JP5185431B1 - Contact microphone and transmitter / receiver provided with contact microphone - Google Patents

Abstract

Provided are a contact microphone and a transmission / reception device that further improve the noise resistance of a contact microphone such as a NAM microphone, and that can easily pick up only normal voices and non-audible murmurs.
A contact-type microphone includes a microphone element 2 having a vibration film 5, a vibration transmission member 7b for storing the microphone element 2, a damping member 8b for storing the vibration transmission member 7b, and a sound collection opening 11. A cover member 9 that houses the microphone element 2, the vibration transmission member 7 b, and the vibration damping member 8 b; and a sound collection contact member 12 a, 12 b, 12 c, 12 d disposed so as to cover the sound collection opening 11 of the cover member 9. The sound collection contact members 12a, 12b, 12c, 12d and the cover member 9 are made of the same material. Moreover, a headphone (transmission / reception device) includes the contact microphone.
[Selection] Figure 11

Description

  The present invention relates to a contact-type microphone and a contact-type microphone that can clearly pick up a target voice during normal speech, a weak sound that cannot be heard by human ears, or a non-audible murmur even in a noisy environment. It is related with the transmitter / receiver provided with.

  Various sounds such as non-audible murmur (hereinafter abbreviated as “NAM”) with a microphone in contact with the surface of the skin just below the deciduous lobe of the skull after the auricle. In addition, there is a so-called NAM microphone for collecting the conduction sound 4 in the body as a transmission vibration (for example, Patent Document 1). Such NAM microphones started with application to voice input / recognition and voiceless telephones with the main purpose of concealing the content of utterances. It is also attracting attention as a vibration pickup detector that constantly monitors noise.

  FIG. 1 is a side sectional view showing a basic structure of a conventional contact microphone.

  A microphone element 2 of a conventional contact microphone (in each embodiment, an electret condenser microphone is used, hereinafter abbreviated as “ECM”) is a voice of a speaker collected from a sound collection target 3 such as skin. When the body conduction sound 4 is transmitted to the vibration film 5 through a vibration transmission member 107 described later, the vibration of the vibration film 5 is converted into an electric signal and transmitted to the outside through the conductive wire 6.

  The vibration transmission member 107 is attached so as to contact or wrap around the microphone element 2, and transmits the vibration of the body conduction sound 4 to the microphone element 2 without loss. For the vibration transmitting member 107, for example, a plastic material such as a silicone elastomer (for example, Patent Document 2) or a urethane elastomer (for example, Patent Document 3) is used. One of them is in contact with the vibrating membrane 5 of the microphone element 2 and the other is in wide contact with the sound pickup object 3. The vibration damping member 108 prevents air conduction sound, which is background noise, from entering from the back side of the contact-type microphone, and covers, for example, the entirety of the microphone element 2 except for the sound collection opening 11 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. The cover member 9 maintains the mechanical strength of the entire contact microphone and plays the role of a resin injection mold during manufacturing.

  In order to pick up the body conduction sound 4 such as the skin with high sensitivity using such a conventional contact microphone, the reflection of vibration at the interface between the sound pickup object 3 and the vibration transmitting member 107 must be kept low. Don't be. The reflectance of sound is represented by the Snell rule shown in the following (Formula 1).

r2 = (Z2−Z1) ² / (Z2 + Z1) ² (Formula 1)
Here, r2 is the reflectance at the interface between the two kinds of different substances 1 and 2, Z1: the acoustic impedance of the substance 1 (including the case of air), and Z2: the acoustic impedance of the substance 2.

  As can be seen from (Equation 1), if the acoustic impedances of two substances in contact with each other are close to each other, the sound reflectance is close to 0 and the degree of attenuation is small. Conversely, if the acoustic impedances of two substances that are in contact with each other are separated, the sound reflectance increases and the degree of attenuation also increases. Therefore, if the acoustic impedance of the vibration transmitting member 107 is made as close as that of the sound collecting object 3 (skin), the reflection of the in-body conduction sound 4 at the boundary surface between the sound collecting object 3 and the vibration transmitting member 107 becomes small. The loss of the body conduction sound 4 is suppressed.

(Table 1) is a table showing acoustic impedance values of various materials. From this (Table 1), it can be seen that the plastic material such as silicone elastomer and urethane elastomer constituting the vibration transmitting 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) is close to 135 × 10 ⁴ (kg / m ² · s). doing. The vibration film 5 of the microphone element 2 is also basically a plastic material, and is the same as the vibration transmission member 107 in that respect.

  As a result, the conventional contact microphone improves the sensitivity of the body conduction sound 4 in the microphone element 2 and widens the sound collection band (particularly reduces attenuation in the high frequency range above 2 kHz) It has been said that vibrations of living soft tissue (skin) during normal speech or inaudible muttering can be picked up with high sensitivity.

International Publication No. 2004/021738 International Publication No. 2005/067340 JP 2007-043516 A

However, in the above conventional technique, background noise (noise) around the person who speaks, that is, the so-called air conduction sound 10 is collected not a little. Similarly, as can be seen from (Table 1), the acoustic impedance of the plastic material such as the silicone elastomer or urethane elastomer employed as the vibration transmitting member 107 = 248 × 10 ⁴ (kg / m ² · s) This is because not only the soft tissue (skin) but also the acoustic impedance of air = 415 (kg / m ² · s) has a fairly close value.

  This point will be described in more detail with reference to FIG. Actually, in most cases, a slight gap 18 is generated between the sound collection target 3 and the opening end of the cover member 9. The vibration transmitting member 107 is in contact with external air in the gap 18.

  Here, as described above, the vibration transmitting member 107 made of a plastic material and air have a substantially similar acoustic impedance. Therefore, background noise (noise) that is not desired to be collected as much as possible, so-called air conduction sound 10a, enters the inside of the contact microphone through the slight gap 18 and is mixed into the body conduction sound 4 that is originally desired to be collected. Sound is collected. Alternatively, there is also an air conduction sound 10b (collectively referred to as “air conduction sound 10” hereinafter) that is collected by the contact microphone via the sound collection target 3 (skin). About the air conduction sound 10c, the arrival to the microphone element 2 can be reduced by reflection by the cover member 9 and absorption by the vibration damping member 108 inside thereof. However, since the air conduction sounds 10a and 10b are mixed into the body conduction sound 4 that is originally desired to be collected, the content of the other party cannot be heard clearly or an error in voice input / recognition on the portable information terminal side occurs. There were problems such as causing it.

  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 collect only normal voices and non-audible murmurs, and a transmission / reception device including the contact microphone Is to provide.

The contact-type microphone of the present invention is a capacitor-type microphone element having a vibration film, and contacts the vibration film of the microphone element and transmits vibration transmitted from the side facing the vibration film to the microphone element. A vibration transmission member, a cover member having an opening and storing the microphone element, the vibration transmission member and the damping member; and being disposed to cover the opening of the cover member and in contact with the vibration transmission member ; A sound collecting contact member including metal or ceramics , wherein the vibration transmitting member is disposed substantially at the center of the sound collecting contact member, and the sound collecting contact member and the cover member are made of the same material. Take the configuration formed.

  The transmission / reception apparatus of the present invention employs a configuration including the contact microphone.

  According to the present invention, noise resistance is further improved, and it is easy to clearly collect not only normal speech but also non-audible speech and sound such as a speaker's murmur from a sound collection target such as skin. can do.

Side sectional view showing the basic structure of a conventional contact microphone (A) Side sectional view of the contact type microphone in Example 1 of Embodiment 1 of the present invention, (b) Side sectional view of the contact type microphone in Example 2 of the present invention. The figure which shows the method of evaluating S / N ratio of the contact-type microphone of this invention The side sectional view of the contact type microphone in Example 3 of the present invention, (a) the whole side sectional view, (b) the enlarged view of the tip of the vibration transmitting member Side sectional view of contact microphone in comparative example in comparison with embodiment 3 of the present invention (a) Side sectional view of a contact microphone in comparative example 1, (b) Side sectional view of a contact microphone in comparative example 2 Side sectional view of a contact type microphone in a comparative example having a comparative relationship with Example 3 of the present invention (a) Side sectional view of a contact type microphone in Comparative Example 3, (b) Side sectional view of a contact type microphone in Comparative Example 4 Sectional side view in the application example of the contact-type microphone using Example 3 of this invention Side sectional view of a contact-type microphone in Example 4 of the present invention, (a) overall side sectional view, (b) enlarged view of the tip of the vibration transmission member Side sectional view of a contact-type microphone in Comparative Example 5 that is in a comparative relationship with Example 4 of the present invention The exploded perspective view of the contact type microphone in Example 5 of the present invention The side sectional view of the contact type microphone in Example 5 of the present invention, (a) the whole side sectional view, (b) the enlarged view of the tip of the vibration transmitting member The figure which shows the example of the manufacturing method of the contact-type microphone in Example 5 of this invention. The figure which shows the example of the manufacturing method of the contact-type microphone in Example 5 of this invention. The figure which shows the example of the manufacturing method of the contact-type microphone in Example 5 of this invention. The figure which shows the example of the manufacturing method of the contact-type microphone in Example 5 of this invention. The figure which shows the example of the manufacturing method of the contact-type microphone in Example 5 of this invention. The perspective view explaining the structure of the sound collection contact member of the contact-type microphone in Example 5 Whole side sectional view at the time of attaching a grounding wire of a contact microphone in Example 5 Side sectional view of a contact microphone according to a sixth embodiment of the present invention. The figure which shows the torsion free damping type viscoelasticity measurement data in Example 7 of this invention The figure which shows the test conditions of the elastic adhesive agent in Example 7 of this invention, a two-component mixed epoxy adhesive, and a rubber-type solvent-type adhesive on a circular characteristic chart. The figure which shows the adhesiveness to the plastic material in Example 7 of this invention The figure which contrasts and shows each characteristic of the two-component elastic adhesive PM210 in Example 7 of this invention, and EP001 The perspective view which shows the transmitter / receiver which mounts the contact-type microphone of Embodiment 2 of this invention. Side view when the transmitter / receiver equipped with the contact microphone according to the second embodiment is mounted on the head The figure explaining arrangement | positioning of the said contact type microphone in the transmission / reception apparatus which mounts the contact type microphone of this Embodiment 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
[Example 1]
FIG. 2A is a side sectional view of the contact microphone according to Example 1 of Embodiment 1 of the present invention. Here, a contact microphone having a sound collection contact member 12a made of SUS (thickness 200 μm) will be described first with reference to FIG. The same or similar members as those of the conventional contact microphone (see FIG. 1) will be described using the same reference numerals. Incidentally, the sound collection contact member 12a is a member that is not included in the conventional contact microphone (see FIG. 1). Further, regarding the vibration transmission member 7a and the vibration damping member 8a described later, the vibration transmission member 107 (see FIG. 1) and the vibration damping member 108 (see FIG. 1) of the conventional contact microphone (see FIG. 1) are slightly different. Have different configurations. These are characteristic parts of the present invention.

  The microphone element 2 of the contact microphone 1a of the first embodiment shown in FIG. 2 (a) has a sound collection contact member that receives a body conduction sound 4 such as a speaker's voice collected from a sound collection target 3 such as skin. When transmitted to the diaphragm 5 through the vibration transmission member 12 a and the vibration transmission member 7 a, the vibration of the diaphragm 5 is converted into an electric signal and transmitted to the outside through the conductor 6.

  The cover member 9 is made of a metal such as aluminum, or a plastic such as acrylic or ABS, like the conventional contact microphone (see FIG. 1), and maintains the mechanical strength of the entire contact microphone 1a and is resin during manufacture. Serves as an injection mold.

  The vibration transmitting member 7a transmits the vibration of the body conduction sound 4 to the microphone element 2 without loss. For example, the vibration transmitting member 7a is made of urethane elastomer, and one of them is in contact with the vibration film 5 of the microphone element 2. This is the same as the contact type microphone (see FIG. 1).

  However, the other side of the vibration transmitting member 7a is not in wide contact with the sound pickup object 3 as in the conventional contact microphone (see FIG. 1). The vibration transmission 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 was not found in the conventional contact microphone (see FIG. 1). The sound collection contact member 12a is made of, for example, SUS304 having a thickness of 200 μm. In the contact microphone 1a according to the first embodiment, the contact portion between the vibration transmitting member 7a and the sound collection contact member 12a is provided at the approximate center of the sound collection contact member 12a. Of the contact area of the contact portion between the vibration transmitting 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 object 3 is vibration. It is below the cross-sectional area in the parallel direction in the other part of the transmission member 7a. Furthermore, in the direction parallel to the surface where the sound collection contact member 12a contacts the sound collection object 3, the centers of the microphone element 2, the vibration transmission member 7a, and the sound collection contact member 12a are the sound collection contact. It can also be said that the member 12a is on substantially the same axis in the direction perpendicular to the surface in contact with the sound pickup object 3.

  With the above-described configuration, the contact microphone 1a according to the first embodiment can reflect and suppress the mixing of surrounding background noise due to the noise environment, and can efficiently collect only the vibration of the target sound pickup object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can. The features and effects will be described in more detail later.

  The vibration damping member 8a prevents the air conduction sound 10 that is background noise from entering from the back surface of the contact microphone 1a, as in the conventional contact microphone (see FIG. 1). The microphone element 2 is configured to cover the whole except for the sound collection opening 11. In addition, unlike the conventional contact microphone (see FIG. 1), the vibration damping member 8a of the first embodiment is also in contact with the sound collection contact member 12a and is disposed so as to surround the vibration transmission member 7a. Has been. The main body of the microphone element 2, the vibration transmitting member 7a, and the damping member 8a are sealed inside by the cover member 9 and the sound collection contact member 12a. The vibration transmitting member 7a is disposed so as to connect a substantially central portion of the sound collecting contact member 12a and a substantially central portion of the sound collecting opening 11 of the microphone element 2. In the case of the first embodiment, the substantially central portion of the sound collection opening 11 of the microphone element 2 is disposed directly below the substantially central portion of the sound collection contact member 12a, and the vibration transmission member 7a is connected so as to connect the shortest distance. Is provided. Note that the vibrating membrane 5 of the microphone element 2 is also basically formed of the same plastic material as the vibration transmitting member 107 (see FIG. 1).

  The materials of the sound collection contact member 12a and the cover member 9 will be described later in Example 7.

  The characteristics of the contact microphone 1a of the first embodiment having the above-described configuration will be described below.

As described above, the sound collection contact member 12a included in the contact microphone 1a according to the first embodiment is made of, for example, SUS304 having a thickness of 200 μm, that is, a metal member. As shown in the above (Table 1), the acoustic impedance of the metal member is 4160 × 10 ⁴ kg / m ² · s, and not only the soft tissue such as the skin assumed as the sound collection target 3 but also the external air It is greatly different from the air transmitting the sound guide 10 and the plastic member constituting the vibration transmitting member 7a.

  That is, in the contact microphone 1a of the first embodiment, such a member with significantly different acoustic impedance is arranged in the transmission path of the in-body conduction sound 4 from the sound collection target 3 to the vibration membrane 5 of the microphone element 2. Will be. In this case, according to the conventional common sense, reflection of the body conduction sound 4 becomes large at the boundary surface between the sound collection contact member 12a and the sound collection object 3 or the vibration transmission member 7a, and the vibration film 5 of the microphone element 2 is not reflected. Should be difficult to communicate.

  However, even if there is such a demerit, the attenuation rate of the external air conduction sound 10 that does not want to be collected as much as possible is greater than the attenuation of the body conduction sound 4 that is desired to be collected. That is, since the contact microphone 1a of the first embodiment has a higher S / N ratio than the conventional contact microphone (see FIG. 1), the body conduction sound 4 can be collected more efficiently. it can.

  The reason is considered as follows. When the in-body 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 the largest at the center of the sound collection contact member 12a. Become. The path from the central portion of the sound collection contact member 12a where the physical vibration due to the internal conduction sound 4 is the largest to the vibration film 5 of the microphone element 2 is the same as the vibration film 5 of the microphone element 2. A vibration transmission member 7a made of a plastic material is disposed. Thereby, the physical vibration by the body conduction sound 4 can be efficiently transmitted to the vibration film 5 of the microphone element 2.

  In addition, a damping member 8a is disposed around the vibration transmitting member 7a. This means that the air conduction sound 10 coming from outside the central portion of the sound collection contact member 12a is blocked by the vibration damping member 8a and hardly reaches the vibration film 5 of the microphone element 2. means. Since the main body of the microphone element 2, the vibration transmission member 7a, and the vibration damping member 8a are sealed inside by the cover member 9 and the sound collection contact member 12a, a conventional contact microphone (FIG. 1) is used. Unlike the reference), there is no room for the air conduction sound 10 from the outside to enter. Therefore, in order for the air conduction sound 10 from the outside to reach the vibration film 5 of the microphone element 2, as a result, the vibration is far away from the periphery of the sound collection contact member 12a and has excellent sound transmission efficiency. The sound collecting contact member 12a with which the transmission member 7a is in contact must be turned to the central portion. During this wraparound, the attenuation of the air conduction sound 10 from the outside becomes larger.

  As described above, the contact microphone 1a according to the first embodiment shown in FIG. 2A is more easily picked up by the in-body conduction sound 4 that is originally desired to pick up sound, and external air conduction that does not want to pick up sound as much as possible. The sound 10 has a structure that makes it difficult to collect sound. Therefore, the S / N ratio of the body conduction sound 4 with respect to the external air conduction sound 10 is improved, and the body conduction sound 4 can be collected more efficiently.

  This shows how much the performance of the contact microphone 1a of the first embodiment actually improved compared to the conventional contact microphone (see FIG. 1). In order to judge whether the performance is good or bad, the S / N ratio and the intelligibility of the contact microphone in a noisy environment were evaluated.

  First, a method for evaluating the S / N ratio of the contact microphone according to the present invention including the first embodiment will be described below.

  FIG. 3 is a diagram illustrating a method for evaluating the S / N ratio of a contact microphone. Note that this S / N ratio evaluation method is commonly used for all contact microphones. First, an audio file (distributed by the Acoustical Society of Japan) recording a crowd at the exhibition hall is reproduced as background noise, that is, an external air conduction sound 10 by the reproduction device 13a in a semi-acoustic room, and a speaker is connected via an amplifier 13b. It flows from 13c. In this state, a contact microphone (the contact microphone 1a shown in FIG. 2A in the first embodiment) is worn around the throat at a position measured by the sound level meter as 100 dB. Then, the characters of the syllable 20-word syllables recommended by the Japan Audiological Society are pronounced and recorded every 2 seconds with normal utterances (about 90 dB). Based on the recorded waveform, the sound pressure ratio between the external air conduction sound 10 collected by the contact microphone 1a and the utterance of the speaker, that is, the body conduction sound 4 is expressed in dB using (Expression 2) below. Convert to S / N ratio and evaluate.

S / N ratio (dB) = 20 log (S / N) (Formula 2)
Further, the recorded voice file of the single syllable 20-word syllable obtained at the time of the previous S / N ratio measurement is listened to by four arbitrary subjects, and the heard characters are recorded. Then, each correct answer rate is calculated to be a single syllable intelligibility, and the single syllable intelligibility is divided by 0.85 and evaluated as a sentence intelligibility. By the way, dividing the syllable intelligibility by 0.85 when calculating the sentence intelligibility is generally said to be "if the correct answer rate of single syllable intelligibility is 85%, the sentence intelligibility will be 100%". This is because.

  Details of such an evaluation method are also described in p117 of “New and Pollution Prevention Technology and Regulation 2009 Noise and Vibration Edition for Qualification Certification Courses such as Pollution Prevention Managers”. As a result of the evaluation by the above method, the S / N ratio of the contact microphone 1a in the first embodiment 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 microphone (see FIG. 1) was 7 dB. From the above, it has been clarified that the S / N ratio of the contact microphone 1a in the first embodiment shown in FIG.

  As described above, the contact microphone 1a of the first embodiment with improved performance can be produced by the following process, for example. 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 transmission member 7a is formed in the vibration damping member 8a by, for example, a casting method of a two-component elastic epoxy resin. Next, a through-hole (not shown) that 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 transmitting member 7a is formed by heating at 80 ° C. for 1 hour. At this time, the vibration transmitting member 7a has a hemispherical tip due to its surface tension. Then, the sound collecting contact member 12a, that is, a SUS lid having a thickness of 200 μm, is heat-cured at 80 ° C. for 1 hour by using the two-component elastic epoxy resin used for forming the vibration damping member 8a as an adhesive. When bonded and fixed by the above, the contact microphone 1a shown in FIG. 2A is completed.

In addition, as an elastic epoxy resin used as the damping member 8a in the first embodiment, for example, EP001 (commercial epoxy resin-based elastic adhesive) manufactured by Cemedine Co., Ltd. is mixed in an equal amount with a modified polyamine curing agent and heated to 80 ° C. A cured product is preferably used. Moreover, as a urethane elastomer used as the vibration transmission member 7a in the first embodiment, for example, a gel stock solution of polyurethane human skin manufactured by Exeal Corporation, Inc. (C-15 main ingredient and curing agent are mixed at 3: 1). , Cured at 80 ° C.) is preferably used. Further, the sound collection contact member 12a and the cover member 9 are made of iron, stainless steel, aluminum or the like having a material whose acoustic impedance value is far from the air (415 kg / m ² · s) for transmitting the body air conduction sound 4. In addition to metal (4160 × 10 ⁴ kg / m ² · s), ceramics such as glass (1122 × 10 ⁴ kg / m ² · s) may be used. Furthermore, the exposed surface of the sound collection contact member 12a, that is, the contact surface with the sound collection target such as human skin, the side surface thereof, or the like may be coated with a coating member such as resin. This is particularly effective when the sound collection contact member 12a is made of metal. When metal touches human skin directly, it may feel cold depending on the temperature, or sweat may adhere to the sound collecting contact member, which may cause rust. The coating member is effective in avoiding such problems.

  As described above, when the contact microphone according to the first embodiment is used, the noise resistance is further improved, and normal voices and non-audible muttering voices can be clearly and easily picked up in a noisy environment.

  Hereinafter, the contact-type microphone according to the first embodiment will be described in comparison with the conventional contact-type microphone.

  Conventional contact microphones are assumed to be used in as quiet a noise-free environment as possible. For example, the present invention is applied to a vibration pickup detector that constantly monitors a patient's body conduction sound such as a pulse and a heart sound. The conventional contact microphone attempts to increase S (signal component) in an environment where the S / N ratio N (noise) is as small as possible. Conventional contact microphones are not supposed to be used in a noisy environment. In a noisy environment, for example, a contact microphone close to the speaker unit such as a headphone, or a contact microphone arranged close to the speaker unit in a narrow housing can be used. According to the present inventor, it has been found that the conventional contact type microphone has N (noise) too large under the above-mentioned noise environment, and is not at a practical level.

  In contrast, the contact microphone 1a according to the first embodiment is arranged so that the sound collection contact member 12a covers the sound collection opening 11 of the cover member. For this reason, there was a concern about a decrease in signal components to be detected. However, according to the experiments of the present inventors, it has been found that the sound collection contact member 12a covers the opening 11, but the signal component reduction is at a level that does not cause a problem in mounting. It is considered that the sound collecting contact member 12a is arranged in the center facing the vibration film 5 and that the material of the sound collecting contact member 12a is greatly different from the acoustic impedance Z. The thickness of the sound collection contact member 12a is also optimized.

  With the above-described configuration, the contact microphone 1a according to the first embodiment can reflect and suppress the mixing of surrounding background noise due to the noise environment, and can efficiently collect only the vibration of the target sound pickup object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can. It can be mounted on a transmission / reception device in which a microphone can be arranged close to a speaker unit such as a headphone.

[Example 2]
FIG.2 (b) is a figure which shows the sectional side view of the contact-type microphone in Example 2 of this invention. Since the configuration of the contact microphone 1b according to the second embodiment has many parts in common with the contact microphone 1a according to the first embodiment described above, description thereof will be omitted. The difference from the first embodiment is a sound collection contact member 12b and a vibration damping member 8b. The contact microphone 1b according to the second embodiment will be described with reference to these points.

  The microphone element 2 of the contact type microphone 1b of the second embodiment shown in FIG. 2 (b) has a sound collection contact member that receives a body conduction sound 4 such as a speaker's voice collected from a sound collection target 3 such as skin. When transmitted to the diaphragm 5 through the vibration transmission member 12 a and the vibration transmission member 7 a, the vibration of the diaphragm 5 is converted into an electric signal and transmitted to the outside through the conductor 6. Also in the contact microphone 1b according to the second embodiment, the contact portion between the vibration transmitting member 7a and the sound collecting contact member 12b is provided substantially at the center of the sound collecting contact member 12b as in the first embodiment. Yes. Of the contact area of the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b, the contact area in the direction parallel to the surface where the sound collection contact member 12b contacts the sound collection object 3 is vibration. It is below the cross-sectional area in the parallel direction in the other part of the transmission member 7a. Furthermore, in the direction parallel to the surface where the sound collection contact member 12b is in contact with the sound collection object 3, the centers of the microphone element 2, the vibration transmission member 7a, and the sound collection contact member 12b are the sound collection contact. It can also be said that the member 12b is on substantially the same axis in the direction perpendicular to the surface in contact with the sound collection object 3.

  With the above configuration, the contact microphone 1b according to the second embodiment reflects and suppresses the background noise from being mixed due to the noise environment, and can efficiently collect only the vibration of the target sound collecting object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can.

  The sound collecting contact member 12b of the second embodiment has a cap-shaped contact member made of aluminum metal with a thickness of 1.5 mm, and is fitted and bonded by a nested structure with the cover member 9. The damping member 8b uses an elastic epoxy resin composite material in which silica powder surface-modified with phenylaminosilane (SC6202-SXC manufactured by Admatechs) is dispersed by 50% by weight. Thus, by including an inorganic material filler such as silica, the elastic modulus is increased, and the adhesion with the cover member 9 and the metal part of the microphone element 2 is increased. Further, since the included microphone element 2 is firmly fixed, loss of transmission vibration due to not only the vibration film 5 of the microphone element 2 but also the entire microphone element 2 is prevented.

  In addition, since the acoustic impedance of the damping member 8b is closer to the acoustic impedance of the metal part of the cover member 9 and the microphone element 2, reflection at the interface between these metal parts and the damping member 8b is suppressed. This is effective in absorption loss of vibration due to the elastic epoxy resin component in the damping member 8b. This will be described in detail in the comparison between Example 4 and Comparative Example 5 described later.

  The material of the sound collection contact member 12b and the cover member 9 will be described later in Example 7.

  As the inorganic material filler dispersed in the vibration damping member 8b, those having a particle size of submicron to 100 microns are preferably used. This is because sub-micron or less generally has poor dispersibility and aggregates and hinders distribution control, and those of 100 micron or more tend to settle and segregate due to poor dispersibility. This is to lower the target strength.

  In addition to the silica described above, alumina, zirconia, silica, calcium carbonate, kaolin, clay, colloidal silica, titania and the like can be used as the inorganic material filler dispersed in the damping member 8b. These may be used alone or in combination of two or more selected from the above.

  Next, regarding the content of the inorganic material filler dispersed in the vibration damping member 8b, when it is 75% or more, handling by the manufacturing process becomes difficult due to an increase in viscosity, and at the same time, there are frequent problems with the two-component epoxy resin. It has been found that if the content is 5% or less, the vibration control effect is not recognized. Accordingly, the content of the inorganic material filler dispersed in the vibration damping member 8b is preferably in the range of 5 to 75%.

  Further, the metal material employed as the sound collection contact members 12a and 12b in the contact microphones 1a and 1b of the first and second embodiments is SUS or aluminum for the following reason.

  In general, the acoustic impedance is determined by the density ρ and the sound velocity c in the material as shown in (Expression 3), and the sound speed c in the material is determined by the density ρ and the bulk modulus k as shown in (Expression 4). .

Z = ρ · c (Formula 3)
c = √ (k / ρ) (Formula 4)
Therefore, from (Equation 3) and (Equation 4), the relationship between the acoustic impedance Z, the density ρ, and the bulk modulus k is derived as follows.

  Z = √ (ρ · k) (Formula 5)

Here, referring to the sound speed c of various metals shown in (Table 2), it can be seen that the sound speed c of iron-based, aluminum-based, and titanium-based metals is relatively larger than other metals. As is clear from (Expression 3), the acoustic impedance Z is proportional to the sound speed c. The acoustic impedance of iron-based, aluminum-based, titanium-based metal, etc. is preferably used because it has a relatively larger value than other metals.

  As described above, when the contact microphone according to the second embodiment is used, noise resistance is further improved, and normal voices and non-audible murmuring voices can be easily picked up clearly in a noisy environment.

[Example 3]
FIG. 4 is a side sectional view of the contact microphone according to the third embodiment of the present invention. FIG. 4A is an overall side cross-sectional view of the contact microphone 1c according to the third embodiment, and FIG. 4B is an enlarged view of the distal end portion of the vibration transmitting member 7a. Since the configuration of the contact microphone 1c of the third embodiment has many parts in common with the above-described first or second embodiment, description thereof will be omitted as much as possible and mainly described above. The difference from the first embodiment will be described below.

  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 transmitting member 7a and the sound collection contact member 12b is substantially the center of the sound collection contact member 12b. Is provided. Of the contact area of the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b, the contact area in the direction parallel to the surface where the sound collection contact member 12b contacts the sound collection object 3 is vibration. It is below the cross-sectional area in the parallel direction in the other part of the transmission member 7a. Furthermore, in the direction parallel to the surface where the sound collection contact member 12b is in contact with the sound collection object 3, the centers of the microphone element 2, the vibration transmission member 7a, and the sound collection contact member 12b are the sound collection contact. It can also be said that the member 12b is on substantially the same axis in the direction perpendicular to the surface in contact with the sound collection object 3.

  With the above-described configuration, the contact microphone 1c according to the third embodiment reflects and suppresses background noise from being mixed due to the noise environment, and can efficiently collect only the vibration of the target sound pickup object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can.

<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 and having a thickness of 1.5 mm. These points are the same as those of the second embodiment described above. However, the sound collection contact member 12b in the second embodiment is directly fitted and bonded by the nesting structure with the cover member 9, whereas the contact microphone 1c in the third embodiment is the following. It has the following structure.

  That is, first, a metal washer 22 is disposed inside the vibration damping member 8 b so as to surround the microphone element 2. Next, the sound collection contact member 12b and the cover member 9 are fitted and bonded by a nested structure with a plastic or metal upper and lower connection tube 23, respectively. Therefore, the sound collection contact member 12 b and the cover member 9 are indirectly joined via the upper and lower connection tube 23.

<Acoustic fiber 19>
Furthermore, a so-called acoustic fiber 19 is disposed between the microphone element 2 inside the vibration damping member 8b and the sound collection contact member 12b. In the acoustic fiber 19, the vibration transmitting member 7a used also in the first and second embodiments is arranged inside an aluminum cylinder 19a. That is, the acoustic fiber 19 is configured by storing the vibration transmitting member 7a in the cylinder 19a, and the cross section of the cylinder 19a is the back of the contact surface with the sound collection target 3 of the sound collection contact member 12b and the microphone element 2. Opposite to the sound collection opening 11, the side surface of the cylinder 19a is in contact with the damping member 8b. The acoustic fiber 19 prevents the vibration of the body conduction sound 4 transmitted from the sound collection contact member 12b to the vibration transmission member 7a from diffusing to a portion other than the vibration film 5 of the microphone element 2. As a result, the in-body conduction sound 4 from the sound collection contact member 12b is efficiently transmitted to the diaphragm of the microphone element 2 with less loss and efficiency. The acoustic fiber 19 also has a role of preventing the vibration of the air conduction sound 10 transmitted as so-called noise from ambient air from being transmitted to the vibration film 5 of the microphone element 2. .

  Furthermore, in addition to the effect of preventing the diffusion of the body conduction sound 4 and the effect of preventing the vibration of the air conduction sound 10 from being transmitted, the acoustic fiber 19 has a microphone as described later with reference to FIGS. There is an effect that the degree of freedom of arrangement of the element 2 can be improved.

  Such an indirect joint structure with the washer 22 arranged around the microphone element 2 and the upper and lower connecting tube 23 is provided at the approximate center of the cover member 9 and the sound collection contact member 12b. This is for arranging the microphone element 2 and the acoustic fiber 19. This is particularly effective in the process for producing the contact microphone 1c of the third embodiment described later.

  Next, an enlarged view of a contact portion between the vibration transmitting member and the sound collection contact member shown in FIG. The vibration transmitting member 7a generally has a hemispherical shape due to the surface tension of the urethane elastomer precursor before curing, and is in contact with the sound collecting contact member 12b through 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 by the excitation force from the air around the contact microphone via the gap 18 slightly present on the contact surface with the sound pickup object 3 (skin) or the surrounding air. A part of the air conduction sound 10 is collected together with the body conduction sound 4 that is originally desired to be collected. As a result, the S / N ratio of the body 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 the diameter of the sound collection opening 11 of the microphone element 2.

  Such a contact-type microphone 1c according to the third embodiment can be manufactured by the following process, for example.

  In FIG. 4 shown above, first, a main agent and a curing agent of a urethane elastomer (for example, a gel stock solution of polyurethane human skin (C-15) manufactured by Exeal Corporation, Inc.) are added through the sound collection opening 11 of the microphone element 2. 1), and a part of the vibration transmitting member 7a is formed by heating at 80 ° C. for 1 hour.

  Next, the upper and lower connection tube 23 is arranged inside the cover member 9, the lead wire 6 of the microphone element 2 is passed through the cover member 9, and the microphone element 2 is installed at a substantially central portion 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 before the vibration damping member 8 b is cured, is filled up to the height of the microphone element 2. Then, an aluminum (metal) washer 22 having a hole corresponding to the diameter of the microphone element 2 is placed on the epoxy resin that is a precursor before the damping member 8b is cured. At this time, the washer 22 is installed so that the microphone element 2 is disposed substantially at the center inside the through hole of the washer 22. At this time, if the outer diameter of the washer 22 is set slightly smaller than the inner diameter of the upper and lower connecting tube 23, the microphone element 2 can be easily installed at the approximate center of the cover member 9. In this state, the resin is cured by heating at 80 ° C. for 1 hour, and a part of the vibration damping member 8b is formed.

  Further, 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 19a is set to substantially match the center of the sound collection opening 11. The aforementioned urethane elastomer is injected into the hollow of the cylinder 19a and heated at 80 ° C. for 1 hour. In this manner, the urethane elastomer previously 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 transmitting member 7a. An acoustic fiber 19 is formed by the vibration transmitting member 7a and the cylinder 19a. Note that the vibration transmitting member 7 a forms a convex hemispherical or semi-elliptical spherical meniscus at the distal end portion of the acoustic fiber 19 by its surface tension.

  Thereafter, the remaining space of the cover member 9 and the upper and lower connecting tube 23 is additionally filled with an appropriate amount of epoxy resin, which is a precursor before the damping member 8b is cured, and is made of aluminum having a thickness of 1.5 mm. When the cup-shaped sound collection contact member 12b is covered and cured at 80 ° C. for 1 hour, the contact microphone 1c of Example 3 is completed.

  Since the sound collection contact member 12b and the cover member 9 of the contact microphone 1c thus completed are substantially concentric cylinders, their centers substantially coincide. 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 collection contact member 12b substantially coincide.

  As described above, the washer 22 helps to arrange the microphone element 2 at substantially the center of the sound collection contact member 12b, and the effect is the same as described in the first embodiment. That is, when the body conduction sound 4 is given to the sound collection contact member 12b, the amplitude due to the physical vibration becomes the largest in the central portion of the sound collection contact member 12b. The path from the central portion of the sound collection contact member 12b where the physical vibration caused by the internal conduction sound 4 is the largest to the vibration film 5 of the microphone element 2 is the same as the vibration film 5 of the microphone element 2. A vibration transmission member 7a made of a plastic material is disposed. Thereby, the physical vibration by the body conduction sound 4 can be efficiently transmitted to the vibration film 5 of the microphone element 2.

  Further, a vibration damping member 8b is disposed around the vibration transmission member 7a. This means that the air conduction sound 10 coming from outside the central portion of the sound collection contact member 12b is blocked by the vibration damping member 8b and hardly reaches the vibration film 5 of the microphone element 2. To do.

  Further, in the case of the third embodiment, the cylinder 19a around the acoustic fiber 19 causes the vibration of the in-body conduction sound 4 transmitted from the sound collection contact member 12b to the vibration transmission member 7a. It is prevented from spreading to other parts. Thereby, the in-body conduction sound 4 from the sound collection contact member 12b is efficiently transmitted to the diaphragm of the microphone element 2 with little loss. The acoustic fiber 19 also has a role of preventing the vibration of the air conduction sound 10 transmitted as so-called noise from ambient air from being transmitted to the vibration film 5 of the microphone element 2. .

  Incidentally, the upper and lower connecting tube 23 helps the acoustic fiber 19 not to fall when the vibration damping member 8b is additionally filled, and prevents the vibration damping member 8b from spilling outside and between the sound collecting contact member 12b. It plays a role of storing an appropriate amount of the damping member 8b so that no space is created in the space.

  The result of evaluating the contact type microphone 1c thus produced by the single syllable 20-word table used in the first embodiment is as follows. That is, the S / N ratio of the contact-type microphone 1c in the third embodiment is 17 dB, and compared with the S / N ratio of 7 dB of the conventional contact-type microphone (see FIG. 1), the S / N ratio under a noise environment. It became clear that there was an improvement. About the following points, the importance is described in detail by the comparative example shown later. First, the first point is that the contact portion between the vibration transmitting 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 vibration transmitting member 7a inside the acoustic fiber 19, that is, the inner diameter of 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. It is preferable. The third point is that no space is provided between the damping member 8b and the sound collecting contact member 12b, and the damping member 8b is in contact with the sound collecting contact member 12b, the upper and lower connecting tubes 23, and the cover member 9. Is fully filled.

  As described above, when the contact microphone according to the third embodiment is used, noise resistance is further improved, and normal voices and non-audible muttering voices can be clearly and easily picked up in a noisy environment.

[Comparative Example 1]
FIG. 5A is a side cross-sectional view of the contact-type microphone in Comparative Example 1 that is in contrast with Example 3 of the present invention.

  Although the configuration and the manufacturing method of the contact microphone 1d in the first comparative example are many in common with the contact microphone 1c in the third embodiment described above, they are different in the following points. One is that the vibration transmitting member 7a is also applied and cured on the entire back side of the sound collecting contact member 12b. As a result, the contact area between the vibration transmitting member 7a and the sound collecting contact member 12b is the microphone element 2. It is outside the range of 0.5 to 5 times the diameter of the sound collection opening 11. The other is that a cavity 21 is formed between the sound collection contact member 12b applied and cured on the entire back side of the sound collection contact member 12b and the vibration damping member 8b.

  The S / N ratio of the contact microphone 1d in the comparative example 1 is 10 dB, and the S / N ratio in a noise environment is much less than the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that there was no improvement. This is because when the vibration transmitting member 7a is applied and cured on the entire back side of the sound collecting contact member 12b, the air conduction sound 10, which is external ambient noise, is transmitted from the periphery of the sound collecting contact member 12b. This is considered to be because the signal is easily transmitted to the microphone element 2 through the member 7a.

  As can be seen from the first comparative example, the vibration transmitting member 7a is accommodated in the inner diameter of the acoustic fiber 19, and is brought into contact with the sound collecting contact member 12b so as not to be excessively large and in contact with the substantially central portion thereof. is necessary. The contact area is preferably at least 0.5 to 5 times the diameter of the sound collection opening 11 of the microphone element 2.

[Comparative Example 2]
FIG. 5B is a side cross-sectional view of the contact type microphone in Comparative Example 2 that is in contrast with Example 3 of the present invention.

  The configuration and method of making the contact-type microphone 1e in Comparative Example 2 are different in the following points, although there are many parts in common with the contact-type microphone 1c in Example 3 described above. One is that the damping member 8b is applied and cured on the entire back side of the sound collecting contact member 12b, and the vibration transmitting member 7a is not in contact with the sound collecting contact member 12b. The other is that a cavity 21 is formed in the vicinity of the sound collection contact member 12b inside the vibration damping member 8b.

  The S / N ratio of the contact microphone 1e in Comparative Example 2 is 5 dB, and the S / N ratio in a noise environment is further increased as compared with the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that it was getting worse. This is because the vibration transmission member 7a is not in contact with the substantially central portion of the sound collection contact member 12b, so that not only the air conduction sound 10 which is noise around the outside, but also the internal conduction sound 4 which is originally desired to be collected. It is thought that absorption loss was caused by the vibration damping member 8b in front.

  As can be seen from Comparative Example 2, the vibration transmitting member 7a needs to be in contact with the sound collecting contact member 12b. The contact is preferably at the approximate center of the sound collection contact member 12b.

[Comparative Example 3]
FIG. 6A is a side cross-sectional view of the contact-type microphone in Comparative Example 3 that is in contrast with Example 3 of the present invention.

  The configuration and method of making the contact microphone 1f in Comparative Example 3 are different in the following points, although there are many parts in common with the contact microphone 1c in Example 3 described above. That is, the vibration transmitting member 7a is in contact with the sound collecting contact member 12b, but a cavity 21 is formed between the vibration damping member 8b and the sound collecting contact member 12b.

  The S / N ratio of the contact microphone 1f in Comparative Example 3 is 12 dB, and the S / N ratio in a noise environment is slightly higher than the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that it was not as good as Example 3. This is because after the air conduction sound 10 that is noise around the outside has entered the inside of the vibration damping member 8b, reflection is repeated at the interface between the vibration damping member 8b and the air in the cavity 21 generated therein. As a result, it is considered that the signal was 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.

  As can be seen from Comparative Example 3, the cavity 21 is not provided between the vibration damping member 8b and the sound collecting contact member 12b, and the vibration suppressing member 8b has the sound collecting contact member 12b, the upper and lower connecting tubes 23, and the cover. It is necessary to be in full contact with the member 9.

[Comparative Example 4]
FIG. 6B is a side cross-sectional view of the contact microphone in the comparative example 4 that is in a comparative relationship with the third embodiment of the present invention.

  The configuration and the manufacturing method of the contact microphone 1g in the comparative example 4 are different in the following points, although there are many parts in common with the contact microphone 1c in the third embodiment described above. That is, the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b in the acoustic fiber 19 does not coincide with the approximate center of the cover member 9 and the sound collection contact member 12b. In the comparative example 4, each of the centers of the microphone element 2 and the acoustic fiber 19 is disposed at a substantially intermediate point of a straight line (radius) connecting the center of the sound collection contact member 12b and the circumference.

  The S / N ratio of the contact microphone 1f in Comparative Example 3 is 9 dB, and the S / N ratio in a noise environment is slightly higher than the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that it was not as good as Example 3. One is that the distance from the contact portion of the vibration transmitting member 7a with the sound collection contact member 12b to one peripheral portion of the sound collection contact member 12b is short, and the air conduction sound 10 which is external ambient noise is generated by the microphone. This is because it is easily transmitted to the element 2. The other is that in the approximate center of the sound collection contact member 12b inside the acoustic fiber 19, the physical vibration of the body conduction sound 4 given to the sound collection contact member 12b is the largest, but this Comparative Example 4 This is because the contact portion between the vibration transmitting member 7a and the sound collecting contact member 12b is not disposed there.

  As can be seen from Comparative Example 4, it is necessary that the microphone element 2 and the acoustic fiber 19 (that is, the center of the vibration transmission member 7a) be arranged at the approximate center of the sound collection contact member 12b.

  As clarified by the above comparative example, the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b needs to be substantially at the center of the sound collection contact member 12b. Moreover, it is preferable that the vibration transmission member 7 a inside the acoustic fiber 19, that is, the inner diameter of the acoustic fiber 19, is at least within a range of 0.5 to 5 times the diameter of the sound collection opening 11 of the microphone element 2. . And, there is no space between the vibration damping member 8b and the sound collection contact member 12b, and the vibration suppression member 8b is in full contact with the sound collection contact member 12b, the upper and lower connecting tubes 23 and the cover member 9. It is necessary to be.

[Modification of Example 3]
As is clear from the previous Example 3 and Comparative Example 4, the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b inside the acoustic fiber 19 is substantially the center of the sound collection contact member 12b. It is necessary to be in However, it is not necessary to arrange the center of the acoustic fiber 19 and the center of the microphone element 2 so as to substantially coincide with the center of the sound collection contact member 12b. An example is described below.

  FIG. 7 is a side sectional view of an application example of a contact microphone using an acoustic fiber according to the third embodiment of the present invention.

  The acoustic fiber 19b of the contact microphone 1k shown in FIG. 7 confines the vibration transmitted to the sound collection contact member 12c to the microphone element 2 by repeating the reflection by the inner wall of the foldable cylinder 19c. It has a function to communicate. Therefore, as shown in FIG. 7, when the curved free-form cylinder 19 c is used, the center of the microphone element 2 can be arranged other than directly below the center of the sound collection contact member 12 c. At this time, if the center of the portion where the vibration transmission member 7a disposed inside the acoustic fiber 19b is in contact with the sound collection contact member 12c is substantially coincident with the center of the sound collection contact member 12c. Good. This is because the physical vibration of the body conduction sound 4 applied to the center of the sound collection contact member 12c is the largest. In this way, the degree of freedom in design can be increased with respect to the shape of the contact microphone 1k.

  For the same reason, as shown in FIG. 6B described in the comparative example 4, the contact portion between the vibration transmission member 7a and the sound collection contact member 12b is not substantially at the center of the sound collection contact member 12b ( Even when the arrangement is not possible due to structural constraints, the acoustic fiber 19a shown in FIG. 6B is folded to the center position of the microphone element 2 shown in FIG. The above constraints can be avoided.

  As described above, the acoustic fiber 19b has the function of confining the vibration transmitted to the sound collection contact member 12c in its internal space and transmitting the vibration to the microphone element 2, so that the vibration of the in-body conduction sound 4 is the vibration of the microphone element 2. It is possible to prevent the vibration of the air conduction sound 10 transmitted to the vibration damping member 8b as noise from being transmitted to the vibration film 5 of the microphone element 2 while preventing diffusion to a portion other than the film 5. 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.

[Example 4]
FIG. 8 is a side sectional view of a contact microphone according to Embodiment 4 of the present invention. FIG. 8A is an overall side sectional view of the contact microphone 1j, and FIG. 8B is an enlarged view of the tip of the vibration transmitting member 7a. Since the configuration of the contact microphone 1j according to the fourth embodiment has many parts in common with the third embodiment described above, description thereof will be omitted as much as possible, and mainly the third embodiment described above. Different parts will be described below. Although the washer 22 arranged in the third embodiment is omitted in the fourth embodiment, the washer 22 may of course be arranged similarly to the third embodiment.

  First, also in the contact microphone 1j of the fourth embodiment, the contact portion between the vibration transmitting member 7a and the sound collecting contact member 12b is substantially the center of the sound collecting contact member 12b as in the first to third embodiments. Is provided. Of the contact area of the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b, the contact area in the direction parallel to the surface where the sound collection contact member 12b contacts the sound collection object 3 is vibration. It is below the cross-sectional area in the parallel direction in the other part of the transmission member 7a. Furthermore, in the direction parallel to the surface where the sound collection contact member 12b is in contact with the sound collection object 3, the centers of the microphone element 2, the vibration transmission member 7a, and the sound collection contact member 12b are the sound collection contact. It can also be said that the member 12b is on substantially the same axis in the direction perpendicular to the surface in contact with the sound collection object 3. In addition, the acoustic fiber 19 is configured by storing the vibration transmitting member 7a in the cylinder 19a. The cross section of the cylinder 19a is the back of the contact surface of the sound collection contact member 12b with the sound collection target 3 and the microphone element. The side surface of the cylinder 19a is in contact with the vibration damping member 8b.

  With the above configuration, the contact microphone 1j according to the fourth embodiment reflects and suppresses the background noise from being mixed due to the noise environment, and can efficiently collect only the vibration of the target sound collecting object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can.

  In the contact-type microphone 1j of the fourth embodiment, a characteristic part that does not exist in the third embodiment is that the acoustic fiber 19 is included in the vibration transmitting member 7a at the tip portion where the acoustic fiber 19 contacts the sound collection contact member 12b. This is a bonded plastic ball 20. That is, a member having a hardness higher than that of the vibration transmission member 7a is provided on the contact surface side of the vibration transmission member 7a with the sound collection contact member 12b. As this plastic ball | bowl 20, the thing made from Sato Iron Works, for example is used. In addition, any of urethane rubber, polyacetal, polyamide 66, Teflon (registered trademark), ABS, styrene, acrylic, silicon resin, and the like may be used. In the fourth embodiment, urethane rubber (with a hardness of 80 °) is used from the viewpoint of reliability (lubricity and reliability) that the adhesive force is good with the urethane elastomer employed as the vibration transmitting member 7a and is used by repeatedly vibrating. And a hardness of 95 °) are preferably used as the plastic sphere 20. This urethane rubber has a higher hardness than the vibration transmission member 7a.

  Further, as such a plastic sphere 20, those 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 vibration film 5 of the microphone element 2 are generally used. It is done.

  Such a plastic ball 20 having a hardness higher than that of the vibration transmission member 7a is encapsulated and bonded to the vibration transmission member 7a at the tip portion where the acoustic fiber 19 contacts the sound collection contact member 12b, thereby collecting the sound. Point contact with the substantially central portion of the contact member 12b is possible. As a result, the vibration transmitted from the sound collection target 3 (skin etc.) to the entire sound collection contact member 12b is concentrated at one point. At the same time, air conduction sound (noise) 10 transmitted from the peripheral portion of the sound collection contact member 12b through the air in the gap 18 with the sound collection target 3 generated when the contact type microphone 1j is attached. However, it becomes easy to be cut. That is, for the air conduction sound 10, the distance to the center of the sound collection contact member 12 b to which it is transmitted as solid vibration (point contact) is farther than the body conduction sound 4 that is originally desired to collect sound. . Then, on the way to the central portion (point contact) of the sound collection contact member 12b, the vibration damping member 8b located in the lower layer of the sound collection contact member 12b absorbs a part of the air conduction sound 10. Therefore, the effect of improving the S / N ratio is increased.

  The results of evaluating the contact microphone 1j thus produced using the single syllable 20-word table as in the first embodiment are as follows. That is, the S / N ratio of the contact microphone in the fourth embodiment is 28 dB, and the S / N ratio under a noise environment is 7 dB compared to the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that it was greatly improved. Compared with the previous Example 3, the S / N ratio is further improved.

  The sentence intelligibility under 100 dB noise using the contact microphone 1j in Example 4 was 85%.

  As described above, when the contact microphone according to the fourth embodiment is used, noise resistance is further improved, and normal voices and non-audible murmuring voices can be easily picked up clearly in a noisy environment.

[Comparative Example 5]
FIG. 9 is a side cross-sectional view of a contact type microphone in Comparative Example 5 that is in contrast with Example 4 of the present invention.

  The configuration and the manufacturing method of the contact microphone 1h in the comparative example 5 are different in the following points, although there are many parts in common with the contact microphone 1j in the fourth embodiment described above. That is, in place of the vibration damping member 8b (two-component elastic epoxy resin containing 50 wt% of silica) in the previous Example 4, the vibration damping member constituted by the elastic epoxy resin alone used in the previous Example 1 8a.

  The S / N ratio of the contact microphone 1d in Comparative Example 5 is 20 dB, which is comparable to the previous Examples 1 and 2. However, when compared with Example 4, the performance difference is more than doubled. I found out. This is due to the difference in the material of the vibration damping member employed. This difference in material results in a loss coefficient that is reflected in the denominator term indicating noise in the S / N ratio equation shown in Equation 5 above.

  In addition, the elastic epoxy resin is combined with silica to increase the elastic modulus and weight, and the resonance frequency changes in a direction in which the resonance frequency greatly deviates from the vibration 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 collection target object 3, and the rate at which the solid vibration from the sound collection target object 3 is converted into the vibration of the vibration film 5 is relatively increased. This plays a role in increasing the numerator term indicating the signal to be collected in the S / N ratio equation shown in (Equation 5).

  From the above, as the vibration damping member to be employed, the vibration damping member 8b made of the composite material of the elastic epoxy resin and silica employed in Example 4 is higher in sound collection than the elastic epoxy resin employed in Comparative Example 5. It turns out that performance can be obtained.

[Example 5]
FIG. 10 is an exploded perspective view of the contact microphone according to the fifth embodiment, and FIG. 11 is a side sectional view of the contact microphone according to the fifth embodiment. FIG. 11A is an overall side sectional view of the contact microphone 1k according to the fifth embodiment, and FIG. 11B is an enlarged view of the distal end portion of the vibration transmitting member 7b. The configuration of the contact microphone 1k according to the fifth embodiment has many parts in common with the above-described second embodiment. Therefore, the description thereof is omitted as much as possible, and mainly the second embodiment described above. Different parts will be described below.

  First, also in the contact type microphone 1k of the fifth embodiment, the contact portion between the vibration transmitting member 7b and the sound collecting contact member 12d is substantially the center of the sound collecting contact member 12d, as in the first to fourth embodiments. Is provided. Of the contact area of the contact portion between the vibration transmitting 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 object 3 is vibration. It is below the cross-sectional area in the parallel direction in the other part of the transmission member 7b. Furthermore, in the direction parallel to the surface where the sound collection contact member 12d is in contact with the sound collection object 3, the centers of the microphone element 2, the vibration transmission member 7b, and the sound collection contact member 12d are the sound collection contact. It can also be said that the member 12d is on substantially the same axis in the direction perpendicular to the surface in contact with the sound pickup object 3. In addition, the acoustic fiber 19d is configured by storing the vibration transmitting member 7b in the cylinder 19e, and the cross section of the cylinder 19e is the back surface of the contact surface of the sound collection contact member 12d with the sound collection target 3 and the microphone element. 2, the side surface of the cylinder 19e is in contact with the vibration damping member 8b.

  With the configuration described above, the contact microphone 1k according to the fifth embodiment can reflect and suppress the background noise in the surroundings due to the noise environment, and can efficiently collect only the vibration of the target sound collecting object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can.

  The washer 22 arranged in the fifth embodiment is not arranged in the previous second embodiment. However, as described above, the washer 22 is arranged at substantially the center of the sound collection contact member 12d. This is not a big difference. Of course, the washer 22 may also be arranged in the fifth embodiment.

  Also, the acoustic fiber 19d of the fifth embodiment is not arranged in the previous second embodiment, and is similar to that which appeared in the previous third and fourth embodiments. The acoustic fiber 19d according to the fifth embodiment is one in which a cavity 19e is filled with a vibration transmitting member 7b (described later), and the length and the composition of the inner vibration transmitting member 7b are the same as those of the third embodiment. This is different from that of Example 4. However, it has a function to prevent the vibration of the body conduction sound 4 transmitted from the sound collection contact member 12d to the vibration transmission member 7b from diffusing to parts other than the vibration film 5 of the microphone element 2. The function is the same as in the third and fourth embodiments. Further, the vibration of the air conduction sound 10 transmitted from the surrounding air to the vibration damping member 8 b as so-called noise is also prevented from being transmitted to the vibration film 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.

  The damping member 8b of the fifth embodiment is a composite material of an elastic epoxy resin (not shown) and silica 27, and the sound collection contact member 12d has a cap shape made of aluminum and having a thickness of 1.5 mm. These points are the same as those in the second embodiment. However, a reverse-tapered perforation 24 (concave portion) is provided at the center of the back surface of the sound collecting contact member 12d of Example 5 that contacts the vibration damping member 8b and the vibration transmitting member 7b. It is formed to such an extent that it does not penetrate (in the case of Example 5, a 6.6 mmφ drill was used to form the hole 24 so that the hole diameter was 5 mm). That is, among the portions where the sound collection contact member 12d has a contact surface with the sound collection target 3, the thickness at the center is thinner than the periphery. And the vibration transmission member 7b is inject | poured into the reverse taper-shaped perforation 24. FIG.

  The diameter of the perforations 24 controls the distance from the outer periphery of the contact microphone 1k that is considered to transmit the air conduction sound 10 and also controls the area that receives the vertical vibration caused by the body conduction sound 4. The depth of the perforations 24 naturally determines the remaining thickness (for example, 0.5 mm) of the sound collection contact member 12d, and affects the followability of the sound collection target 3 to solid vibration. By adopting such a structure, the solid vibration from the sound collection target 3 (skin etc.) is reduced in the approximate center of the sound collection contact member 12d where the thickness is reduced by an area corresponding to the hole diameter of the perforations 24. Enables highly sensitive sound collection. At the same time, the air conduction sound 10 (noise) is transmitted from the peripheral portion of the sound collection contact member 12d through the ambient air or the air in the gap 18 with the sound collection target 3 generated when the contact type microphone 1k is attached. Even if it is done, since the distance to the substantially central portion of the sound collecting contact member 12d, which is transmitted as solid vibration, is far, it is effective in improving the S / N ratio.

  In addition, as the vibration transmission member 7b employed in the fifth embodiment, an inorganic filler (silica 27 in the fifth embodiment) is combined with the urethane elastomer used in the first to third embodiments to obtain a volume elasticity. What inclined the rate was used. For example, the slope of the volume modulus of elasticity is obtained by using a natural sedimentation method based on the difference in specific gravity of these components before curing, so that a large amount of inorganic filler (silica 27) exists on the sound collection contact member 12d side, and the microphone element 2 This is possible if there is a small amount on the vibrating membrane 5 side. In this way, the volume elastic modulus of the vibration transmitting member 7b is set to the sound collection contact member 12d or the vibration on each of the contact surface with the sound collection contact member 12d and the contact surface with the vibration film 5 of the microphone element 2. It can be close to the membrane 5. In this way, acoustic impedance matching is achieved at each contact surface, and the reflection attenuation of vibration due to the body conduction sound 4 is reduced.

  Next, the sound collection contact member 12d will be described.

  FIG. 17 is a perspective view illustrating the structure of the sound collection contact member 12d.

<Dimple>
As shown in FIG. 17, the sound collection contact member 12d has a bottomed cylindrical cap shape that is nested with a cylindrical cover member 9 (see FIG. 11). The sound collection contact member 12d includes dimples that are concave portions at the inner center of the contact portion, that is, substantially at the center of the bottom surface of the bottomed cylindrical shape. This dimple is a reverse-tapered perforation 24 (concave portion) formed by a drill as described above. The dimple has a shape that expands toward the opening side 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 on the side (upper side) in contact with the sound collection target object 3 is thin in a dotted shape, and the opening side (lower side) of the cover member 9 is wide open. In the fifth embodiment, the dimple is a reverse taper-shaped perforation 24, but the center on the side in contact with the sound pickup object 3 (directly above the vibration film 5) is thin and the opening side of the cover member 9 is wide. As long as the dimple has any shape, for example, a curved concave portion may be used. If the dimple shape is formed in a curved concave portion, the area between the sound collection contact member 12d and the opening is slightly increased, but the volume of the vibration transmitting member 7b injected therein is also increased. Can do.

  As described above, the sound collection contact member 12d is provided with dimples at the center inside the contact portion of the sound collection contact member 12d, so that the air conduction sound 10 (noise) is solid vibration and the outer periphery of the contact microphone 1k. The distance transmitted from the center to the central portion of the sound collection contact member 12d is increased (that is, the distance to the area through which sound passes) is increased, while the area that receives the vertical vibration due to the body conduction sound 4 is decreased. Thus, sound collection from the sound collection object 3 is ensured satisfactorily. As a result, since the portion other than the central portion of the contact portion of the sound collection contact member 12d is thick, there is an effect of reducing noise mixed from around the speaker wearing the contact microphone 1k. Thus, providing the dimples has an effect of improving the S / N ratio and improving the sound collecting performance of the conversational voice of the speaker wearing the contact microphone 1k.

<Attaching the ground wire>
FIG. 18 is a cross-sectional side view of the contact microphone 1k according to the fifth embodiment when the ground wire is attached. The same components as those in FIG. 11A are denoted by the same reference numerals, and description of overlapping portions is omitted.

  As shown in FIGS. 17 and 18, the contact microphone 1 k is provided with a through hole 31 at the corner of the cap-shaped inner wall of the sound collection contact member 12 d, and a ground wire 32 is passed through the through hole 31.

  One end portion of the ground wire 32 communicates from the outside of the sound collection contact member 12d to the inside through the through hole 31, and the end portion is a ring along the corner of the inner wall of the sound collection contact member 12d. (See FIG. 17), and a conductive adhesive (not shown) is applied and fixed. The other end of the ground wire 32 is connected to the negative wire of the conducting wire 6 of the microphone element 2.

  In this way, by attaching the ground wire 32 to the sound collection contact member 12d (here, the inside of the sound collection contact member 12d) that contacts the sound collection target 3 (skin etc.), a hum sound generated at the time of wearing the skin. Can be reduced. In addition, it is possible to reduce high-frequency noise generated from digital equipment existing in the vicinity.

  Even if the ground wire 32 is attached not to the sound collection contact member 12d but to a cover member (not shown) for storing the microphone element 2, there is some effect. However, it is more effective if it is attached to the sound collecting contact member 12d that is in direct contact with the speaker's skin.

  In addition, by arranging one end or more of the ground wire 32 in a ring shape and fixing it, even if the ground wire 32 may be pulled, the strength that can resist the pulling force can be ensured. . When the contact type microphone 1k is assembled, the vibration damping member is further filled from above, so that the strength is further increased.

  Such a contact microphone 1k according to the fifth embodiment can be manufactured by the following process, for example.

  12-16 is a figure which shows the example of the manufacturing method of the contact type microphone 1k in Example 5 of this invention.

  First, as shown in FIG. 12A, a perforation 24 (a hole that does not pass through) is formed in the center of the back side of the sound collection contact member 12d by a lathe drill 26 or the like. Next, as shown in FIG. 12 (b), the metal cylinder 19e is bonded to the center of the back side of the sound collecting contact member 12d using the damping member 8b, and cured at 80 ° C. for 1 hour. At this time, the metal cylinder 19e is arranged so that the end cross section of the metal cylinder 19e surrounds the outline of the perforation 24. And as shown in FIG.12 (c), the vibration transmission member 7b which compounded the inorganic filler in the urethane elastomer is inject | poured inside the cavity of the cylinder 19e. This vibration transmission member 7b in which an inorganic filler is combined with a urethane elastomer is preliminarily applied to, for example, a urethane elastomer (for example, a main ingredient and a curing agent of a gel stock solution of polyurethane human skin (C-15) manufactured by Exeal Corporation). A silica filler (particle diameter: several tens to several hundreds μ) surface-treated with γ-aminopropyltrialkoxysilane or glycidoxypropyltrialkoxysilane was dispersed at 20 wt%.

  Further, as shown in FIG. 13A, the vibration transmitting member 7b is left at room temperature for 5 hours, and then cured at 80 ° C. for 1 hour. By such a leaving treatment, as shown in FIG. 13B, the filler (silica 27) contained in the vibration transmitting member 7b naturally settles due to the difference in specific gravity with the urethane elastomer. An acoustic fiber 19d is formed in which a large amount of silica filler is present on the sound collection contact member 12d side and a small amount is present on the vibration film 5 side of the microphone element 2. In other words, the volume elastic modulus of the vibration transmitting member 7b is inclined, and the volume elastic modulus of the vibration transmitting member 7b is set on each of the contact surface with the sound collection contact member 12d and the contact surface with the vibration film 5 of the microphone element 2. The sound collecting contact member 12d or the vibrating membrane 5 can be used. In this way, acoustic impedance matching is achieved at each contact surface, and the reflection attenuation of vibration due to the body conduction sound 4 is reduced. Thereafter, as shown in FIG. 13C, the vibration damping member 8b before curing is filled in the peripheral portion of the acoustic fiber 19d.

  On the other hand, as shown in FIG. 14A, the microphone element 2 connected to the conductive wire 6 is disposed at a substantially central portion of the cover member 9. At this time, the lead wire 6 of the microphone element 2 is passed through a through hole (not shown) provided in the cover member 9 and is taken out of the cover member 9.

  Next, in this state, a two-component elastic epoxy resin containing, for example, 50 wt% of silica, which is a precursor before the vibration damping member 8 b is cured, is filled up to the height of the microphone element 2. Then, as shown in FIG. 14 (b), a washer 22 having a hole in accordance with the diameter of the microphone element 2 is placed on the epoxy resin that is a precursor before the damping member 8 b is cured. At this time, the washer 22 is installed so that the microphone element 2 is disposed substantially at the center inside the through hole of the washer 22. In this state, the resin is cured by heating at 80 ° C. for 1 hour, and a part of the vibration damping member 8b is formed.

  Furthermore, as shown in FIG. 14 (c), the main component and the curing agent of urethane elastomer (for example, a gel stock solution of polyurethane human skin (C-15) manufactured by EXCIAL Corporation) from the sound collection opening 11 of the microphone element 2. 7c) is injected and heated and cured at 80 ° C. for 1 hour. This urethane elastomer 7c is equivalent to the one in which the inorganic filler is not combined in the process of producing the vibration transmitting member 7b.

  As shown in FIG. 15, the sound collecting contact member 12d (see FIGS. 12 and 13) and the cover member 9 (see FIG. 14), which have finished the respective operations as described above, are fitted together. At this time, as shown in FIG. 16A, the surplus of the epoxy resin, which is a precursor before the vibration damping member 8b is cured, is discharged from the discharge hole 25 provided in the sound collecting contact member 12d in advance. . By doing so, a necessary and sufficient damping member 8b is filled without causing a cavity in the damping member 8b or the like. Thereafter, as shown in FIG. 16 (b), the contact microphone 1k according to the fifth embodiment is completed by heating and curing at 80 ° C. for 1 hour with a weight 31 of about 400 g placed thereon.

  At this time, the urethane elastomer 7c filled on the vibrating membrane 5 side inside the microphone element 2 is originally the same as that in which the inorganic filler is not combined in the process of manufacturing the previous vibration transmitting member 7b. Therefore, the urethane elastomer 7c is integrated with the vibration transmission member 7b filled in the cylinder 19e of the acoustic fiber 19d. As a result, the integrated one is also the vibration transmission member 7b. Then, an acoustic fiber 19d is formed in which a large amount of silica filler is present on the sound collection contact member 12d side and hardly exists on the vibration film 5 side of the microphone element 2. In other words, the volume elastic modulus of the vibration transmitting member 7b is inclined, and the volume elastic modulus of the vibration transmitting member 7b is set on each of the contact surface with the sound collection contact member 12d and the contact surface with the vibration film 5 of the microphone element 2. The sound collecting contact member 12d or the vibrating membrane 5 can be used. In this way, acoustic impedance matching is achieved at each contact surface, and the reflection attenuation of vibration due to the body conduction sound 4 is reduced.

  The results of evaluating the contact microphone 1k thus produced using the single syllable 20-word table as in Example 1 are as follows. In other words, the S / N ratio of the contact microphone 1c in the third embodiment is 28.5 dB, which is higher than the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that the N ratio was greatly improved. Further, a part of the vibration transmitting member 7b is structured so as to enter the substantially central portion of the sound collecting contact member 12d, which contributes to a reduction in the height and size of the contact microphone 1k itself.

  As described above, when the contact microphone according to the fifth embodiment is used, the noise resistance is further improved, and normal voices and non-audible muttering voices can be easily picked up clearly in a noisy environment.

[Example 6]
FIG. 19 is a side sectional view of a contact microphone according to Embodiment 6 of the present invention. FIG. 19A is an overall side sectional view of the contact microphone 1m according to the sixth embodiment, and FIG. 19B is a perspective view of the contact microphone 1m according to the sixth embodiment as viewed from above. Since the configuration of the contact microphone 1c of the third embodiment has many parts in common with the above-described first or second embodiment, description thereof will be omitted as much as possible and mainly described above. The difference from the first embodiment will be described below.

  First, also in the contact type microphone 1m of the sixth embodiment, the sound collection contact in the contact area of the contact portion between the vibration transmitting member 7a and the sound collection contact member 12b is the same as in the first to fourth embodiments. The contact area in the direction parallel to the surface where the member 12b contacts the sound collection object 3 is equal to or less than the cross-sectional area in the parallel direction at the other part of the vibration transmitting member 7a. In addition, the acoustic fiber 19 is configured by storing the vibration transmitting member 7a in the cylinder 19a. The cross section of the cylinder 19a is the back of the contact surface of the sound collection contact member 12b with the sound collection target 3 and the microphone element. 2, the side surface of the cylinder 19e is in contact with the vibration damping member 8b.

  With the above configuration, the contact microphone 1m according to the sixth embodiment reflects and suppresses surrounding background noise due to the noise environment, and can efficiently collect only the vibration of the target sound collecting object. it can. As a result, noise resistance is further improved, and not only normal speech but also non-audible speech and sound such as speaker's murmur can be clearly and easily collected from the sound collection target such as skin. it can.

  The contact 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 transmission 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 enlargement of the molecular term of (Formula 5).

  Note that the central axes of the microphone element 2 and the vibration transmitting 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 object 3, and are described above. It is desirable that the virtual barycentric point obtained from each center of the plurality of combinations substantially coincides with the center of the sound collection contact member 12b. Incidentally, when the number of the microphone elements 2 increases, the wiring of the conducting wire 6 that they have is hindered. For example, at least two microphone elements 2 may be electrically connected in series.

  The result of evaluation of the contact microphone 1m thus produced using the single syllable 20-word table as in the first embodiment is as follows. The S / N ratio of the contact microphone 1c in the third embodiment is 25 dB, and the S / N ratio under a noise environment is still higher than the S / N ratio of 7 dB of the conventional contact microphone (see FIG. 1). It became clear that it was improving. That is, increasing the number of microphone elements 2 contributes to improving the S / N ratio of the contact microphone.

  As described above, when the contact microphone according to the sixth embodiment is used, noise resistance is further improved, and normal voices and non-audible murmuring voices can be easily picked up clearly in a noisy environment.

  In addition, the Example of this invention is not restricted to said Example 1- Example 6, What combined these each part can also be considered.

[Example 7]
Next, the material of the sound collection contact members 12a, 12b, 12c, 12d and the cover member 9 will be described.

<Sound collecting contact member and cover member are the same material>
As described in the first embodiment, the sound collection contact member 12a is a material whose acoustic impedance is far from air, and is, for example, SUS304 having 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 a resin injection mold at the time of manufacture, and is a metal such as aluminum or a zinc alloy for die casting, or a plastic such as acrylic or ABS. .

  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 and aluminum-based materials such as SUS304, titanium-based metals, and zinc alloys for die casting.

  By using the same material for the sound collection contact members 12a, 12b, 12c, 12d and the cover member 9, the characteristics (thermal expansion coefficient, resonance characteristics, etc.) in the material system are uniform, which is advantageous in design. Reduction of parts costs and simplification of assembly process can be expected.

<Sound collecting contact member and cover member are different materials>
The sound collecting contact members 12a, 12b, 12c, and 12d and the cover member 9 can be made of an optimum material in accordance with their functions.

  As described above, the sound collection contact members 12a, 12b, 12c, and 12d are preferably made of metal materials. Among them, iron, aluminum, titanium-based metals, and die castings are used as metals that are far away from acoustic impedance. A zinc alloy or the like is preferable. On the other hand, the cover member 9 is not limited as long as the mechanical strength 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 the use of different materials in this way has an effect of further enhancing the respective functions. 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, it does not adhere as it is, and an adhesive is required. This inventor examined the adhesive agent and confirmed that the following elastic adhesive agents were suitable.

  20 to 23 are diagrams illustrating an adhesive that bonds the sound collection contact member and the cover member.

  FIG. 20 is a diagram showing torsion free damping viscoelasticity measurement data.

  As shown in FIG. 20, the glass transition temperature (Tg) of the elastic adhesive is −60 ° C. Further, the cured film of the 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 provides good results for various adhesive properties.

From the above, the cured adhesive is preferably a rubber-like elastic body. Specifically, for the following reasons.
-Absorbs stress such as external vibration and shock.
-Because it absorbs thermal strain such as expansion and contraction, it is resistant to heat cycles.
・ Stress is hard to concentrate on the bonding interface.
・ Suitable for bonding dissimilar materials with large differences in linear expansion coefficient.
-Suitable for bonding to substrates with weak surface strength (gypsum board, calcium silicate board, ALC (autoclaved lightweight aerated concrete, etc.)).
・ Shows high peel adhesion strength.

  FIG. 21 is a diagram showing, as a circular characteristic chart, test conditions for an elastic adhesive, a two-component mixed epoxy adhesive, and a rubber solvent adhesive.

  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 exhibiting stable adhesiveness.

  FIG. 22 is a diagram showing adhesion to a plastic material. 22A shows the tensile shear bond strength of the general-purpose plastic, and FIG. 22B shows the tensile shear bond strength of the engineering plastic.

  Epoxy / modified silicone resin-based elastic adhesives, PM165 and PM200, and two-component elastic adhesives PM210 and EP001 exhibit good adhesion to plastic materials. In particular, as shown in FIG. 22 (b), EP001 can bond an engineering plastic material that has been difficult to bond.

  FIG. 23 is a diagram comparing the characteristics of the two-component elastic adhesives PM210 and EP001.

As shown in FIG. 23, EP001 shows good adhesion to engineering plastic materials. Specifically, EP001 has the following advantages.
・ Adhesion of materials that are easily broken by impact and vibration, and other external forces Large tiles, wall glass, mirrors, thin stones, etc. ・ Adhesion of materials with low surface strength Gypsum board, calcium silicate board, ALC, etc. Adhesion of materials Combination of plastic and metal and ceramic boards etc. ・ Manufacture of interior and exterior, large panels ・ Filling adhesion to uneven base and surface materials ・ Adhesion of places with significant temperature changes Kitchen (top, wall surface), bathroom, etc. In particular, the two-component elastic adhesive EP001 is excellent in adhesion of materials having different coefficients of thermal expansion, and filling adhesion to uneven bases and surface materials.

  From the above, when different materials are used for the sound collecting contact members 12a, 12b, 12c, 12d and the cover member 9, it is preferable to use an elastic adhesive to improve the adhesion, The shape elastic adhesive EP001 is suitable.

  As described in detail above, according to the present embodiment, the contact microphone 1k according to the fifth embodiment includes the microphone element 2 having the vibration film 5, the vibration transmission member 7b for storing the microphone element 2, and the vibration. A vibration damping member 8b for storing the transmission member 7b, a cover member 9 having the sound collection opening 11 for storing the microphone element 2, the vibration transmission member 7b and the vibration suppression member 8b, and a sound collection opening 11 for the cover member 9. And a cap-shaped sound collection contact member 12d disposed so as to cover the cover. The sound collection contact member 12d is formed with a perforation (concave portion) 24 having a thin thickness immediately above the vibration film 5 and a wide shape on the sound collection opening 11 side of the cover member 9 at a position facing the vibration film 5. Yes.

  With this configuration, the distance that 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 collection contact member 12d is increased, and the vertical direction due to the body conduction sound 4 is increased. The area subjected to vibration can be reduced to ensure good sound collection from the sound collection object 3. Further, since the portion other than the central portion of the contact portion of the sound collection contact member 12d is thick, there is an effect of reducing noise mixed from the periphery of the speaker wearing the contact microphone 1k. As a result, the S / N ratio can be improved by increasing the distance of the area through which the sound passes, and the sound collecting performance of the conversation voice of the speaker wearing the contact microphone 1k can be improved.

(Embodiment 2)
In the first embodiment, the contact microphones 1a to 1h and 1j to 1m have been described.

  In the second embodiment, a transmission / reception apparatus including contact microphones 1a to 1h and 1j to 1m will be described.

  FIG. 24 is a perspective view showing a transmitting / receiving device on which the contact microphone according to Embodiment 2 of the present invention is mounted. FIG. 25 is a side view of the transmitter / receiver mounted on the head. FIG. 26 is a diagram illustrating the arrangement of the contact microphones in the transmission / reception device.

  This embodiment is an example in which the transmission / reception apparatus of the present invention is applied to headphones in which a speaker unit and a microphone are arranged close to each other.

  As shown in FIGS. 24 and 25, the headphone 100 is a sealed headphone worn on the head so as to cover the ear shell through a headband.

  The headphone 100 mainly includes a left ear covering headphone 110, a right ear covering headphone 120, and a curved headband 130 that connects the left ear covering headphone 110 and the right ear covering headphone 120 to the left and right.

  The headband 130 comes into contact with the heads on both sides via the top of the user's head.

  In the left ear covering headphone 110 and the right ear covering headphone 120, each member is arranged symmetrically in the head.

  The left ear covering headphone 110 is attached to a circular baffle plate 111 as an overall support substrate, an outer peripheral portion on the front surface side of the baffle plate 111, and is supported on an outer pad portion on the back side of the baffle plate 111 and an ear pad 112 covering the ear shell. And a housing 114 fixed through a ring 113. Although not shown, a speaker unit is fixed to the central portion on the back side of the baffle plate 111. The baffle plate 111 has a large number of holes as sound holes in the center.

  The ear pad 112 is formed in a ring shape large enough to surround the ear shell.

  The support ring 113 and the housing 114 cover the back side of the baffle plate 111 and the speaker unit (not shown).

  The housing 114 is larger than the ear shell, the ear pad 112 is in close contact with the temporal region around the ear shell, and the ear shell is completely covered by the ear pad 112 and the speaker unit. This sealed type has a good wearing feeling and can prevent sound leakage to the outside. In addition, bass can be reproduced richly.

  In the present embodiment, the headphone 100 is characterized in that a microphone can be disposed in the vicinity of the speaker unit.

  24 and 25, the left ear covering headphone 110 is characterized in that, in addition to the configuration of the above general sealed headphone, the contact microphone 1a is disposed in the vicinity of the speaker unit. Further, the transmission / reception apparatus of the present invention is characterized in that the contact microphone 1a according to the first embodiment is arranged as follows.

  In this embodiment, the contact microphone 1a is mounted on the left ear covering headphone 110, but may be mounted on the right ear covering headphone 120. It is sufficient that the contact microphone 1 a is disposed on one side of the headphones 100. However, it may be attached to both.

  As shown in FIGS. 24 and 25, the headphone 100 has a central part of the sealed headphone, that is, a central part of the circular baffle plate 111, and the baffle plate 111 is connected to the first reference axis in the longitudinal direction of the headband 130 and the first reference axis. Dividing into four parts by a second reference axis orthogonal to one reference axis, and among the parts divided into four parts, the part that is separated from the headband 130 and is in contact with the frontal side of the user from the receiving means The contact microphone 1a is disposed. That is, as shown in FIGS. 24 and 25, when the contact microphone 1a is represented by regions I to IV, respectively, the region divided by four is below the frontal portion of the user's frontal region among the four divided regions I to IV. The contact type microphone 1a is arranged in the area III. Further, when the user wears the contact-type microphone 1a on the head in the four-divided portion (region III in FIGS. 24 and 25) that contacts the frontal side, the user's chin root or It is arranged at a position that makes the best contact with the cheekbone (hereinafter referred to as the vicinity of the cheekbone) (see the circle in FIG. 26). According to the experiment of the present inventor and the like, when the contact microphone 1a is mounted on the headphones 100, it has been confirmed that the detection accuracy is improved when the contact microphone 1a is disposed near the cheekbone. However, the contact-type microphone 1a is not limited to the vicinity of the cheekbones, and may be disposed at a site (region III in FIGS. 24 and 25) that abuts on the frontal head divided into four parts. Further, since the contact microphone 1a has an excellent S / N ratio, the contact microphone 1a is disposed in, for example, a part (region IV in FIGS. 1 and 2) that is out of the part (region III in FIGS. 24 and 25). It is also possible.

  In this way, the contact microphone 1a is arranged at a position where the general user best contacts the vicinity of the user's cheekbone when the headphone 100 is normally used. In other words, the arrangement position in contact with the vicinity of the user's cheekbone is a region III below the user's forehead.

  In addition, although the said transmission / reception apparatus demonstrated in the example provided with the contact-type microphone 1a, you may apply the contact-type microphones 1b-1h and 1j-1m.

  As described above in detail, according to this embodiment, the present invention is applied to the headphone 100 (see FIGS. 24 and 25) as a transmission / reception device on which the contact microphones 1a to 1h and 1j to 1m are mounted. The headphone 100 includes contact microphones 1a to 1h and 1j to 1m close to the speaker unit. Specifically, the contact microphones 1a to 1h and 1j to 1m are divided into four parts by a first reference axis in the longitudinal direction of the headband 130 and a second reference axis orthogonal to the first reference axis, and the four parts are divided. Among these, the headband 130 is disposed on the side farther from the headband 130 and in contact with the frontal side of the user than the receiving means.

  Thereby, the sound wave from the receiving means is output to the same side as the temporal contact portion. Since the sound waves from the receiving means directly enter the ear, they can be heard as usual, and with the above-mentioned transmitting means, the sound waves picked up from the receiving means are smaller than the user's utterance, so that the other party does not cause howling. A clear and stress-free conversation can be realized.

  As described above, in the present embodiment, the contact microphones 1a to 1h and 1j to 1m having extremely excellent noise resistance are used in the transmission / reception device, thereby realizing a headphone in which the speaker unit and the microphone are arranged close to each other. can do.

  In the present embodiment, the example in which the transmission / reception device is used as headphones has been described. However, the headphones may be any type of headphones such as a single-ear headphones or a neckband type.

  Moreover, if it is a transmission / reception apparatus provided with contact-type microphone 1a-1h and 1j-1m, you may mount in portable terminal devices other than headphones. In other words, any device may be used as long as it has a transmission / reception function. For example, the device may be applied to a mobile terminal device such as a mobile phone.

  In general, the casing of such a portable terminal device is narrow, and the speakers and the contact microphones 1a to 1h and 1j to 1m must be arranged close to each other. In addition, it is assumed that the mobile terminal device is used in a noisy environment. For this reason, conventionally, there has been no example of mounting a contact microphone on a mobile terminal device such as a mobile phone.

  According to the present embodiment, the contact type microphones 1a to 1h and 1j to 1m having noise resistance and capable of clearly collecting only normal voices and non-audible murmuring voices are mounted on the portable terminal device. Therefore, it is possible to realize a clear and stress-free conversation with the other party, which has been difficult in the past, without causing howling.

  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.

  In the above embodiments, the names of the contact microphone and the transmission / reception device are used. However, this is for convenience of explanation, and the contact microphone may be a microphone device, and the transmission / reception device may be a communication device.

  Furthermore, the parts constituting the contact microphone, for example, the type and shape of the sound collection contact member, the mounting method, etc. are not limited to the above-described embodiment.

  The contact-type microphone of the present invention can clearly collect a speaker's voice and an inaudible murmur without mixing background noise in a general noise environment such as outdoors or construction sites. Also, by applying it to normal voice calls, voice input, voice recognition, and voiceless telephones, voice input without errors to portable information terminals, etc. Realization is possible. Furthermore, the contact microphone according to the present invention can be incorporated into a chin strap of a working or construction helmet, an ear cover for cold protection, or 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 object without collecting surrounding speech. For example, it is a water flow detection sensor for general household use. In addition, the present invention can be applied to the security field such as detecting a pedestrian's walking pattern by embedding it in the floor and specifying an intruder.

  The transmission / reception apparatus including the contact microphone according to the present invention can be applied to a transmission / reception apparatus such as a headphone or a portable wireless device in which the contact microphone is disposed in the vicinity of the speaker unit. It can also be applied to equipment.

1a to 1h, 1j to 1m Contact type microphone 2 Microphone element 3 Sound collecting object (skin, etc.)
4 Body conduction sound 5 Vibration membrane 6 Conductor 7a, 7b, 107 Vibration transmission 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 Clearance 19, 19b, 19d Acoustic fiber (conduit)
19a, 19c, 19e Cylinder 20 Plastic sphere 21 Cavity 22 Washer 23 Vertical connection tube 24 Perforation (recess)
25 Discharge hole 26 Lathe drill 27 Silica 31 Through hole 32 Ground wire 100 Headphone (transceiver)

Claims (3)

A condenser microphone element having a vibrating membrane;
A vibration transmission member that contacts the vibration membrane of the microphone element and transmits vibration transmitted from a side facing the vibration membrane to the microphone element;
A cover member having an opening and storing the microphone element, the vibration transmitting member and the damping member;
A sound collection contact member including metal or ceramics, which is disposed to cover the opening of the cover member and is in contact with the vibration transmission member,
The vibration transmission member is disposed at a substantially center of the sound collection contact member,
The sound collection contact member and the cover member are formed of the same material,
Contact microphone.   The contact microphone according to claim 1, wherein the sound collection contact member and the cover member are made of a metal material including iron-based, aluminum-based, titanium-based metal, and die casting zinc alloy.   A transmission / reception device comprising the contact microphone according to claim 1.