Patent Grant
10264360
This application is a national stage application, filed under 35 U.S.C. § 371, of International Application No. PCT/CN2015/095680, filed on Nov. 26, 2015, which claims priority to Chinese Application No. 201510149780.0 filed on Mar. 31, 2015 and Chinese Application No. 201520763528.4 filed on Sep. 29, 2015, the contents of which are hereby incorporated by reference in their entirety.
The present disclosure relates to a structure for detecting vibration displacement of a speaker and an acoustoelectric inter-conversion dual-effect device.
In the prior art, whether for a micro speaker or a large speaker, the problem which limits the maximum power application of the product when operating in low frequency conditions lies in that: under a large power, the voice coil operating in low frequency conditions produces an excessive displacement which will cause abrupt raising distortion and even causes an obvious collision problem between the voice coil and the magnetic circuit system, which will cause mechanical damage to the product system.
For this problem, the current solution is to adopt an intelligent power amplification control unit to control the power of the speaker product. The actual displacement of the vibration system of the speaker is “deduced” according to input information (such as voltage) and monitored information (such as current) and physical parameters of the speaker. The power of the speaker product is reduced when the actual displacement exceeds a preset threshold.
However, the deduction of the actual displacement by the intelligent power amplification control unit is still built on a hypothetical theoretical model which still has certain differences from the actual product. In addition, for micro speakers produced in batch, there are always some deviations in the physical parameters of the speakers and 100% consistence cannot be realized. The above reason causes that it is difficult for the deduction of the actual displacement by the intelligent power amplification control unit to reflect the real displacement of each speaker product precisely and in real time.
An object of embodiments of the present invention is to provide a new solution for detecting the vibration displacement of a speaker device.
According to a first aspect of embodiments of the present invention, a structure for detecting the vibration displacement of a speaker is provided, including: a vibration system having a movable pole plate; a magnetic circuit system; and a fixed pole plate provided under the vibration system and opposite to the movable pole plate, the movable pole plate and the fixed pole plate constituting a capacitor.
Optionally, the vibration system includes a diaphragm and a voice coil located under the diaphragm, the diaphragm includes an electret layer and a metal layer attached to the electret layer, and the electret layer and the metal layer constitute the movable pole plate.
Optionally, the diaphragm also includes a plastic film layer laminated with the movable pole plate and the plastic film layer is a film with a single layer or a film with a plurality of layers which are laminated.
Optionally, the vibration system includes a diaphragm and a voice coil located under the diaphragm, the diaphragm includes a diaphragm body portion and a reinforcement portion, the diaphragm body portion includes a planar portion in the middle, a surround portion located at the edge of the planar portion and a fixture portion located on the outermost, the reinforcement portion is provided on the planar portion; and the diaphragm body portion includes an electret layer and a metal layer attached to the electret layer, and the electret layer and the metal layer constitute the movable pole plate.
Optionally, the diaphragm body portion also includes a plastic film layer laminated with the movable pole plate and the plastic film layer is a film with a single layer or a film with a plurality of layers which are laminated.
Optionally, the electret layer covers the whole area of the diaphragm body portion or merely covers the area of the planar portion.
Optionally, the metal layer covers the whole area of the diaphragm body portion; or, the metal layer includes a first area completely covering the planar portion, a second area completely covering the fixture portion and a third area partially covering the surround portion, wherein the third area communicates with the first area and the second area.
Optionally, the metal layer is located at the uppermost layer of the diaphragm body portion, wherein an electrical connector is set on the metal layer above the fixture portion.
Optionally, the electrical connector is a metal connector or conductive resin coated on the metal layer.
Optionally, the structure further comprises a thermal insulator material layer provided between the diaphragm and the voice coil, the thermal insulator material layer covers the whole area of one side of the diaphragm close to the voice coil or merely covers the area of the diaphragm connected to the voice coil.
Optionally, the magnetic circuit system is located under the vibration system and includes a washer, the washer being the fixed pole plate.
Optionally, the magnetic circuit system further includes a magnet and a frame located under the washer, and an opening is provided at the center of the washer, the magnet and the frame.
Optionally, the material of the electret layer includes any or a combination of: polytetrafluoroethylene, polyvinyl-difluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyetherimide, or polyethylene terephthalate.
Optionally, the vibration system includes a diaphragm and a voice coil located under the diaphragm, and the magnetic circuit system is located under the vibration system and includes a washer and a magnet; and the movable pole plate is attached to the diaphragm, the upper surface of the washer is provided with an electret film, and the electret film is a fixed pole plate.
Optionally, the movable pole plate is a metal layer or a flexible circuit board layer with a metal layer in the middle; or, the metal layer or the flexible circuit board layer with a metal layer in the middle are attached on or under the diaphragm.
According to a second aspect of embodiments of the present invention, an acoustoelectric inter-conversion dual-effect device is provided, comprising the structure mentioned above and an impedance transformer connected to the capacitor and including a field effect transistor and a diode.
The inventors of embodiments of the present invention have found that there is no technical solution to detect the actual displacement of a vibration system by detecting the change in capacitance. Thus, such a solution for solving problems has never been contemplated or predicted by those skilled in the art. Therefore, each of embodiments of the present invention is a new technical solution.
The embodiments of the present invention designs a capacitor structure for detecting the vibration displacement of a vibration system. The movable pole plate of the capacitor is provided on a vibration system and a fixed pole plate is provided under the vibration system and fixed in position. When the vibration system vibrates, the change in capacitance is detected to calculate the actual displacement of the vibration system, which can reduce the power of the speaker device when the actual displacement of the vibration system exceeds a safety threshold. For an electronic device adopting such a speaker structure, the displacement of each speaker product can be detected in real time at the system end of the electronic device.
The other features and advantages of the present invention will become clear according to the detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.
The accompanying drawings incorporated in the description and constituting a part of the description illustrate the embodiments of the present invention and used to explain the principle of the present invention along therewith.
1 diaphragm, 2 voice coil, 3 washer, 4 magnet, 5 frame, 61 electrical connector, 6, metal connector, 7 opening, 8 field effect transistor, 9 inner magnetic gap; 11 planar portion, 12 surround portion, 13 fixture portion, 101 electret layer, 102 metal layer, 103 plastic film layer, 104 thermal insulator material layer; 1021 first area, 1022 second area, 1023 third area; 100 metal layer, 200 flexible circuit board layer with metal layer in the middle, 300 electret film, 201 central portion, 202 ring portion, and 203 connector portion.
Various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that unless stated specifically otherwise, the relative arrangement of the components and steps illustrated in these embodiments, the numeral expressions and the values do not limit the scope of the present invention.
The description of at least one exemplary embodiment of the present invention is actually merely illustrative rather than limiting the present invention and the application or use thereof.
Technologies, methods and devices known to those skilled in the art may not be described in detail, but when appropriate, the technologies, methods and devices shall be regarded as a part of the description.
Any particular value in all examples illustrated and described here shall be construed as merely illustrative rather than limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that similar signs and letters represent similar items in the following figures, and thus, once a certain item is defined in a figure, there is no need to further describe the same in the following figures.
The embodiments of the present invention designs a capacitor structure for detecting the actual vibration displacement of a vibration system of a speaker. The capacitor is constituted by a movable pole plate and a fixed pole plate opposite to the movable pole plate. The movable pole plate is a part of the vibration system and vibrates along with the vibration system. The fixed pole plate is provided under the vibration system and fixed relative to the housing location of the speaker. When the vibration system vibrates, the movable pole plate also vibrates. The distance between two pole plates changes, causing change in capacitance. The actual displacement of the vibration system can be calculated by directly monitoring the value change of the capacitor or indirectly monitoring the current change of the circuit connected to the capacitor.
During the application of embodiments of the present invention, whether the actual displacement of the vibration system has exceeded a preset safety threshold can be monitored, and if yes, the input power of the speaker will be reduced. Whether the value change of the capacitor has exceeded a preset safety threshold can be monitored, and if yes, the input power of the speaker will be reduced. Whether the current change of the circuit connected to the capacitor has exceeded a preset safety threshold can be monitored, and if yes, the input power of the speaker will be reduced.
The embodiments of the present invention may connect an intelligent power amplification control unit to the capacitor to monitor the actual displacement of the vibration system and reduce the input power of the speaker when necessary, protecting the speaker from overdue distortion or being subjected to physical damage.
(I) Description of a Structure for Detecting the Vibration Displacement of a Speaker According to a First Implementation of the Present Invention with Reference to
The vibration system of a speaker includes a diaphragm and a voice coil located under the diaphragm. The embodiments of the present invention may use the diaphragm to constitute a movable pole plate. In particular, the diaphragm at least includes an electret layer and a metal layer attached to the electret layer. The electret layer and the metal layer constitute the movable pole plate. When the energized voice coil vibrates under the effect of the magnetic circuit system, the voice coil drives the diaphragm to vibrate. The vibration of the diaphragm will make the capacitor constituted by the movable pole plate and the fixed pole plate change. Since the electret layer has stable charges, the actual displacement of the vibration system can be calculated by monitoring the change in capacitance of the capacitor. Alternatively, the actual displacement of the vibration system can be calculated by indirectly monitoring the current change of the circuit connected to the capacitor.
Referring to
The diaphragm body portion at least includes an electret layer and a metal layer attached to the electret layer. The electret layer and the metal layer constitute the movable pole plate. In order to improve the elastic property of the diaphragm, the diaphragm body portion may also include a conventional plastic film layer (a film with a single layer or a film with a plurality of layers which are laminated). The material of the electret layer may include any or a combination of: polytetrafluoroethylene, polyvinyl-difluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyetherimide, or polyethylene terephthalate.
Referring to
In order to improve the elastic property of the diaphragm, the diaphragm body portion may also include a conventional plastic film layer (a film with a single layer or a film with a plurality of layers which are laminated), that is, being formed by coating an electret layer and a metal layer attached to the electret layer on an upper surface or a lower surface of the conventional plastic film layer.
The embodiments of the present invention may also include a thermal insulator material layer 104 provided between the diaphragm 1 and the voice coil 2 to avoid the heat of the voice coil under large power being transferred to the electret layer 101 to cause the performance of the electret layer 101 reduced.
Referring to
Referring to
Since the speaker with an impedance transformer possesses all core parts of a capacitive microphone, it may also be used as a capacitive microphone. The embodiments of the present invention also provides an acoustoelectric inter-conversion dual-effect device, including: a vibration system having a movable pole plate; a magnetic circuit system; a fixed pole plate provided under the vibration system and opposite to the movable pole plate, the movable pole plate and the fixed pole plate constituting a capacitor; and an impedance transformer connected to the capacitor and including a field effect transistor 8 and a diode. The dual-effect device may be used as a speaker or a microphone.
(II) Description of a Structure for Detecting the Vibration Displacement of a Speaker According to a Second Implementation of the Present Invention with Reference to
The upper surface of the washer 3 is provided with an electret film 300. The electret film 300 is a fixed pole plate. In order to keep pressure equalization between the diaphragm and the washer 3, provided is an inner magnetic gap 9 between the diaphragm and the washer 3.
The electret film 300 may be formed by an electret material which is polarized. The electret film 300 may cover the whole area of the upper surface of the washer 3. The material of the electret layer 300 may be any or a combination of: polytetrafluoroethylene, polyvinyl-difluoride, polyvinylidene fluoride, polyethylene, polypropylene, polyetherimide, or polyethylene terephthalate. The material of the electret layer 300 is preferably polytetrafluoroethylene and has charges after polarization.
The movable pole plate may be formed using the diaphragm. The movable pole plate in
The material of the diaphragm is preferably silica or silicon rubber. Both the two materials can be resistant to high temperature of 140□ to avoid product performance degradation at high temperature. In order to improve the elastic property of the diaphragm, the diaphragm may also include a conventional plastic film layer (a film with a single layer of film or a film with a plurality of layers which are laminated).
When the energized voice coil 2 vibrates under the effect of the magnetic circuit system, the voice coil 2 drives the diaphragm to vibrate. The vibration of the diaphragm will make the capacitance value of the capacitor constituted by the movable pole plate and the fixed pole plate change. Since the electret film 300 has stable charges, the actual displacement of the vibration system can be calculated by monitoring the change in capacitance of the capacitor. Alternatively, the actual displacement of the vibration system can also be calculated by indirectly monitoring the current change of the circuit connected to the capacitor.
It can be seen from
Referring to
Since the magnet 4 and the frame 5 are both conductors, the fixed pole plate may be connected to an impedance transformer through the bottom of the frame 5. The impedance transformer includes a field effect transistor 8 and a diode (not shown). The impedance transformer is then connected to a power amplifier of the system end. Furthermore, the power amplifier may be connected to an intelligent power amplification control unit which is used for detecting the change in the capacitance value of the capacitor and calculating the actual displacement of the vibration system to control the input power of the speaker device.
Since the speaker with an impedance transformer possesses all core parts of a capacitive microphone, it may also be used as a capacitive microphone. The embodiments of the present invention also provides an acoustoelectric conversion dual-effect device, including: a vibration system having a movable pole plate; a magnetic path system; a fixed pole plate provided under the vibration system and opposite to the movable pole plate, the movable pole plate and the fixed pole plate constituting a capacitor; and an impedance transformer connected to the capacitor and including a field effect transistor 8 and a diode. The dual-effect device may be used as a speaker or a microphone.
Although some specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are merely for the sake of description rather than limiting the scope of the present invention. It should be understood by those skilled that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is limited by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015 2 0763528 U | Sep 2015 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2015/095680 | 11/26/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/155340 | 10/6/2016 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20040202347 | Koike | Oct 2004 | A1 |
| 20120177215 | Bose | Jul 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 1198759 | Nov 1998 | CN |
| 2519575 | Oct 2002 | CN |
| 102128641 | Jul 2011 | CN |
| 104780489 | Jul 2015 | CN |
| 204518064 | Jul 2015 | CN |
| 0885918 | Dec 1998 | EP |
| Entry |
|---|
| International Search Report dated Jan. 29, 2016 in International Patent Application No. PCT/CN2015/095680. |
| Written Opinion dated Jan. 29, 2016 in International Patent Application No. PCT/CN2015/095680. |
| Number | Date | Country | |
|---|---|---|---|
| 20180035212 A1 | Feb 2018 | US |
