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JPH03153200

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DESCRIPTION JPH03153200
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
acoustic pickup device, and more particularly to an improvement of the acoustic pickup device
which directly contacts an acoustic vibration transmission system to convert acoustic vibration
into an electrical signal and wirelessly transmit it. 2. Description of the Related Art Electrically
detecting vibrations in the voice, musical tone or audio frequency range is widely demanded in
various industrial fields, and is known as an acoustic microphone. Conventional acoustic
microphones generally detect air-borne waves, and are widely used as carbon microphones,
moving coil microphones, ribbon microphones, condenser microphones, or electret condenser
microphones. 17 However, this type of acoustic microphone requires an amplification system
with a sufficient amplification degree to detect weak vibration, and as a compact, low-power
acoustic pickup device, 17 is always sufficient as a general-purpose It has not reached sex. For
this purpose, there has been proposed a pick-up device in which the pick-up device is brought
into direct contact with the acoustic vibration system to significantly increase the detection level.
According to such a direct contact type pickup device, there is an advantage that the
amplification system of the detection voltage can be considerably simplified and the device N can
be miniaturized. As a conventional direct contact type pickup device of this type, for example, it
is known as Japanese Patent Publication No. 53-39763, and it is used mainly in a communication
device 17 that transmits voice. That is, the conventional device inserts the vibration pickup into
the ear canal 17 and directly picks up the bone conduction sound vibration. The voice
transmission is performed, thereby improving the voice transmission under a noisy environment
L, known as an ear microphone, for example. Of course, this kind of blind sound pickup device is
not limited to the above-mentioned ear microphones, but it is mounted on various parts of the
body to detect bone conduction sound, and is widely used in vibration transmission systems such
as telephones and the like. It has various uses. [Problems to be Solved by the Invention 17] While
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the conventional pickup apparatus of this type has a configuration in which a long and narrow
vibration sensor made of a piezoelectric element is disposed in parallel with the axial direction of
the ear canal, the axial line of the vibration sensor The weak vibration of the ear canal wall in the
direction perpendicular to the direction is greatly enlarged, and the piezoelectric element is
deformed in a predetermined mode to pick up the vibration. Therefore, in the pickup device of
this type in the prior art, since the ceramic piezoelectric element is usually supported and
vibrated in the form of a cantilever, there is a problem that it is extremely fragile against an
externally applied impact, It is difficult to put into practical use H-C 5 ° for practical use, and the
big-up device that is in direct contact with the vibration transmission system can be used as
another mechanical vibration system. It is preferable that this only allows the detection of
vibrations that are "".
For this reason, it is preferable that the pickup device itself be as small and light as possible 17 to
reduce the disturbance factor to the vibration system to be detected (7). (7) Further, when the
detection signal of the pickup device is taken out to the outside, if the wired transmission is
performed by the lead wire as in the above-mentioned ((7) conventional device, the pickup device
itself is small by this lead wire However, there is a problem that the vibration stiffness of the
whole becomes large 17 and the SN ratio drops remarkably. Also, there has been a problem that
the lead wire transmits its own vibration or vibration from another external vibration system,
thereby generating a large noise and further reducing the SN ratio. Furthermore, in the prior art,
in the case where the signal extraction is carried out by radio signal transmission 11 · (where, the
above-mentioned j, the harmful effect due to the lead wire is eliminated ii 1 function, but on the
other hand, for radio wave transmission) The need for a large energy V-, 12, and the reduction in
size and weight of the device have had the problem of becoming "T fM a:". In order to transmit
radio waves, it is necessary to store a battery with a relatively large capacity in the pickup device,
and it is necessary to replace the battery because the power consumption is large and the sealing
performance of the pickup device is impaired. Even if a secondary battery is adopted to eliminate
this problem, the sealing performance of the device is impaired due to battery charging, or the
body etc. is provided to provide a charging terminal on the outer surface of the device. As a
pickup device to be mounted, there has been a fear of inflammation or allergic disease due to
direct contact of the electrode part. The present invention has been made in view of the abovedescribed conventional problems, and its object is to detect vibrations with high efficiency and
high SN ratio reliably from a vibration transmission system while being small and lightweight,
and to propagate this detection signal by radio It is an object of the present invention to provide
a compact and lightweight acoustic pickup device which can be taken out to the outside. Another
object of the present invention is to provide an acoustic pickup device in which a piezoelectric
pickup for picking up vibration from a vibration transmission system is resistant to an external
impact and can be sufficiently miniaturized. Another object of the present invention is to provide
a name-pickup device in which the battery contained in the pickup device η can be charged
from the outside without contact. [Means for Solving the Problems] In order to achieve the above
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object, according to the present invention, a case in direct contact with a vibration transmission
system, a piezoelectric pickup housed in the case, and a piezoelectric feeder housed in the case
And a vibration-sensing support plate having a piezoelectric vibrator fixed thereto and at least a
part of the periphery supported by the case, and a vibrating weight fixed to the vibration-sensing
support plate. The ultrasonic wave transmitter G4 includes a transmission ultrasonic transducer
which is excited by the electrical output signal of the piezoelectric pickup and emits the pickup
signal as an air-borne ultrasonic wave.
Further, according to the present invention, in the case, a charging iiT capable secondary battery
for supplying a power supply voltage to each electric circuit, and a charging secondary coil
electromagnetically coupled to an external charging primary coil for charging the secondary
battery. It is characterized by being inside. Further, according to the present invention, the
vibrating weight is characterized by comprising a high magnetic permeability core fixed at one
end to the vibration supporting plate, and penetrating through the inside of the charging
secondary coil. Therefore, according to the present invention, it is possible to provide a compact
and lightweight pickup device having a sufficient resistance against external shocks 1 to 1, and
the piezoelectric pickup is fixed to a piezoelectric vibrator. At least a part of the outer periphery
of the vibration-sensitive support plate is held in the case, and the support plate and the vibrating
weight are engaged to detect the vibration of the vibration transmission system with high
efficiency. Further, according to the present invention, the detection signal of the pickup device
can be transmitted to the outside using an ultrasonic wave, and as a result, the detection SN ratio
can be reduced by two. . Furthermore, according to the present invention, the pickup device
incorporates the secondary battery, and since the secondary battery can be charged from the
outside without contact, the device can withstand long-time use with a sufficiently airtight
structure and 1- It is possible to provide a pickup device. DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described
based on the following drawings. FIG. 1 shows a sound pickup device according to the present
invention as a preferred embodiment mounted on the ear canal and detecting bone conduction
sound vibration. According to such a pickup device, voice transmission can be performed at a
sufficient SN ratio even under noise recovery, and further, such a pickup device may be a type, a
word processor or other office equipment or a vending machine, an automatic door, etc. It is also
extremely useful as a pointing device by means of voice input. In FIG. 1, a case 10 is comprised of
a base end gate 1 inserted into an ear canal and adhesively fixed to a tip end case of-. The abovementioned 1: 1 end lens I2 incorporates a piezoelectric pickup 16, a pre-charge sensor 1c18, a
charge / Ih 20 and a charge next coil 22. On the other hand, the ultrasonic transmitter 23 and
the transmission IC 24 are built in the base case 14, and in the embodiment, both cases 12.14
are fitted with the respective members fixed to the tip case 12 and the base case 14 respectively.
Part 1. Adhesive fitting is fixed at Oa. The piezoelectric pickup 16 includes a pickup substrate 26
press-fit into the tip case 12. The vibration-sensitive support plate 28 having a cup shape in the
embodiment is fixed to the substrate 26 by at least a part of the periphery thereof. The cup-
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shaped vibration support plate 28 is fixed to the substrate 26 or the open end face thereof.
The vibration supporting plate 28 is formed by drawing a thin metal plate in the embodiment,
and in the embodiment, the flange portion 28a is in direct contact 17 with the inner periphery of
the tip case 2]. Therefore, according to the present embodiment, the tip case 12 inserted in the
external auditory canal transmits bone conduction vibration through the 17 'L contact via the
pickup substrate 26 or to the flange portion 28 a of the vibration sensing support plate 28 as it
is. Can. The vibration supporting plate 28 has a ceramic piezoelectric vibrator 30 such as PZT
bonded or fixed to the inner bottom surface thereof as a t i: I, and further, the other surface of
the pressure 7 h vibration-F 30 is The coating is solidified by the resin layer 3: 2. Accordingly,
the vibration of the vibration transmission system is reliably transmitted to the piezoelectric
vibrator 30. Furthermore, in the piezoelectric pickup 16 according to the present embodiment,
one end of the vibrating weight 34 is adhesively fixed to the center of the outer surface of the
vibration supporting plate 28 in order to further increase the distortion of the piezoelectric
vibrator 30 due to the vibration. There is. In the embodiment, the vibrating weight 34 is
supported at its free end in a vibratable manner by the elastic support 36. The elastic support
portion 36 is made of, for example, a plastic such as neobrene, and in the case of the vibration
weight 34 or the vibration 12 in the audio frequency range, the vibration weight 34 is not
substantially damped by this vibration. With respect to an applied impact or the like, the free end
of the vibrating weight 34 is held and braking is performed with the excessive amplitude 17 to
prevent its breakage reliably. Therefore, according to the vibrating weight 34 of the embodiment,
the vibration applied to the piezoelectric pickup 16 via the tip nose 12 can be reliably
transmitted to the piezoelectric vibrator 30 with high efficiency. That is, the presence of the
vibration mass 34 makes it possible to provide the piezoelectric vibrator 30 with a sufficiently
large strain. As is apparent from the above embodiment, the ceramic piezoelectric vibrator 30
which is fragile and easily broken is accommodated and fixed in a cup-shaped vibration-sensitive
support plate 28 in a form protected from external impact. Then, the vibration supporting plate
28 itself is deformed according to the vibration, and this vibrational deformation is amplified by
the vibration weight and transmitted to the piezoelectric vibrator 30, so that the piezoelectric
conversion action with a sufficiently high efficiency is made iiJ function. . As described above, the
electrical conversion by l−, the positive and negative signals are supplied from the piezoelectric
vibrator 30 to the preamplifier I CIR. The preamplifier IC13 is mounted on an IC fixing plate 38
press-fitted and fixed to the front end case 12 and amplifies the weak output of the piezoelectric
vibrator 30 to a voltage suitable for ultrasonic wave transmission of the next stage.
In order to supply sufficient power to the preamplifier IC13 and a transmission circuit described
later, the battery 20 is built in the case O, and in the embodiment, the battery 20 is made of a
rechargeable lithium secondary battery. The battery case 40 is fixed to the battery case 40
pressed into the front end case 12. In the pickup device of the embodiment, as described later,
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the case 10 can be permanently sealed because the battery 20 is fully in contact with the outside
without being in contact with the outside. As described above, the external vibration is converted
into an electric signal with high efficiency by the piezoelectric pickup 16, but in the present
invention, the converted electric signal can be further transmitted to the 4'1 part by the river
noise 17f7. Do. Real FIL! ('A ((: to 7-1; d33 wave transmitter 23 nails four transmitter substrates
2 press-fit and fixed to Buf / Yt 14a of the base tongue 14 and The acoustic transducer holding
plate 44 is fixed. The ultrasonic transducer holding plate 44 has a thin plate shape, and is fixed
to an inner bottom surface thereof with an ultrasonic transducer 46 such as PZT, and the other
surface is covered with a resin layer 48. The outer surface of the ultrasonic transmitter 23 is
protected by a protective layer 50. Therefore, the ultrasonic transducer 46 is not limited to the
above-mentioned 1. If the excitation voltage is supplied based on the electrical signal detected as
above, the ultrasonic transducer 46 emits ultrasonic waves, and wireless communication can be
performed within a relatively short distance by ultrasonic waves due to air propagation. It
becomes. The excitation action is controlled by the transmission IC 24. The transmission IC 24 is
fixed to the transmission substrate 52, and the substrate 52 is pressed into the bracket 14a of
the base case 14 by the above-described extraction, and the other surface of the transmission IC
24 is the resin layer 54. Sealed. On the contrary, when the output of the preamplifier IC13 is
supplied to the transmission IC 24, a predetermined excitation signal is supplied to the ultrasonic
transducer 46 by the transmission circuit described later, and the above-mentioned ultrasonic
communication becomes possible. A power supply voltage is also supplied from the battery 20 to
the transmission IC 24. As described above, according to the present embodiment, the
piezoelectric pickup by direct contact with the vibration transmission system and ultrasonic wave
transmission modulated with the pickup voltage signal become possible, but in the present
embodiment, the battery 20 is used. In order to charge from the outside without contact, the
leading case 12 incorporates a charging secondary coil 22. Then, when the charging secondary
coil 22 is electromagnetically coupled to an external primary coil and receives a current supply,
the secondary output is rectified and supplied to the battery 20 as a charging current to perform
a desired charging operation. It becomes.
In the present embodiment, the vibrating weight 34 penetrates between the centers of the
charging secondary coil 22. As a result, at the time of charging as described above, the vibrating
weight 34 is a secondary coil core for charging. Share 1. It is understood that it is. For this
purpose, it is preferable that the vibrating weight 34 in the embodiment is formed of a high
magnetic permeability material such as ferrite. Therefore, according to the present embodiment,
it is possible to efficiently transmit the vibration directly transmitted through the piezoelectric
conversion 17 or to the outside as an ultrasonic wave, while effectively utilizing the internal
space of the case 1 o. It is possible to provide a device which is compact and light, and which can
be used over a long period of time, though it is a pickup device completely charged with a built-in
secondary battery without external contact and charging. FIG. 2 shows an example of a
piezoelectric boost-up and ultrasonic transmission / reception circuit suitable for the present
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invention. As shown in the embodiment of FIG. 1, the piezoelectric pick-up] 6 detects the
vibration of the vibration transmission system with a ceramic piezoelectric vibrator 1 to 1 and
detects the voltage generated at the time of strain deformation from the electrodes stuck on both
sides.狛,? ). The preamplifier IC13 amplifies the weak detection signal to perform desired
processing, and in the embodiment, it amplifies about 40 to 60 dB in the audio frequency band.
The detection signal thus amplified at 17 is subjected to transmission processing in the
transmission IC 24. In FIG. 2, this transmission IC 24 is a characteristic correction circuit 60. It
includes an amplitude limiter 62, a voltage control oscillation circuit 64 and an amplifier 66. The
characteristic correction circuit 6 () in the embodiment performs correction according to the
vibration transmission system, for example, when dealing with the f4 conduction vibration as
shown in FIG. 1, when the case 1o is inserted in the ear canal, the signal in the low frequency
region is As emphasized, the characteristic correction circuit 60 performs compensation (preemphasis) in the high frequency region. The characteristic corrected signal is further limited to a
peak value by the amplitude limiter 62 to prevent overmodulation, and the output is supplied to
the voltage control oscillation circuit. The voltage controlled oscillation circuit 64 converts the
detected inclination of the audio frequency 'LY': i: range as described above into a frequency for
ultrasonic wave transmission 1 and the detected voltage 1 ° with the control voltage. Frequency
change 1 +, J J · · ·. The output of the voltage control oscillation circuit 64 is buffered and
amplified by the amplifier 66 and supplied to the ultrasonic transducer 46 at the excitation
voltage 17. Therefore, the ultrasonic transducer 46 can emit the ultrasonic wave modulated
based on the signal detected by the pressure pickup 16 into the air.
In FIG. 2, on the receiving side, a transducer emitted by the vibration of the ultrasonic transducer
46 is electrically detected 17 by an ultrasonic detector 68, and such a detector 68 is an
ultrasonic wave using, for example, PZT or the like. Trans deco and 17 are well known. The
electrical signal electrically converted by the ultrasonic detector 68 is band amplified by the
amplifier 70, and then the detection circuit 72 detects frequency modulation on the transmission
side. In practice, such a detection circuit 72 preferably uses a phase lock loop (PLL) circuit or the
like. The detection output is further subjected to high-frequency area reduction (de-emphasis)
corresponding to high-frequency area strengthening (pre-emphasis) on the transmission side by
a characteristic capture 1F9 circuit 74, and the output is supplied to an amplifier 76 , A sound t,
a binding, or an electrical j 声 double signal (2 is supplied to a desired processing unit. As
described above, according to the illustrated embodiment, ultrasonic waves can be used to
reliably communicate the detected vibration wirelessly. Of course, since the ultrasonic waves
have large attenuation in the air, it is impossible to perform long-distance transmission, but since
there is little noise mixing from the outside, they are extremely high in L'i degree for shortdistance wireless communication. Communication can be performed, and it is extremely useful,
for example, when performing communication at a relatively short distance 6 to re-input or give
voice instructions to various' H11 devices or automatic devices. FIG. 3 shows an example of a
charging device suitable for the present invention, and the acoustic pickup device 10D of FIG. 1
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described above is very easily accommodated inside by being mounted on the charging device
200. Are you secondary? The pond can be charged contactlessly to I ′ ′. The charger 200
includes a bottom plate 2 (] 2 and a housing 204, and an insertion hole 206 is formed in the
central portion of the housing 2C) 4 at which the pickup device 100 is inserted. And, the
charging primary coil 208 is disposed around the insertion hole 206, and in the embodiment, it
is fixed to the front 1: C bottom plate 202, and the bragg! The charging secondary coil 208 is
fixed at -210. In addition, the attachment detection switch 212 is fixed to the bottom of the
insertion hole 206, and when the pickup device 10 is firmly inserted into the insertion hole 206,
the switch 212 is turned on to start the charging operation. It becomes scarce. Inside the housing
204, a charging power source is formed, for example, 11l-a dry charge tlh 214, and an inverter
device 216 for supplying a charging current to the charging primary coil 208 is provided.
In order to replace the battery 214, a battery lid 21G is detachably provided on the housing 204.
Furthermore, the outer surface of the housing 204 The charging time is set as shown in Table 7.
First, the optional charging time is selected iiJ function, and in the present embodiment (in The
function of the sound pickup device 1 [] O and the detector 1. However, a changeover switch 220
is provided for use. Therefore, by mounting the acoustic pickup device 100 in the insertion hole
206 as shown by the arrow in FIG. 3 and supplying a desired charging current to the charging
secondary coil 208, the desired secondary current is supplied to the charging secondary coil 22.
It is possible to perform an electromagnetic induction and rectify it to perform the charging
operation of the battery 20 reliably and without contact. Therefore, according to the present
embodiment, since the charging operation is performed without any contact, the acoustic pickup
device 100 can be completely sealed, and no charging electrode is required outside the device, l:
1. Because it is not used, it does not cause any problems such as inflammation or allergic disease
or irritation caused by contact with electrodes when used in the body. In FIG. 4, the circuit
configuration of the charger shown in FIG. 3 and the charging circuit in the acoustic bias knob
device are schematically reduced. Fig. 4-1; “The primary side circuit is to supply the transistor
222 to the DC coil pressure of the battery 214, and to supply it to the DC primary coil 208, its
collector is connected to one end of the primary coil 208 and its emitter is to the battery 2] 4. It
is connected to the cathode. In FIG. 4, only one of the push-pull circuits is shown, and a primary
excitation current is efficiently supplied to the primary coil 208 by configuring the push-pull
circuit as is well known. The base of the transistor 222 is connected to the other end of the
switch 212 via a resistor 224 and is connected to the other end of the primary coil 208 via a
capacitor 226. The charge / function check switch 220 is connected in parallel with the
condenser 226, and the auxiliary capacitor 228 is connected in series with the switch 220. On
the other hand, a charging circuit not shown in detail in the acoustic pickup device includes a
rectifier 230 connected to the charging secondary coil 220 in FIG. 4 and the rectified output is
supplied to the battery 20. From the illustrated output terminal, i'-2 '2.234, the power supply
voltage is supplied to each circuit shown in FIG. In FIG. 4, in the normal charging state, the
changeover switch 220 is in the off state, and as a result, the oscillation frequency of the 1 to 2
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transistor 222 is determined by the capacitor 226, and an arbitrary frequency of 10 k Hz or
more is set, for example. Ru.
Therefore, in this state, as shown by the arrow in FIG. 3, when the pickup device 100 is correctly
inserted into the charger 20 (in the insertion hole 206 of 'J, the switch 2] 2 detects the tip case
12 and turns on. The oscillating action is performed at the predetermined frequency, and the
primary coil 208 is excited at this oscillating frequency. As a result, a desired secondary current
is induced in the secondary coil 22 in the pinkup device 100 disposed coaxially with the primary
coil 208, which is rectified by the rectifier 7230 to ensure charging of the battery 20. I can do it.
Next, when using the charger 20C! As a function check, the changeover switch 220 is turned on.
As a result, the capacitance of the base of the transistor 222 is increased by the insertion of the
auxiliary capacitor 228, whereby the excitation frequency of the primary coil 208 can be set
sufficiently low. As a result, in the embodiment shown in FIG. 1, the oscillating weight 34 forming
the core of the secondary coil 22 is provided with an electrical vibration instead of the
mechanical vibration applied from the normal part. The piezoelectric pickup 16 vibrates due to
the electric vibration. Therefore, in this state, it is possible to inspect the performance of the
apparatus with the external coil reception signal 1 nobel set to 4 (if set, the primary coil output
of the function check section as the reference level). Nondestructive inspection is carried out as
opposed to conventional inspection. Therefore, it is understood that the vibration weight in the
embodiment is 1'J- which has the vibration amplification action of itself, the core and the
function at the time of charging, and the three kinds of action of the electric vibration at tucking.
FIG. 5 shows an acoustic pick-up device inserted into the ear canal to detect sfi conduction
vibration according to the second embodiment of the present invention, but unlike the first
embodiment, the vibration weight is formed small. Also, since the secondary coil for charging is
removed, and the other dead-body is similar to the first embodiment, 300 is added to the
reference of FIG. 1 and the description is omitted. Also in the second embodiment, the oscillating
weight 334 forms a portion having a different mass relative to the vibration sensing support
plate 328. As a result, externally applied vibrations are mechanically amplified by the oscillating
weight 334. Of course, although the degree of mechanical amplification changes depending on
the size of the oscillating weight, it is possible to select the optimum mass in relation to the
material or thickness of the vibration-sensitive support plate 328, as shown in FIG. The small
vibration weight 334 provided on the ring line of the vibration-sensitive support plate 328 can
sufficiently perform a practical vibration detection operation. The 1 ° C) diagram in the third
embodiment of the present invention Since an example is shown and similar to the second
embodiment 4), 100 is further added to the code of FIG. 5 and the detailed description of r4 is
omitted.
In the third embodiment, when the position of the oscillating weight is indicated by reference
numeral 434 (the displacement from the axis of the cup-shaped vibration supporting plate 428
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to the position of 4'- of its radius is provided (7 As a result, even when the mass of the vibrating
weight 434 is small, the vibration-sensitive support plate 428 can be sufficiently distorted. That
is, according to the third embodiment, the mass distribution of the vibration-sensitive support
plate 428 is changed by the installation of the eccentric vibration mass 434. As a result, the
vibration distribution plate 428 is opposed to the vibration given by direct transmission from the
outside. The large displacement distortion occurs due to the displacement of the <It is possible to
improve. The fourth embodiment of the present invention is shown in FIG. 7, and while the
above-described embodiments are the ear microphone type pickup apparatus mounted on the
ear canal, in the present embodiment any vibration transmission is carried out. The system can
be directly attracted to, for example, a telephone, an apparatus having a vibration source, etc.
Therefore, according to the fourth embodiment, the pickup device of the telephone and Or as a
noise level sensor for equipment. As shown in the figure, the vibration-sensing support plate 528
of the piezoelectric pickup 516 is drawn between the suction cup 500 and the case 510, and the
vibration transmitted from the outside through the suction cup 500 is transmitted to the
vibration-sensing support plate 528, This can be effectively transmitted to the piezoelectric
vibrator 530. Also in this embodiment, the vibration weight 534 is fixed at an eccentric position
on the outer bottom surface of the vibration support plate 528, and the vibration obtained from
the outside can be mechanically amplified. Also in the fourth embodiment, the ultrasonic wave
transmitter provided in the case 510 is the same as the above-described embodiment, and the
description thereof will be omitted. As described above, according to the present invention, the
vibration is effectively detected by the piezoelectric pickup disposed in direct contact with the
vibration transmission system, and the vibration is detected mechanically by the vibration weight
at this time. Since the amplification is accompanied by a high efficiency piezoelectric pickup
action with a low S / N ratio. (7) The electric signal thus obtained by i- is transmitted from the
pickup device to the outside at a short distance using ultrasonic waves, and as a result, since the
pickup device can transmit wirelessly, the device can be miniaturized Weight reduction 17, noise
level mixed from the outside can be made extremely small. Further, according to the present
invention, the battery in the acoustic pickup device can be charged from the outside without any
contact from the outside by the built-in secondary coil l, so that the sound can be effectively
transmitted for a long period of time by the pickup device complete pair +) =. It is iiJ ability to
pick up.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a sectional view showing a first preferred embodiment in which the acoustic pickup
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device according to the present invention is used for an ear microphone, and FIG. 2 is a
piezoelectric pick-up tab and an ultrasonic transmission circuit shown in FIG. FIG. 3 is a block
circuit diagram showing an example of the ultrasonic ossification circuit, FIG. 3 is a crosssectional view showing a construction table of the charger in the first embodiment, and FIG. 4 is
the charger and function checker shown in FIG. FIG. 5 is a fragmentary view showing a second
preferred embodiment using the acoustic pickup device according to the present invention as an
ear microphone, and FIG. 6 is a main portion showing a third embodiment of the present
invention. FIG. 7 is a fragmentary cutaway view of an adsorption type pickup showing a fourth
embodiment of the present invention.
10.310, 410.510 ・ ・ ・ Case 16.316.416.516 ・ ・ ・ Piezoelectric pickup 20 ・ ・ ・ Battery
22 ・ Charging secondary coil 23 ・ ・ ・ Ultrasonic transmitter 28.328.42 B, 52 B · · ·
Vibration-sensitive support plate 30.330 · · 13C], 1): ((-) · · · Piezoelectric vibrator
34.334.434.534 · · · Vibration weight 46 · Ultrasonic vibrator 100 · Sound Pickup device 200 ・
・ ・ Charger
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