close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP5079913

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 JP5079913
Abstract: A contact microphone and a transmitter / receiver are provided to further improve the
noise resistance of a contact microphone such as a NAM microphone and to easily pick up only
normal voice and inaudible tweets and the like clearly. A contact-type microphone 1k includes a
microphone element 2 having a diaphragm 5, a vibration transfer member 7b for storing the
microphone element 2, a damping member 8b for storing the vibration transfer member 7b, and
a sound collecting opening 11. A cover member 9 having the microphone element 2, the
vibration transfer member 7b and the vibration damping member 8b, and a cap-like sound
collection contact member 12d arranged to cover the sound collection opening 11 of the cover
member 9; Equipped with In the sound collection contact member 12 d, a hole (concave portion)
24 having a small thickness immediately above the vibration film 5 and having a shape with a
wide sound collection opening 11 side of the cover member 9 is formed at a position facing the
vibration film 5. There is. In addition, the headphones (transmission / reception device) include
the contact microphone 1k. [Selected figure] Figure 11
Contact-type microphone and transmitter-receiver equipped with contact-type microphone
[0001]
The present invention provides a contact microphone and a contact microphone capable of
clearly picking up an objectionable voice or a faint noise or inaudible tweets that can not be
heard by the human ear even in a noisy environment. A transmitter / receiver comprising the
[0002]
18-04-2019
1
A variety of voices including a non-audible tweet voice (hereinafter referred to as "NAM") with
the microphone placed on the skin surface just below the auricle of the skull in the lower rear
part of the auricle and immediately below the calvaria of the skull There are contact
microphones, so-called NAM microphones, for collecting internal conduction sound 4 as
transmission vibration (for example, Patent Document 1).
Although such NAM microphones have begun to be applied to voice input / recognition and
voiceless telephones whose main purpose is concealment of voiced content, in recent years the
pulse and heart sound that is the body's internal conduction sound of a patient for medical use It
is also attracting attention as a vibration pickup detector that constantly monitors the
[0003]
FIG. 1 is a side sectional view showing the basic structure of a conventional contact-type
microphone.
[0004]
A microphone element 2 of a conventional contact-type microphone (in each embodiment, an
electret condenser microphone is used, hereinafter abbreviated as "ECM") is a voice of a speaker
collected from an object 3 to be collected such as skin. When the internal conduction sound 4 is
transmitted to the vibrating membrane 5 through the vibration transmitting member 107
described later, the vibration of the vibrating membrane 5 is converted into an electric signal,
and is transmitted to the outside through the conducting wire 6.
[0005]
The vibration transfer member 107 is attached so as to be in contact with or surround the
microphone element 2 and transmits the vibration of the internal conduction sound 4 to the
microphone element 2 without loss.
For the vibration transfer member 107, for example, a plastic material such as silicone elastomer
(for example, Patent Document 2) or urethane elastomer (for example, Patent Document 3) is
used.
Then, one of them is in contact with the vibrating film 5 of the microphone element 2, and the
18-04-2019
2
other is in wide contact with the sound collection target 3. The damping member 108 prevents
air conduction sound, which is background noise, from intruding from the back of the contact
type microphone, and for example, covers the entire sound collection opening 11 of the
microphone element 2 with an elastic epoxy resin. It is configured. The cover member 9 is made
of a metal such as aluminum or a plastic such as acrylic or ABS, and maintains the mechanical
strength of the entire contact microphone and plays a role of a resin injection mold at the time of
manufacture.
[0006]
In order to pick up the internal conduction sound 4 such as skin with high sensitivity using such
a conventional contact-type microphone, the reflection of the vibration at the interface between
the object to be collected 3 and the vibration transfer member 107 must be suppressed low. It
does not. The reflectance of sound is represented by the Snell's law shown in the following
(Expression 1).
[0007]
r2 = (Z2-Z1) <2> / (Z2 + Z1) <2> (formula 1) where, r2: reflectance at the interface between two
different substances 1 and 2, Z1: acoustic impedance of substance 1 (air Z2: the acoustic
impedance of the substance 2
[0008]
As understood from (Equation 1), if the acoustic impedances of two substances in contact with
each other are close to each other, the reflectance of sound is close to zero and the degree of
attenuation is also small.
Conversely, if the acoustic impedances of two materials in contact with each other are separated,
the reflectance of sound increases and the degree of attenuation also increases. Therefore, if the
acoustic impedance of the vibration transfer member 107 is made as close as that of the sound
collection object 3 (skin), the reflection of the body conduction sound 4 at the interface between
the sound collection object 3 and the vibration transfer member 107 is reduced. , Loss of internal
conduction sound 4 is suppressed.
18-04-2019
3
[0009]
Table 1 shows the values of acoustic impedance of various materials. From this (Table 1), it can
be seen that the plastic material such as silicone elastomer or urethane elastomer constituting
the vibration transfer member 107 has a value close to the acoustic impedance of the soft tissue
(skin). That is, the acoustic impedance of the plastic material is about 248 × 10 <4> (kg / m <2>
· s), and the acoustic impedance of the soft tissue (skin) = 135 × 10 <4> (kg / m <2>) It has a
value close to s). The vibrating film 5 of the microphone element 2 is also basically a plastic
material, and is the same as the vibration transfer member 107 in that respect.
[0010]
As a result, in the conventional contact-type microphone, the sensitivity of the in-vivo conduction
sound 4 in the microphone element 2 is improved, and the sound collection band is broadened
(in particular, the attenuation in the high frequency range above 2 kHz is reduced) It has been
said that the vibration of the soft tissue (skin) of the living body can be picked up with good
sensitivity during normal speech and inaudible tweets.
[0011]
WO 2004/021738 WO 2005/067340 JP 2007-043516
[0012]
However, in the above-mentioned prior art, background noise (noise) existing around a person
who speaks, that is, so-called air conduction sound 10 is also collected.
This is also understood from the same (Table 1) that the acoustic impedance of a plastic material
such as the silicone elastomer or urethane elastomer employed as the vibration transmitting
member 107 is 248 × 10 <4> (kg / m <2 This is because not only soft tissue (skin) but also the
acoustic impedance of air = 415 (kg / m <2> · s) has a value close to> · s).
[0013]
This point will be described in more detail with reference to FIG.
18-04-2019
4
Actually, in most cases, a slight gap 18 is generated between the sound pickup object 3 and the
open end of the cover member 9. The vibration transfer member 107 is in contact with the
external air in the gap 18.
[0014]
As mentioned earlier, the vibration transfer member 107 made of a plastic material and air have
acoustic impedances that are quite similar. Therefore, background noise (noise), which is not
desired to be collected as much as possible, so-called air conduction sound 10a intrudes into the
inside of the contact type microphone via this slight gap 18, and mixes in with internal
conduction sound 4 which is originally intended to be collected. It is picked up. Alternatively,
there is an external air conduction sound 10 b (hereinafter collectively referred to as “air
conduction sound 10”) collected by the contact-type microphone via the sound collection target
3 (skin). With regard to the air conduction sound 10c, the arrival at the microphone element 2
can be reduced by the reflection by the cover member 9 and the absorption by the damping
member 108 inside thereof. However, since the air conduction sounds 10a and 10b are mixed in
the internal conduction sound 4 which is originally intended to be collected, the content of the
other party's speech can not be clearly heard, or an error in voice input and speech recognition
on the portable information terminal side. There were problems such as causing it.
[0015]
An object of the present invention is to further improve the noise resistance of a contact
microphone such as a NAM microphone, and to make it easy to clearly pick up only normal voice
and inaudible tweets, etc. To provide.
[0016]
The contact-type microphone according to the present invention comprises a microphone
element having a vibrating membrane, and a vibration transmitting member that contacts the
vibrating membrane of the microphone element and transmits the vibration transmitted from the
side facing the vibrating membrane to the microphone element. And a cover member having an
opening and containing the microphone element and the vibration transmitting member, and a
sound pickup contact member disposed to cover the opening of the cover member and in contact
with the vibration transmitting member. The sound collection contact member has a
configuration in which a recess is formed on the opposite surface of the vibrating membrane.
18-04-2019
5
[0017]
A transmitter-receiver according to the present invention includes the contact-type microphone.
[0018]
According to the present invention, the noise resistance is further improved, and it is easy to
clearly pick up not only normal voice but also inaudible voice and noise such as the speaker's
tweet from the sound collection object such as skin clearly. can do.
[0019]
A side sectional view showing a basic structure of a conventional contact-type microphone (a) A
side sectional view of a contact-type microphone in Example 1 of Embodiment 1 of the present
invention, (b) A contact-type microphone in Example 2 of the present invention Side sectional
view Figure showing a method for evaluating the S / N ratio of the contact type microphone of
the present invention Side sectional view of the contact type microphone in the third
embodiment of the present invention, (a) whole side sectional view, (b) vibration transmission
member Enlarged view of the tip A side sectional view of a contact type microphone in a
comparative example in comparison with Example 3 of the present invention (a) A side sectional
view of a contact type microphone in comparative example 1, (b) A contact type in comparative
example 2 Side sectional view of the microphone Side sectional view of the contact type
microphone in a comparative example in comparison with Example 3 of the present invention (a)
Side sectional view of the contact type microphone in comparative example 3, (b) in comparative
example 4 A side sectional view of a contact type microphone A side sectional view of an
application of a contact type microphone according to a third embodiment of the present
invention A side sectional view of a contact type microphone according to a fourth embodiment
of the present invention (a) b) An enlarged view of the tip portion of the vibration transfer
member A side sectional view of the contact type microphone in the comparative example 5
which is in a comparative relationship with the fourth embodiment of the present invention an
exploded perspective view of the contact type microphone in the fifth embodiment of the present
invention 5 is a side sectional view of the contact type microphone in Example 5, (a) is an entire
side sectional view, (b) is an enlarged view of a tip portion of a vibration transfer member,
showing an example of a method of manufacturing the contact type microphone in Embodiment
5 of the present invention Figure showing an example of a manufacturing method of a contact
type microphone in the fifth embodiment of the invention. Figure showing an example of a
manufacturing method of a contact type microphone in the fifth embodiment of the present
invention. Contact type microphone in the fifth embodiment of the present invention. A diagram
showing an example of a method for producing a phone A diagram showing an example of a
method for producing a contact type microphone in the fifth embodiment of the present
invention A perspective view for explaining the structure of a sound pickup contact member of
18-04-2019
6
the contact type microphone in the present embodiment 5 Whole side sectional view at the time
of attaching the earth wire of the contact-type microphone in Example 5 Side sectional view of
the contact-type microphone in Example 6 of this invention A figure showing torsion free
damping type viscoelasticity measurement data in Example 7 of this invention The test
conditions of the elastic adhesive, the two-component mixed epoxy adhesive, and the rubber
solvent adhesive in Example 7 of the present invention are shown as a circular characteristic
chart. Adhesiveness to the plastic material in Example 7 of the present invention Figure showing
the characteristics of the two-component elastic adhesives PM210 and EP001 in Example 7 of
the present invention in comparison. The contact type microphone of the second embodiment of
the present invention is mounted. 3 is a perspective view showing a transmitting / receiving
apparatus according to a second embodiment of the present invention, the side view of the
transmitting / receiving apparatus equipped with the contact type microphone according to the
second embodiment mounted on the head, the contact type microphone in the transmitting /
receiving apparatus according to the second embodiment. A diagram to explain the placement of
[0020]
Hereinafter, each embodiment of the present invention will be described in detail with reference
to the drawings.
[0021]
First Embodiment Example 1 FIG. 2A is a side cross-sectional view of a contact type microphone
in a first example of the first embodiment of the present invention.
Here, first, with reference to FIG. 2A, a contact type microphone having the sound collecting
contact member 12a made of SUS (200 μ thick) will be described.
The components common or similar to those of the conventional contact microphone (see FIG. 1)
will be described using the same reference numerals.
Incidentally, the sound pickup contact member 12a is a member which is not included in the
conventional contact type microphone (see FIG. 1).
Further, with regard to the vibration transmitting member 7a and the vibration damping member
18-04-2019
7
8a described later, the vibration transmitting member 107 (see FIG. 1) and the vibration damping
member 108 (see FIG. 1) which the conventional contact type microphone (see FIG. 1) has It has
a different configuration.
And these are the characteristic parts of the present invention.
[0022]
In the microphone element 2 of the contact type microphone 1a of the first embodiment in FIG.
2A, the internal conduction sound 4 such as the voice of the speaker collected from the sound
collection target 3 such as skin is a sound collection contact member When the vibration is
transmitted to the vibrating membrane 5 via 12a and the vibration transmitting member 7a, the
vibration of the vibrating membrane 5 is converted into an electric signal, and is transmitted to
the outside via the conducting wire 6.
[0023]
The cover member 9 is made of metal such as aluminum, acrylic, or plastic such as ABS as in the
conventional contact microphone (see FIG. 1), and maintains the mechanical strength of the
entire contact microphone 1a, and at the time of manufacture It serves as an injection mold.
[0024]
The vibration transmitting member 7a transmits the vibration of the internal conduction sound 4
to the microphone element 2 without loss, and is made of, for example, urethane elastomer, and
in the point that one of them is in contact with the diaphragm 5 of the microphone element 2,
The same as the contact microphone (see FIG. 1).
[0025]
However, the other of the vibration transfer members 7a is not itself in wide contact with the
sound pickup object 3 as in the conventional contact microphone (see FIG. 1).
The vibration transfer member 7a of the first embodiment is in contact with the vicinity of the
substantially central portion of the sound collection contact member 12a, which is not included
in the conventional contact microphone (see FIG. 1).
18-04-2019
8
The sound pickup contact member 12 a is made of, for example, SUS 304 with a thickness of 200
μm.
In the contact type microphone 1a of the first embodiment, the contact portion between the
vibration transfer member 7a and the sound collection contact member 12a is provided
substantially at the center of the sound collection contact member 12a.
Further, among the contact areas of the contact portion between the vibration transfer member
7a and the sound collection contact member 12a, the contact area in the direction parallel to the
surface where the sound collection contact member 12a contacts the sound collection target 3 is
vibration It is smaller than the cross-sectional area in the parallel direction in the other part of
the transmission member 7a. Furthermore, in the direction parallel to the plane where the sound
collection contact member 12a contacts the sound collection target 3, the centers of the
microphone element 2, the vibration transfer member 7a and the sound collection contact
member 12a are in contact with sound collection It can also be said that the member 12 a is on
substantially the same axis in the direction perpendicular to the surface in contact with the sound
collection target 3.
[0026]
According to the above configuration, the contact type microphone 1a of the first embodiment
can reflect and suppress the mixing of background noise around it due to a noise environment,
and efficiently pick up only the vibration of the target sound collection object it can. As a result,
the noise resistance is further improved, and it is easy to clearly pick up not only normal voice
but also inaudible voice and noise such as the speaker's tweet from the sound collection object
such as skin clearly. it can. The features and effects will be described in more detail later.
[0027]
The damping member 8a, like the conventional contact type microphone (see FIG. 1), prevents
the air conducted sound 10 which is background noise from intruding from the back surface of
the contact type microphone 1a. The microphone element 2 is configured to cover the entire area
except the sound collection opening 11. In addition to that, unlike the conventional contact-type
microphone (see FIG. 1), the damping member 8a of the first embodiment is also in contact with
18-04-2019
9
the sound pickup contact member 12a, and is disposed so as to surround the vibration
transmission member 7a. It is done. The main body of the microphone element 2 and the
vibration transfer member 7a and the damping member 8a are sealed inside by the cover
member 9 and the sound collection contact member 12a. The vibration transfer member 7 a is
disposed to connect a substantially central portion of the sound collection contact member 12 a
and a substantially central portion of the sound collection opening 11 of the microphone element
2. In the case of the first embodiment, the substantially central portion of the sound pickup
opening 11 of the microphone element 2 is disposed immediately below the substantially central
portion of the sound pickup contact member 12a, and the vibration transmitting member 7a is
connected to connect the shortest distance. Is provided. The vibrating film 5 of the microphone
element 2 is also basically formed of the same plastic material as the vibration transfer member
107 (see FIG. 1).
[0028]
The materials of the sound collection contact member 12a and the cover member 9 will be
described later in a seventh embodiment.
[0029]
The features of the contact-type microphone 1a according to the first embodiment having the
configuration described above will now be described.
[0030]
As described above, the sound pickup contact member 12a of the contact type microphone 1a
according to the first embodiment is made of, for example, SUS304 having a thickness of 200 μ,
that is, a metal member.
As shown in (Table 1) above, the acoustic impedance of the metal member is 4160 × 10 <4> kg
/ m <2> · s, and of course the soft tissue such as the skin assumed as the sound collection object
3, It differs greatly from the air which transmits the air conduction sound 10 from the outside,
and the plastic member which constitutes vibration transmission member 7a.
[0031]
18-04-2019
10
That is, in the contact-type microphone 1a of the first embodiment, such members having
significantly different acoustic impedances are disposed in the transmission path of the internal
conduction sound 4 from the sound collection target 3 to the diaphragm 5 of the microphone
element 2. It will be.
In this case, in the conventional common sense, reflection of the internal conduction sound 4
becomes large at the interface between the sound collection contact member 12a and the sound
collection target 3 or the vibration transfer member 7a, and the diaphragm 5 of the microphone
element 2 It should be difficult to communicate.
[0032]
However, even if there is such a disadvantage, the attenuation factor of the air conduction sound
10 from the outside that you do not want to collect as much as possible is larger than the
attenuation of the internal conduction sound 4 that you want to collect. That is, since the contact
microphone 1a according to the first embodiment has a higher S / N ratio than the conventional
contact microphone (see FIG. 1), the internal conduction sound 4 can be picked up more
efficiently. it can.
[0033]
The reason is considered as follows. When the internal conduction sound 4 is given to the sound
collection contact member 12a of the first embodiment shown in FIG. 2A, the amplitude due to
the physical vibration is largest at the central portion of the sound collection contact member
12a. Become. Then, in the path from the central portion of the sound collection contact member
12 a where the physical vibration due to the internal conduction sound 4 is largest to the
diaphragm 5 of the microphone element 2, like the diaphragm 5 of the microphone element 2, A
vibration transmitting member 7a made of a plastic material is disposed. Thereby, the physical
vibration by the internal conduction sound 4 can be efficiently transmitted to the vibrating film 5
of the microphone element 2.
[0034]
In addition, a damping member 8a is disposed around the vibration transfer member 7a. This
18-04-2019
11
means that the air conduction sound 10 coming from the outside which tries to enter from the
part other than the central part of the sound pickup contact member 12a is fixed by the damping
member 8a and hardly reaches the diaphragm 5 of the microphone element 2. means. Since the
main body of the microphone element 2 and the vibration transfer member 7a and the damping
member 8a are sealed inside them by the cover member 9 and the sound pickup contact member
12a, the conventional contact type microphone (FIG. 1) Unlike reference), there is no room for
external air conduction noise 10 to penetrate. Therefore, in order for the air conduction sound
10 from the outside to reach the vibrating membrane 5 of the microphone element 2, the
vibration is as a result of being far from the peripheral portion of the sound pickup contact
member 12 a, and vibration excellent in sound transmission efficiency. The central portion of the
sound pickup contact member 12a with which the transmission member 7a is in contact must be
rolled up. During this penetration, the attenuation of the airborne sound 10 from the outside will
be greater.
[0035]
As described above, the contact-type microphone 1a of the first embodiment shown in FIG. 2A is
more likely to be picked up for the internal conduction sound 4 which is originally intended to be
picked up, and the external air conduction which is not desired to be picked up as much as
possible. The sound 10 has a structure that is less likely to be picked up. Therefore, the S / N
ratio of the internal conduction sound 4 to the external air conduction sound 10 is improved, and
the internal conduction sound 4 can be picked up more efficiently.
[0036]
This indicates how much the performance of the contact microphone 1a of the first embodiment
is actually improved with respect to the conventional contact microphone (see FIG. 1). In order to
judge the performance, we evaluated the S / N ratio and the intelligibility of the contact
microphone under the noise environment.
[0037]
First, a method for evaluating the S / N ratio of the contact microphone of the present invention
including the first embodiment will be described below.
[0038]
18-04-2019
12
FIG. 3 is a diagram showing a method of evaluating the S / N ratio of the contact microphone.
The S / N ratio evaluation method is commonly used for all contact microphones. First, an audio
file (distributed by the Japan Acoustical Society) recorded in the semi-non-acoustic room as the
background noise, that is, the external air conduction sound 10 is reproduced by the
reproduction device 13a by the reproduction device 13a, and the speaker via the amplifier 13b It
flows from 13c. In this state, a contact-type microphone (in the first embodiment, the contacttype microphone 1a shown in FIG. 2A) is mounted around the throat at a position measured as
100 dB by the sound level meter. Then, the characters of the monosyllabic 20-word phonetic
table recommended by the Japanese Association of Hearing Aids are pronounced and recorded at
regular intervals (about 90 dB) every two seconds. Based on the recorded waveform, the sound
pressure ratio between the external air conduction sound 10 collected by the contact
microphone 1a and the voice of the speaker, ie, the internal conduction sound 4 is expressed in
dB using the following (Equation 2) Convert to S / N ratio and evaluate.
[0039]
S / N ratio (dB) = 20 log (S / N) (Equation 2) Furthermore, a recorded voice file of a single
syllable 20-word phonetic table obtained at the time of the S / N ratio measurement above is
listened to by four arbitrary subjects, Ask them to record the letters they heard. Then, each
correct answer rate is calculated to be a monosyllable articulation degree, and the monosyllable
articulation degree is divided by 0.85 and evaluated as a sentence intelligibility degree. By the
way, when calculating the sentence intelligibility, dividing the monosyllable articulation by 0.85
is generally said, "If the correct answer rate of the monosyllable articulation is 85%, the sentence
intelligibility will be 100%." It is because
[0040]
The details of such an evaluation method are also described in p.117 of "Technology and Laws
and Regulations for New Pollution Prevention 2009: Noise and Vibration Edition for Qualification
Training for Pollution Prevention Managers, etc.". As a result of evaluating by the above method,
the S / N ratio of the contact type microphone 1a in the present embodiment 1 shown in FIG. 2A
is 20 dB, and the sentence intelligibility under 100 dB noise is 75%. all right. On the other hand,
the S / N ratio of the conventional contact type microphone (see FIG. 1) was 7 dB. From the
18-04-2019
13
above, it is clear that the S / N ratio of the contact microphone 1a in the present embodiment 1
shown in FIG. 2A is considerably improved.
[0041]
Thus, the contact-type microphone 1a of the first embodiment with improved performance can
be produced, for example, by the following process. First, in FIG. 2A, the damping member 8 a is
filled in the cover member 9. At this time, a storage portion (not shown) for storing the
microphone element 2 and the vibration transfer member 7a is formed in the damping member
8a by, for example, a casting method of two-component elastic epoxy resin. Next, a through hole
(not shown) which penetrates the damping member 8a and the cover member 9 is formed, and
after the lead wire 6 of the microphone element 2 is passed through the through hole, the
storage portion in the damping member 8a The microphone element 2 is installed on the bottom
surface. Thereafter, urethane elastomer is injected and potted into the sound collection opening
11 of the microphone element 2, and the vibration transfer member 7a is formed by heating at
80 ° C. for one hour. At this time, the tip of the vibration transfer member 7a is hemispherical
due to its own surface tension. Then, the sound absorbing contact member 12a, that is, the SUS
lid having a thickness of 200 μ is heated at 80 ° C. for one hour, using the two-component
elastic epoxy resin used similarly when forming the damping member 8a. When adhesively fixed
by curing, the contact microphone 1a shown in FIG. 2A is completed.
[0042]
In addition, as an elastic epoxy resin used as the damping member 8a in Example 1, for example,
an equal amount of EP001 (commercial epoxy resin-based elastic adhesive) manufactured by
Cemedine is mixed with a modified polyamine curing agent, and the temperature is 80 ° C.
Those cured in the above are preferably used. In addition, as the urethane elastomer used as the
vibration transfer member 7a in Example 1, for example, a gel stock solution of polyurethane
human skin (C-15 main agent and a curing agent mixed in 3: 1 by Excile Corporation, Inc.) And
those cured at 80 ° C. are preferably used. Furthermore, the sound collection contact member
12a and the cover member 9 are made of iron, stainless steel, aluminum having a material whose
acoustic impedance value is different from that of air (415 kg / m <2> · s) transmitting the
internal air conduction sound 4. In addition to metals (4160 × 10 <4> kg / m <2> · s), etc.,
ceramics (1122 × 10 <4> kg / m <2> · s) such as glass may be used. Furthermore, the exposed
surface of the sound pickup contact member 12a, that is, the contact surface with the sound
pickup object such as human skin or the side surface thereof may be coated with a coating
member such as resin. This is particularly effective when the sound pickup contact member 12a
18-04-2019
14
is metal. When the metal directly touches human skin, depending on the temperature, the metal
may feel cold or sweat may adhere, and the sound collecting contact member may be rusted. The
coating member is effective in avoiding such a defect.
[0043]
As described above, when the contact type microphone of the first embodiment is used, the noise
resistance is further improved, and normal voice and inaudible tweet voice can be easily collected
clearly under a noise environment.
[0044]
Hereinafter, the contact-type microphone of the first embodiment and the conventional contacttype microphone will be described in comparison.
[0045]
Conventional contact microphones are intended to be used in an environment as quiet and quiet
as possible.
For example, it is an application to a vibration pick-up detector etc. which always monitors a
pulse which is a body conduction sound of a patient, and a heart sound.
Conventional contact microphones attempt to increase S (signal component) under an
environment where N (noise) of S / N ratio is as small as possible. Conventional contact
microphones are not supposed to be used in noisy environments. Under the noise environment,
for example, a contact type microphone close to a speaker unit such as headphones, and a
contact type microphone arranged in a narrow case close to a speaker unit can be mentioned.
According to the inventors of the present invention, it has been found that the conventional
contact-type microphone has too large N (noise) under the above-mentioned noise environment
and is not in the practical level.
[0046]
On the other hand, in the contact type microphone 1a of the first embodiment, the sound
18-04-2019
15
collection contact member 12a is disposed so as to cover the sound collection opening 11 of the
cover member. For this reason, there is a concern that the signal component to be detected is
reduced. However, according to experiments of the present inventor and the like, it has been
found that, although the sound collection contact member 12 a covers the opening 11, the signal
component reduction is at a level that causes no problem in mounting. It is considered that the
arrangement of the sound collection contact member 12a at the center opposite to the vibrating
membrane 5 and the use of a material having a large difference in acoustic impedance Z as the
material of the sound collection contact member 12a are effective. The thickness of the sound
pickup contact member 12a is also optimized.
[0047]
According to the above configuration, the contact type microphone 1a of the first embodiment
can reflect and suppress the mixing of background noise around it due to a noise environment,
and efficiently pick up only the vibration of the target sound collection object it can. As a result,
the noise resistance is further improved, and it is easy to clearly pick up not only normal voice
but also inaudible voice and noise such as the speaker's tweet from the sound collection object
such as skin clearly. it can. It is possible to mount in the transmission / reception apparatus
which can arrange | position a microphone in proximity to the speaker part like headphones.
[0048]
Embodiment 2 FIG. 2 (b) is a view showing a side cross-sectional view of a contact type
microphone in Embodiment 2 of the present invention. The configuration of the contact-type
microphone 1b according to the second embodiment has many parts in common with the
contact-type microphone 1a according to the first embodiment described above, and thus the
description thereof will be omitted. What differs from the first embodiment is the sound pickup
contact member 12b and the damping member 8b. The contact type microphone 1b of the
second embodiment will be described with reference to these figures.
[0049]
In the microphone element 2 of the contact type microphone 1b of the second embodiment in
FIG. 2B, the internal conduction sound 4 such as the voice of the speaker collected from the
sound collection target 3 such as skin is a sound collection contact member When the vibration
18-04-2019
16
is transmitted to the vibrating membrane 5 through 12 b and the vibration transmitting member
7 a, the vibration of the vibrating membrane 5 is converted into an electric signal, and is
transmitted to the outside through the conducting wire 6. Also in the contact type microphone
1b of the second embodiment, the contact portion between the vibration transfer member 7a and
the sound collection contact member 12b is provided substantially at the center of the sound
collection contact member 12b as in the first embodiment. There is. Further, in the contact area
of the contact portion between the vibration transfer member 7a and the sound pickup contact
member 12b, the contact area in the direction parallel to the surface where the sound pickup
contact member 12b contacts the sound pickup object 3 is vibration. It is smaller than the crosssectional area in the parallel direction in the other part of the transmission member 7a.
Furthermore, in the direction parallel to the plane where the sound collection contact member
12b contacts the sound collection target 3, the centers of the microphone element 2, the
vibration transfer member 7a and the sound collection contact member 12b are in sound
collection contact. It can be said that the member 12 b is on substantially the same axis in the
direction perpendicular to the surface in contact with the sound collection target 3.
[0050]
According to the above configuration, the contact type microphone 1b according to the second
embodiment can reflect and suppress the mixing of surrounding background noise due to a noise
environment, and efficiently pick up only the vibration of the target sound collection target it
can. As a result, the noise resistance is further improved, and it is easy to clearly pick up not only
normal voice but also inaudible voice and noise such as the speaker's tweet from the sound
collection object such as skin clearly. it can.
[0051]
The sound pickup contact member 12b of the second embodiment has a cap-shaped 1.5 mm
thick contact member made of aluminum metal and is fitted and bonded by a nested structure
with the cover member 9. The damping member 8b is made of an elastic epoxy resin composite
material in which 50% by weight of silica powder (SC6202-SXC manufactured by Admatex Co.,
Ltd.) surface-modified with phenylaminosilane is dispersed. Thus, by including an inorganic
material-based filler such as silica, the elastic modulus is increased, and the adhesion to the cover
member 9 and the metal portion of the microphone element 2 is increased. Further, since the
incorporated microphone element 2 is firmly fixed, the loss of the transmission vibration due to
the movement of not only the vibrating film 5 of the microphone element 2 but the entire
microphone element 2 is prevented.
18-04-2019
17
[0052]
In addition, the acoustic impedance of the damping member 8b is closer to the acoustic
impedance of the metal portion of the cover member 9 and the microphone element 2, so that
reflection at the interface between these metallic portions and the damping member 8b is
suppressed And the absorption loss of the vibration by the elastic epoxy resin component in the
damping member 8b is effective. This point will be described in detail in comparison with
Example 4 and Comparative Example 5 described later.
[0053]
The materials of the sound collection contact member 12b and the cover member 9 will be
described later in a seventh embodiment.
[0054]
In addition, as the inorganic material filler dispersed in the damping member 8b, one having a
particle size of submicron to 100 microns is preferably used.
This is because the submicron ones generally have poor dispersibility, aggregation and interfere
with distribution control, and the ones 100 microns or more are prone to sedimentation /
segregation due to poor dispersibility, and the mechanical of the contact microphone 1b This is
to reduce the target strength.
[0055]
In addition to the silica described above, alumina, zirconia, silica, calcium carbonate, kaolin, clay,
colloidal silica, titania, or the like can be used as the inorganic material-based filler dispersed in
the damping member 8 b. And these may be individual and what was selected and mixed 2 or
more types from the above may be used.
[0056]
18-04-2019
18
Next, the content of the inorganic material based filler dispersed in the damping member 8b is
75% or more, and the handling by the manufacturing process becomes difficult due to the
increase of the viscosity, and the two-component epoxy resin often causes problems It is known
that the damping effect can not be recognized if the content rate is 5% or less. From these things,
the content rate of the inorganic material based filler dispersed in the damping member 8 b is
preferably in the range of 5 to 75%.
[0057]
Furthermore, the metal materials adopted as the sound collection contact members 12a and 12b
in the contact microphones 1a and 1b of the first and second embodiments are SUS and
aluminum, for the following reasons.
[0058]
Generally, the acoustic impedance is determined by the density ρ and the speed of sound c in
the material as shown in (Equation 3), and the speed of sound c in the material is determined by
the density と and the bulk modulus k as shown in (Equation 4) .
[0059]
Z = ρ · c (Equation 3) c = √ (k / ρ) (Equation 4) Therefore, according to (Equation 3) and
(Equation 4), the relationship between acoustic impedance Z, density ρ and bulk modulus k is as
follows It is led like.
[0060]
Z = √ (ρ · k) (Equation 5)
[0061]
Here, referring to the sound speeds c of various metals shown in (Table 2), it is understood that
the sound speeds c of iron-based, aluminum-based and titanium-based metals are relatively
larger than those of other metals.
As apparent from (Equation 3), the acoustic impedance Z is proportional to the speed of sound c.
18-04-2019
19
The acoustic impedance of iron-based, aluminum-based, titanium-based metals, etc. is preferably
used because it has a relatively large value compared to other metals.
[0062]
As described above, when the contact type microphone of the second embodiment is used, the
noise resistance is further improved, and normal voices and inaudible tweets can easily be picked
up clearly under a noise environment.
[0063]
Example 3 FIG. 4 is a side cross-sectional view of the contact microphone in Example 3 of the
present invention.
FIG. 4 (a) is an overall side sectional view of the contact microphone 1c in the third embodiment,
and FIG. 4 (b) is an enlarged view of the tip of the vibration transfer member 7a.
The configuration of the contact type microphone 1c of the third embodiment has many parts in
common with the first embodiment or the second embodiment described above, and therefore
the description thereof is omitted as much as possible, and mainly described above. The parts
different from the first embodiment will be described below.
[0064]
First, also in the contact type microphone 1c of the third embodiment, as in the first and second
embodiments, the contact portion between the vibration transfer member 7a and the sound
collection contact member 12b is substantially at the center of the sound collection contact
member 12b. Provided in
Further, in the contact area of the contact portion between the vibration transfer member 7a and
the sound pickup contact member 12b, the contact area in the direction parallel to the surface
where the sound pickup contact member 12b contacts the sound pickup object 3 is vibration. It
18-04-2019
20
is smaller than the cross-sectional area in the parallel direction in the other part of the
transmission member 7a. Furthermore, in the direction parallel to the plane where the sound
collection contact member 12b contacts the sound collection target 3, the centers of the
microphone element 2, the vibration transfer member 7a and the sound collection contact
member 12b are in sound collection contact. It can be said that the member 12 b is on
substantially the same axis in the direction perpendicular to the surface in contact with the sound
collection target 3.
[0065]
According to the above configuration, the contact type microphone 1c according to the third
embodiment reflects and suppresses mixing of surrounding background noise due to noise
environment, and efficiently collects only the vibration of the target sound collection object it
can. As a result, the noise resistance is further improved, and it is easy to clearly pick up not only
normal voice but also inaudible voice and noise such as the speaker's tweet from the sound
collection object such as skin clearly. it can.
[0066]
<Cap-shaped Sound Collection Contact Member 12b> The damping member 8b is a composite
material of an elastic epoxy resin and silica, and the sound collection contact member 12b has a
cap shape made of aluminum 1.5 mm thick. These points are the same as the second
embodiment described above. However, while the sound pickup contact member 12b in the
second embodiment is directly fitted and bonded by the nested structure with the cover member
9, in the contact type microphone 1c in the third embodiment, the following occurs. It has a
structure like.
[0067]
That is, first, a metal washer 22 is disposed inside the damping member 8 b so as to surround the
microphone element 2. Next, the sound pickup contact member 12 b and the cover member 9
are respectively fitted and bonded by a nested structure with a plastic or metal upper and lower
connecting tube 23. Therefore, the sound pickup contact member 12 b and the cover member 9
are indirectly joined via the upper and lower connecting tubes 23.
18-04-2019
21
[0068]
<Acoustic Fiber 19> Further, a so-called acoustic fiber 19 is disposed between the microphone
element 2 located inside the damping member 8b and the sound collecting contact member 12b.
In the acoustic fiber 19, the vibration transfer member 7a, which is also used in the first
embodiment and the second embodiment, is disposed inside the aluminum cylinder 19a. That is,
the acoustic fiber 19 is configured by storing the vibration transfer member 7a in the cylinder
19a, and the cross section of the cylinder 19a corresponds to the back surface of the contact
surface of the sound collection contact member 12b with the object 3 and the microphone
element 2 It faces the sound collection opening 11, and the side surface of the cylinder 19a is in
contact with the damping member 8b. The acoustic fiber 19 prevents the vibration of the internal
conduction sound 4 transmitted from the sound collection contact member 12 b to the vibration
transfer member 7 a from diffusing to the portion of the microphone element 2 other than the
vibrating film 5. Thereby, the internal conduction sound 4 from the sound collection contact
member 12 b is efficiently transmitted to the diaphragm of the microphone element 2 with less
loss. The acoustic fiber 19 also has a role of preventing the vibration of the air conduction sound
10 transmitted from the surrounding air to the damping member 8 b as so-called noise to be
transmitted to the vibrating film 5 of the microphone element 2. .
[0069]
Furthermore, in addition to the diffusion preventing effect of the vibration of the internal
conduction sound 4 and the transmission preventing effect of the vibration of the air conduction
sound 10 as described above, the acoustic fiber 19 is a microphone as described later with FIG.
This has the effect of improving the degree of freedom of the arrangement of the elements 2.
[0070]
Such an indirect bonding structure by the washer 22 disposed around the microphone element 2
and the upper and lower connection tubes 23 is substantially at the center of the cover member
9 and the sound pickup contact member 12b. This is for disposing the microphone element 2
and the acoustic fiber 19.
It is particularly effective in the process of producing the contact microphone 1c of the third
embodiment described later.
18-04-2019
22
[0071]
Next, an enlarged view of the contact portion between the vibration transfer member and the
sound collection contact member shown in FIG. 4B will be described. The vibration transfer
member 7a has a generally hemispherical shape due to the surface tension of the urethane
elastomer precursor before curing, and is in contact with the sound pickup contact member 12b
with an arbitrary contact area. In general, the transmitted vibrational energy (sound pressure) is
proportional to the contact area. If this contact area is too large, it is transmitted from the air
around the contact type microphone via the surrounding air or by the exciting force from the air
around the contact type microphone, which is slightly present in the contact surface with the
sound pickup object 3 (skin) A part of the air conduction sound 10 is picked up together with the
internal conduction sound 4 which is originally to be picked up. As a result, the S / N ratio of the
internal conduction sound 4 to the air conduction sound 10 becomes a low value. Therefore, the
inner diameter of the acoustic fiber 19 is preferably in the range of 0.5 to 5 times at least the
diameter of the sound collection opening 11 of the microphone element 2.
[0072]
Such a contact-type microphone 1c in the third embodiment can be manufactured, for example,
by the following process.
[0073]
In FIG. 4 shown above, first, from the sound collection opening 11 of the microphone element 2,
a urethane elastomer (for example, polyurethane main skin gel undiluted solution (C-15)
manufactured by Excile Corporation Co., Ltd. 1) is injected, and a part of the vibration
transmitting member 7a is formed by heating at 80 ° C. for 1 hour.
[0074]
Next, the upper and lower connection tube 23 is disposed inside the cover member 9, the lead
wire 6 of the microphone element 2 is penetrated through the cover member 9, and the
microphone element 2 is installed substantially at the center of the cover member 9.
In that state, a two-component elastic epoxy resin containing, for example, 50 wt% of silica,
which is a precursor of the damping member 8 b before curing, is filled to near the height of the
18-04-2019
23
microphone element 2.
Then, an aluminum (metal) washer 22 provided with a hole in accordance with the diameter of
the microphone element 2 is placed on the epoxy resin which is a precursor of the damping
member 8b before curing. At this time, the washer 22 is installed so that the microphone element
2 is disposed substantially at the center of the inside of the through hole of the washer 22. At
this time, if the outer diameter of the washer 22 is set to be slightly smaller than the inner
diameter of the upper and lower connection tubes 23, the microphone element 2 can be easily
installed at the approximate center of the cover member 9. In that state, it is cured by heating at
80 ° C. for one hour to form a part of the damping member 8 b.
[0075]
Furthermore, a cylinder 19 a is disposed on the sound collection opening 11 of the microphone
element 2. At this time, the center of the cylinder 19 a is substantially aligned with the center of
the sound collection opening 11. The above-mentioned urethane elastomer is injected into the
cavity of the cylinder 19a, and heating is performed at 80 ° C. for one hour. Thus, the urethane
elastomer injected from the sound collection opening 11 of the microphone element 2 and the
urethane elastomer injected into the cylinder 19a are integrated to form the vibration transfer
member 7a. An acoustic fiber 19 is formed by the vibration transfer member 7a and the cylinder
19a. The vibration transmitting member 7a forms a convex hemispherical or semielliptical
spherical meniscus at its tip end portion by its own surface tension.
[0076]
Thereafter, the remaining space of the cover member 9 and the upper and lower connection tube
23 is additionally filled with an appropriate amount of epoxy resin which is a precursor of the
damping member 8b before curing, and made of aluminum having a thickness of 1.5 mm. When
the cup-shaped sound pickup contact member 12b is covered and cured at 80 ° C. for one hour,
the contact microphone 1c of the third embodiment is completed.
[0077]
Since the sound pickup contact member 12b of the contact type microphone 1c completed in this
manner and the cover member 9 have a substantially concentric cylindrical shape, their centers
substantially coincide with each other.
18-04-2019
24
The microphone element 2 is disposed substantially at the center of the cover member 9 by the
washer 22 described above. Therefore, it can be said that the center of the microphone element 2
and that of the sound pickup contact member 12 b substantially coincide with each other.
[0078]
Thus, the washer 22 helps to arrange the microphone element 2 substantially at the center of the
sound pickup contact member 12b, and the effect is the same as that described in the first
embodiment. That is, when the internal conduction sound 4 is given to the sound collection
contact member 12b, the amplitude due to the physical vibration becomes the largest at the
central portion of the sound collection contact member 12b. Then, in the path from the central
portion of the sound collection contact member 12 b where the physical vibration due to the
internal conduction sound 4 is largest to the diaphragm 5 of the microphone element 2, like the
diaphragm 5 of the microphone element 2, A vibration transmitting member 7a made of a plastic
material is disposed. Thereby, the physical vibration by the internal conduction sound 4 can be
efficiently transmitted to the vibrating film 5 of the microphone element 2.
[0079]
In addition, a damping member 8b is disposed around the vibration transfer member 7a. This
means that the air conduction sound 10 from the outside which is going to intrude from the part
other than the central part of the sound pickup contact member 12 b is blocked by the damping
member 8 b and hardly reaches the diaphragm 5 of the microphone element 2. Do.
[0080]
Further, in the case of the third embodiment, in the cylinder 19 a around the acoustic fiber 19,
the vibration of the internal conduction sound 4 transmitted from the sound collection contact
member 12 b to the vibration transmission member 7 a is the diaphragm 5 of the microphone
element 2. It prevents it from spreading to the rest. Thereby, the internal conduction sound 4
from the sound collection contact member 12 b is efficiently transmitted to the diaphragm of the
microphone element 2 with a small loss. The acoustic fiber 19 also has a role of preventing the
vibration of the air conduction sound 10 transmitted from the surrounding air to the damping
18-04-2019
25
member 8 b as so-called noise to be transmitted to the vibrating film 5 of the microphone
element 2. .
[0081]
Incidentally, the vertical connection tube 23 assists the acoustic fiber 19 from falling down when
the damping member 8b is additionally filled, and between the sound collecting contact member
12b and the damping member 8b so as not to spill out. It has a role of storing the damping
member 8 b in an appropriate amount so as to prevent the space from being generated.
[0082]
The results of evaluation of the contact-type microphone 1c manufactured in this manner using
the 20-syllable phonetic syllable used also in the first embodiment are as follows.
That is, the S / N ratio of the contact type microphone 1c in the third embodiment is 17 dB, and
the S / N ratio under the noise environment as compared to the S / N ratio 7 dB of the
conventional contact type microphone (see FIG. 1). It became clear that was improving. The
importance of the following points will be described in detail by means of comparative examples
described later. The first point is that the contact portion between the vibration transfer member
7a and the sound collection contact member 12b is substantially at the center of the sound
collection contact member 12b. The second point is that the inner diameter of the vibration
transmitting member 7 a inside the acoustic fiber 19, that is, the acoustic fiber 19 is at least 0.5
to 5 times the diameter of the sound collection opening 11 of the microphone element 2. Is
preferred. The third point is that no space is provided between the damping member 8b and the
sound collecting contact member 12b, and the vibration damping member 8b is in contact with
the sound collecting contact member 12b, the upper and lower connecting tube 23 and the cover
member 9. Completely filled.
[0083]
As described above, when the contact type microphone of the third embodiment is used, noise
resistance is further improved, and normal voice and inaudible tweet voice can be easily collected
clearly under a noise environment.
[0084]
Comparative Example 1 FIG. 5A is a side cross-sectional view of a contact type microphone in
18-04-2019
26
Comparative Example 1 which is in a comparative relationship with Example 3 of the present
invention.
[0085]
The configuration and method of producing the contact type microphone 1d in the present
comparative example 1 are different in the following point, although there are many parts in
common with the contact type microphone 1c in the third embodiment described above.
One is that the vibration transfer member 7a is also coated and cured on the entire back side of
the sound collection contact member 12b, and as a result, the contact area between the vibration
transfer member 7a and the sound collection contact member 12b is the microphone element 2
It is out of the range of 0.5 to 5 times the diameter of the sound collection opening 11 of the
above.
The other is that a cavity 21 is formed between the sound collecting contact member 12 b and
the damping member 8 b which are applied and hardened on the entire back side of the sound
collecting contact member 12 b.
[0086]
The S / N ratio of the contact type microphone 1d in the comparative example 1 is 10 dB, and
the S / N ratio under the noise environment is so much as compared with the S / N ratio 7 dB of
the conventional contact type microphone (see FIG. 1). It became clear that it did not improve.
This is because the vibration transmitting member 7a is applied and hardened on the entire back
side of the sound collecting contact member 12b, so that the air conduction sound 10, which is
the noise around the outside, is transmitted from the peripheral portion of the sound collecting
contact member 12b. It is considered that this is because the signal is easily transmitted to the
microphone element 2 through the member 7a.
[0087]
As can be seen from this comparative example 1, the vibration transfer member 7a should be
18-04-2019
27
accommodated in the inner diameter of the acoustic fiber 19 and should be in contact with the
sound collection contact member 12b at an approximately central portion thereof. is necessary.
The contact area is preferably at least 0.5 to 5 times as large as the diameter of the sound
collection opening 11 of the microphone element 2.
[0088]
Comparative Example 2 FIG. 5B is a side cross-sectional view of the contact-type microphone in
Comparative Example 2 in comparison with Example 3 of the present invention.
[0089]
The configuration and production method of the contact type microphone 1e in the present
comparative example 2 are different in the following point, although there are many parts in
common with the contact type microphone 1c in the third embodiment described above.
One is that the damping member 8b is applied and cured on the entire back side of the sound
collection contact member 12b, and the vibration transfer member 7a is not in contact with the
sound collection contact member 12b. The other is that a cavity 21 is formed in the vicinity of
the sound pickup contact member 12b inside the damping member 8b.
[0090]
The S / N ratio of the contact type microphone 1e in the comparative example 2 is 5 dB, and the
S / N ratio under the noise environment is further compared with the S / N ratio 7 dB of the
conventional contact type microphone (see FIG. 1). It became clear that it was getting worse. This
is because not only the air conduction sound 10 which is the noise around the outside but also
the internal conduction sound 4 which is originally intended to be collected, because the
vibration transfer member 7a is not in contact with the substantially central portion of the sound
pickup contact member 12b. It is considered that the absorption loss is caused by the damping
member 8b located on the front side.
[0091]
18-04-2019
28
As can be seen from this second comparative example, the vibration transfer member 7a needs to
be in contact with the sound pickup contact member 12b. The contact is preferably substantially
at the center of the sound pickup contact member 12b.
[0092]
Comparative Example 3 FIG. 6A is a side cross-sectional view of the contact-type microphone in
Comparative Example 3 which is in a comparative relationship with Example 3 of the present
invention.
[0093]
The configuration and the method of producing the contact microphone 1f in the present
comparative example 3 are different in the following point, although there are many parts in
common with the contact microphone 1c in the third embodiment described above.
That is, although the vibration transfer member 7a is in contact with the sound collection contact
member 12b, a cavity 21 is generated between the damping member 8b and the sound collection
contact member 12b.
[0094]
The S / N ratio of the contact type microphone 1f in the comparative example 3 is 12 dB, and the
S / N ratio under a noise environment is slightly smaller than that of the conventional contact
type microphone (see FIG. 1). It turned out to be better, but not as good as in Example 3. This is
because the air conduction sound 10, which is noise from the outside, intrudes into the inside of
the damping member 8b and then repeats reflections at the interface between the damping
member 8b and the air in the cavity 21 generated inside the damping member 8b, As a result, it
is considered that the signal is transmitted from the acoustic fiber 19 to the microphone element
2. That is, the absorption loss of the air conduction sound 10 by the damping member 8b is
inhibited by the cavity 21 generated inside the damping member 8b.
[0095]
As can be seen from this Comparative Example 3, no cavity 21 is provided between the damping
member 8b and the sound collecting contact member 12b, and the vibration damping member
18-04-2019
29
8b is the sound collecting contact member 12b, the upper and lower connecting tube 23, and the
cover. It is necessary to be in full contact with the member 9.
[0096]
Comparative Example 4 FIG. 6 (b) is a side cross-sectional view of a contact type microphone in
Comparative Example 4 in contrast with Example 3 of the present invention.
[0097]
The configuration and the method of producing the contact type microphone 1g in the present
comparative example 4 are different in the following point, although there are many parts in
common with the contact type microphone 1c in the third embodiment described above.
That is, the contact portion between the vibration transmitting member 7a and the sound
collecting contact member 12b inside the acoustic fiber 19 does not coincide with the
approximate center of the cover member 9 and the sound collecting contact member 12b.
In the fourth comparative example, the centers of the microphone element 2 and the acoustic
fiber 19 are disposed substantially at the midpoint of a straight line (radius) connecting the
center of the sound collection contact member 12b and the circumference.
[0098]
The S / N ratio of the contact type microphone 1f in the comparative example 3 is 9 dB, and the S
/ N ratio under the noise environment is slightly smaller than the S / N ratio 7 dB of the
conventional contact type microphone (see FIG. 1). It turned out to be better, but not as good as
in Example 3. One is that the distance between the contact portion of the vibration transfer
member 7a with the sound pickup contact member 12b and the one peripheral portion of the
sound pickup contact member 12b is short, and the air conduction sound 10, which is noise from
the outside, is a microphone This is because they are easily transmitted to the element 2. The
other is that although the physical vibration of the internal conduction sound 4 given to the
sound collection contact member 12 b is the largest at the approximate center of the sound
collection contact member 12 b inside the acoustic fiber 19, the present comparative example 4
The contact portion between the vibration transfer member 7a and the sound collection contact
18-04-2019
30
member 12b is not disposed there.
[0099]
As can be seen from this comparative example 4, the microphone element 2 and the acoustic
fiber 19 (that is, the center of the vibration transfer member 7a needs to be disposed
substantially at the center of the sound pickup contact member 12b.
[0100]
As clarified by the above comparative example, the contact portion between the vibration
transfer member 7a and the sound collection contact member 12b needs to be substantially at
the center of the sound collection contact member 12b.
In addition, it is preferable that the inner diameter of the vibration transfer member 7 a inside
the acoustic fiber 19, that is, the inside diameter of the acoustic fiber 19 be at least 0.5 to 5 times
the diameter of the sound collecting opening 11 of the microphone element 2. . Then, no space is
provided between the damping member 8b and the sound collecting contact member 12b, and
the vibration damping member 8b is in full contact with the sound collecting contact member
12b, the upper and lower connecting tube 23 and the cover member 9 It is necessary to be done.
[0101]
[Modification of Embodiment 3] As clarified from the above-mentioned Embodiment 3 and
Comparative Example 4, the contact portion between the vibration transfer member 7a and the
sound pickup contact member 12b inside the acoustic fiber 19 is collected. It is necessary to be
approximately at the center of the sound contact member 12b. However, it is not necessary to
arrange the center of the acoustic fiber 19 and the center of the microphone element 2
substantially in line with the center of the sound pickup contact member 12b. An example is
described below.
[0102]
FIG. 7 is a side sectional view of an application example of a contact type microphone using an
acoustic fiber according to a third embodiment of the present invention.
18-04-2019
31
[0103]
The acoustic fiber 19b of the contact type microphone 1k shown in FIG. 7 confines the vibration
transmitted to the sound pickup contact member 12c in its internal space, and repeats reflections
by the inner wall of the bendable cylinder 19c to the microphone element 2 It has a function to
transmit.
Therefore, as shown in FIG. 7, when the curve-free cylinder 19c is used, the center of the
microphone element 2 can be arranged other than immediately below the center of the sound
collection contact member 12c. At this time, if the center of the portion in which the vibration
transmitting member 7a disposed inside the acoustic fiber 19b is in contact with the sound
collecting contact member 12c is substantially coincident with the center of the sound collecting
contact member 12c. Good. The reason is that the center of the sound collection contact member
12c is the largest physical vibration of the internal conduction sound 4 applied thereto. Thus,
with regard to the shape of the contact microphone 1k, the degree of freedom in design can be
increased.
[0104]
For the same reason, when the contact portion between the vibration transfer member 7a and
the sound collection contact member 12b is not substantially at the center of the sound
collection contact member 12b (see FIG. 6B described in Comparative Example 4) Even if the
arrangement is not possible due to the structural limitations, etc.), the acoustic fiber 19a shown
in FIG. 6 (b) is bent to the center position of the microphone element 2 shown in FIG. 6 (a). The
above limitations can be avoided.
[0105]
As described above, the acoustic fiber 19b has the function of confining the vibration transmitted
to the sound pickup contact member 12c in its internal space and transmitting it to the
microphone element 2, so that the vibration of the internal conduction sound 4 is the vibration of
the microphone element 2 It is possible to prevent diffusion to the portion other than the film 5
and to prevent the vibration of the air conduction sound 10 transmitted to the damping member
8 b as noise to be transmitted to the diaphragm 5 of the microphone element 2.
18-04-2019
32
In addition to these effects, by using the acoustic fiber 19b (conduit) for the sound collection
opening 11 of the microphone element 2, the degree of freedom of arrangement of the
microphone element 2 can be improved.
[0106]
Example 4 FIG. 8 is a side cross-sectional view of a contact microphone in Example 4 of the
present invention. FIG. 8 (a) is an overall side sectional view of the contact microphone 1j, and
FIG. 8 (b) is an enlarged view of a tip portion of the vibration transfer member 7a. The
configuration of the contact-type microphone 1j of the fourth embodiment has many parts in
common with the third embodiment described above, so the description thereof will be omitted
as much as possible, mainly the third embodiment described above. This section will explain the
differences from Although the washer 22 disposed in the third embodiment is omitted in the
fourth embodiment, the washer 22 may of course be disposed in the same manner as the third
embodiment.
[0107]
First, also in the contact-type microphone 1j of the fourth embodiment, as in the first to third
embodiments, the contact portion between the vibration transfer member 7a and the sound
collection contact member 12b is substantially at the center of the sound collection contact
member 12b. Provided in Further, in the contact area of the contact portion between the
vibration transfer member 7a and the sound pickup contact member 12b, the contact area in the
direction parallel to the surface where the sound pickup contact member 12b contacts the sound
pickup object 3 is vibration. It is smaller than the cross-sectional area in the parallel direction in
the other part of the transmission member 7a. Furthermore, in the direction parallel to the plane
where the sound collection contact member 12b contacts the sound collection target 3, the
centers of the microphone element 2, the vibration transfer member 7a and the sound collection
contact member 12b are in sound collection contact. It can be said that the member 12 b is on
substantially the same axis in the direction perpendicular to the surface in contact with the sound
collection target 3. In addition, the acoustic fiber 19 is configured by storing the vibration
transfer member 7a in the cylinder 19a, and the cross section of the cylinder 19a is the back
surface of the contact surface of the sound collection contact member 12b with the object 3 and
the microphone element The side surface of the cylinder 19a is in contact with the damping
member 8b.
18-04-2019
33
[0108]
According to the above configuration, the contact type microphone 1j according to the fourth
embodiment reflects and suppresses mixing of background noise in the surrounding
environment under a noise environment, and efficiently collects only the vibration of the target
sound collection object it can. As a result, the noise resistance is further improved, and it is easy
to clearly pick up not only normal voice but also inaudible voice and noise such as the speaker's
tweet from the sound collection object such as skin clearly. it can.
[0109]
In the contact type microphone 1j according to the fourth embodiment, the characteristic part
which is not included in the third embodiment is included in the vibration transmitting member
7a at the tip portion where the acoustic fiber 19 contacts the sound collecting contact member
12b. It is a glued plastic ball 20. That is, a member having a hardness higher than that of the
vibration transfer member 7a is provided on the side of the surface of the vibration transfer
member 7a in contact with the sound pickup contact member 12b. As this plastic ball 20, for
example, one made by Sato Iron Works Ltd. is used. Besides, any of urethane rubber, polyacetal,
polyamide 66, Teflon (registered trademark), ABS, styrene, acrylic, silicone resin, etc. may be
used. In the fourth embodiment, the urethane rubber (having a hardness of 80 °) has good
adhesion with the urethane elastomer employed as the vibration transmitting member 7 a and is
used with repeated vibration (lubricity and reliability). And a hardness of 95 °) are preferably
used as the plastic balls 20. This urethane rubber has a hardness higher than that of the
vibration transfer member 7a.
[0110]
Further, as such a plastic ball 20, one having a diameter of 2 mmφ, 3/32 inch, 1/8 inch, 5/32
inch or the like corresponding to the diameter of the opening of the diaphragm 5 of the
microphone element 2 is generally used. Be
[0111]
A sound collection is performed by incorporating and adhering such plastic balls 20 having
hardness higher than that of the vibration transfer member 7a to the vibration transfer member
18-04-2019
34
7a at the tip portion where the acoustic fiber 19 contacts the sound collection contact member
12b. Point contact with the substantially central portion of the contact member 12b is possible.
And thereby, the vibration transmitted to the whole sound collection contact member 12b from
the sound collection target object 3 (skin etc.) is concentrated on one point. At the same time, the
air conducted sound (noise) 10 transmitted from the peripheral portion of the sound pickup
contact member 12b through the air in the space 18 with the surrounding air or the sound
collection object 3 generated when the contact type microphone 1j is attached But it is easier to
cut. That is, for the air conduction sound 10, the distance to the central portion (in point contact)
of the sound pickup contact member 12b to which it is transmitted as solid vibration is longer
than the body conducted sound 4 that is originally intended to be picked up . Then, the damping
member 8b located in the lower layer of the sound collection contact member 12b absorbs and
loses part of the air conduction sound 10 on the way to the central portion (point contact) of the
sound collection contact member 12b. Thus, the effect of improving the S / N ratio is increased.
[0112]
The results of evaluation of the contact-type microphone 1j manufactured in this manner using
the monosyllabic 20-word sound surface as in the first embodiment are as follows. That is, the S
/ N ratio of the contact type microphone in the fourth embodiment is 28 dB, and the S / N ratio
under the noise environment is 7% smaller than the S / N ratio of 7 dB of the conventional
contact type microphone (see FIG. 1). It turned out that it has improved significantly. And, the S /
N ratio is further improved as compared with the third embodiment.
[0113]
In addition, the sentence intelligibility under 100 dB noise using the contact type microphone 1j
in the fourth embodiment was 85%.
[0114]
As described above, when the contact type microphone of the fourth embodiment is used, the
noise resistance is further improved, and normal voice and inaudible tweet voice can be easily
collected clearly under a noise environment.
[0115]
Comparative Example 5 FIG. 9 is a side cross-sectional view of a contact type microphone in
18-04-2019
35
Comparative Example 5 which is in a comparative relationship with Example 4 of the present
invention.
[0116]
The configuration and production method of the contact type microphone 1h in the present
comparative example 5 are different in the following point, although there are many parts in
common with the contact type microphone 1j in the fourth embodiment described above.
That is, instead of the damping member 8 b (two-component elastic epoxy resin containing 50
wt% of silica) in the previous example 4, a damping member composed of only the elastic epoxy
resin used also in the previous example 1 It is assumed that 8a.
[0117]
The S / N ratio of the contact type microphone 1d in the comparative example 5 is 20 dB, which
is not inferior to the examples 1 and 2 of the previous examples, but the performance difference
is doubled or more when compared with the example 4. I found it to be.
This is due to the difference in the material of the adopted damping member.
This material difference is the magnitude of the loss coefficient, and is reflected in the term of the
denominator indicating noise in the above S / N ratio equation shown in (Equation 5).
[0118]
In addition, the elastic epoxy resin becomes larger in elastic modulus and weight due to the
complexation with the silica, and the resonance frequency changes in the direction of being
largely deviated from the vibrating film 5 of the microphone element 2. As a result, the vibration
of the microphone element 2 itself is reduced by the solid vibration from the sound pickup object
3, and the ratio of the conversion of the solid vibration from the sound pickup object 3 into the
vibration of the vibrating film 5 is relatively increased. This serves to increase the term of the
18-04-2019
36
numerator indicating the signal to be picked up in the S / N ratio equation shown in the above
(Equation 5).
[0119]
From the above, as the damping member to be employed, the damping member 8b made of the
composite material of the elastic epoxy resin and the silica employed in Example 4 has a higher
sound collection than that of the elastic epoxy resin employed in Comparative Example 5. It
turned out that performance can be obtained.
[0120]
Fifth Embodiment FIG. 10 is an exploded perspective view of a contact type microphone
according to a fifth embodiment, and FIG. 11 is a side sectional view of the contact type
microphone according to the fifth embodiment.
FIG. 11A is an overall side sectional view of the contact microphone 1k in the fifth embodiment,
and FIG. 11B is an enlarged view of a tip portion of the vibration transfer member 7b. The
configuration of the contact-type microphone 1k of the fifth embodiment has many parts in
common with the second embodiment described above, so the description thereof will be omitted
as much as possible, mainly the second embodiment described above. This section will explain
the differences from
[0121]
First, also in the contact type microphone 1k of the fifth embodiment, as in the first to fourth
embodiments, the contact portion between the vibration transfer member 7b and the sound
collection contact member 12d is substantially the center of the sound collection contact
member 12d. Provided in Further, in the contact area of the contact portion between the
vibration transfer member 7b and the sound collection contact member 12d, the contact area in
the direction parallel to the surface where the sound collection contact member 12d contacts the
sound collection target 3 is vibration. It is equal to or less than the cross-sectional area in the
parallel direction in the other portion of the transmission member 7b. Furthermore, in the
direction parallel to the plane where the sound pickup contact member 12d contacts the sound
pickup object 3, the centers of the microphone element 2, the vibration transfer member 7b and
the sound pickup contact member 12d are sound pickup contact It can be said that the member
18-04-2019
37
12 d is on substantially the same axis in the direction perpendicular to the surface in contact
with the sound collection target 3. In addition to that, the vibration transmitting member 7b is
housed in the cylinder 19e to constitute the acoustic fiber 19d, and the cross section of the
cylinder 19e is the back surface of the contact surface of the sound collecting contact member
12d with the object 3 and the microphone element The side surface of the cylinder 19e is in
contact with the damping member 8b.
[0122]
According to the above-described configuration, the contact type microphone 1k of the fifth
embodiment can reflect and suppress the mixing of surrounding background noise due to noise
environment and efficiently collect only the vibration of the target sound collection object it can.
As a result, the noise resistance is further improved, and it is easy to clearly pick up not only
normal voice but also inaudible voice and noise such as the speaker's tweet from the sound
collection object such as skin clearly. it can.
[0123]
Although the washer 22 arranged in the fifth embodiment is not arranged in the second
embodiment described above, as described above, the microphone element 2 is substantially at
the center of the sound collecting contact member 12d. It is intended to be placed, not a big
difference. The washer 22 may of course be arranged in the fifth embodiment as well.
[0124]
Also, the acoustic fiber 19d of the fifth embodiment is not disposed in the previous second
embodiment, and is similar to that appearing in the third and fourth embodiments. The acoustic
fiber 19d in the fifth embodiment is the one in which the vibration transmission member 7b
(described later) is filled in the hollow of the cylinder 19e, and the length and the composition of
the vibration transmission member 7b in the inside are the same as those of the third
embodiment. It differs from that of Example 4. However, it has a function of preventing the
vibration of the internal conduction sound 4 transmitted from the sound collection contact
member 12 d to the vibration transfer member 7 b from diffusing to the portion other than the
diaphragm 5 of the microphone element 2. The function is similar to that of the third
embodiment or the fourth embodiment. Furthermore, it also has a role of preventing the
18-04-2019
38
vibration of the air conduction sound 10 transmitted from the surrounding air to the damping
member 8 b as so-called noise to be transmitted to the diaphragm 5 of the microphone element
2. In that respect, the acoustic fiber 19d of the fifth embodiment has the same function as that
shown in the third and fourth embodiments.
[0125]
The damping member 8b of the fifth embodiment is a composite material of an elastic epoxy
resin (not shown) and the silica 27, and the sound pickup contact member 12d has a cap shape
made of aluminum and having a thickness of 1.5 mm. These points are the same as in the second
embodiment. However, at the approximate center of the back surface of the sound collection
contact member 12d according to the fifth embodiment that is in contact with the damping
member 8b and the vibration transfer member 7b, a hole 24 (concave portion) having a reverse
taper shape is used. It is formed to such an extent that it does not penetrate (in the case of the
present Example 5, a drill 24 having a diameter of 5 mm was formed using a drill of 6.6 mmφ).
That is, the thickness of the central portion of the portion where the sound collection contact
member 12d has a contact surface with the sound collection target 3 is thinner than the
peripheral portion. The vibration transmission member 7 b is injected into the reverse tapered
bore 24.
[0126]
The diameter of the perforations 24 controls the distance from the outer peripheral portion of
the contact microphone 1 k to which the air conduction sound 10 is considered to be
transmitted, and also controls the area subjected to vertical vibration by the internal conduction
sound 4. Further, the depth of the perforations 24 naturally determines the remaining thickness
(for example, 0.5 mm) of the sound collection contact member 12 d and influences the
followability to the solid vibration of the sound collection target 3. By adopting such a structure,
solid vibrations from the sound pickup object 3 (such as the skin) are reduced in thickness by an
area corresponding to the hole diameter of the perforation 24 and substantially at the center of
the sound pickup contact member 12d. Enables sensitive sound collection. At the same time, the
air conduction sound 10 (noise) is transmitted from the peripheral portion of the sound pickup
contact member 12d through the air in the space 18 with the surrounding air or the sound
collection object 3 generated when the contact type microphone 1k is attached. Even if this is
done, the distance to the approximate center of the sound collection contact member 12d to
which it is transmitted as solid vibration is long, so it is also effective in improving the S / N ratio.
18-04-2019
39
[0127]
In addition, as the vibration transfer member 7b employed in the fifth embodiment, the urethane
elastomer used in the first to third embodiments is compounded with an inorganic filler (silica 27
in the fifth embodiment) to provide bulk elasticity. An inclined rate was used. The slope of the
bulk modulus is, for example, a natural sedimentation method based on the difference in specific
gravity of those components before curing, so that many inorganic fillers (silica 27) are present
on the sound collecting contact member 12 d side. It is possible if the number is small on the
vibrating membrane 5 side. In this way, the volume elastic modulus of the vibration transfer
member 7b at each of the contact surface with the sound collection contact member 12d and the
contact surface with the vibrating membrane 5 of the microphone element 2 It can be close to
the membrane 5. In this way, matching of the acoustic impedance is achieved at each contact
surface, and reflection attenuation of vibration due to the internal conduction sound 4 is reduced.
[0128]
Next, the sound pickup contact member 12d will be described.
[0129]
FIG. 17 is a perspective view for explaining the structure of the sound collection contact member
12 d.
[0130]
<Dimple> As shown in FIG. 17, the sound pickup contact member 12d has a bottomed cylindrical
cap shape which is nested with the cylindrical cover member 9 (see FIG. 11).
The sound pickup contact member 12d includes a dimple, which is a recess, at the inner center
of the contact portion, that is, substantially at the center of the back surface of the bottomed
cylindrical shape.
This dimple is a reverse tapered hole 24 (recess) formed by drilling as described above. The
18-04-2019
40
dimple extends toward the opening of the cover member 9 and has a thin central thickness on
the side in contact with the sound collection target 3. That is, in the dimple, the center of the side
(upper side) in contact with the sound collection target 3 is thin like a point, and the opening side
(lower side) of the cover member 9 is widely opened. In the fifth embodiment, this dimple is a
reverse tapered perforation 24 but has a shape in which the center (immediately above the
diaphragm 5) on the side in contact with the sound collection target 3 is thin and the opening
side of the cover member 9 is wide. The shape of the dimple may be any shape, for example, it
may be a curved concave portion. When the dimples are formed in a curved concave portion, the
area between the sound collection contact member 12d and the opening is slightly increased,
and the volume of the vibration transfer member 7b injected into the region is also increased.
Can.
[0131]
As described above, the sound collection contact member 12d is provided with a dimple at the
inner center of the contact portion of the sound collection contact member 12d, so that the air
conduction sound 10 (noise) becomes solid vibration and the outer periphery of the contact
microphone 1k. Increase the distance transmitted from the center to the central portion of the
sound collection contact member 12d (ie increase the distance to the area through which the
sound passes), while reducing the area subjected to vertical vibration by the internal conduction
sound 4 Sound collection from the sound collection object 3 is well secured. As a result, since the
area other than the central portion of the contact portion of the sound collection contact member
12d is thick, there is an effect of reducing the noise mixed from the periphery of the speaker
wearing the contact type microphone 1k. As described above, by providing the above-described
dimples, there is an effect that the S / N ratio is improved, and the sound collecting property of
the conversation voice of the speaker wearing the contact type microphone 1 k is enhanced.
[0132]
<Attachment of Ground Wire> FIG. 18 is an overall side sectional view of the contact type
microphone 1k according to the fifth embodiment when the ground wire is attached. The same
components as in FIG. 11A are denoted by the same reference numerals and the description of
the overlapping portions will be omitted.
[0133]
As shown in FIGS. 17 and 18, in the contact microphone 1k, a through hole 31 is provided at a
18-04-2019
41
corner of the cap-shaped inner wall of the sound collection contact member 12d, and the ground
wire 32 is passed through the through hole 31.
[0134]
One end of the ground wire 32 communicates with the inside from the outside of the sound
collection contact member 12d through the through hole 31, and the end is a ring along the
corner of the inner wall of the sound collection contact member 12d. (See FIG. 17) and fixed by
applying a conductive adhesive (not shown).
The other end of the ground wire 32 is connected to the negative side of the lead 6 of the
microphone element 2.
[0135]
As described above, by attaching the ground wire 32 to the sound pickup contact member 12d
(here, the inner side of the sound pickup contact member 12d) contacting the sound pickup
object 3 (skin etc.), the hum sound generated at the time of wearing the skin Can be reduced.
Further, it is possible to reduce the mixing of high frequency noise generated from digital devices
present in the periphery.
[0136]
Even if the grounding wire 32 is attached to a cover member (not shown) that houses the
microphone element 2 instead of the sound collection contact member 12d, there are some
effects. However, it is more effective to be attached to the sound pickup contact member 12d in
direct contact with the speaker's skin.
[0137]
Also, by arranging and fixing one end of the ground wire 32 in one or more turns in a ring shape,
even if the ground wire 32 may be pulled, it is possible to secure strength that can resist the
18-04-2019
42
pulling force. . At the time of assembly of the contact type microphone 1k, since the damping
member is further filled thereon, the strength is further enhanced.
[0138]
The contact-type microphone 1k in the fifth embodiment can be manufactured, for example, by
the following process.
[0139]
12 to 16 illustrate an example of a method of manufacturing the contact microphone 1k
according to the fifth embodiment of the present invention.
[0140]
First, as shown in FIG. 12A, a hole 24 (a hole which does not penetrate) is made in the center on
the back side of the sound collection contact member 12d by a lathe drill 26 or the like.
Next, as shown in FIG. 12B, a metal cylinder 19e is bonded to the back central portion of the
sound pickup contact member 12d using the damping member 8b, and is cured at 80 ° C. for
one hour.
At that time, the metal cylinder 19 e is disposed so that the end cross section of the metal
cylinder 19 e surrounds the outline of the perforation 24. And as shown in FIG.12 (c), the
vibration transmission member 7b which compounded the inorganic filler with the urethane
elastomer is inject | poured inside the cavity of the cylinder 19e. The vibration transmitting
member 7b in which an inorganic filler is compounded with the urethane elastomer is, for
example, used in advance as a urethane elastomer (for example, main agent and curing agent of
gel stock solution (C-15) of polyurethane human skin manufactured by EXCIL Corporation). 20
wt% of silica filler (particle diameter: several tens of μ to several hundreds of μ) surface-treated
with γ-aminopropyltrialkoxysilane or glycidoxypropyltrialkoxysilane is dispersed.
[0141]
Further, as shown in FIG. 13A, the vibration transfer member 7b is allowed to stand at room
18-04-2019
43
temperature for 5 hours and then cured at 80 ° C. for 1 hour. By such a standing process, as
shown in FIG. 13 (b), the filler (silica 27) contained in the vibration transfer member 7b
spontaneously precipitates due to the difference in specific gravity with the urethane elastomer.
Then, a large amount of silica filler is present on the sound collection contact member 12 d side,
and an acoustic fiber 19 d is formed in a small state on the vibrating film 5 side of the
microphone element 2. That is, the bulk modulus of the vibration transfer member 7b is inclined,
and the bulk modulus of the vibration transfer member 7b is determined on each of the contact
surface with the sound pickup contact member 12d and the contact surface with the vibrating
membrane 5 of the microphone element 2. It can be made close to the sound pickup contact
member 12 d or the vibrating film 5. In this way, matching of the acoustic impedance is achieved
at each contact surface, and reflection attenuation of vibration due to the internal conduction
sound 4 is reduced. After that, as shown in FIG. 13C, the damping member 8b before curing is
filled in the peripheral portion of the acoustic fiber 19d.
[0142]
On the other hand, as shown to Fig.14 (a), the microphone element 2 connected with the
conducting wire 6 is arrange | positioned in the approximate-central part of the cover member 9.
As shown in FIG. At this time, the conducting wire 6 of the microphone element 2 is passed
through a through hole (reference numeral is not shown) provided in the cover member 9 and is
taken out of the cover member 9.
[0143]
Next, in this state, a two-component elastic epoxy resin containing, for example, 50 wt% of silica,
which is a precursor of the damping member 8 b before curing, is filled to near the height of the
microphone element 2. Then, as shown in FIG. 14 (b), a washer 22 provided with a hole in
accordance with the diameter of the microphone element 2 is placed on the epoxy resin which is
a precursor of the damping member 8b before curing. At this time, the washer 22 is installed so
that the microphone element 2 is disposed substantially at the center of the inside of the through
hole of the washer 22. In that state, it is cured by heating at 80 ° C. for one hour to form a part
of the damping member 8 b.
[0144]
18-04-2019
44
Furthermore, as shown in FIG. 14C, from the sound collection opening 11 of the microphone
element 2, a urethane elastomer (for example, a main agent and a curing agent of a gel undiluted
solution (C-15) of polyurethane human skin manufactured by EXCIL CORPORATION) (3: 1) 7c is
injected, and heated and cured at 80.degree. C. for 1 hour. The urethane elastomer 7c is
equivalent to one in which the inorganic filler is not compounded in the process of producing the
vibration transmitting member 7b.
[0145]
As shown in FIG. 15, the sound collection contact member 12d (see FIGS. 12 and 13) and the
cover member 9 (see FIG. 14) which have finished their work as described above are fitted to
each other. At this time, as shown in FIG. 16A, a surplus portion of the epoxy resin which is a
precursor of the damping member 8b before curing is discharged from the discharge hole 25
provided in advance in the sound collecting contact member 12d. . In this case, the necessary and
sufficient damping member 8b is filled without a cavity being generated inside the damping
member 8b or the like. Thereafter, as shown in FIG. 16B, heating and curing at 80 ° C. for one
hour with the weight 31 of about 400 g placed thereon, a contact type microphone 1k according
to the fifth embodiment is completed.
[0146]
At this time, the urethane elastomer 7c filled on the side of the vibrating film 5 in the inside of
the microphone element 2 is originally the same as the urethane elastomer 7c in which the
inorganic filler is not compounded in the process of producing the vibration transmitting
member 7b. Therefore, the urethane elastomer 7c is integrated with the vibration transfer
member 7b filled in the cylinder 19e of the acoustic fiber 19d, and as a result, the integrated one
is also referred to as the vibration transfer member 7b. Then, a large amount of silica filler is
present on the side of the sound collection contact member 12d, and an acoustic fiber 19d which
is hardly present on the vibrating film 5 side of the microphone element 2 is formed. That is, the
bulk modulus of the vibration transfer member 7b is inclined, and the bulk modulus of the
vibration transfer member 7b is determined on each of the contact surface with the sound pickup
contact member 12d and the contact surface with the vibrating membrane 5 of the microphone
element 2. It can be made close to the sound pickup contact member 12 d or the vibrating film 5.
In this way, matching of the acoustic impedance is achieved at each contact surface, and
reflection attenuation of vibration due to the internal conduction sound 4 is reduced.
18-04-2019
45
[0147]
The results of evaluation of the contact-type microphone 1k manufactured in this manner using
the monosyllabic 20-word sound table in the same manner as the first embodiment are as
follows. That is, the S / N ratio of the contact type microphone 1c in the third embodiment is
28.5 dB, and the S / N ratio under the noise environment is 7 / l compared with the S / N ratio 7
dB of the conventional contact type microphone (see FIG. 1). It was revealed that the N ratio was
significantly improved. In addition, a part of the vibration transfer member 7b is in a
substantially central portion of the sound pickup contact member 12d, which contributes to
reduction in size and size of the contact microphone 1k itself.
[0148]
As described above, when the contact type microphone of the fifth embodiment is used, the noise
resistance is further improved, and normal voice and inaudible tweet voice can be easily collected
clearly under a noise environment.
[0149]
Sixth Embodiment FIG. 19 is a side sectional view of the contact microphone in the sixth
embodiment of the present invention.
FIG. 19A is an overall side sectional view of the contact microphone 1m in the sixth embodiment,
and FIG. 19B is a perspective view of the contact microphone 1m in the sixth embodiment
viewed from above. The configuration of the contact type microphone 1c of the third
embodiment has many parts in common with the first embodiment or the second embodiment
described above, and therefore the description thereof is omitted as much as possible, and mainly
described above. The parts different from the first embodiment will be described below.
[0150]
First, also in the contact type microphone 1m of the sixth embodiment, as in the first to fourth
embodiments described above, the sound collection contact of the contact area of the contact
portion between the vibration transfer member 7a and the sound collection contact member 12b
The contact area in the direction parallel to the surface of the member 12b in contact with the
18-04-2019
46
sound collection target 3 is equal to or less than the cross-sectional area in the parallel direction
in the other portion of the vibration transfer member 7a. In addition, the acoustic fiber 19 is
configured by storing the vibration transfer member 7a in the cylinder 19a, and the cross section
of the cylinder 19a is the back surface of the contact surface of the sound collection contact
member 12b with the object 3 and the microphone element The side surface of the cylinder 19e
is in contact with the damping member 8b.
[0151]
According to the above-described configuration, the contact type microphone 1m of the sixth
embodiment can reflect and suppress the mixing of surrounding background noise due to noise
environment and efficiently collect only the vibration of the target sound collection target it can.
As a result, the noise resistance is further improved, and it is easy to clearly pick up not only
normal voice but also inaudible voice and noise such as the speaker's tweet from the sound
collection object such as skin clearly. it can.
[0152]
The contact type microphone 1m shown in the sixth embodiment has a plurality of pairs of the
acoustic fiber 19 (may be 19b or 19d) having the vibration transfer member 7a (may be 7b or
7e) and the microphone element 2 described above. doing. By increasing these pairs, the S / N
ratio is improved. That is, it leads to enlarging the numerator term of the above (Formula 5).
[0153]
The respective central axes of the microphone element 2 and the vibration transfer member 7a
are on substantially the same axis in the direction perpendicular to the surface where the sound
collection contact member 12b contacts the sound collection target object 3, and It is desirable
that the virtual center of gravity obtained from the center of each of the plurality of combinations
substantially coincides with the center of the sound pickup contact member 12b. Incidentally, if
the number of microphone elements 2 is increased, the wiring of the conducting wire 6
possessed by them will be disturbed, so, for example, at least two or more microphone elements
2 may be electrically connected in series.
18-04-2019
47
[0154]
The results of evaluation of the contact-type microphone 1m manufactured in this manner using
the monosyllabic 20-word sound table in the same manner as the first embodiment are as
follows. The S / N ratio of the contact type microphone 1c in the third embodiment is 25 dB, and
the S / N ratio under the noise environment is still compared with the S / N ratio of 7 dB of the
conventional contact type microphone (see FIG. 1). It became clear that it was improving. That is,
increasing the number of microphone elements 2 leads to the improvement of the S / N ratio of
the contact microphone.
[0155]
As described above, when the contact type microphone of the sixth embodiment is used, the
noise resistance is further improved, and normal voice and inaudible tweet voice can be easily
collected clearly under a noise environment.
[0156]
The embodiments of the present invention are not limited to the above-described first to sixth
embodiments, and combinations of the respective parts are also conceivable.
[0157]
Seventh Embodiment Next, materials of the sound collection contact members 12 a, 12 b, 12 c,
12 d and the cover member 9 will be described.
[0158]
<Sound Collection Contact Member and Cover Member are the Same Material> As described in
the first embodiment, the sound collection contact member 12 a is a material whose acoustic
impedance is different from that of air, and is, for example, SUS 304 with a thickness of 200 μm.
.
On the other hand, the cover member 9 is a material suitable for maintaining the mechanical
strength of the entire contact microphone and for a resin injection mold at the time of
manufacture, and is, for example, a metal such as aluminum or zinc alloy for die casting, or a
plastic such as ABS. .
18-04-2019
48
[0159]
Therefore, if a metal material is selected as the material of the sound collection contact members
12a, 12b, 12c, 12d and the cover member 9, both materials can be made the same.
Examples of the metal material include iron-based materials such as SUS304 described above,
aluminum-based materials, titanium-based metals, and zinc alloys for die casting.
[0160]
By using the same material as the sound collection contact members 12a, 12b, 12c, 12d and the
material of the cover member 9, the characteristics (thermal expansion coefficient, resonance
characteristics, etc.) in the material system are uniform, which is advantageous in design Part
cost reduction and simplification of the assembly process can be expected.
[0161]
<Different Materials of Sound Collection Contact Member and Cover Member> The sound
collection contact members 12a, 12b, 12c, and 12d and the cover member 9 can be made of an
optimum material in accordance with the respective functions.
[0162]
As described above, the sound collecting contact members 12a, 12b, 12c and 12d are suitably
made of metal materials, and among them, as metals whose acoustic impedance is far apart, ironbased, aluminum-based, titanium-based metals, for die casting Zinc alloy is preferred.
On the other hand, the cover member 9 does not have such a restriction, as long as the
mechanical strength and the like of the entire contact microphone can be maintained.
Therefore, the sound collection contact members 12a, 12b, 12c, and 12d can be made different
from the cover member 9, and using different materials in this way has the effect of enhancing
the respective functions.
18-04-2019
49
However, adhesion is a problem between different materials. For example, when a metal material
is used for the sound collection contact members 12a, 12b, 12c, and 12d and a plastic such as
acrylic or ABS is used for the cover member 9, they do not adhere as they are and an adhesive is
required. The present inventors examined the adhesive and confirmed that the following elastic
adhesive was suitable.
[0163]
20 to 23 are diagrams for explaining an adhesive for bonding the sound collection contact
member and the cover member.
[0164]
FIG. 20 is a diagram showing torsional free damped viscoelasticity measurement data.
[0165]
As shown in FIG. 20, the glass transition temperature (Tg) of the elastic adhesive is −60 ° C.
In addition, a cured film of an elastic adhesive exhibits a flexible rubber-like elastic body at a
temperature range of -60 to 100 ° C. which is stricter than the general use temperature range
of adhesive bonding, and gives good results for various adhesive properties.
[0166]
From the above, the cured product of the adhesive is preferably a rubber-like elastic body.
Specifically, due to the following reasons. ・ Absorb external stress such as vibration and impact.
・ It is resistant to heat cycles because it absorbs thermal strain such as expansion and
contraction. ・ It is difficult for stress to concentrate on the adhesive interface. It is suitable for
adhesion of dissimilar materials having a large difference in linear expansion coefficient. Suitable for bonding to a substrate with weak surface strength (gypsum board, calcium silicate
board, ALC (autoclaved lightweight aerated concrete). ・ Indicates high peel adhesion strength.
18-04-2019
50
[0167]
FIG. 21 is a diagram showing test conditions of an elastic adhesive, a two-component mixed
epoxy adhesive, and a rubber solvent adhesive as a circular characteristic chart.
[0168]
As shown in FIG. 21, the elastic adhesive exhibits stable adhesion under a wide range of
environments.
Since the elastic adhesive has a strong and flexible elastic film, it has an effect of dispersing and
absorbing internal stress. It is preferable to use an elastic adhesive that exhibits stable adhesion.
[0169]
FIG. 22 is a view showing adhesion to a plastic material. FIG. 22 (a) shows the tensile shear
adhesive strength of the general-purpose plastic, and FIG. 22 (b) shows the tensile shear adhesive
strength of the engineering plastic.
[0170]
Epoxy / modified silicone resin elastic adhesive, PM165, PM200, and two-component elastic
adhesive PM210, EP001 show good adhesion to plastic materials. In particular, as shown in FIG.
22 (b), EP 001 is capable of bonding engineering plastic materials that have been difficult to
bond.
[0171]
FIG. 23 is a view showing the characteristics of the two-component elastic adhesive PM210 and
EP001 in comparison.
[0172]
18-04-2019
51
As shown in FIG. 23, EP 001 exhibits good adhesion to engineering plastic materials.
Specifically, EP 001 has the following advantages. ・ Adhesion of materials that are easily broken
by shock and vibration, other external force Large tile, wall-mounted glass, mirror, thin stone etc.
・ Adhesion of material with weak surface strength Gypsum board, calcium silicate board, ALC
etc ・ The coefficient of thermal expansion is different Bonding of materials Combinations of
plastic, metal and ceramic boards etc.-Manufacture of interior and exterior, large panels-Fill
bonding on uneven base and surface materials-Bonding of parts where temperature changes are
remarkable-Outer wall (support metal fittings used together), Kitchen (top, wall surface),
bathroom, etc. In particular, the two-component elastic adhesive EP 001 is excellent in adhesion
of materials having different coefficients of thermal expansion, and filling adhesion to an uneven
base or surface material.
[0173]
From the above, when different materials are used for the sound collection contact members 12a,
12b, 12c, 12d and the material of the cover member 9, it is preferable to use an elastic adhesive
to enhance the adhesion, in particular Elastomeric adhesive EP 001 is suitable.
[0174]
As described above in detail, according to the present embodiment, the contact-type microphone
1k of the fifth embodiment includes the microphone element 2 having the diaphragm 5, the
vibration transfer member 7b storing the microphone element 2, and the vibration. A vibration
damping member 8b for storing the transmission member 7b, a cover member 9 having a sound
collection opening 11 and the microphone element 2, the vibration transmission member 7b and
the vibration damping member 8b, a sound collection opening 11 of the cover member 9 And a
cap-like sound pickup contact member 12d disposed to cover the
In the sound collection contact member 12 d, a hole (concave portion) 24 having a small
thickness immediately above the vibration film 5 and having a shape with a wide sound
collection opening 11 side of the cover member 9 is formed at a position facing the vibration film
5. There is.
18-04-2019
52
[0175]
With this configuration, the distance by which the air conduction sound 10 (noise) is transmitted
as solid vibration from the outer peripheral portion of the contact microphone 1k to the central
portion of the sound pickup contact member 12d is increased. The area subject to vibration is
reduced, and sound collection from the sound collection target 3 can be satisfactorily secured.
Further, since the area other than the central portion of the contact portion of the sound
collection contact member 12d is thick, the noise mixed from the periphery of the speaker
wearing the contact type microphone 1k can be reduced. As a result, by increasing the distance
of the area through which the sound passes, the S / N ratio can be improved, and it is possible to
improve the sound collection of the conversational voice of the speaker wearing the contact type
microphone 1k.
[0176]
Second Embodiment In the first embodiment, the contact microphones 1a to 1h and 1j to 1m
have been described.
[0177]
Embodiment 2 demonstrates the transmission / reception apparatus provided with contact-type
microphones 1a-1h and 1j-1m.
[0178]
FIG. 24 is a perspective view showing a transmitting / receiving apparatus mounting the contact
type microphone of the second embodiment of the present invention.
FIG. 25 is a side view of the transmitter / receiver mounted on the head.
FIG. 26 is a view for explaining the arrangement of the contact type microphone in the
transmission / reception device.
[0179]
The present embodiment is an example in which the transmitting and receiving apparatus of the
18-04-2019
53
present invention is applied to a headphone in which a speaker unit and a microphone are
disposed close to each other.
[0180]
As shown in FIG. 24 and FIG. 25, the headphone 100 is a sealed headphone mounted on the head
so as to cover the auricle via the headband.
[0181]
The headphone 100 mainly includes a left ear cover headphone 110, a right ear cover
headphone 120, and a curved headband 130 connecting the left ear cover headphone 110 and
the right ear cover headphone 120 to the left and right.
[0182]
The headband 130 abuts against the head on both sides via the top of the head of the user.
[0183]
The members of the left ear cover headphone 110 and the right ear cover headphone 120 are
arranged symmetrically on the head.
[0184]
The left ear cover headphone 110 is attached to the circular baffle plate 111 as a whole
supporting substrate, the outer periphery of the front surface side of the baffle plate 111, the ear
pad 112 covering the ear shells, and the outer periphery of the back surface side of the baffle
plate 111 And a housing 114 fixed via a ring 113.
Moreover, although illustration is abbreviate | omitted, the speaker unit is being fixed to the back
surface side center part of the baffle plate 111. As shown in FIG.
The baffle plate 111 has a large number of holes as sound holes in the center.
[0185]
18-04-2019
54
The ear pad 112 is formed in a ring shape large enough to surround the auricle.
[0186]
The support ring 113 and the housing 114 cover the back side of the baffle plate 111 and the
speaker unit (not shown).
[0187]
The housing 114 is larger than the auricle, the ear pad 112 is in close contact with the side of
the auricle, and the ear pad is completely covered by the ear pad 112 and the speaker unit.
This closed type has a good feeling of wearing and can also prevent sound leakage to the outside.
Also, the bass can be reproduced richly.
[0188]
In the present embodiment, the headphone 100 is characterized in that the microphone can be
disposed in proximity to the speaker unit.
[0189]
In FIGS. 24 and 25, in addition to the configuration of the above-mentioned general closed-type
headphone, the left-ear cover headphone 110 is characterized in that the contact microphone 1a
is disposed in the vicinity of the speaker unit.
The transmission / reception apparatus of the present invention is characterized in that the
contact microphone 1a in the first embodiment is arranged as follows.
[0190]
18-04-2019
55
In the present embodiment, the contact-type microphone 1a is attached to the left ear cover
headphone 110, but may be attached to the right ear cover headphone 120.
It is sufficient if the contact microphone 1a is disposed on either side of the headphone 100.
However, they may be attached to both.
[0191]
As shown in FIG. 24 and FIG. 25, the headphone 100 has a baffle plate 111, a first reference axis
in the longitudinal direction of the headband 130 and a first reference axis in the longitudinal
direction of the headband 130. Of the parts divided into four by the second reference axis
orthogonal to the one reference axis, in the part separated from the headband 130 and in contact
with the forehead side of the user than the receiving means , And the contact type microphone
1a.
That is, as shown in FIG. 24 and FIG. 25, when the contact microphone 1 a represents the four
divided regions respectively as the regions I to IV, the lower region of the front of the user of the
four divided regions I to IV The contact type microphone 1a is disposed in the area III of FIG.
Further, when the user wears the contact microphone 1a on the head in a region (region III in
FIGS. 24 and 25) that abuts on the frontal side divided into four parts, the base of the user's jaw
or It is disposed at the position where it best abuts on the cheekbone (hereinafter referred to as
the vicinity of the cheekbone) (refer to the circle mark in FIG. 26). According to experiments of
the present inventor and the like, it was confirmed that when the contact type microphone 1a is
mounted on the headphone 100, the detection accuracy is improved if the contact type
microphone 1a is disposed in the vicinity of the cheekbone. However, the contact-type
microphone 1a is not limited to the vicinity of the cheekbone, and may be disposed in a portion
(region III in FIGS. 24 and 25) to be in contact with the forehead divided into four. In addition,
since the contact microphone 1a has an excellent S / N ratio, it is disposed, for example, at the
site (region IV in FIGS. 1 and 2) outside the region (region III in FIGS. 24 and 25). It is also
possible.
[0192]
18-04-2019
56
Thus, the contact-type microphone 1a is disposed at a position where the general user abuts best
near the cheekbone of the user when the headphone 100 is normally used. In other words, the
arrangement position in contact with the vicinity of the cheekbone of the user is the area III
below the forehead of the user.
[0193]
In addition, although the said transmission / reception apparatus was demonstrated by the
example provided with the contact-type microphone 1a, you may apply the contact-type
microphones 1b-1h and 1j-1m.
[0194]
As described above in detail, according to the present embodiment, the present invention is
applied to the headphone 100 (see FIGS. 24 and 25) as a transmitting and receiving device on
which the contact type microphones 1a to 1h and 1j to 1m are mounted.
The headphone 100 includes contact microphones 1 a to 1 h and 1 j to 1 m in proximity to the
speaker unit. In detail, the contact microphones 1a to 1h and 1j to 1m are divided into four by
the first reference axis in the longitudinal direction of the headband 130 and the second
reference axis orthogonal to the first reference axis, and the divided parts are Among them, the
head band 130 is disposed at a side away from the head band 130 and at a portion that abuts on
the forehead side of the user than the receiving means.
[0195]
Thereby, the sound wave from the receiving means is output to the same side as the temporal
abutment portion. The sound wave from the receiving means is directly heard in the ear, so it can
be heard as usual, and in the case of the transmitting means of the above configuration, the
sound wave picked up from the receiving means is smaller than the user's speech. A clear, stressfree conversation with you can be achieved.
[0196]
As described above, in the present embodiment, by using the contact microphones 1a to 1h and
18-04-2019
57
1j to 1m having extremely excellent noise resistance for the transmitting and receiving device, a
headphone in which the speaker unit and the microphone are disposed close to each other is
realized. can do.
[0197]
In the present embodiment, an example in which the transmitting and receiving device is used
for headphones has been described. However, the headphone may be any headphone such as a
single ear type headphone and a neck band type.
[0198]
Moreover, as long as it is a transmitting and receiving apparatus provided with the contact type
microphones 1a to 1h and 1j to 1m, it may be mounted on a portable terminal apparatus other
than the headphones.
That is, any device may be used as long as the device has a transmission / reception function,
and may be applied to, for example, a mobile terminal device such as a mobile phone.
[0199]
Generally, the casing of such a portable terminal device is narrow, and the speaker and the
contact microphones 1a to 1h and 1j to 1m have to be disposed close to each other.
Moreover, it can not but be assumed that a portable terminal device is used under a noise
environment. Therefore, conventionally, there has been no example in which a contact type
microphone is mounted on a mobile terminal device such as a mobile phone.
[0200]
According to the present embodiment, the contact type microphones 1a to 1h and 1j to 1m
having noise resistance and capable of clearly picking up only normal voice and inaudible tweet
voice etc. are mounted on the portable terminal device. As a result, it is possible to realize a clear
and stress-free conversation with the other party, which was conventionally difficult to realize,
without causing howling.
18-04-2019
58
[0201]
The above description is an illustration of a preferred embodiment of the present invention, and
the scope of the present invention is not limited to this.
[0202]
Further, although the names of the contact type microphone and the transmitting and receiving
device are used in the above embodiments, this is for convenience of explanation, and the contact
type microphone may be a microphone device, and the transmitting and receiving device may be
a communication device or the like.
[0203]
Furthermore, the parts constituting the contact type microphone, for example, the type and
shape of the sound collection contact member, the mounting method, and the like are not limited
to the above-described embodiment.
[0204]
The contact-type microphone of the present invention can clearly collect the voice of the speaker
and the inaudible tweet without mixing of background noise under noise environment such as
general outdoor and construction site.
In addition, by applying to normal voice communication, voice input, voice recognition, voiceless
telephone, error-free voice input to a portable information terminal etc., and communication
having very clear voice and sound quality in secret call. Realization is possible.
Furthermore, the contact-type microphone in the present invention can be incorporated into the
chin strap of a helmet for work or work, an ear cover for cold protection, and the like.
Furthermore, for the purpose of privacy protection, it can also be used as a sensor that detects
only the vibration of the vibration detection target without collecting surrounding speech.
18-04-2019
59
For example, it is a water flow rate detection sensor for general household use. In addition, it can
be applied to the security field such as detecting a walking pattern of a pedestrian and
identifying an intruder by embedding it on the floor.
[0205]
The transmitting and receiving apparatus provided with the contact type microphone of the
present invention can be applied to a transmitting and receiving apparatus such as a headphone
or a portable wireless apparatus in which the contact type microphone is disposed in proximity
to a speaker unit. It is also possible to apply to an apparatus.
[0206]
1a to 1h, 1j to 1m Contact type microphone 2 Microphone element 3 Sound collecting object
(skin etc.) 4 Internal conduction sound 5 Vibrating film 6 Conductor 7a, 7b, 107 Vibration
transmitting member 7c Urethane elastomer 8a, 8b, 108 Damping member 9 cover member 10,
10a, 10b, 10c air conduction sound 11 sound collection opening 12a, 12b, 12c, 12d sound
collection contact member 18 gap 19, 19b, 19d acoustic fiber (conduit) 19a, 19c, 19e cylinder
20 plastic Ball 21 Cavity 22 Washer 23 Upper and lower connection tube 24 Perforated
(recessed portion) 25 Ejection hole 26 Lathe drill 27 Silica 31 Through hole 32 Ground wire 100
Headphones (transmitter / receiver)
18-04-2019
60
Документ
Категория
Без категории
Просмотров
0
Размер файла
92 Кб
Теги
description, jp5079913
1/--страниц
Пожаловаться на содержимое документа