of the dynamic loudspeaker driver;

[0038] FIG. 7 is a substrate of the diaphragm;

[0039] FIG. 8 is a top view of a layer of the diaphragm.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0040] FIG. 1 shows a mobile phone 1 as an example of a mobile device. The mobile phone 1 comprises a microphone, a wireless sender-receiver unit and a loudspeaker 2 schematically shown as side and sectional views in FIGS. 2 and 3.

[0041] The loudspeaker 2 comprises an enclosure 3 and a dynamic loudspeaker driver 41 shown as a side and sectional view in FIG. 4. FIG. 5 shows a top view of the loudspeaker 2. The enclosure 3 is in particular a sealed or closed enclosure 3 and the dynamic loudspeaker driver 41 is mounted in the enclosure 3.

[0042] The dynamic loudspeaker driver 41 comprises a magnet-system 42, a membrane, and a voice coil 45. The membrane comprises a semi-rigid diaphragm 43 and a flexible annulus 44 surrounding the diaphragm 43. The voice-coil 45 is attached to the diaphragm 43 by means, for instance, of a glue. The diaphragm 43 is movably mounted with respect to the magnet-system 42 by means of the annulus 44.

[0043] The dynamic loudspeaker driver 41 further comprises a basket 46. The annulus 44 is attached to the basket 46.

[0044] The magnet-system 42 comprises a pot 47 and a magnet 48. The pot 47 and the magnet 48 form an air gap 49. The voice coil 45 is located within the air gap 49 and is operatively coupled with the magnet 48.

[0045] A side view of the diaphragm 43 is shown in FIG. 6.

[0046] The diaphragm 43 may have a circular, an oval shape or, as shown in FIG. 5 a rectangular shape.

[0047] The diaphragm 43 comprises a substrate 50 shown as a side view in FIG. 7, a first layer 61 and a second layer 62. The substrate 50 may be made from plastics, in particular made from a foamed plastics.

[0048] The first and second layers 61, 62 may be made from metal, in particular from aluminum.

[0049] The substrate 50 comprises a first surface 51 and a second surface 52. The first layer 61 is attached to and covers the first surface 51. The second layer 62 is attached to and covers the second surface 52.

[0050] In the present embodiment, the second surface 52 of the substrate 50 faces towards the magnet-system 42 and the first surface 51 faces away from the magnet-system 42.

[0051] The first and second layers 61, 62 may, for instance, be 8 m thin.

[0052] The first layer 61 is a continuous layer covering continuously the entire first surface 51.

[0053] The diaphragm 43 is in particular a flat diaphragm 43. As a result, the second layer 62 has a flat surface. Preferably, the flat surface has an area of less than 2 cm.sup.2, particularly between 0.5 cm.sup.2 and 1.7 cm.sup.2. Preferably, the flat surface has an area of around 1.0 cm2. The flat diaphragm 43 may be between 80 m and 320 m thick, preferably about 120 m thick. A top view of the second layer 62 is shown in FIG. 8.

[0054] The second layer 62 is an interrupted layer which is interrupted by a plurality of holes 63 having a predefined pattern. The plurality of holes 63 may be a plurality of slit-shaped holes. The slit-shaped holes may have a width of less than 100 m.

[0055] When operating, an electric signal is applied to the voice coil 45, for instance, by an amplifier. Then, the diaphragm 43 moves with respect to the magnet system 42 in response to the electric signal, resulting in moving air.

[0056] FIG. 2 illustrates a scenario when the electric signal forces the diaphragm 43 to move towards the enclosure 3. This is indicated by arrows 4a. Then, the air within the enclosure 3 applies a pressure or force to the second surface 52 and to the second layer 62. This is indicated by arrows 5a.

[0057] FIG. 3 illustrates a scenario when the electric signal forces the diaphragm 43 to move away from the enclosure 3. This is indicated by arrows 4b. Then, the ambient air applies a pressure or force to the first surface 51 and to the first layer 61. This is indicated by arrows 5b.

[0058] Since the enclosure 3 is a closed enclosure 3, the pressure applied by the ambient air is less than the pressure applied by the air within the enclosure 3. This is indicated by the different lengths of the arrows 5a, 5b.

[0059] Particularly, the pressure applied to the diaphragm 43 by the air within the enclosure 3 is greater than the pressure applied by the ambient pressure. By applying the plurality of holes 63 to the second layer 62 and choosing an appropriate pattern dependent on the enclosure 3 and the properties of the diaphragm 43, it is possible to influence the stiffness of the diaphragm 43 in such a way that the diaphragm 43 bends at least to a similar degree when moving towards or moving away from the enclosure 3.

[0060] In the present embodiment, the flat surface has a center 53 and at least two of the holes of the plurality of holes 63 are arranged symmetrically with respect to the center 53 of the flat surface.

[0061] In the present embodiment, the holes 63 are arranged along the perimeters of two dimensional shapes. The two dimensional shapes may, for instance, be ellipses, rectangles or, as shown in FIG. 8 circles.

[0062] In the embodiment shown in FIG. 8, the circles are non-intersecting and specifically concentric with respect to the center 53 of the flat surface.

[0063] Specifically, the circles comprise an inner circle 80 having an inner radius ri, a first outer circle 81 having a first outer radius r1, a second outer circle 82 having a second outer radius r2, and a third outer circle 83 having a third outer radius r3. The first outer radius r1 is greater than the inner radius ri, the second outer radius r2 is greater than the first outer radius r1, and the third outer radius r3 is greater than the second outer radius r2.

[0064] Specifically, beginning from the inner circle 80, the radius of a subsequent outer circles 81-83 increases by a constant value.

[0065] Specifically, the number of holes 63 per circle 80-83 is the same.

[0066] Specifically, the holes 63 are equidistant spaced apart along the perimeter of each circle 80-83.

[0067] Specifically, the holes 63 are arranged along the relevant perimeters such that holes 63 of two subsequent circles 80-83 do not overlap with respect to the center 53.

[0068] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the invention to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art.