JP2000224685

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DESCRIPTION JP2000224685
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
microphone device, and more particularly, to a sound source tracking microphone device which
automatically follows a moving sound source and always faces the microphone in the direction of
the sound source.
[0002]
2. Description of the Related Art A microphone is a device for converting sound into electricity.
When classified according to conversion method, there are a dynamic type, a capacitor type, and
the like. FIG. 7 is a structural view of a dynamic type microphone. In the dynamic type
microphone 45, a conductor (voice coil) 47 is disposed in the gap between the N pole and the S
pole of the magnet 46, and the diaphragm 48 is attached to the conductor 47. It has a structure.
When the conductor 47 crosses the magnetic flux in the air gap, current flows across the
conductor 47, and current flows in response to the movement of the diaphragm 48 moved by
sound. A feature of the dynamic microphone is that it has no battery and has a strong structure.
[0003]
FIG. 8 is a structural view of a capacitor type microphone. The capacitor type microphone 50 has
a structure in which a capacitor (electrostatic capacitance) is formed by the vibrating film 51 and
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the pole (back electrode) 52 opposed to the diaphragm 51. When the vibrating membrane 51 is
moved by the sound, the distance between the vibrating membrane 51 and the back electrode 52
is changed, and hence the electric capacity is changed. The proximal end of the back electrode 52
is supported by an insulator 53, and a load resistor 54 is connected in parallel between output
terminals, and a battery 55 is also connected. The feature of the condenser microphone is that it
is small and light.
[0004]
Next, when microphones are classified into directional gender, they are roughly classified into
superdirectivity, unidirectionality, and omnidirectionality. Superdirective microphones have
narrow angle directivity and are used to pick up the voice of a specific person out of a large
number of people. A unidirectional microphone is a slightly wide-angle directivity, and a typical
example is a vocal microphone found in a singing program. The omnidirectional microphone can
record 360-degree sound and is placed at the center of the conference desk and used to record
the contents of speech.
[0005]
By the way, in the microphone as described above, a unidirectional microphone is most suitable
for collecting human voice, but the speaker moves in front of the microphone In this case, there
is a problem that a single directional microphone can not cover. Therefore, although it is
conceivable to use a nondirectional microphone, the nondirectional microphone can not clearly
pick up a moving speaker's voice. Therefore, in the past, it was necessary for a person to hold a
unidirectional microphone and to point the microphone in the direction in which the speaker
moved.
[0006]
Therefore, an object of the present invention is to provide a microphone device in which a
moving sound source is automatically followed so that the microphone always points in the
direction of the sound source.
[0007]
A microphone device according to the present invention comprises a microphone for converting
sound into electricity, a sound source direction detecting means for detecting a direction of a
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sound source based on the microphone, and a drive for changing the direction of the
microphone. And control means for controlling the drive means such that the microphone is
directed to the direction of the sound source based on a detection signal from the sound source
direction detection means.
[0008]
In the microphone device according to the present invention, when the sound source direction
detection means detects the direction of the sound source, the control means controls the drive
means based on the detection signal from the sound source direction detection means to make
the microphone face the direction of the sound source. .
[0009]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a microphone
device according to the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a microphone device according to the present invention.
The microphone device 1 has, for example, a unidirectional main microphone 2, a sound source
direction detecting means 3 for detecting which direction the sound source is in, a drive means 4
and 5 for moving the main microphone 2 vertically and horizontally, and a sound source
direction detection The control device 6 is a control unit that drives and controls the drive units
4 and 5 so that the main microphone 2 faces the direction of the sound source based on the
detection signal from the unit 3, the main microphone 2, the sound source direction detection
unit 3 and the drive unit 4 , 5 and a stand 7 for supporting the control device 6.
In the present invention, the main microphone 2 is always directed to the direction of the sound
source detected by the sound source direction detection means 3.
[0010]
The stand 7 is composed of a circular base 10 and a pole 11, and at the upper end of the pole 11,
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a U-shaped frame 13 in a side view is fixed. Both ends of the shaft 15 are rotatably supported by
the upper portion 13a and the lower side portion 13b of the frame 13, and a large diameter disc
16 is fixed to the shaft 15. A gear is engraved on the outer periphery of the large diameter disk
16 to form a worm wheel 16a. A motor 19 is fixed to the rear side 13 c of the frame 13 with a
shaft 18 oriented in the left-right direction via a bracket 18, and a worm 20 is fixed to the shaft
of the motor 19. The worm 20 is engaged with the worm wheel 16a, and the motor 19 is driven
to rotate the worm 20 so that the worm wheel 16a and the large-diameter disc 16 rotate in a
substantially horizontal direction. The motor 19, the worm 20, the worm wheel 16a, and the disc
16 constitute the left-right direction driving means 4.
[0011]
The left and right microphones 21a and 21b, which are, for example, unidirectional directivity
capacitor type microphones, which are detection units for detecting the left and right direction of
the sound source, are fixed to the opposing portions of the circumferential portion of the large
diameter disk 16. A U-shaped notch 16b is provided in an intermediate portion between the left
and right microphones 21a and 21b of the large diameter disc 16 in plan view, and a small
diameter disc 24 is vertically rotated in the notch 16b via a shaft 23 It is supported possible.
Upper and lower microphones 25a and 25b, which are, for example, unidirectional directivity
capacitor type microphones, which are detection means for detecting the sound source in the
vertical direction, are fixed to opposing portions of the circumference of the small diameter disc
24. The main microphone 2 is fixed to an intermediate portion between the upper and lower
microphones 25a and 25b of the small-diameter disk 24, and the shaft 23 passes through the
main microphone 2. The sound source direction detecting means 3 is composed of the left and
right microphones 21a and 21b and the upper and lower microphones 25a and 25b.
[0012]
A gear is engraved on the outer peripheral portion of the small diameter disc 24 and a helical
gear 24a is formed on the helical gear 24a. The shaft of a motor 27 fixed on the large diameter
disc 16 is formed on the helical gear 24a. The fixed helical gear 28 is engaged. By driving the
motor 27 and rotating the helical gear 28, the helical gear 24a and the small-diameter disc 24
are vertically rotated. The motor 27, the helical gears 28 and 24 a, and the disc 24 constitute the
vertical driving means 5. Furthermore, a box 30 containing the control device 6 is fixed to the
lower end of the frame 13, and a power cord 31 is connected to the control device 6.
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[0013]
FIG. 2 shows a system block diagram of the microphone device. Signals from the sound source
tracking switch 33, the main microphone 2, the left and right microphones 21a and 21b, and the
upper and lower microphones 25a and 25b are input to the control device 6 and processed. The
control device 6 drives and controls the motors 19 and 27 based on the signals from the sound
source tracking switch 33, the main microphone 2, the left and right microphones 21a and 21b,
and the upper and lower microphones 25a and 25b. It is controlled to turn. Furthermore, the
control device 6 is provided with an output terminal 35 for outputting an audio signal from the
main microphone 2.
[0014]
Next, the operation of the microphone device will be described along the flowcharts of FIGS. 3
and 4. First, when the sound source tracking switch 33 is pressed and turned on (step 101), it is
determined whether there is an output from the left and right microphones 21a and 21b and the
upper and lower microphones 25a and 25b (step 102). If there is no output from the
microphones 21a, 21b, 25a, 25b for a certain period of time, the motor 27 is driven to rotate the
disk 24 to a predetermined position via the helical gears 28, 24a, and the main microphone The
state 2 is inclined downward (step 103).
[0015]
If there is an output from the microphones 21a, 21b, 25a, 25b in step 102, it is determined
whether the output of the left microphone 21a and the output of the right microphone 21b are
equal (step 104). If the output of the left microphone 21a and the output of the right microphone
21b are not equal, it is determined whether the output of the left microphone 21a is larger than
the output of the right microphone 21b (step 105), and the output of the left microphone 21a is
the output of the right microphone 21b If so, the motor 19 is rotated forward, and the disk 16 is
rotated clockwise via the worm 20 and the worm wheel 16a (step 106). Then, it is determined
whether the outputs of the left and right microphones 21a and 21b are equal (step 107). When
the outputs of the left and right microphones 21a and 21b become equal, the driving of the
motor 19 is stopped (step 108). Although it is determined in step 102 whether there is an output
from the left and right microphones 21a and 21b and the upper and lower microphones 25a and
25b, it may be determined whether there is an output from the main microphone 2.
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[0016]
If the output of the left microphone 21a is not larger than the output of the right microphone
21b in step 105, it is determined whether the output of the right microphone 21b is larger than
the output of the left microphone 21a (step 109). Is larger than the output of the left microphone
21a, the motor 19 is reversely rotated, and the disc 16 is rotated counterclockwise via the worm
20 and the worm wheel 16a (step 110). Then, it is determined whether the outputs of the left
and right microphones 21a and 21b are equal (step 107). When the outputs of the left and right
microphones 21a and 21b become equal, the driving of the motor 19 is stopped (step 108).
[0017]
Then, as shown in FIG. 4, it is judged whether the output of the upper microphone 25a and the
output of the lower microphone 25b are equal (step 111), and if the output of the upper
microphone 25a and the output of the lower microphone 25b are not equal, the upper
microphone If the output of the upper microphone 25a is larger than the output of the lower
microphone 25b, the motor 27 is rotated forward to rotate the helical gears 28, 24a (step 112).
And the disc 24 is rotated upward (step 113). Then, it is determined whether the outputs of the
upper and lower microphones 25a and 25b are equal (step 114), and when the outputs of the
upper and lower microphones 25a and 25b become equal, the driving of the motor 27 is stopped
(step 115).
[0018]
If the output of the upper microphone 25a is not larger than the output of the lower microphone
25b in step 112, it is determined whether the output of the lower microphone 25b is larger than
the output of the upper microphone 25a (step 116). Is larger than the output of the upper
microphone 25a, the motor 27 is reversely rotated, and the disk 24 is rotated downward via the
helical gears 28 and 24a (step 117). Then, it is determined whether the outputs of the upper and
lower microphones 25a and 25b are equal (step 114), and when the outputs of the upper and
lower microphones 25a and 25b become equal, the driving of the motor 27 is stopped (step
115).
[0019]
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Next, it is determined whether the sound source tracking switch 33 is off (step 118). If the sound
source tracking switch 33 is not off, the process proceeds to step 102 to determine whether
there is an output from the microphones 21a, 21b, 25a, 25b ( Step 102), the sound source
tracking is continued, and when the sound source tracking switch 33 is turned off, the sound
source tracking is stopped (step 119). If the output of the left microphone 21a is equal to the
output of the right microphone 21b in step 104, the motor 19 is not driven, and the process
proceeds to step 111 to determine whether the output of the upper microphone 25a is equal to
the output of the lower microphone 25b. If the output of the upper microphone 25a and the
output of the lower microphone 25b are equal, the motor 27 is not driven, and the process
proceeds to step 118.
[0020]
Therefore, since the main microphone 2 can always be directed to the direction of the sound
source, even moving sound sources can be reliably picked up. In addition, when there are a large
number of speakers in a meeting or the like, the main microphone 2 having a single directivity
can be directed to the direction of the speakers, and the speech of the speakers can be picked up
clearly.
[0021]
In addition, when the main microphone 2 operates in response to the movement of the sound
source and no sound is detected for a predetermined time, the main microphone 2 faces
downward, so it is possible to play with the main microphone 2, It can also be used as a toy.
[0022]
FIG. 5 is a perspective view showing a microphone device of the second embodiment.
In the microphone device 38, a flower-shaped decoration, for example, a sunflower flower
decoration 39 is attached to the tip of the main microphone 2, and the others are configured in
the same manner as the microphone device 1 of the first embodiment.
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[0023]
Therefore, since a flower-shaped decorative body, for example, a decorative body 39 of a
sunflower flower is attached to the tip of the main microphone 2, the sunflower flower is always
directed to the direction of the sound source, and without speech Because it points down so as to
wither, it is possible to play more fun with the microphone device.
[0024]
FIG. 6 is a perspective view showing the main part of the microphone device of the third
embodiment.
The microphone device 41 has no mechanism for following up the sound source in the vertical
direction, and the main microphone 2 is fixed on the disk 16 'rotating in a substantially
horizontal direction, and the others are the microphone device 1 of the first embodiment
described above. It is configured in the same way.
[0025]
Therefore, since the sound source only follows in the left-right direction, it is possible to provide
an inexpensive microphone device with a simple mechanism, few failures, and the like.
[0026]
In the first to third embodiments described above, the microphones 21a, 21b, 25a, 25b as the
sound source direction detecting means are capacitor type microphones, but the invention is not
limited to this, and other microphones such as dynamic type microphones may be used. Of
course.
[0027]
Although the motor 19, the worm 20, the worm wheel 16a, and the disk 16 are used as the leftright direction driving means 4, the invention is not limited thereto, and other driving means
such as a motor directly connected to the shaft 15 may be used.
Although the motor 27, the helical gears 28, 24a and the disc 24 are used as the vertical driving
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means 5, the invention is not limited thereto, and other driving means such as a motor directly
connected to the shaft 23 may be used.
[0028]
Although the flower-shaped decoration is a sunflower flower decoration, it is of course possible
to use other flower decoration such as tulip without being limited thereto.
[0029]
As described above, according to the present invention, since the microphone can always be
directed to the direction of the sound source, even a moving sound source can be reliably picked
up.
Furthermore, when there are a large number of speakers in a meeting or the like, the microphone
can be directed to the direction of the speaker, and the speech of the speaker can be collected
clearly.
[0030]
In addition, since the microphone follows the direction of the sound source sensitively and does
not detect sound for a predetermined time, the microphone is directed downward, so it is
possible to play with the microphone and can be used as a toy.
[0031]
Furthermore, since the flower-shaped decoration is attached to the microphone, the flowershaped decoration always points in the direction of the sound source, and if there is no remark,
the flower-shaped decoration lowers as if the flower is bloated. You can play more fun because
you are facing.
[0032]
When the driving means is only the left and right direction driving means, the sound source is
only followed in the left and right direction, so it is possible to provide an inexpensive
microphone device with a simple mechanism and less failure.
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