CN201571198U - Moving magnet plane coil type microphone - Google Patents
Moving magnet plane coil type microphone Download PDFInfo
- Publication number
- CN201571198U CN201571198U CN2009202560642U CN200920256064U CN201571198U CN 201571198 U CN201571198 U CN 201571198U CN 2009202560642 U CN2009202560642 U CN 2009202560642U CN 200920256064 U CN200920256064 U CN 200920256064U CN 201571198 U CN201571198 U CN 201571198U
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- coil
- planar coil
- moving magnet
- magnetic film
- type microphone
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Abstract
A moving magnet plane coil type microphone comprises a spiral plane coil and a magnetic film facing to each other, wherein a clearance is arranged between the spiral plane coil and the magnetic film. Compared with the prior art, the moving magnet plane coil type microphone has the following advantages: the original magnetic body which does not move is changed to be movable and move along with the function of sound pressure, thus changing the structure that a movable coil is connected with a vibrating film (sound film) in a movable coil microphone; the movable coil adopted in the utility model is changed from a common solenoid coil to a plane coil formed by spiral plane arrangement, thus reducing the size on the height direction in a large scale and achieving miniaturization. In the utility model, impedance is depended on the parameter of the spiral plane coil, so the moving magnet plane coil type microphone is low-impedance and can conduct transmission in long distance, without an impedance transformer.
Description
Technical field
The utility model relates to a kind of microphone, relates in particular to a kind of moving magnet planar coil type microphone.
Background technology
Common moving-coil microphone is that cover poises a coil (moving-coil) on the fixing permanent magnet core body, above the coil and a vibrating membrane (sound film) bonding under unstressed, the state that do not stress, when extraneous acoustic pressure makes the vibrating membrane vibration.At this moment it just drives coil movement, as the coil that moves in magnetic field, will produce motional electromotive force, and this motional electromotive force that corresponding sports produces with the acoustic pressure effect just becomes the voltage output with the audio frequency variation by sound-electricity after the output.This has just finished the effect of sound-electricity conversion.This moving coil microphone is because its part is difficult to microminiaturization.Though condenser microphone can be realized microminiaturization, but, condenser microphone (electret microphone) commonly used, it is that a film applying that has metallized is formed a zona on a becket for general condenser microphone, this zona is separated relative with the backplane of a sheet metal thirty years of age by a packing ring, formed a capacitor,, the relation of Q=CV has been arranged between the voltage V between the charge Q on the capacitor and the capacitor C of capacitor and capacitor two-plate according to physics principle.If acting on, external acoustic pressure makes on the vibrating membrane between vibrating diaphragm and backplane when changing apart from d, at this moment, the capacitor C of this capacitor can be by following relationship change: C=ε s/d, s: be the area of capacitor plate, ε: be the dielectric constant of capacitor medium, just when acoustic pressure strengthens, diminish apart from d between two-plate, then C can become greatly, when upwards vibrating as if vibrating diaphragm, d can become greatly, and then C diminishes.By the variation relation of Q=CV, then V is also with regard to respective change.Like this, along with sound pressure variations then d change, output voltage V respective change then is so just by because the sound-electric transformation that electric capacitance change is finished.
But because its capacitance of capacitive device is at the PF order of magnitude, then its impedance then is a high impedance.Like this, unfavorable to the signal transmission, owing to be high impedance, then the circuit transmission attenuation is big, can not long-distance transmissions.Therefore, just need an impedance transformer, what this impedance transformer was commonly used at present finishes with a field effect transistor (as: J-FET).Although now J-FET can do very for a short time, because its temperature characterisitic, be subjected to electromagnetic interference effect etc. that the performance of condenser microphone (electret microphone) is affected.
Summary of the invention
The utility model provides a kind of miniature Low ESR moving magnet planar coil type microphone.
The utility model adopts following technical scheme:
A kind of moving magnet planar coil type microphone comprises spiral planar coil and magnetic film, and the spiral planar coil faces mutually with magnetic film, is provided with the gap between spiral planar coil and magnetic film.
Compared with prior art, the utlity model has following advantage:
(1) the utility model has adopted and has allowed original motionless magnet become movably, and with acoustic pressure effect campaign, so changed the structure that moving-coil links to each other with vibrating membrane (sound film) in the moving coil microphone again, moving-coil of the present utility model changes the planar coil that the mode of spiral planar alignment is made into by general screwed pipe shape coil.Like this, just greatly reduce the size on its short transverse, thereby realized miniaturization.In the utility model, the parameter of spiral planar coil is depended in impedance, therefore, the utility model is low-impedance, and it need not impedance transformer, just can carry out long-distance transmissions thus, can not influence the performance of microphone because of temperature characterisitic, electromagnetic interference etc. as condenser microphone yet.This just makes the utility model have the advantage that volume is little, impedance is low simultaneously, and makes it become miniature low-impedance moving magnet planar coil type microphone.
(2) sensitivity that the neodymium iron boron micro mist film that the utility model adopted can improve microphone.
(3) along with the microminiaturization of microphone, vibrating diaphragm also can be more and more littler.In order to improve the compliance of system, the utility model has been offered pore, and this pore reduces vibrating diaphragm (magnetic film) damping action, thereby can make its sensitivity be able to further raising.
In addition, the moving magnet planar coil type micro-microphone has cost low, makes advantages such as simple, that performance is good.
Description of drawings
Fig. 1 is a structural representation of the present utility model.
Fig. 2 is another structural representation of the present utility model.
Fig. 3 is a structural representation more of the present utility model.
Embodiment
A kind of moving magnet planar coil type microphone comprises spiral planar coil 1 and magnetic film 2, and spiral planar coil 1 faces mutually with magnetic film 2, is provided with the gap between spiral planar coil 1 and magnetic film 2.In the present embodiment:
Be provided with cover 3 at spiral planar coil 1 and magnetic film 2 outsides, on cover 3, be provided with passage, dustcloth 4 is arranged at sound passage upper cover.
The gap is formed by the pad 7 that is located between spiral planar coil 1 and the magnetic film 2, and described pad 7 can directly be placed between spiral planar coil 1 and the magnetic film 2, also can be connected on the magnetic film 2, can also be located on the cover 3.The specific implementation of described pad 7 has multiple, for example:
(1) described pad 7 is a cushion block;
(2) described pad 7 is ring;
(3) described pad 7 is for being provided with thrust (with reference to Fig. 3) at the edge of spiral planar coil;
(4) be fixed magnetic film 2 and make it smooth, usually magnetic film 2 be fixed on the zona that present embodiment just can use this zona simultaneously as filling up.
Present embodiment is provided with pore 5 on magnetic film 2, also can be provided with the pore 8 that communicates with gap between the magnetic film 2 with spiral planar coil 1 on 3 at cover; The magnetic film 2 of present embodiment is a neodymium iron boron micro mist film.
For obtaining magnetic film 2 or neodymium iron boron micro mist film sneaks into Nd iron boron micro mist in the glue, utilize lacquering technique to make it evenly to be coated with again on the polymer film, cover polymer film more thereon with the following Yi Tu Nd iron same material of boron micro mist film (or different material), after this composite membrane magnetized, promptly can be made into strong magnetic film.In addition,
(1) feature of the present utility model just be on the principle and general microphone inequality.It is magnetic, planar coil, Low ESR, midget microphone.
In the general moving-coil microphone, the magnetic flux density of permanent magnet is B, and moving-coil is being 1 perpendicular to the length on the direction in magnetic field.When making coil movement velocity be v on perpendicular to magnetic direction, then because acoustic pressure effect and " moving giving birth to " electromotive force of producing on coil is owing to the acoustic pressure effect:
And in the utility model patent, if the area of coil is S, the vibrating diaphragm of Dai You Nd iron boron micro mist moves under the acoustic pressure effect, and makes its magnetic induction density B time to time change.At this moment rate of change is
At this moment the electromotive force that produces on coil is " inducting " electromotive force, and its size is:
This is two different notions on physical principle.
(2) moving magnetic part Shi of the present utility model constitutes Nd iron boron micro mist with the method that embeds (sandwiching).
First kind of manufacture method Shi sneaks in the polymeric liquid of fusion behind Nd iron boron micro mist parcel, makes it in the embedded polymer thing film by hot pressing, stretching.
Second kind of manufacture method Shi all has Nd iron boron micro mist in the colloid of being scattered in, and makes it evenly to be coated on the polymeric film surface by whirl coating.
After second kind, the third method are coated in polymeric film surface with Nd iron boron micro mist, cover the one layer of polymeric film more thereon, this tunic and have the polymer film of Nd iron boron micro mist to make also can to make different material with material.
(3) shape of planar coil is pressed shape requirement and is decided, and can be circular vortex solid matter formula coiling, also can be racetrack close around arranging of rectangle (square).
Along with the microminiaturization of device, planar coil also can be the mode etching formation with photoengraving.
If then need to consider its sense of current, with the consistency of the sense of current that guarantees generation with the multilayer planar coil.
(4) because the sensitivity of microphone is to be proportional to
, S
dIt is the equivalent stiffness of vibrating diaphragm; S
bIt is the equivalent stiffness of cavity between vibrating diaphragm and planar coil.Therefore, in order to improve the sensitivity of microphone.The magnetic power of Chu Nd iron boron film outside the factors such as the number of turns of planar coil, reduces the equivalent stiffness of vibrating diaphragm, and promptly the tension force size of film influences again sensitivity.S
dLittle then sensitivity will improve, if use the laser method perforate on the vibrating diaphragm, then makes S
bReduce and sensitivity is improved.
Claims (6)
1. a moving magnet planar coil type microphone is characterized in that comprising spiral planar coil (1) and magnetic film (2), and spiral planar coil (1) faces mutually with magnetic film (2), is provided with the gap between spiral planar coil (1) and magnetic film (2).
2. moving magnet planar coil type microphone according to claim 1 is characterized in that being provided with cover (3) at spiral planar coil (1) and magnetic film (2) outside, is provided with passage on cover (3), at sound passage upper cover dustcloth (4) is arranged.
3. moving magnet planar coil type microphone according to claim 1 is characterized in that magnetic film (2) is a neodymium iron boron micro mist film.
4. moving magnet planar coil type microphone according to claim 1 is characterized in that the gap is formed by the pad (7) that is located between spiral planar coil (1) and the magnetic film (2).
5. moving magnet planar coil type microphone according to claim 1 is characterized in that being provided with pore (5) on magnetic film (2).
6. moving magnet planar coil type microphone according to claim 1 or 5 is characterized in that being provided with the pore (8) that communicates with gap between the magnetic film (2) with spiral planar coil (1) on cover (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202560642U CN201571198U (en) | 2009-12-02 | 2009-12-02 | Moving magnet plane coil type microphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202560642U CN201571198U (en) | 2009-12-02 | 2009-12-02 | Moving magnet plane coil type microphone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201571198U true CN201571198U (en) | 2010-09-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202560642U Expired - Lifetime CN201571198U (en) | 2009-12-02 | 2009-12-02 | Moving magnet plane coil type microphone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201571198U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8718317B2 (en) | 2011-05-19 | 2014-05-06 | Zonghan Wu | Moving-magnet electromagnetic device with planar coil |
| CN104703103A (en) * | 2015-03-24 | 2015-06-10 | 安徽理工大学 | Super-magnetostrictive thin film type sound sensor |
-
2009
- 2009-12-02 CN CN2009202560642U patent/CN201571198U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8718317B2 (en) | 2011-05-19 | 2014-05-06 | Zonghan Wu | Moving-magnet electromagnetic device with planar coil |
| CN104703103A (en) * | 2015-03-24 | 2015-06-10 | 安徽理工大学 | Super-magnetostrictive thin film type sound sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100901 Effective date of abandoning: 20091202 |
|
| RGAV | Abandon patent right to avoid regrant |