close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP2012104906

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 JP2012104906
PROBLEM TO BE SOLVED: To provide a condenser microphone which can easily adjust the
sensitivity of a plurality of condenser microphone units with a simple configuration, and in
particular, can easily adjust the sensitivity even when using a plurality of condenser microphone
units having large variations in sensitivity. . SOLUTION: A plurality of condenser microphone
units 10, 20 have sensitivity adjustment means 1 for changing the sensitivity of each condenser
microphone unit 10, 20, and the sensitivity adjustment means 1 is a variable connected between
a power supply and ground. The sliding terminals of the variable resistors corresponding to the
condenser microphone units on the side of the diaphragms 11 and 21 and the fixed electrodes
12 and 22 of the condenser microphone units, which are configured by the resistors 104 and
105 and that face the electret layer. Is connected. [Selected figure] Figure 2
コンデンサマイクロホン
[0001]
The present invention relates to a condenser microphone capable of adjusting sensitivity, and
more particularly, to a condenser microphone capable of adjusting variations in sensitivity
among a plurality of condenser microphone units.
[0002]
The electret condenser microphone unit has an electret material such as fluoroethylene polymer
(FEP) on at least one of the diaphragm and the fixed electrode disposed opposite to each other,
and uses it as electret.
18-04-2019
1
As a method of electretizing an electret material, for example, as shown in Patent Document 1, a
method using corona discharge is known. Generally, corotrons or scorotrons are used as devices
for generating corona discharge. The formation of an unequal electric field in these devices
causes a corona discharge to generate negative ions, and the electret material is exposed to the
negative ions to effect electretization. Since the electret material thus electretized has variations
in surface potential due to discharge, the sensitivity of the electret condenser microphone unit
using the electret material is dispersed by about 10%.
[0003]
On the other hand, there is a condenser microphone constituted by a plurality of condenser
microphone units such as a stereo condenser microphone and a variable directional condenser
microphone. In such condenser microphones, the sensitivity setting of each condenser
microphone unit needs to be made constant, and inconvenience occurs when there is a variation
in the sensitivity of each condenser microphone unit. Therefore, for example, in the case where
the above-described electret condenser microphone is applied to such a microphone, it is
necessary to select and combine units with little variation in sensitivity or to adjust the
sensitivity. However, it takes a lot of time and cost to search for a plurality of units with little
variation in sensitivity among many units, and even if the sensitivity is adjusted, a simple
adjustment method has not been proposed conventionally.
[0004]
Further, the cause of the variation of the sensitivity of the condenser microphone unit is not only
the variation of the surface potential of the electret layer. For example, it may arise by the
relationship between the members used for a condenser microphone unit. Therefore, it is more
desirable to be able to adjust sensitivity after assembly as a condenser microphone unit.
[0005]
Therefore, in the invention described in Patent Document 2, an ion needle electrode having a tip
end side in the vicinity of the back surface of the fixed pole of the electret condenser microphone
unit is used to neutralize the electret by a voltage applied to the needle electrode. A condenser
18-04-2019
2
microphone is disclosed to generate the signal and to adjust the sensitivity of the condenser
microphone unit. According to Patent Document 2, this condenser microphone unit is supposed
to be capable of adjusting the sensitivity of the condenser microphone unit even after the
microphone unit is assembled, by the ions neutralizing the electret.
[0006]
However, in the case of using for a plurality of condenser microphone units, the condenser
microphone unit described in Patent Document 2 has a complicated configuration because it is
necessary to perform adjustment of each sensitivity by providing a needle electrode for each. In
addition, since it is necessary to provide a plurality of needle electrodes, there is a problem that
the manufacturing cost of the condenser microphone unit increases. Furthermore, it is not
envisaged to adjust the sensitivity of multiple condenser microphone units.
[0007]
JP, 11-117172, A JP, 2008-131160, A
[0008]
The present invention has been made in view of the above problems, and the adjustment of the
sensitivity of a plurality of condenser microphone units can be facilitated with a simple
configuration, and particularly when using a condenser microphone unit having a large variation
in sensitivity. It is an object of the present invention to provide a condenser microphone that can
facilitate adjustment.
[0009]
The condenser microphone according to the present invention is a condenser microphone
including a plurality of electret condenser microphone units each having a diaphragm and a fixed
electrode opposed to the diaphragm and having an electret layer on one side of the diaphragm
and the fixed electrode, The plurality of condenser microphone units individually have sensitivity
adjustment means for changing the sensitivity of each condenser microphone unit, and each
sensitivity adjustment means is configured of a variable resistor connected between the power
supply and the ground. Among the diaphragms and the fixed electrodes of the unit, on the side
facing the electret layer, the sliding terminals of the variable resistors corresponding to the
respective condenser microphone units are most mainly characterized.
18-04-2019
3
[0010]
The condenser microphone according to the present invention faces the electret layer of the
diaphragm and the fixed electrode of each condenser microphone unit by adjusting variable
resistors as sensitivity adjustment means individually provided to a plurality of condenser
microphone units. Since the voltage on the drive side changes and the polarization voltage
changes, the sensitivity of each condenser microphone unit can be adjusted.
Thus, the sensitivity of a plurality of condenser microphone units can be adjusted by a simple
component called a variable resistor and by a simple operation, and even with a plurality of
condenser microphone units having large variations in sensitivity, it is easy The sensitivity can be
adjusted.
[0011]
FIG. 1 is a cross-sectional view showing an embodiment of a condenser microphone according to
the present invention.
It is a circuit diagram showing an example of a circuit applicable to a condenser microphone
concerning the present invention.
It is a circuit diagram showing another example of a circuit applicable to a condenser
microphone concerning the present invention. It is a circuit diagram showing another example of
a circuit applicable to a condenser microphone concerning the present invention.
[0012]
Hereinafter, embodiments of a condenser microphone according to the present invention will be
described with reference to the drawings.
[0013]
As shown in FIG. 1, the condenser microphone 1001 comprises cylindrical condenser
18-04-2019
4
microphone units 10 and 20 with a bottom, sensitivity adjusting means 1 inside a cylindrical
casing 103, a circuit board 101, and a cylindrical peripheral wall. It has a protected connector
portion 102.
The connector portion 102, the circuit board 101, the sensitivity control means 1, and the
condenser microphone units 10 and 20 are disposed in this order from the bottom in FIG. The
condenser microphone units 10 and 20 are housed in a cylindrical microphone cover 100 which
is meshed for capturing sound. As shown, a fixing member for reinforcement may be provided on
the upper end (upper side in FIG. 1) of the microphone cover 100. The sensitivity adjustment
means 1 is electrically connected to the diaphragms 11 and 21 inside the condenser microphone
units 10 and 20 by a wire 30. In addition, the sensitivity adjustment means 1 can be arrange |
positioned based on not only the above-mentioned position but an appropriate design concept.
Further, the shapes of the peripheral walls of the microphone cover 100, the housing 103, and
the connector portion 102 are not limited to those described above, and can be designed based
on appropriate design concepts.
[0014]
For example, as shown in FIG. 2, a power supply circuit or impedance converters 13 and 23
including FETs or vacuum tubes, buffer amplifiers 15 and 25 and the like are incorporated in the
circuit board 101 inside the housing 103. . Below the circuit board 101, a connector portion 102
is provided so that audio signals obtained from the capacitor micron units 10 and 20 can be
extracted to the outside and voltages can be applied to the capacitor microphone units 10 and
20. . As described later, the condenser microphone units 10 and 20, the sensitivity control unit 1,
the circuit board 101, and the connector portion 102 are electrically connected by the wiring 30
as shown in FIGS. 2 to 4, respectively.
[0015]
FIG. 1 shows an example of a microphone whose directivity is variable by arranging the
condenser microphone units 10 and 20 back to back. However, the units 10 and 20 may be
parallel or left and right with an appropriate opening angle. , And may constitute a stereo
microphone. The configuration of the condenser microphone unit 1001 is not limited to that
described above, and can be configured based on an appropriate design concept. For example,
each component is preferably separated by a shield material and disposed so as to be shielded
from external electromagnetic waves. Further, it is preferable that the connector portion 102 be
18-04-2019
5
covered in the periphery as shown.
[0016]
Next, an example of a circuit used in the present invention will be described. In FIG. 2, reference
numerals 10 and 20 respectively indicate condenser microphone units. The condenser
microphone unit 10 has a diaphragm 11 and a fixed electrode 12 opposed thereto, and the
diaphragm 11 and the fixed electrode 12 constitute a capacitor. When the diaphragm 11 vibrates
upon receiving a sound wave, the capacitance of the capacitor changes, and electroacoustic
conversion is performed between the diaphragm 11 and the fixed electrode 12 to output an
audio signal. The output signal is output from the connector section 102 in FIG. 1 to the outside
through an impedance converter 13 including a FET and the like, a buffer amplifier 15. Similarly,
the condenser microphone unit 20 also has the diaphragm 21 and the fixed electrode 22
opposed thereto, and when the diaphragm 21 vibrates upon receiving an acoustic wave, the
capacitance of the capacitor formed of the diaphragm 21 and the fixed electrode 22 changes.
Then, electroacoustic conversion is performed between the diaphragm 11 and the fixed electrode
12 to output an audio signal. This output signal is output from the connector section 102 in FIG.
1 to the outside through an impedance converter 23 including a FET and the like, a buffer
amplifier 25.
[0017]
The output signal of the buffer amplifier 15 on one capacitor microphone unit 10 side is the hotside signal of the balanced output signal, and the output signal of the buffer amplifier 25 on the
other capacitor microphone unit 20 is a balanced output signal. It is considered as the cold side
signal. The connector section 102 shown in FIG. 1 is a 3-pin connector standardized as a socalled XLR. The first pin is a ground terminal, the second pin is a hot side signal terminal, and the
third pin is a cold side signal terminal. ing. In the case of a stereo microphone, for example, the
left and right channels are divided into balanced signals, and a 5-pin connector standardized as a
so-called XLR, with pin 1 being grounded, pin 2 being hot on the L (left) side, The third pin can
be configured to be output as an L side cold, the fourth pin as an R (right) side hot, and the fifth
pin as an R side cold.
[0018]
18-04-2019
6
The two condenser microphone units 10, 20 have sensitivity adjustment means 1 for changing
the sensitivity of the respective condenser microphone units 10, 20. The sensitivity adjustment
means 1 is constituted by variable resistors 104 and 105 connected between the power supply
Vcc and the ground. The two variable resistors 104 and 105 are connected in parallel between
the power supply Vcc and the ground, and the sliding terminal of the variable resistor 104 is
connected to the diaphragm 11 of the condenser microphone unit 10 and the diaphragm 21 of
the condenser microphone unit 20. The sliding terminal of the variable resistor 105 is connected
to. The variable resistors 104 and 105 are connected to divide the voltage of the power supply
Vcc according to the position of their sliding terminals and apply the divided voltages to the
diaphragms 11 and 21, respectively. . The voltage from the power supply Vcc is supplied from
the power supply circuit on the circuit board 101, and the power supply Vcc is common to the
power supplies of the impedance converters 13 and 23 and the buffer amplifiers 15 and 25. That
is, the power supply Vcc applies a voltage from the connector 102 shown in FIG. 1 through the
power supply circuit on the circuit board 101 to the variable resistors 104 and 105 which are
the sensitivity adjustment means 1. Moreover, although two variable resistors which are the
sensitivity adjustment means 1 are provided in the present embodiment, they are illustrated as
being omitted in FIG.
[0019]
As described above, in this embodiment, the fixed electrodes 12 and 22 of the diaphragms 11
and 21 and the fixed electrodes 12 and 22 of the condenser microphone units 10 and 20 have
the electret layer and are opposed to the electret layer. The sliding terminals of the variable
resistors 104 and 105 are connected to the other side, that is, the diaphragms 11 and 21. The
variable resistors 104 and 105 are connected such that when the respective sliding terminals
move in the same direction, the voltages applied to the diaphragms 11 and 21 rise and fall in the
same direction.
[0020]
In the circuit example shown in FIG. 2 configured as described above, when there is a sensitivity
difference between the two capacitor microphone units 10 and 20, at least one of the variable
resistors 104 and 105 is adjusted. Can eliminate the difference in sensitivity. For example, when
the sensitivity of the condenser microphone unit 10 is higher than that of the condenser
microphone unit 20, the variable resistor 104 is adjusted so that the polarization voltage of the
condenser microphone unit 10 becomes lower, or the condenser microphone unit 20 is The
variable resistor 105 is adjusted to increase the polarization voltage of
18-04-2019
7
[0021]
Here, a specific voltage value is shown, and the example of sensitivity adjustment of each
capacitor | condenser microphone unit 10, 20 is demonstrated. Assuming that the surface
potential of the electret layer to be aimed is -100 V and the voltage of the power supply Vcc is 30
V in each of the condenser microphone units 10 and 20, the side that makes a pair with the
electret of each condenser microphone unit 10 and 20, that is, this embodiment Then, the
potential on the side of the diaphragms 11 and 21 can be varied between 0 and 30V. Therefore,
the polarization voltage can be adjusted in the range of ± 15%.
[0022]
According to the present embodiment, each capacitor microphone unit 10, 20 is provided with
the variable resistor 104, 105, a voltage is applied to the side facing the electret layer, and the
applied voltage is adjusted to adjust each capacitor microphone unit 10, 20 polarization voltages
can be adjusted. By adjusting the polarization voltage, the sensitivity of each condenser
microphone unit 10, 20 can be adjusted. Therefore, variable resistors 104 and 105 are added,
and sensitivity adjustment is possible only by adjusting these variable resistors 104 and 105, so
that each condenser microphone unit 10 or 20 can be configured with a simple configuration
and a simple operation. The sensitivity can be adjusted. In particular, the present invention is
effective in stereo microphones and variable directional microphones which are provided with a
plurality of condenser microphone units and in which variation in sensitivity of each condenser
microphone unit needs to be reduced as much as possible.
[0023]
In the condenser microphone according to the present invention, it is assumed that the
sensitivity adjustment of the condenser microphone unit is mainly performed in the adjustment
step in the microphone manufacturing process. For example, as in the example of the condenser
microphone 1001 shown in FIG. 1, after assembling the condenser microphones 1001 other than
the housing 103, the sensitivity adjustment means 1 is adjusted while measuring the sensitivities
of the microphone units 10 and 20 by the measuring device. Thus, the sensitivity of each
condenser microphone unit 10, 20 is adjusted. Thereafter, the housing 103 is attached.
Alternatively, a hole is provided in the housing 103, and the sensitivity of the condenser
18-04-2019
8
microphone units 10 and 20 is adjusted using the sensitivity adjustment unit 1 as described
above by the jig from the hole, and then the cover of the hole in the housing 103 is closed. do. By
doing this, the sensitivity adjustment of the condenser microphone units 10 and 20 and the
subsequent shipment of condenser microphone products become smooth.
[0024]
The two condenser microphone units 10 and 20 may be an electret type in which the fixed pole
12 is electretized, or may be another condenser microphone unit. Since the electret condenser
microphone tends to have a particularly different sensitivity as described above, it is preferable
to apply the construction of the condenser microphone of the present invention. In addition, the
number of condenser microphone units used for one condenser microphone 1001 may be any as
long as there are a plurality.
[0025]
Next, a second embodiment shown in FIG. 3 will be described. The embodiment shown in FIG. 3
uses a dual variable resistor as the variable resistors 104 and 105 in the embodiment shown in
FIG. The variable resistors 104 and 105 are connected in parallel between the power supply Vcc
and the ground, but reverse the connection of the variable resistors 104 and 105 to the power
supply and the power supply, respectively. The other circuit configuration is the same as the
embodiment shown in FIG.
[0026]
According to the embodiment shown in FIG. 3, when the common axis of the variable resistors
104 and 105 composed of two-piece variable resistors is operated, the voltage applied to the
diaphragm of one of the microphone units rises while the other increases. The voltage applied to
the diaphragm of the microphone unit drops. In response to this, the polarization voltage of one
of the microphone units is increased to raise the sensitivity of that unit, while the polarization
voltage of the other microphone unit is lowered to lower the sensitivity of that unit. Therefore,
when the adjustment axis of the two-piece variable resistor is operated, the sensitivities of both
microphone units always coincide at one point, and the sensitivity difference between both
condenser microphone units can be eliminated by one adjustment.
18-04-2019
9
[0027]
Next, a third embodiment shown in FIG. 4 will be described. This embodiment is an example in
which the sensitivity adjusting means 1 which is a feature of the present invention is provided in
a variable directional condenser microphone. The configuration of the sensitivity control means 1
is the same as that of the sensitivity control means 1 shown in FIG. 2, and has variable resistors
104 and 105 provided corresponding to the respective condenser microphone units 10 and 20.
The microphone unit 10 side is a front element, the microphone unit 20 is a rear element, and
the microphone unit 20 is switched between directivity converter 23 and buffer amplifier 25 as
described below including an inverting amplifier 24 The circuit is built in. The output signal of
the impedance converter 23 is input to the inverting input terminal of the inverting amplifier 24
through the input resistor, and the input resistor is composed of two input resistors Rs1 and Rs2
connected in series. The noninverting input terminal of the inverting amplifier 24 is grounded. A
feedback resistor is connected between the output terminal and the inverting input terminal of
the inverting amplifier 24. The feedback resistor is composed of two feedback resistors Rf1 and
Rf2 connected in series. The gain of the inverting amplifier 24 is determined by the ratio of the
feedback resistance to the input resistance. As described above, the input resistance is divided by
the two resistances Rs1 and Rs2, the feedback resistance is divided by the two resistances Rf1
and Rf2, and the division point and the non-division point are switched by the changeover switch
30 as switching means. The directivity of the balanced output signal is made variable by
switching the output on one side of the balanced output. Although the values of the two input
resistors Rs1 and Rs2 and the two feedback resistors Rf1 and Rf2 are described to be the same,
they may be set to different values according to the design concept.
[0028]
The changeover switch 30 has five changeover contacts (fixed contacts), and the movable contact
is connected to the input terminal of the buffer amplifier 25. The first switching contact 201 of
the changeover switch 30 is connected to the output terminal of the impedance converter 23.
The second switching contact 202 of the changeover switch 30 is connected to the connection
point of the input resistors Rs1 and Rs2. The third switching contact 203 of the changeover
switch 30 is connected to the inverting input terminal of the inverting amplifier 24. The fourth
switching contact 204 of the changeover switch 30 is connected to the connection point of the
feedback resistors Rf1 and Rf2. The fifth switching contact 205 of the changeover switch 30 is
connected to the output terminal of the inverting amplifier 24.
18-04-2019
10
[0029]
Thus, in the embodiment shown in FIG. 4, the inverting amplifier 24 in which the input resistance
and the feedback resistance are divided into the output signal system on one side of the balanced
output, and the division point of the input resistance and the feedback resistance of the inverting
amplifier 24. Is arbitrarily selected to switch the signal extraction point, so that the directivity of
the balanced output signal can be made variable. In the embodiment shown in FIG. 4, both the
input resistance and the feedback resistance of the inverting amplifier 24 are divided, and one
directivity is selected from among the entire division points of the input resistance and the
feedback resistance to switch the directivity. However, only the input resistance may be divided
and one of these division points may be selected, or only the feedback resistance may be divided
and one of these division points may be selected.
[0030]
However, if only the input resistance or the feedback resistance is divided and division points are
selected, the directivity switching range is limited, so if the directivity switching range is made
wider, the input resistance It is desirable to divide both of and the feedback resistance so as to
select one of the division points. The switching means described above is a variable resistor with
a center tap, one side of the center tap of the variable resistor is the input resistance of the
inverting amplifier, and the other side of the center tap is the feedback resistor of the inverting
amplifier. The directivity of the balanced output signal can also be made variable by setting the
output signal of the balanced output on one side of the balanced output.
[0031]
The technical concept of the condenser microphone according to the present invention can be
applied to other than electret condenser microphones, and can also be used, for example, as a DC
bias condenser microphone.
[0032]
DESCRIPTION OF SYMBOLS 1 sensitivity adjustment means 10 microphone unit 11 diaphragm
13 impedance converter 15 buffer amplifier 20 microphone unit 22 diaphragm 23 impedance
converter 1001 condenser microphone
18-04-2019
11
Документ
Категория
Без категории
Просмотров
0
Размер файла
22 Кб
Теги
description, jp2012104906
1/--страниц
Пожаловаться на содержимое документа