CN210927933U

CN210927933U - Electret bone conduction microphone

Info

Publication number: CN210927933U
Application number: CN201922484182.5U
Authority: CN
Inventors: 张金宇; 王凯
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-07-03
Anticipated expiration: 2029-12-30

Abstract

The utility model provides an electret bone conduction microphone, which comprises a shell with an accommodating space, a circuit board fixed on the shell and enclosing with the shell to form the accommodating space, and a diaphragm assembly, a back plate and an insulating spacer accommodated in the accommodating space, wherein the insulating spacer is fixed on one side of the back plate away from the circuit board; the diaphragm assembly comprises a conductive diaphragm and a mass block; the conductive diaphragm comprises a fixed part, a folding ring surrounding the fixed part and a supporting part surrounding the folding ring and fixed on the insulating isolator; the mass block is fixed on the fixing part and can displace relative to the back plate along the vibration direction of the conductive vibration film after responding to external vibration. By adopting the conductive vibrating diaphragm with the folding rings, the stress generated by the movement of the mass block can be effectively distributed in the whole folding ring area, the stress is dispersed, and the fatigue, deformation or fracture of materials are not easy to occur.

Description

Electret bone conduction microphone

[ technical field ] A method for producing a semiconductor device

The utility model relates to an electret bone conduction microphone specifically indicates an electret bone conduction microphone with novel conductive vibrating diaphragm structure.

[ background of the invention ]

The MEMS bone conduction microphone has a complex structure, so that the manufacturing cost is high, and the development of the MEMS bone conduction microphone is restricted. In order to reduce the cost, an electret microphone is adopted to replace an MEMS microphone so as to realize the reduction of the cost and better reliability.

In a conventional electret bone conduction microphone, a mass block is fixed on a conductive diaphragm so as to be capable of moving in response to external vibration. The movement of the mass block is limited by the conductive diaphragm, and material fatigue easily occurs due to stress concentration at the fixed end of the conductive diaphragm in the movement process.

Therefore, there is a need for an electret bone conduction microphone with a novel conductive diaphragm structure.

[ Utility model ] content

An object of the utility model is to provide an electret bone conduction microphone to solve the stiff end of conductive vibrating diaphragm in traditional electret bone conduction microphone and take place the tired technical problem of material easily because of stress concentration.

The technical scheme of the utility model as follows:

an electret bone conduction microphone comprises a shell with an accommodating space, a circuit board fixed on the shell and enclosing the shell into the accommodating space, a diaphragm assembly, a back plate and an insulating isolating piece, wherein the diaphragm assembly, the back plate and the insulating isolating piece are accommodated in the accommodating space;

the diaphragm assembly comprises a conductive diaphragm fixed on the insulating isolation piece and a mass block fixed on the conductive diaphragm;

the conductive diaphragm comprises a fixed part positioned in the center, a folding ring surrounding the fixed part and a supporting part surrounding the folding ring and fixed on the insulating isolating piece;

the mass block is fixed on the fixing part and can be displaced relative to the back plate along the vibration direction of the conductive vibrating diaphragm after responding to external vibration.

The beneficial effects of the utility model reside in that:

according to the electret bone conduction microphone, the conductive vibrating diaphragm with the folding rings is adopted, so that stress generated by movement of the mass block can be effectively distributed in the whole folding ring area, the stress is dispersed, and material fatigue, deformation or fracture is not easy to occur.

[ description of the drawings ]

Fig. 1 is a schematic perspective exploded view of an electret bone conduction microphone according to the present invention;

fig. 2 is a front view of the electret bone conduction microphone of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is an enlarged view of the portion I of FIG. 3;

FIG. 5 is a partial cross-sectional view of a hinge according to an embodiment of the present invention;

fig. 6 is a partial sectional view of a corrugated rim according to another embodiment of the present invention.

[ detailed description ] embodiments

The present invention will be further described with reference to the accompanying drawings and embodiments.

Referring to fig. 1 to 4, an electret bone conduction microphone 100 according to the present invention will now be described. The electret bone conduction microphone 100 includes a housing 110, a metal washer 120, a diaphragm assembly 130, an insulating spacer 140, a back plate 150, a support ring 160, and a circuit board 170. The housing 110 has a receiving space. The circuit board 170 is fixed to the housing 110 and encloses a receiving space with the housing 110. The diaphragm assembly 130, the back plate 150 and the insulating spacer 140 are accommodated in the accommodating space. The insulating spacer 140 is fixed to a side of the back plate 150 away from the circuit board 170. The diaphragm assembly 130 is fixed to a side of the insulating spacer 140 away from the back plate 150 and is spaced apart from the back plate 150. The surface of the backplate 150 adjacent to the diaphragm assembly 130 is provided with an electret. An electret is a dielectric that can maintain an electrically polarized state for a long time. The dielectric is a high molecular weight polymer. The high molecular polymer is an existing material. Free charges are distributed on the electret. Electrets have low circuit requirements but are moisture sensitive. The housing space formed by the circuit board 170 and the housing 110 circumvents the environment sensitive characteristics of the electret.

Further, the diaphragm assembly 130 includes a conductive diaphragm 131 fixed to the insulating spacer 140 and a mass 132 fixed to the conductive diaphragm 131. The conductive diaphragm 131 includes a fixing portion 1311 at a central position, a corrugated rim 1312 surrounding the fixing portion 1311, and a supporting portion 1313 surrounding the corrugated rim 1312 and fixed to the insulating spacer 140. The mass 132 is fixed to the fixing portion 1311 and is capable of being displaced relative to the back plate 150 in a vibration direction of the conductive diaphragm 131 in response to external vibration. The vibration direction is parallel to the direction indicated by the arrow X in fig. 3. The conductive diaphragm 131 is connected to the housing 110 through the metal gasket 120, and the backplate 150 is connected to the circuit board 170 through the support ring 160. Since the insulating spacer 140 is disposed between the backplate 150 and the conductive diaphragm 131, the circuit between the backplate 150 and the conductive diaphragm 131 is not conducted, thereby forming a capacitor. Since the electret has free charges distributed thereon. So that there is an amount of charge between both poles of the capacitor body formed between the back plate 150 and the conductive diaphragm 131.

In this embodiment, the mass 132 is fixed to the fixing portion 1311 on a surface away from the backplate 150. When the bone conduction signal is transmitted to the electret bone conduction microphone 100 in a vibration acceleration manner, the mass 132 can be displaced relative to the back plate 150 in a vibration direction after responding to external vibration. When the distance between the conductive diaphragm 131 and the backplate 150 is changed, the capacitance of the capacitor body is changed, the potential of the backplate 150 with the charge Q is changed, a voltage signal corresponding to the bone conduction signal is generated, and the voltage signal is amplified and outputted through a FET (field effect transistor)/ASIC (application specific integrated circuit) 180 provided on the circuit board 170. Namely, the voltage signal generated by the displacement of the mass 132 is amplified and outputted. In this embodiment, the electret is a layer of electret material coated on the back plate 150 and is polarized in advance. It is understood that in other embodiments, the electret may be disposed on the back-plate 150 in other manners, such as adhesion, chemical deposition, physical deposition, or the like.

Please refer to fig. 3 and 4 together. In the embodiment, by using the conductive diaphragm 131 with the corrugated rim 1312, the stress generated by the movement of the mass 132 can be effectively distributed in the whole corrugated rim 1312 area, and the stress is relatively dispersed, so that the material fatigue, deformation or fracture is not easy to occur. The inner edge 1313a of the support 1313 is suspended above the back plate 150. Inner edge 1313a of support 1313 is connected to edge 1312. Making non-rigid connection between edge 1312 and inner edge 1313a of support 1313 is more advantageous for preventing stress concentration.

In this embodiment, the bending ring 1312 protrudes away from the back plate 150. Specifically, the corrugated rim 1312 has a top subsection 1312a adjacent to the outer case 110 in the vibration direction, and a first side subsection 1312b and a second side subsection 1312c connected to the top subsection 1312a and disposed opposite to each other. The top portion 1312a, the first side portion 1312b and the second side portion 1312c form a hinge 1312. The end of the first side portion 1312b remote from the top portion 1312a is connected to the outer edge 1311a of the fixing portion 1311. The end of the second side section 1312c remote from the top section 1312a is connected to the inner edge 1313a of the support 1313. With the above arrangement, not only the stress generated by the movement of the mass 132 can be effectively distributed in the whole area of the corrugated rim 1312, but also the stress can be distributed more optimally and the movement of the mass 132 can be controlled quantitatively by changing the shapes, sizes and included angles of the top part 1312a, the first side part 1312b, the second side part 1312c, the fixing part 1311, the corrugated rim 1312 and the supporting part 1313 and the suspension position of the inner edge 1313a of the supporting part 1313.

Specifically, the included angle between the generatrix of the first side branch 1312b and the plane surrounded by the outer edge 1311a of the fixing portion 1311 is greater than 90 ° and less than 180 °. The fixing portion 1311 is used to connect with the mass 132. To avoid unnecessary vibration, the mass 132 needs to be attached to the fixing portion 1311. The shape of the fitting of the fixing portion 1311 and the mass 132 depends on the shape of the fitting of the mass 132. The topography can be flat, concave, convex, corrugated or wavy, etc. Therefore, the positional relationship between the generatrix of the first side branch 1312b and the outer edge 1311a of the fixing portion 1311 can be defined by the positional relationship between the generatrix of the first side branch 1312b and the plane surrounded by the outer edge 1311a of the fixing portion 1311, regardless of the specific shape of the fixing portion 1311.

Further, the included angle between the generatrix of the second side branch 1312c and the plane surrounded by the inner edge 1313a of the support 1313 is greater than 0 ° and less than 90 °. Similarly, the positional relationship between the generatrix of second side branch 1312c and inner edge 1313a of support 1313 may be defined by the positional relationship between the generatrix of second side branch 1312c and the plane surrounded by inner edge 1313a of support 1313, regardless of the specific topography of support 1313.

In this embodiment, the mass 132 is a flat cylinder, and the mass 132 has a side surface 1321, a bottom surface 1322 and a top surface 1323 which are parallel to each other. The fixing portion 1311, the top portion 1312a and the supporting portion 1313 are planar and parallel to each other. The bottom of the mass 132 abuts the fixing portion 1311. That is, the bottom surface 1322 is attached to the fixing portion 1311. Bottom surface 1322 may be attached to the entire retainer 1311 or only to a portion of retainer 1311. The vertical distance from the top portion 1312a to the fixing portion 1311 is equal to the thickness of the mass 132. During the movement of the mass 132, the included angle between the generatrix of the first side branch 1312b and the side surface 1321 is changed, and further, the included angle between the first side branch 1312b and the top branch 1312a, the included angle between the top branch 1312a and the second side branch 1312c, and the included angle between the generatrix of the second side branch 1312c and the support 1313 are changed, so as to relieve the stress concentration.

In this embodiment, the insulating spacer 140 has a ring shape. The shapes of the outer edge of the bottom surface 1322, the outer edge 1311a of the fixing portion 1311, the inner edge of the top portion 1312a, the inner edge 1313a of the supporting portion 1313 and the inner edge 141 of the insulating spacer 140 are enlarged in equal proportion, so that stress concentration is relieved better. Further, the included angle between the generatrix of the first side branch 1312b and the plane of the top branch 1312a is equal to the included angle between the generatrix of the second side branch 1312c and the plane of the top branch 1312a, so that the stress of the corrugated rim 1312 is more uniform in the deformation process.

In this embodiment, the fixing portion 1311 and the supporting portion 1313 are located in the same plane. The first and second side portions 1312b and 1312c are mirror images, i.e. the edge 1312 has an isosceles trapezoid cross-section. It will be appreciated that in other embodiments, the cross-sectional shape of bellows 1312 may be other due to the relationship between the plane of support portion 1313, the plane of top portion 1312a and the plane of retainer portion 1311, for example, as shown in fig. 5, the plane of support portion 1313 is located between the plane of top portion 1312a and the plane of retainer portion 1311, and as shown in fig. 6, the plane of retainer portion 1311 is located between the plane of top portion 1312a and the plane of support portion 1313.

Please refer to fig. 1, fig. 3 and fig. 4 together. The back plate 150 is provided with a central through hole 151. The back plate 150 is circumferentially provided with a plurality of through grooves 152. The bottom of the through slots 152 extends above the circuit board 170. That is, the through-groove 152 is disposed to make the upper and lower spaces of the back plate 150 conductive. The central through hole 151 and the through slots 152 are arranged such that the back plate 150 allows air to pass through the electret and the back plate 150 up and down during movement of the mass 132. And the through slots 152 can further reduce the mass of the electret bone conduction microphone 100.

The above embodiments of the present invention are only described, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept, but these all fall into the protection scope of the present invention.

Claims

1. An electret bone conduction microphone is characterized by comprising a shell with an accommodating space, a circuit board fixed on the shell and enclosing the shell into the accommodating space, a diaphragm assembly, a back plate and an insulating isolating piece, wherein the diaphragm assembly, the back plate and the insulating isolating piece are accommodated in the accommodating space;

2. The electret bone conduction microphone of claim 1, wherein: the mass block is fixed on the surface of the fixing part, which is far away from the back plate.

3. The electret bone conduction microphone of claim 1, wherein: the folding ring is convex towards the direction far away from the back plate.

4. The electret bone conduction microphone of claim 3, wherein: the edge has a top part close to the shell along the vibration direction, and a first side part and a second side part which are connected with the top part and are oppositely arranged;

the end of the first side branch part far away from the top branch part is connected with the outer edge of the fixing part, and the end of the second side branch part far away from the top branch part is connected with the inner edge of the supporting part.

5. The electret bone conduction microphone of claim 4, wherein: the included angle range of the bus of the first side subsection and the plane surrounded by the outer edge of the fixing part is more than 90 degrees and less than 180 degrees;

the included angle range of the bus of the second side subsection and the plane enclosed by the inner edge of the supporting part is more than 0 degree and less than 90 degrees.

6. The electret bone conduction microphone of claim 5, wherein: the fixing part, the top part and the supporting part are planar and parallel to each other, and the vertical distance from the top part to the fixing part is equal to the thickness of the mass block.

7. The electret bone conduction microphone of claim 6, wherein: the included angle between the generatrix of the first side subsection and the plane of the top subsection is equal to the included angle between the generatrix of the second side subsection and the plane of the top subsection.

8. The electret bone conduction microphone of claim 7, wherein: the fixing part and the supporting part are positioned in the same plane.

9. The electret bone conduction microphone of claim 8, wherein: the insulating spacer is annular.

10. The electret bone conduction microphone of any one of claims 1 to 9, wherein: the circuit board is provided with an FET or an ASIC;

the FET is used for amplifying and outputting the voltage signal generated by the displacement, and the ASIC is used for amplifying and outputting the voltage signal generated by the displacement.

11. The electret bone conduction microphone of claim 10, wherein: the backboard is provided with a central through hole, the backboard is circumferentially provided with a plurality of through grooves, and the groove bottoms of the through grooves extend to the upper part of the circuit board.

12. The electret bone conduction microphone of claim 11, wherein: the conductive diaphragm is connected with the shell through a metal gasket.

13. The electret bone conduction microphone of claim 12, wherein: the back plate is connected with the circuit board through a support ring.