close

Вход

Забыли?

вход по аккаунту

?

JP2011066475

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 JP2011066475
PROBLEM TO BE SOLVED: To obtain a stereo microphone unit which can be miniaturized as
compared with the conventional one and has excellent frequency characteristics. SOLUTION:
Fixed poles of two unidirectional condenser microphone units are opposed to each other and
integrally formed, and an insulating seat in which a gap is formed between the fixed poles in a
direction from an outer peripheral portion to an inner diameter direction A stereo condenser
microphone unit having a rear acoustic terminal common to the microphone units by having the
gap portion communicate the fixed pole back surface space of each microphone unit to the
external space. [Selected figure] Figure 1
Stereo microphone unit and stereo microphone
[0001]
The present invention relates to a stereo microphone, and more particularly to a stereo
microphone unit that can be miniaturized as compared with the prior art, and a stereo
microphone provided with the same.
[0002]
Conventionally, XY stereo and MS stereo are known as sound collection methods used by stereo
microphones.
In the XY stereo system, two unidirectional microphone units are mechanically fixed at an
10-05-2019
1
appropriate angle (for example, 120 degrees), the left unit output is L channel, the right unit
output is R channel, and stereo sound collection is performed. This is possible (see, for example,
Patent Document 1).
[0003]
On the other hand, in the MS stereo system, the main signal M is obtained from the
unidirectional microphone unit, and the directional signal S is obtained from the bidirectional
microphone unit arranged to be orthogonal to this, and these respective signals are matrix
circuits , And (M + S) and (M−S) left and right (LR) channel signals are produced to enable stereo
sound collection (see, for example, Patent Document 2).
[0004]
Among the above-mentioned conventional stereo microphones, an example of an XY stereo
system stereo microphone is shown in FIG.
In FIG. 5, the stereo condenser microphone unit 100 according to the XY stereo system has a
configuration in which the unidirectional microphone unit 100L on the L (left) channel side and
the unidirectional microphone unit 100R on the R (right) channel side are paired. Have. Note that
FIG. 5 shows only the left and right unidirectional microphone units, and the other parts are
omitted.
[0005]
The XY stereo method is mainly applied to inexpensive stereo microphones because the circuit
configuration is simpler than the MS stereo method. However, as shown in FIG. 5, it is necessary
to fix each unidirectional microphone unit by a holder (not shown) so that directional axes DL
and DR of unit 100L and unit 100R become an appropriate angle, and each microphone unit
There is a need for a microphone holder that holds an angle relative to the Also, in order to make
the spread of stereo variable, it is necessary to further provide a mechanism that allows the
relative angle of the microphone unit to be changed.
[0006]
Normally, the two microphone units in the XY stereo system are housed in one head case
10-05-2019
2
(windshield), so when the microphone units have an angle as in the XY stereo system, the head
case is large and special shape It is necessary to
[0007]
As described above, the main axis of the general-purpose unidirectional microphone unit is
oriented 180 degrees in order to reduce the number of components of the stereo microphone of
the XY stereo system, which has many components and is easy to increase in size, and to reduce
the size. A sound insulation cover is provided so as to cross the space between fixed poles of the
left and right microphone units (which will be the rear acoustic terminals), and the position of the
rear acoustic terminals is shifted to orient the stereo sound collection There is known a stereo
microphone unit that can adjust (see, for example, Patent Document 3).
[0008]
An example of a stereo microphone unit described in Patent Document 3 is shown in FIG.
In FIG. 6, the stereo microphone unit 200 has the sound insulation cover 201 so as to bridge the
space between the fixed poles of the units 200L and 200R with the principal axes of the generalpurpose unidirectional condenser microphone units 200L and 200R directed in the 180 degree
direction. Have.
Due to the sound insulation cover 201, the position offset from the main axis becomes the rear
acoustic terminal RT. As a result, the directional axes DL and DR form a predetermined angle as
shown in FIG. 6, and have directivity capable of stereo sound collection.
[0009]
Japanese Patent Publication No. 6-35597 Japanese Patent Laid-Open No. 2002-374592
Japanese Patent Laid-Open No. 2008-227779
[0010]
However, in the stereo microphone unit described in Patent Document 3, an air chamber serving
as a rear acoustic terminal is always formed between the left and right units and the sound
10-05-2019
3
insulation cover.
Since this air chamber operates as a resonator common to the rear acoustic terminals of the left
and right units, in particular, the acoustic characteristics and the S / N ratio in the high region
deteriorate, causing the directivity to collapse.
[0011]
FIG. 7 is a graph showing an example of the frequency characteristic of the stereo microphone
unit 200. In FIG. 7, the horizontal axis represents the frequency of the signal emitted from the
sound source, and the vertical axis represents the gain in the microphone unit. FIG. 7 shows an
output on the L channel side of the stereo microphone unit 200. Graph a shown in FIG. 7
represents the case where the sound source is located in front of the main axis of the
microphone unit, that is, on the main axis on the diaphragm side of the unit 100L (FIG. 6). The
graph b shows the case where the sound source is located in the direction of 90 degrees from the
main axis of the microphone unit 200, that is, on the sound insulation cover 201 side. Graph c
shows the case where the sound source is located behind the main axis of the unit 100L, that is,
on the side of the unit 100R. Graph d shows the case where the sound source is located on the
rear acoustic terminal RT side.
[0012]
As shown in FIG. 7, when the frequency of the sound source is lower than 5 kHz, the gain in front
of the main axis (graph a) and the gain in the other sound source direction are separated and the
left and right sounds are distinguished and collected. Since it can be done, stereo sound
collection is possible. However, if the frequency is 5 kHz or more, resonance occurs due to the air
chamber, and it becomes as if it is a characteristic like omnidirectional, so it is not possible to
distinguish and collect the left and right sounds, and stereo sound pickup is impossible. It
becomes.
[0013]
In order to prevent such a resonance phenomenon, it is effective to dispose an acoustic
resistance in the air chamber, but since the acoustic resistance requires a predetermined
10-05-2019
4
thickness, the overall stereo microphone unit can be miniaturized. There was a limit to In
addition, since each of the left and right units has an acoustic terminal at the front and back, it is
susceptible to wind noise, and there is room for further improvement.
[0014]
The present invention has been made in view of the above problems, and aims to fix the principal
axes of two unidirectional condenser microphone units through an insulating seat with the
direction of 180 degrees, and make the rear acoustic terminals common. To provide a stereo
micro unit capable of preventing the conventional resonance phenomenon, reducing the
influence of wind noise, and reducing the number of parts and downsizing, and a stereo macro
phone using the same. With the goal.
[0015]
The present invention is a stereo condenser microphone unit in which fixed poles of two
unidirectional condenser microphone units are opposed and integrally formed, and a gap portion
is formed between the fixed poles in a direction from the part of the outer periphery toward the
inner diameter. The most important feature is that it has a built-in insulating seat, and the gap
part communicates the fixed pole back space of each microphone unit to the external space, and
it becomes the rear acoustic terminal common to the microphone unit. .
[0016]
Further, according to the present invention, in the stereo condenser microphone unit, the gap
portion is formed near the middle point in the thickness direction of the insulating seat with a
predetermined depth dimension from the outer peripheral surface of the insulating seat to the
center It is characterized by
[0017]
Further, according to the present invention, in the stereo condenser microphone unit, an acoustic
resistance is provided in the gap.
[0018]
In the stereo condenser microphone unit according to the present invention, the directional axes
of the microphone units are offset from the main axes of the microphone units at a
predetermined angle.
10-05-2019
5
[0019]
The present invention is characterized in that, in the stereo condenser microphone unit, the angle
formed by the directional axes of the microphone units is an angle corresponding to 120 degrees
at the midpoint on the main axis of the stereo microphone unit.
[0020]
Further, the present invention is the above-mentioned stereo condenser microphone, which is a
stereo condenser microphone in which the above stereo condenser microphone unit is
incorporated in a microphone case.
[0021]
According to the present invention, the main axes of the two unidirectional condenser
microphone units are fixed to face in the opposite direction 180 degrees, and an insulation seat
is interposed on the fixed pole back side of each microphone unit. The rear acoustic terminals of
the two condenser microphone units can be made common by making the gap formed in the
back side air chamber of the fixed pole of each microphone unit and the external space
communicate with each other. It is possible to obtain a stereo micro unit excellent in frequency
characteristics by preventing the conventional resonance phenomenon and reducing the
influence of wind noise while achieving reduction and downsizing, and a stereo microphone
using the unit.
[0022]
It is a sectional view showing the example of the stereo condenser microphone unit concerning
the present invention.
It is a side view showing the example of the stereo condenser microphone unit concerning the
present invention.
It is a graph which shows the example of the frequency characteristic of the stereo capacitor |
condenser microphone unit which concerns on this invention.
It is a graph which shows the example of the directional characteristic of the stereo capacitor |
condenser microphone unit which concerns on this invention.
10-05-2019
6
It is sectional drawing which shows the example of the conventional stereo condenser
microphone unit.
It is sectional drawing which shows another example of the conventional stereo condenser
microphone unit.
It is a graph which shows the example of the frequency characteristic of the conventional stereo
condenser microphone unit.
[0023]
Hereinafter, embodiments of the stereo condenser microphone unit according to the present
invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a stereo condenser microphone unit
according to the present invention.
The stereo microphone according to this embodiment includes a stereo condenser microphone
unit 10 (hereinafter referred to as "unit 10") as shown in FIG. In FIG. 1, in the unit 10, a fixed
pole 14 forming a uni-directional condenser microphone unit, a spacer ring (not shown), and a
diaphragm ring 12 with a diaphragm 13 stretched are disposed on the left and right around the
insulating seat 15, respectively. And a fixing plate 11 which holds these members and fixes them
at a predetermined position. The insulating seat 15 is a circular member having a diameter larger
than that of the diaphragm ring 12.
[0024]
A side view of the unit 10 is shown in FIG. As shown in FIG. 2, in the unit 10, the fixing tool 112
is inserted into the holes formed at the four corners of the two fixing plates 11 consisting of
plate-like members having a substantially rectangular outer shape, and the two fixing plates are
provided. By fastening 11, the respective members are fixed centering on the insulating seat 15.
10-05-2019
7
[0025]
The fixture 112 is, for example, a screw. The screw is inserted into the hole of one fixing plate 11
and screwed into the screw hole of the other fixing plate 11 or a nut corresponding to the fixing
tool 112 is used in the hole of the other fixing plate 11 As a result, a pressing force is generated
inwardly from the left and right fasteners 112. By this pressing force, the diaphragm ring 12, the
diaphragm 13, the spacer ring (not shown), and the fixed pole 14 are fixed together with the
insulating seat 15 in a predetermined positional relationship. A plurality of holes are formed in
the vicinity of the center of the fixed plate 11, and these holes become the front acoustic terminal
holes 111. The opening of the front acoustic terminal hole 111 is covered with a mesh such as a
wire mesh so as to prevent foreign matter such as dust from entering.
[0026]
Further, in FIG. 2, dotted lines drawn at positions slightly lower than the center of the fixed plate
11 indicate the end of the gap portion provided in the insulating seat 15 described later.
[0027]
Return to FIG.
The diaphragm 13 is made of, for example, a synthetic resin thin film having a vapor deposited
metal film, and a metal plate such as aluminum is used for the fixed electrode 14. However, the
diaphragm 13 is not limited thereto. An electret film may be used, and in the case of the back
electret system, the electret film may be integrally attached to the fixed electrode 14.
[0028]
A circuit board (not shown) is disposed outside the unit 10 shown in FIG. The circuit board is
mounted with an FET (field effect transistor) as an impedance converter, and the gate terminal of
the FET 17 is electrically connected to the fixed pole 14 through a relay electrode (not shown).
10-05-2019
8
[0029]
A gap 152 is formed in the insulating seat 15 and is cut in the inner diameter direction from a
part of the outer periphery. The gap portion 152 is formed in the vicinity of the middle point in
the thickness direction (left and right in FIG. 1) of the insulating seat 15 and is cut away with a
predetermined depth from the outer peripheral surface of the insulating seat 15 toward the
center. .
[0030]
In the gap portion 152, a communication hole 151 for communicating the rear air chamber 142
formed between the back surface of the fixed pole 14 and the insulating seat 15 to the external
space is formed. Further, by providing the acoustic resistance 153 made of a mesh or non-woven
fabric in the gap portion 152, the influence of wind noise can be reduced.
[0031]
Among the sound waves coming from the sound source (not shown), the unit 10 having the
above configuration is common to the sound waves from the front acting directly on the front
surface of the diaphragm 13 through the front acoustic terminal hole 111 The sound wave that
wraps around from the gap portion 152 serving as the rear acoustic terminal acts on the back
surface of the diaphragm 13 from the communication hole 151 via the rear air chamber 142 of
the fixed pole 14.
[0032]
Assuming that the left and right directional axes of the unit 10 are DL and DR, as shown in FIG. 1,
the directional axes DL and DR form a predetermined angle with respect to the principal axis X
passing through the centers of the left and right diaphragms 13. Become.
This is because the gap 152 shifts the position of the rear acoustic terminal from the main axis X.
In addition, as for the angle of the suitable directional axis in a stereo microphone unit, 120
degrees is desirable. The angle formed by the directional axes DL and DR can be adjusted by the
thickness and depth of the gap 152, so that the angle between the directional axes DL and DR at
the center of the unit 10 is 120 degrees. The dimensions of the part 152 may be determined.
10-05-2019
9
[0033]
FIG. 3 is a graph showing an example of the frequency characteristic of the stereo condenser
microphone unit 10 according to this embodiment, and shows the output of the unit 10 when the
frequency of the signal emitted from the sound source is changed. The frequency characteristic
shown in FIG. 3 is that of one of the two unidirectional condenser microphone units forming the
unit 10. In FIG. 3, the horizontal axis represents the frequency of the signal emitted from the
sound source, and the vertical axis represents the gain of the unidirectional condenser
microphone unit to be measured. Graph A shown in FIG. 3 represents the case where the sound
source is located in front of the main axis X of the microphone unit. The graph B shows the case
where the sound source is in the direction of 90 degrees from the main axis X and is located
above in FIG. Graph C shows the case where the sound source is located behind the main axis of
the unidirectional condenser microphone unit to be measured.
[0034]
As shown in FIG. 3, even when the frequency of the sound source is 5 kHz or more, the frequency
characteristic curves are separated, and stereo sound collection is possible without deterioration
of directivity due to resonance. Further, as is clear from the directivity characteristic curve of the
unit 10 according to the present embodiment shown in FIG. 4, according to the unit 10 according
to the present embodiment, stereo sound collection is possible as a stereo microphone unit.
[0035]
In this way, the unit 10 shares the rear acoustic terminals of the left and right unidirectional
condenser microphone units formed by the gap 152 in common, and the dimensions of the gaps
152 direct the pointing of the left and right unidirectivity condenser microphone units. The axes
DL, DR can be offset from the main axis X at a predetermined angle, which can form a stereo
condenser microphone unit capable of stereo sound collection.
[0036]
According to the stereo condenser microphone unit according to the embodiment described
above, the space of the rear acoustic terminal portion is extremely small, and the resonance due
10-05-2019
10
to the air chamber does not occur, so that the S / N ratio in the high region is deteriorated. It is
possible to achieve excellent stereo sound collection in a wide band.
Further, by sharing the rear acoustic terminals of the two unidirectional condenser microphone
units, significant downsizing can be achieved.
[0037]
Also, by using two uni-directional condenser microphone units, normally four right and left
acoustic terminals are provided in front and rear, the number of acoustic terminals can be
reduced by making the rear acoustic terminals common. Wind noise can be reduced.
[0038]
The stereo condenser microphone unit according to the embodiment described above can
constitute a stereo condenser microphone by incorporating it into a microphone case.
[0039]
11 fixed plate 12 diaphragm ring 13 diaphragm 14 fixed pole 15 insulator seat 151
communicating hole 152 gap portion 153 acoustic resistance
10-05-2019
11
Документ
Категория
Без категории
Просмотров
0
Размер файла
20 Кб
Теги
jp2011066475
1/--страниц
Пожаловаться на содержимое документа