close

Вход

Забыли?

вход по аккаунту

?

JP2010050866

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2010050866
To secure an electromagnetic shield at a rear acoustic terminal without cost increase by a simpler
method. An acoustoelectric converter 30 including a diaphragm and a fixed pole is housed in a
unit case 20 having a front acoustic terminal 21 on the front and a rear acoustic terminal 22 on
the side. A unit in which the circuit board 130 mounted with the microphone unit 10 and the
impedance converter 131 which is detachably connected to the unit case 20 and connected at
the time of connection via the fixed pole and the predetermined electrical connection means is
accommodated In the unidirectional condenser microphone including the support housing 110,
the rear acoustic terminal is enclosed in the unit support housing 110 around the impedance
converter 131, and when the unit case 20 and the unit support housing 110 are connected. An
electromagnetic shielding member 150 is provided at a position facing the inner surface of the
housing 22. [Selected figure] Figure 1
Unidirectional Condenser Microphone
[0001]
The present invention relates to a unidirectional condenser microphone in which a microphone
unit is detachable, and more particularly to a technique for shielding a rear acoustic terminal of
the microphone unit.
[0002]
First, FIG. 3 is a cross-sectional view showing a general configuration example of a microphone
unit provided in a unidirectional condenser microphone.
03-05-2019
1
The microphone unit 10 is unidirectional, and in this example, it is shown as a microphone unit
applied to, for example, a tie pin type or goose neck type microphone which is detachable
(replaceable) with respect to a microphone body (not shown).
[0003]
The microphone unit 10 includes a cylindrical unit case 20 made of, for example, a brass alloy,
and in the unit case 20, the diaphragm and the fixed electrode are disposed opposite to each
other via a spacer ring (not shown). And an electrostatic type acoustoelectric converter 30 for
converting an incoming sound wave into an electrical signal is accommodated.
[0004]
In addition to the front acoustic terminal (front acoustic wave inlet directed to the sound source)
21 in the front of the unit case 20, a rear acoustic terminal (rear Sound inlet (22) is provided.
[0005]
Usually, in the unit case 20, a metal mesh 40 covering the rear acoustic terminal 22 from the
inside is provided.
The metal mesh 40 is provided to prevent foreign matter from entering the unit case 20 from the
rear acoustic terminal 22, and contacts the inner wall surface of the unit case 20 with its own
spring property, but is easily caused by vibration or the like. It may be fixed with an adhesive so
as not to come off (for example, see Patent Documents 1 and 2).
[0006]
Although a metal mesh is similarly provided on the inner surface side of the front acoustic
terminal 21 for the purpose of preventing entry of foreign matter, the illustration thereof is
omitted here.
[0007]
The signal extraction electrode 31 connected to the fixed pole is extracted from the
acoustoelectric converter 30, and the signal extraction electrode 31 is not shown in the
03-05-2019
2
microphone body as the microphone unit 10 is connected to the microphone body. Although
connected to the audio output circuit, since the acoustoelectric converter 30 has a very high
impedance, an impedance converter is provided on the input side of the audio output circuit.
[0008]
In general, a FET (field effect transistor) is used for the impedance converter, the signal
extraction electrode 31 is connected to the gate electrode of the FET, and the audio output circuit
is connected between the source and drain of the FET.
In rare cases, a vacuum tube may be used as an impedance converter.
[0009]
Since this type of impedance converter also acts as a detection element, when, for example, a
high frequency current due to an electromagnetic wave is added to the microphone unit 10 as a
disturbance, it is detected by the impedance converter to generate audio frequency noise.
This kind of noise hardly occurs when the electromagnetic shielding of the microphone unit 10 is
reliable.
[0010]
A diaphragm is disposed opposite to the front acoustic terminal 21 and a metal layer formed on
the diaphragm is connected to a unit case 20 which is grounded via a metal support ring
(diaphragm ring). Therefore, the electromagnetic wave entering from the front acoustic terminal
21 does not cause much problem.
[0011]
However, with regard to the rear acoustic terminal 22, the contact between the metal mesh 40
covering it from the inside and the inner wall surface of the unit case 20 depends on the spring
property of the metal mesh 40 itself as described above, and the contact area is necessarily small.
Shielding is not enough.
03-05-2019
3
[0012]
In recent years, mobile phones are rapidly spreading, but from mobile phones, electromagnetic
waves that are quite strong (for example, within a range of several centimeters to several tens of
centimeters reach tens of thousands times the electric field strength generated in the market by
commercial radio waves. Electric field strength) is emitted.
[0013]
Therefore, when the mobile phone is used near the microphone, the contact between the metal
mesh 40 and the unit case 20 is insufficient, so the contact portion has high impedance in high
frequency, and the high frequency current by the high frequency is the microphone It may get
into the body and generate a loud noise.
[0014]
In addition, since the contact state also differs individually, the generation of noise due to the
high frequency current also varies.
In addition, if the opening of the rear acoustic terminal 22 is increased in order to improve the
acoustic characteristics, the high frequency current is more likely to enter.
[0015]
Therefore, in the invention described in Patent Document 3, as shown in FIG. 4, the metal mesh
40 covering the rear acoustic terminal 22 from the inside is pressed toward the inner wall
surface of the unit case 20 by the coil spring 50. .
[0016]
According to this, since the metal mesh 40 contacts the unit case 20 at many points, a reliable
electromagnetic shield can be obtained.
In addition, it is not necessary to fix the metal mesh 40 with an adhesive.
03-05-2019
4
[0017]
Preferably, by gold-plating the coil spring 50, the contact resistance between the coil spring 50
and the metal mesh 40 becomes extremely low, and the contact portion can be made to have no
impedance even in high frequency.
[0018]
JP-A-55-105492 JP-A-56-43985 JP-A-2008-166909
[0019]
However, in the invention described in Patent Document 3, not only the component procurement
cost of the coil spring 50 is increased, but also the operation cost for mounting the coil spring 50
in the unit case 20 newly occurs, so there is a problem in cost. is there.
[0020]
Therefore, an object of the present invention is to secure an electromagnetic shield at the rear
acoustic terminal without increasing costs in a simpler manner.
[0021]
In order to solve the above problems, the present invention provides an acoustoelectric
conversion including a diaphragm and a fixed electrode in a metal unit case having a front
acoustic terminal on the front and a rear acoustic terminal on the side. The unit case is
detachably connected with a microphone unit whose housing is housed and the velocity
component taken in from the rear acoustic terminal is guided to the back side of the diaphragm,
and when connected, the fixed pole and predetermined electrical A unidirectional capacitor
microphone including a metal unit support housing containing a circuit board on which an
impedance converter connected via a connection means is mounted, the impedance being
provided in the unit support housing. It is arranged around the transducer and at a position
facing the inner surface of the rear acoustic terminal when the unit case and the unit support
housing are connected. Is characterized in that electromagnetic shielding member is provided.
[0022]
In the present invention, it is preferable that the electromagnetic shielding member is electrically
connected to the ground pattern formed on the circuit board and / or the unit support housing.
03-05-2019
5
[0023]
Moreover, although the metal plate and metal block which consist of a ferrite etc., for example
may be used for the said electromagnetic shielding member, Preferably electrically conductive
cloth is used.
[0024]
According to the present invention, an electromagnetic shielding member is provided in the unit
support housing so as to surround the impedance converter, and the electromagnetic shielding
member faces the inner surface of the rear acoustic terminal when the unit case and the unit
support housing are connected. Since the rear acoustic terminal does not require a metal mesh
by being arranged, the electromagnetic shielding at the opening portion of the rear acoustic
terminal can be reliably performed.
[0025]
Further, by electrically connecting the electromagnetic shielding member to the ground pattern
and / or the unit support housing formed on the circuit board, the electromagnetic shield
becomes more reliable.
[0026]
By using a conductive cloth as the electromagnetic shielding member, the weight of the
microphone unit can be reduced, and since the conductive cloth can be easily cut, the assembly
work can be easily performed.
[0027]
Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2,
but the present invention is not limited to this.
FIG. 1 (a) is a front sectional view showing a unidirectional directivity condenser microphone
according to the present invention, FIG. 1 (b) is a side sectional view showing a microphone unit
and a unit supporting case separately, and FIG. It is the sectional view on the AA line of 1 (a).
[0028]
Referring to FIGS. 1A and 1B, the unidirectional condenser microphone 1 includes a microphone
03-05-2019
6
unit 10 and a microphone body 11, and the microphone unit 10 is detachably connected to the
microphone body 11. Ru.
[0029]
The microphone unit 10 includes the cylindrical unit case 20 made of, for example, a brass alloy
as described in FIG. 3 above, and in the unit case 20, the diaphragm and the fixed electrode are
spacer rings (both not shown And an electrostatic type acousto-electric converter 30 for
converting an incoming sound wave into an electric signal.
[0030]
In addition to the front acoustic terminal (front acoustic wave inlet directed to the sound source)
21 in the front of the unit case 20, a rear acoustic terminal (rear Sound inlet (22) is provided.
[0031]
In this embodiment, a metal mesh (net) is not particularly provided on the inner surface side of
the rear acoustic terminal 22.
Although not shown, a metal mesh may be provided on the inner surface side of the front
acoustic terminal 21 for the purpose of preventing the entry of foreign matter.
[0032]
In the unit case 20, the signal extraction electrode 31 connected to the fixed pole is drawn from
the acoustoelectric converter 30.
Further, on the inner surface of the rear end opening of the unit case 20, a female screw 23 for
connecting to the microphone main body 11 is engraved.
[0033]
03-05-2019
7
The microphone body 11 includes a cylindrical unit support housing 110 made of a metal
material such as brass alloy.
In the upper end opening of the unit support housing 110, a female screw 111 for connecting
the microphone unit 10 is engraved.
[0034]
Further, a cord bush 112 is attached to the rear end of the unit support housing 110, and a
microphone cord (not shown) is drawn into the unit support housing 110 through the cord bush
112.
[0035]
A shield cup 120 made of, for example, an aluminum material is accommodated in the unit
support housing 110, and the circuit board 130 is disposed on the upper end side of the shield
cup 120 so as to close the inside of the unit support housing 110.
[0036]
An FET (field effect transistor) 131 as an impedance converter is mounted on the circuit board
130.
Further, the circuit board 130 is provided with a contact piece 132 made of a plate spring
material.
[0037]
Although not shown in detail, the base end side of the contact piece 132 is connected to the gate
electrode of the FET 131, and the free end side of the contact piece 132 is elastically connected
to the signal extraction electrode 31 when connected to the microphone unit 10. Contact.
[0038]
Although not shown, solder lands for the gate electrode, drain electrode, and source electrode of
the FET 131 are formed on the circuit board 130, and ground patterns (grounded on both front
and back sides of the peripheral portion of the circuit board 130). Circuit) is formed.
03-05-2019
8
[0039]
In this embodiment, the ground pattern is electrically connected to the unit support housing 110
via the shield cup 120.
The microphone cable includes a feed line, a signal line, and a shield line. For example, in the
shield cup 120, the feed line is connected to the land for drain electrode, the signal line is
connected to the land for source electrode, and the shield line is connected to the ground pattern
Each is soldered.
[0040]
The unidirectional condenser microphone 1 includes a connecting cylinder 140 for connecting
the microphone unit 10 to the microphone body 11.
The connecting cylinder 140 is made of a metal material, and a male screw 141 is formed on the
outer peripheral surface thereof.
[0041]
The lower half of the male screw 141 is screwed into the female screw 111 of the unit support
housing 110, whereby the circuit board 130 is fixed and the connecting cylinder 140 is
electrically connected to the ground pattern of the circuit board 130. .
[0042]
The female screw 23 of the microphone unit 10 is screwed into the upper half of the male screw
141.
Thereby, the unit case 20 is electrically and mechanically connected to the unit support housing
110 via the connecting cylinder 140, and the unit case 20 and the unit support housing 110 are
03-05-2019
9
the shield case of the entire unidirectional condenser microphone 1. Act as.
[0043]
Referring also to FIG. 2, in the present invention, around the FET 131 on the circuit board 130 in
order to prevent noise generation due to an external electromagnetic wave (in particular, an
electromagnetic wave emitted from a mobile phone) entering from the rear acoustic terminal 22.
The electromagnetic shielding member 150 is disposed to surround it.
[0044]
For the electromagnetic shielding member 150, for example, a metal plate or a metal block made
of ferrite or the like may be used, but it is preferable that the conductive cloth can be easily
processed by cutting or the like.
[0045]
As shown in FIG. 1A, the electromagnetic shielding member 150 enters the unit case 20 when
the unit case 20 of the microphone unit 10 is connected to the unit support housing 110 of the
microphone main body 11, and It has a height disposed at a position opposite to the inner
surface.
[0046]
Thereby, the opening portion of the rear acoustic terminal 22 is shielded without providing the
metal mesh 40 (see FIGS. 3 and 4) on the rear acoustic terminal 22.
[0047]
In this embodiment, the connecting cylinder 140 is also inserted into the unit case 20 with the
same height as the electromagnetic shielding member 150, but the height of the connecting
cylinder 140 is lowered and the electromagnetic shielding member 150 directly faces the inner
surface of the rear acoustic terminal 22. You may do it.
[0048]
It is preferable that the gap between the inner surface of the rear acoustic terminal 22 and the
connecting cylinder 140 (or the electromagnetic shielding member 150) be as narrow as
possible, provided that the acoustic characteristics are not impaired.
03-05-2019
10
[0049]
The electromagnetic shielding member 150 is pressed onto the circuit board 130 by the stepped
portion 142 formed on the inner surface of the connecting cylinder 140, and at this time, the
electromagnetic shielding member 150 is electrically contacted with the ground pattern of the
circuit board 130. Make it
This makes the shield more reliable.
[0050]
As described above, according to the present invention, the rear acoustic terminal 22 can be
shielded by the electromagnetic shielding member 150 on the circuit component side without
providing the rear acoustic terminal 22 with the metal mesh that causes noise generation even if
it is caused by the external electromagnetic wave. it can.
[0051]
Note that a mesh body made of synthetic resin may be attached to the inner surface of the rear
acoustic terminal 22 for the sole purpose of dust prevention.
The skirt of the electromagnetic shielding member 150 may be deformed to directly connect the
electromagnetic shielding member 150 to the unit support housing 110.
[0052]
(A) Front view sectional drawing which shows the unidirectional directivity condenser
microphone by this invention, (b) Side view sectional drawing which isolate | separates and
shows a microphone unit and a unit support housing | casing.
The sectional view on the AA line of Drawing 1 (a).
03-05-2019
11
FIG. 5 is a schematic cross-sectional view showing a first conventional example of a condenser
microphone unit.
FIG. 10 is a schematic cross-sectional view showing a second conventional example of a
condenser microphone unit.
Explanation of sign
[0053]
DESCRIPTION OF SYMBOLS 1 unidirectional directivity condenser microphone 10 microphone
unit 11 microphone main body 20 unit case 21 front acoustic terminal 22 rear acoustic terminal
23 female screw 30 acoustic electrical converter 31 signal extraction electrode 110 unit support
housing 130 circuit board 131 FET (impedance conversion ) 140 connected cylinder 150
electromagnetic shielding member
03-05-2019
12
Документ
Категория
Без категории
Просмотров
0
Размер файла
21 Кб
Теги
jp2010050866
1/--страниц
Пожаловаться на содержимое документа