WO2020057009A1

WO2020057009A1 - Miniature sound production device

Info

Publication number: WO2020057009A1
Application number: PCT/CN2018/125700
Authority: WO
Inventors: 刘迎新; 王建建; 刘存帅; 刘春发
Original assignee: 歌尔股份有限公司
Priority date: 2018-09-21
Filing date: 2018-12-29
Publication date: 2020-03-26
Also published as: CN109246562A; CN109246562B

Abstract

The present invention discloses a miniature sound production device. The device comprises a vibration system consisting of a voice coil and a centering disk made of an insulating material; the centering disk comprises a central portion located at the center, an edge portion located at the periphery, and a cantilever located between the central portion and the edge portion; one end of the voice coil in an axial direction is fixed at the central portion; the voice coil comprises a body portion and a lead wire, the lead wire is led out along the cantilever and is fixed on the cantilever; the centering disk is a single-layer structure made of one material layer; or, the centering disk is of a multi-layer structure composed of a plurality of material layers or a multi-layer structure composed of a plurality of material layers and glue layers, and the material layers are made of the same material or different materials; the material layers are made of a high molecular polymers; and the thickness of the centering disk is 8 to 225 microns.

Description

Miniature sound device

Technical field

The invention relates to the technical field of electro-acoustic conversion, and more particularly, to a miniature sounding device.

Background technique

Micro-sounding devices usually include a vibration system and a magnetic circuit system. The vibration system includes a diaphragm and a voice coil. One end of the voice coil is fixed at the center of the diaphragm, and the other end is inserted into the magnetic gap of the magnetic circuit system. Micro-sounding devices face polarization problems. Increasing the volume will increase the polarization amplitude of the vibration system, resulting in loss of sound quality. To reduce polarization, in some examples, the vibration system is provided with a centering support. The centering piece is fixed between the diaphragm and the voice coil. The centering support forms an elastic supporting force, which effectively reduces polarization.

Existing centering brackets are usually made of FPCB. The FPCB usually includes a conductive metal layer and an insulating layer covering the outside of the conductive metal layer. The conductive metal layer is used for conduction between the voice coil and external components, and can provide good resilience.

However, the existing centering bracket made of FPCB has a complicated structure, high cost, and the effect of reducing polarization is not obvious.

Therefore, it is necessary to provide a new technical solution to solve the above technical problems.

Summary of the Invention

An object of the present invention is to provide a new technical solution for a miniature sounding device.

According to a first aspect of the present disclosure, a micro-sounding device is provided. The micro sounding device includes a vibration system including a voice coil and a centering support made of an insulating material, the centering support including a center portion located at a center, an edge portion located at an outer periphery, and the center portion and A cantilever between the edge portions, and one end of the voice coil in the axial direction is fixed to the central portion;

The voice coil includes a body portion and a lead wire, and the lead wire is led out along the cantilever and is fixed on the cantilever;

The centering support piece is a single-layer structure made of one material layer; or,

The centering support sheet is a multilayer structure composed of multiple material layers or a multilayer structure composed of multiple material layers and glue layers, and the materials of the multiple material layers are the same or different;

The material layer is made of a high molecular polymer; the thickness of the centering support piece is 8-225 μm.

Optionally, the material of the material layer is polyimide.

Optionally, the material of the material layer is any one of polyimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, and thermoplastic elastomer.

Optionally, the thickness of the centering branch is 75-200 μm.

Optionally, the centering support sheet includes two of the material layers and the damping rubber layer between the two material layers; or

The centering support piece includes three layers of the material and two layers of the damping rubber disposed between the three layers of the material.

Optionally, the damping rubber layer is at least one of an acrylic rubber, an epoxy rubber, a polyurethane rubber, and a silicone rubber.

Optionally, the tensile modulus of the centering support at room temperature is 1-7 GPa.

Optionally, the tensile modulus of the centering branch at room temperature is 3-5 GPa.

Optionally, the body portion includes two leading edges opposite to each other, the leads are respectively led out from the two leading edges, and the centering branch includes two first edges corresponding to the two leading edges. One of the cantilevers is disposed on each of the first sides, and the two leads are respectively fixed on the two cantilevers.

Optionally, one end of the two first sides is defined as a first end, and the other end is defined as a second end;

One end of one of the cantilevers is connected to a first end of a central portion on the first side, and the other end is connected to a second end of an edge portion on the first side;

One end of the other cantilever is connected to a second end of a central portion on the first side, and the other end is connected to a first end of an edge portion on the first side.

Optionally, the lead includes an arc-shaped portion close to the body portion, and at least a portion of the arc-shaped portion is suspended between the cantilever and the edge portion.

Optionally, the long-term use temperature of the material layer is above 160 ° C.

According to an embodiment of the present disclosure, the micro-sounding device has a feature of low polarization.

Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a cross-sectional view of a portion of a centering leg according to an embodiment of the present disclosure.

FIG. 2 is a cross-sectional view of a portion of a three-layer structure centering leg according to an embodiment of the present disclosure.

3 is a cross-sectional view of a portion of a five-layer structured centering leg according to an embodiment of the present disclosure.

4 is a cross-sectional view of a portion of yet another centering leg according to an embodiment of the present disclosure.

FIG. 5 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of a micro-sounding device provided with a lead suspended.

FIG. 6 is a graph showing changes in amplitude and frequency of different portions of a diaphragm of a micro-sounding device in which a lead is fixed on a centering support according to an embodiment of the present disclosure.

FIG. 7 is a THD curve of a micro-sounding device and a micro-sounding device of an FPC material centering support according to an embodiment of the present disclosure.

FIG. 8 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of a micro-sounding device according to an embodiment of the present disclosure.

FIG. 9 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of another micro-sounding device according to an embodiment of the present disclosure.

FIG. 10 is an exploded view of a micro sounding device according to an embodiment of the present disclosure.

Reference sign description:

11: polyimide film layer; 12: damping rubber layer; 13: edge portion; 14: center portion; 15: cantilever; 16: lead wire; 17: voice coil; 18: reinforcement layer; 19: diaphragm; 20 : Centering support piece; 21: housing; 22: permanent magnet; 23: magnetic yoke; 24: first side; 25: first end; 26: second end.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of at least one exemplary embodiment is actually merely illustrative and is in no way intended to limit the invention and its application or uses.

Techniques, methods, and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but where appropriate, the techniques, methods, and equipment should be considered as part of the description.

In all examples shown and discussed herein, any specific value should be construed as exemplary only and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, so once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

According to one embodiment of the present disclosure, a micro sounding device is provided. Micro sound devices usually refer to embedded sound units or sound modules used in portable electronic products. This sounding device has the characteristics of small size, flatness, and thinness. For example, a sound generating device for a headset, a mobile phone, a tablet computer, a game console, a wearable device, and the like.

As shown in FIG. 10, the micro sound generating device includes a housing 21, a vibration system, and a magnetic circuit system. The magnetic circuit system includes a magnetic yoke 23 and a permanent magnet 22 fixed on the magnetic yoke 23. The permanent magnet 22 forms a magnetic gap.

The vibration system includes a diaphragm 19, a voice coil 17, and a centering support 20 made of an insulating material. The centering piece 20 is fixed between the voice coil 17 and the diaphragm 19.

As shown in FIG. 4, the centering leg includes a center portion 14 located at the center, an edge portion 13 located at the outer periphery, and a cantilever 15 located between the center portion 14 and the edge portion 13. The voice coil 17 includes a body portion and a lead 16. The lead 16 extends from the body portion. The lead is drawn out along the cantilever 15 and is fixed on the cantilever 15. Compared with the manner in which the lead 16 is suspended, in this arrangement, the lead 16 is not easily oscillated due to the fixation of the lead to the cantilever 15, and the resonance peak generated by the lead 16 can be effectively reduced.

In addition, the lead 16 can move with the centering support 25, reducing the risk of disconnection during operation of the micro-sounding device.

In this example, the centering support 20 is a single-layer structure made of one material layer; or, the centering support 20 is a multi-layer structure composed of a plurality of material layers or a plurality of material layers and glue A multi-layer structure composed of layers, the materials of multiple material layers are the same or different. The material layer is made of a high molecular polymer. The centering support 20 can effectively reduce the polarization of the vibration system.

In this example, one end of the voice coil 17 in the axial direction is fixed to the center portion 14. A reinforcing layer 18 is further provided in the middle of the diaphragm. The casing 21 has a ring structure, such as a rectangular ring. An edge portion 13 of the centering leg 20 is fixed to the housing 21.

In this example, the thickness of the centering leg 20 is 8-225 μm. The centering piece in this thickness range takes into account both high stiffness and a wide linear range.

In one example, the material of the material layer is polyimide.

In one example, the material of the material layer is any one of polyimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, and thermoplastic elastomer. The material of the material layer may be any of the foregoing, or the material layer may be a composite of the above-mentioned multiple materials.

For example, the centering leg 20 has a single-layer structure. The centering support sheet 20 is a polyimide film layer 11. As shown in FIG. 1, the centering support sheet includes only one polyimide film layer 11. or,

The centering support sheet 20 has a composite structure. For example, the centering support sheet 20 includes a plurality of polyimide film layers 11, and a damping adhesive layer 12 is disposed between adjacent polyimide film layers 11. or,

The centering support 20 has a composite structure. For example, the centering support 20 includes a polyimide film layer 11 and a polyetheretherketone film layer, a polyetherimide film layer and a polyphenylene sulfide film layer, or a thermoplastic elastomer. Body film layer and polyetheretherketone. Multiple film layers are laminated together by a glue layer.

Of course, the composite film layer is not limited to the above embodiments, and those skilled in the art may select according to actual needs.

FIG. 2 is a cross-sectional view of a portion of a three-layer structure centering leg according to an embodiment of the present disclosure. In this example, the centering support includes two layers of material and a layer of damping glue between the two layers of material. For example, the material layer is the polyimide film layer 11. The two polyimide film layers 11 serve as surface layers. The damping adhesive layer 12 is located between the two polyimide film layers 11 to bond the two polyimide film layers 11 together.

FIG. 3 is a cross-sectional view of a part of a five-layer structure centering leg according to an embodiment of the present disclosure. In this example, the centering support sheet includes three material layers and two damping rubber layers 12 disposed between the three material layers. For example, the material layer is the polyimide film layer 11. The two polyimide film layers 11 serve as a surface layer, and the other serves as an intermediate layer. The damping rubber layer 12 is located on the upper and lower sides of the middle layer to bond the three polyimide film layers 11 together.

Of course, the polyimide film layer 11 in the centering support sheet may also be four, five, six layers, etc., which is not limited in this disclosure.

The polyimide film layer 11 is made of polyimide. The polyimide film layer 11 serves as a base material layer of the centering support. Polyimide (PI) means that the main chain contains imide groups

Polymer. The polyimide (PI) includes, but is not limited to, at least one of an aromatic imide, a semi-aromatic imide, an aliphatic imide, and a modified polyimide. Polyimide is polymerized from dianhydride polymer, tetraacid polymer and diamine polymer as raw materials. For example, the raw materials include aromatic diamines, aromatic diacid anhydrides, aromatic tetracarboxylic acids, aromatic dicarboxylic acid dialkyl esters, aliphatic diacid anhydrides, maleic anhydride, and the like.

In one example, the polyimide film layer 11 is formed by casting or injection molding. For example, a raw material is filled into a mold for molding to form a polyimide film layer 11 having a set shape.

Alternatively, a polyimide film or a polyimide and damping rubber composite film may be cut to form a polyimide film layer 11 having a predetermined shape.

When the micro-sounding device works for a long time and high power, the temperature will continue to rise, for example, the temperature can reach 150 ° C. It is difficult for ordinary centering branches to maintain stable operation at this temperature.

In one example, the long-term use temperature of the material layer is 160 ° C or higher. This makes the centering piece 20 have good durability. The miniature sounding device with the centering support 20 of this embodiment still has good resilience performance, good transient response, and low distortion under long-term, high-power working conditions.

For example, the polyimide film layer 11 has high-temperature resistance characteristics. The melting temperature can reach above 400 ° C. Long-term use temperature can reach above 200 ° C. The centering support including the polyimide film layer 11 has more excellent durability.

The damping adhesive layer 12 has good adhesion and damping effects, and can make the polyimide film layer 11 firmly compound together. For example, the damping rubber layer 12 is at least one of an acrylic rubber, an epoxy rubber, a urethane rubber, and a silicone rubber. The adhesion of the damping rubber layer 12 made of the above materials is firm and the damping effect is good, which can effectively reduce the noise of the micro sound device and enhance the sound quality of the micro sound device.

In addition, the damping rubber layer 12 can improve the resilience performance of the centering support.

In the centering support sheet 20 of the composite structure, the thicknesses of the respective polyimide film layers 11 may be the same or different. The thickness of the damping rubber layer 12 may be the same or different. Those skilled in the art can choose according to actual needs.

The thickness of the centering support 20 has a large effect on performance. If the thickness is too thin, the rigidity of the centering support is insufficient, and the improvement of polarization during vibration is small. If the thickness is too large, the linear range of the centering support sheet during vibration is small, and the pulling effect on the vibration system of the miniature sounding device is large. The micro-sounding device has large distortion and poor sound quality. The linear range refers to a range in which the change in displacement and the change in elastic force have a linear relationship.

The miniature sounding device has the characteristics of small polarization, good sounding effect, fast transient response and small distortion.

In one example, the thickness of the centering support 20 is 75-200 μm. The rigidity and linearity range of the centering branch in this thickness range are more moderate.

In one example, the tensile modulus of the centering support 20 at room temperature is 1-7 GPa. The elasticity and rigidity of the centering support within the stretched film range are good, and the polarization of the micro-sounding device is small.

Further, the tensile modulus of the centering support 20 at room temperature is 3-5 GPa. The polarization of the micro-sounding device is smaller in the stretched film amount range.

In one example, as shown in FIG. 4, the entire centering leg 20 is rectangular. The main body portion includes two opposite leading edges. The leads 16 are led out from two lead-out edges, respectively. The centering leg 20 includes two first edges 24 corresponding to the two lead-out edges. A cantilever 15 is provided on each first side 24. The two leads 16 are fixed to the two cantilevers 15 respectively. In this example, the outgoing line and the incoming line of the lead 16 are oppositely disposed. This makes the pulling effect of the lead 16 on the voice coil 17 more balanced, and further reduces the occurrence of polarization.

In one example, as shown in FIG. 4, one end of the two first edges 24 is defined as a first end 25 and the other end is defined as a second end 26. One end of one of the cantilevers 15 is connected to the first end 25 of the central portion on the first side 24 and the other end is connected to the second end 26 of the edge portion on the first side 24. One end of the other cantilever 15 is connected to the second end 26 of the central portion on the first side 24, and the other end is connected to the first end 25 of the edge portion on the first side 24. In this example, the outgoing line and the incoming line of the lead 16 are basically center symmetrical, which makes the structure of the vibration system more regular, the pulling effect of the lead is more balanced, and the polarization of the miniature sounding device is smaller.

In one example, the lead 16 includes an arcuate portion near the body portion. The arc-shaped portion is at least partially suspended between the cantilever 15 and the edge portion. For example, the arc-shaped portion is at least partially suspended between the cantilever 15 and the edge portion. The lead-out portion of the outgoing line and the incoming line forms an arc portion. Here, the length of the arc portion and the radius of curvature can be set according to actual needs. Generally, the starting end of the cantilever 15 is also curved. The radius of curvature of the arc-shaped portion should be larger than the starting end of the cantilever 15 so that the arc-shaped portion can be empty in the hollowed-out area between the cantilever 15 and the edge portion. The length of the arc-shaped portion is larger, which can effectively reduce the stress concentration of the lead 16, prevent breakage, and improve the reliability of the micro-sounding device.

In other examples, the whole of the centering support piece may also have a structure such as a circle, an ellipse, or a runway, and a person skilled in the art may select it according to the actual needs of the vibration system.

Figure 5-9 is a test curve of several miniature sounding devices. FIG. 5 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of a micro-sounding device provided with a lead suspended. FIG. 6 is a graph showing changes in amplitude and frequency of different portions of a diaphragm of a micro-sounding device in which a lead is fixed on a centering support according to an embodiment of the present disclosure. FIG. 7 is a THD curve of a micro-sounding device and a micro-sounding device of an FPC material centering support according to an embodiment of the present disclosure. FIG. 8 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of a micro-sounding device according to an embodiment of the present disclosure. FIG. 9 is a graph showing changes in amplitude and frequency of different parts of a diaphragm of another micro-sounding device according to an embodiment of the present disclosure.

Among them, FIG. 5, FIG. 6, FIG. 8, and FIG. 9 are the change curves of the amplitude of different parts of the diaphragm with frequency. The diaphragm has a rectangular structure. The abscissa is frequency (Hz), and the ordinate is amplitude (mm). Among them, a curve is a change curve of the lead-out side of the diaphragm; b curve is a change curve of the opposite side of the lead opposite to the lead-out side; and c curve is a change curve of the center portion of the diaphragm.

FIG. 7 is a THD curve of a micro sound device using a single-layer polyimide centering support and a micro sound device using an FPC centering support. The abscissa is frequency (Hz) and the ordinate is THD. Among them, the d curve is the THD variation curve of the micro sounding device using the FPC centering support piece; the e curve is the variation curve of the micro sounding device using the single-layer polyimide centering support piece.

It can be seen from FIG. 5 that the curve on the opposite side of the lead has a resonance peak between 500-600 Hz. In the frequency range of 100-1000Hz, the amplitudes of the lead-out side, the opposite side of the lead, and the center are quite different. It can be seen from FIG. 6 that the curve of the opposite side of the lead changes relatively smoothly between 500-600 Hz, and almost no resonance peak appears. In the frequency range of 100-1000Hz, the amplitude difference between the lead-out side, the opposite side of the lead and the center is small. This indicates that the polarization of the micro-sounding device can effectively suppress polarization due to the use of the centering support of the present disclosure. The vibration of each part of the diaphragm is more balanced, and the sound generation effect of the miniature sound device is better.

In FIG. 8, the thickness of the centering support used in the micro sounding device is 50 μm. It can be seen from FIG. 8 that in the range of 100-800 Hz, the amplitudes of the lead-out side of the diaphragm, the opposite side of the lead, and the center portion are relatively large. Especially between 400-800Hz, the amplitude difference of each part is larger. This indicates that the thickness of the centering support is insufficient due to its thin thickness. The effect of the centering support on the improvement of polarization is not obvious.

In FIG. 9, the thickness of the centering bracket used in the micro sounding device is 150 μm. It can be seen from FIG. 9 that in the visible frequency range, the amplitude difference between the lead-out side of the diaphragm, the opposite side of the lead, and the center is small, and the vibration of each part is balanced. This shows that the thickness-improving effect of the centering support sheet on the polarization is obvious.

It can be seen from FIG. 7 that at 3000 Hz and 8000 Hz, the THD (Higher Harmonic Distortion) curve of the micro-sounding device using the FPC centering plate appears sharp. However, the THD curve of the micro-sounding device of the present disclosure is significantly lower at the above two frequencies, and no obvious peak appears. This shows that the higher-order harmonic distortion of the micro-sounding device of the present disclosure is significantly smaller than that of a micro-sounding device using an FPC centering support. The miniature sound emitting device of the embodiment of the present disclosure has a good effect of suppressing distortion.

In one example, the miniature sound device is a sound module. The sound generating module includes the above-mentioned centering support piece. The sound generating module includes a module housing and a miniature sound generating device arranged in the module housing. The module housing has a sound outlet hole which is in communication with the miniature sounding device. The vocal unit includes a diaphragm, a centering support, and a voice coil.

For example, the sound generating module is a side-out sound generating module. The side-out sounding module is to point out that the sound direction is located beside the vibration direction of the miniature sounding device. For example, the direction of sound is perpendicular to the direction of vibration. The stiffness of the side of the centering support piece near the sound hole is smaller than the stiffness of the side opposite to the side.

For example, the entire centering leg is rectangular. One of the two long sides is close to the sound hole and the other is away from the sound hole. One cantilever 15 is provided on the side close to the sound hole, and two cantilevers 15 are provided on the opposite side to change the stiffness of the two sides. Under normal circumstances, the amplitude of the side of the centering branch near the sound hole is smaller than the amplitude of the side opposite to the side. By reducing the rigidity of the cantilever 15 on this side, the occurrence of polarization can be effectively suppressed.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims

A miniature sounding device includes a vibration system including a voice coil and a centering support made of an insulating material. The centering support includes a central portion at a center, an edge portion at an outer periphery, and A cantilever between a central portion and the edge portion, and one end of the voice coil in the axial direction is fixed to the central portion;

It is characterized by,

The voice coil includes a body portion and a lead wire, and the lead wire is led out along the cantilever and is fixed on the cantilever;

The centering support piece is a single-layer structure made of one material layer; or,

The centering support sheet is a multilayer structure composed of multiple material layers or a multilayer structure composed of multiple material layers and glue layers, and the materials of the multiple material layers are the same or different;

The material layer is made of a high molecular polymer;

The thickness of the centering branch is 8-225 μm.
The micro sound device according to claim 1, wherein a material of the material layer is polyimide.
The micro-sounding device according to claim 1, wherein a material of the material layer is any one of polyimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, and thermoplastic elastomer.
The micro-sounding device according to claim 1, wherein the thickness of the centering branch is 75-200 μm.
The micro-sounding device according to claim 1, wherein the centering support includes two layers of the material and the damping rubber layer between the two layers of materials; or

The centering support piece includes three layers of the material and two layers of the damping rubber disposed between the three layers of the material.
The micro sound generating device according to claim 1, wherein the damping rubber layer is at least one of an acrylic rubber, an epoxy rubber, a urethane rubber, and a silicone rubber.
The micro-sounding device according to claim 1, wherein a tensile modulus of the centering support at room temperature is 1-7 GPa.
The micro-sounding device according to claim 7, wherein a tensile modulus of the centering branch at room temperature is 3-5 GPa.
The micro-sounding device according to claim 1, wherein the body portion includes two lead-out edges opposite to each other, the leads are led out from the two lead-out edges, and the centering branch piece includes a corresponding one One of the two cantilevers is provided on each of the two first sides, and the two leads are respectively fixed on the two cantilevers.
The micro-sounding device according to claim 9, wherein one end defining two first sides is a first end, and the other end is a second end;

One end of one of the cantilevers is connected to a first end of a central portion on the first side, and the other end is connected to a second end of an edge portion on the first side;

One end of the other cantilever is connected to a second end of a central portion on the first side, and the other end is connected to a first end of an edge portion on the first side.
The micro-sounding device according to claim 1, wherein the lead includes an arc portion near the body portion, and at least a portion of the arc portion is suspended between the cantilever and the edge portion.
The micro-sounding device according to claim 1, wherein a long-term use temperature of the material layer is 160 ° C or higher.