JPWO2007129500A1 - Vibration detector - Google Patents

Abstract

Provided is a vibration detection device having high practicality, stable sensitivity, and noise resistance. The vibration detection device 1 includes a silicone 4 whose one surface can contact a vibration source, a microphone element 3 having a vibration film 33 that abuts on the other surface of the silicone 4, the silicone 4 and the microphone element 3. An inner case 2 for housing is provided. Further, a rib 23 is stretched between the contact surface of the silicone 4 with the vibration source and the vibration film 33 on the inner wall of the inner case 2 that houses the silicone 4, and the rib 23 is formed of the silicone 4 is embedded.

Description

  The present invention relates to a vibration detection apparatus that detects individual vibrations transmitted through a soft tissue of a human body.

2. Description of the Related Art Conventionally, a speaker using sound transmission using a human bone as a medium, that is, a so-called bone conduction, has been developed.
In recent years, attention has been paid to a transmission mechanism called meat conduction, in which the sound medium is a soft tissue such as human muscle, fat, skin, etc., and a microphone device using this meat conduction has been developed. (For example, refer nonpatent literature 1). Meat conduction is a vibration transmission mechanism that conducts mainly soft tissue of the human body after an unvoiced breathing sound that uses airflow turbulent noise as a sound source is tuned by acoustic filter characteristic changes due to the movement of the speech organ. According to meat conduction, airway sound transmitted through soft tissue is directly sampled, so that it is possible to detect even whispering voices and the like that are much smaller than normal utterance volume with high sensitivity.

  Products using meat conduction are in the process of development, and various studies are underway for practical application. For example, a vibration detection device such as the above-described microphone device is still manufactured manually, and has yet to reach a practical stage in terms of durability and productivity of the product itself for mass production.

A configuration example of a conventional microphone device using meat conduction is shown in FIG.
This microphone device M is formed in a cylindrical shape, a microphone element m5 is installed in a case m1 having an opening at the top, the periphery is filled with hard silicone m7, and the space released by the remaining opening is filled with soft silicone m8. It is what. An O-ring m9 is provided at the outer peripheral end of the case m1.

  In use, the microphone device M brings the exposed soft silicone m8 surface into contact with the soft tissue (usually skin) of the human body, and transmits the sound vibration transmitted through the soft tissue of the human body to the soft silicone m8 layer. Is transmitted to the microphone element m5 via.

A method for manufacturing the microphone device M of FIG. 31 will be described with reference to FIGS. 32A to 32D.
First, as shown in FIG. 32A, a soundproof sheet is processed to create a cylindrical case m1 having an upper opening. Next, a rubber member m3 for sound absorption is laid on the bottom portion in the cylinder, and the base is produced by covering the rubber member m3 with a soundproof sheet. When the base is completed, a pedestal m4 made of hard silicone is placed at the center of the base, and the microphone element m5 is placed on the pedestal m4. In the microphone element m5, a cable m6 for electrical connection with the outside is disposed through the side surface of the case m1.

  Next, as shown in FIG. 32B, hard silicone m7 is filled around the microphone element m5. The hard silicone m7 is shaped so that its inner diameter decreases from the opening of the case m1 toward the microphone element m7 in order to act as a sound vibration reflector. Further, since the O-ring m9 is disposed at the opening end, the opening end portion is formed into a flat surface having a width.

Next, as shown in FIG. 32C, an O-ring m9 is installed at the opening end portion at the top of the case m1, and is fixed with an adhesive. The O-ring m9 is used as a filling frame for soft silicone to be filled later. When the position of the O-ring m9 is fixed, the outer peripheral surface of the case m1 is coated with the polymerization resin m2. Thereafter, as shown in FIG. 32D, soft silicone m8 is injected into case m1 until the upper surface of O-ring m9 is reached. When the soft silicone m8 is cured, the microphone device M is completed.
Yuki Nakamura, “NAM Interface Communication”, Nara Institute of Technology, Doctoral Dissertation, February 2, 2005

Since the conventional microphone device M is manufactured manually as described above, improvement is necessary for mass production and quality improvement of the product.
For example, the microphone element m5 is placed on the base m4 and the periphery thereof is filled with hard silicone m7 to fix the position. However, the hard silicone m7 itself does not have sufficient hardness to support the microphone element m5. The fixation was unstable. Since the microphone element m5 detects vibration due to its own movement, if the fixation is unstable, its sensitivity characteristic may be affected.

  Moreover, the structure which fixes the O-ring m9 on the hard silicone m7 and the soundproof sheet using an adhesive is not sufficient in strength, and may peel off in long-term use or messy use. In addition, although the adhesion between the hard silicone m7 and the soft silicone m8 is good, it is preferable to improve the peel resistance in consideration of the period of use of the product and the usage situation.

  Furthermore, in order to prevent the vibration from wrapping around the microphone element m5 from behind, the soundproof sheet is processed to create the case m1 or the sound absorbing rubber material m3 is installed in the case m1. With this configuration, the number of manufacturing steps is increased and the production efficiency is poor.

  Further, when such a microphone device M is actually used for voice detection or the like, it is necessary to mount the microphone device M on a mounting part for mounting on a human body or the like. However, the conventional microphone device M does not consider mounting on such mounting parts.

  An object of the present invention is to provide a vibration detection device having high practicality, stable sensitivity, and noise resistance.

The invention described in claim 1
A vibration transmission medium whose one surface can contact the vibration source;
A vibration detection element having a vibration film in contact with the other surface of the vibration transmission medium;
In a vibration detection apparatus comprising: the vibration transmission medium and an inner case that houses the vibration detection element;
An inner wall of the inner case that houses the vibration transmission medium, wherein a rib is stretched between a contact surface of the vibration transmission medium with a vibration source and the vibration film, and the rib is formed in the vibration transmission medium. It is characterized by being buried.

The invention described in claim 8
A vibration transmission medium whose one surface can contact the vibration source;
A vibration detection element having a vibration film in contact with the other surface of the vibration transmission medium;
In a vibration detection apparatus comprising: the vibration transmission medium and an inner case that houses the vibration detection element;
A space is provided between the vibration film and the vibration transmission medium,
It is an inner wall of the inner case that houses the vibration transmission medium, and a dome-shaped cover is provided on a boundary surface between the space and the vibration transmission medium.

  According to the present invention, when a pressure is received when the vibration transmission medium contacts the vibration source, a repulsive force of the rib is generated and the pressure received by the rib is dispersed in the inner case. Since the repulsive force of the rib is proportional to the pressing force, the pressure applied to the vibration detection element can be made substantially constant and the sensitivity characteristic of the vibration detection element can be made constant regardless of the contact pressure. In addition, since the case that houses the vibration detection element and the vibration transmission medium is a separate body of the inner case and the outer case that have different acoustic impedances, noise vibration from the outside can enter the vibration detection element further from the inner case. Can be prevented, and the noise resistance of the vibration detecting element can be improved.

Furthermore, since the protruding portion formed on the outer case comes into contact with the vibration source prior to the contact surface of the vibration transmission medium with the vibration source, the pressure on the vibration transmission medium can be relieved by the outer case. In addition, since the outer case is made of silicone, it is possible to reduce the shock at the time of contact and prevent the noise vibration caused by this shock from entering the vibration source side and attenuating the vibration from the vibration source that should be detected originally. it can. Thereby, the detection accuracy of vibration can be improved.
In addition, the vibration detection device can be fixed to the surrounding member, is highly practical, and an air layer having an acoustic impedance different from that of the outer case is interposed between the outer case and the outer case. It is possible to suppress external noise.

  According to the present invention, since the space is provided between the vibration film and the vibration transmission medium, the vibration film can be protected from the pressure applied by the contact with the vibration source, and the vibration detection element can be prevented from being damaged. . Moreover, protection can be strengthened by providing a dome-shaped cover on the boundary surface between the space and the vibration transmission medium. By making the space, the vibration transmission medium and the boundary surface dome-shaped, the vibration transmission efficiency to the vibration film can be improved, and the same sensitivity characteristics as when the vibration transmission medium and the vibration film are in close contact can be realized. it can.

It is a top view of the vibration detection apparatus in a 1st embodiment. It is sectional drawing in the II line | wire of FIG. It is sectional drawing of an inner case. It is sectional drawing of a microphone element. It is sectional drawing of an outer case. It is sectional drawing of the components for mounting. It is a figure explaining the manufacturing method of a vibration detection apparatus. It is a figure explaining the filling process of silicone. It is a figure explaining the filling process of silicone. It is sectional drawing which shows the structure of the vibration detection apparatus which concerns on a comparative example. It is a figure which shows the sensitivity characteristic of the vibration detection apparatus which concerns on an Example. It is a figure which shows the sensitivity characteristic of the vibration detection apparatus which concerns on a comparative example. It is a figure which shows the noise tolerance of the vibration detection apparatus which concerns on an Example and a comparative example. It is a voice spectrum of the audio | voice detected by the vibration detection apparatus which concerns on an Example, Comprising: It is a figure which shows an audio | voice spectrum when it detects by applying an appropriate press. It is a voice spectrum of the sound detected by the vibration detection apparatus according to the embodiment, and shows the sound spectrum when detection is performed by applying a pressure equal to or higher than the appropriate pressure. It is an audio | voice spectrum detected by the vibration detection apparatus which concerns on a comparative example, Comprising: It is a figure which shows an audio | voice spectrum when it detects by applying an appropriate press. It is an audio | voice spectrum detected by the vibration detection apparatus which concerns on a comparative example, Comprising: It is a figure which shows an audio | voice spectrum when it detects by applying the press more than an appropriate press. It is a figure which shows the case where the positional relationship of the diaphragm of a microphone element and a back electrode is normal. It is a figure which shows the case where the positional relationship of the diaphragm of a microphone element and a back electrode is abnormal. It is a top view which shows the structure of the rib which concerns on other embodiment. It is sectional drawing of the inner case in the II-II line of FIG. 16A. It is a figure which shows the structure of the outer case which concerns on other embodiment. It is a figure which shows the structure of the outer case which concerns on other embodiment. It is sectional drawing of the vibration detection apparatus which concerns on other embodiment. It is a top view of the vibration detection apparatus concerning a 2nd embodiment. It is sectional drawing in the XX line of FIG. It is a figure explaining the manufacturing method of the vibration detection apparatus which concerns on 2nd Embodiment. It is a figure explaining the manufacturing method of the vibration detection apparatus which concerns on 2nd Embodiment. It is a figure which shows the measurement environment at the time of measuring the sensitivity characteristic of a vibration detection apparatus. It is a figure which shows the mounting position of the vibration detection apparatus at the time of measuring the sensitivity characteristic of a vibration detection apparatus. It is a figure which shows the measurement result at the time of outputting sweep sound. It is a figure which shows the measurement result at the time of outputting an audio | voice. It is a figure which shows the audio | voice spectrum of a comparative example. It is a figure which shows the audio | voice spectrum of an Example. It is a figure explaining how to transmit the vibration from space to a diaphragm. It is a top view of the vibration detection apparatus using a cover instead of a rib. It is sectional drawing in the YY line | wire of FIG. It is a figure which shows the conventional vibration detection apparatus. It is a figure explaining the manufacturing method of the conventional vibration detection apparatus. It is a figure explaining the manufacturing method of the conventional vibration detection apparatus. It is a figure explaining the manufacturing method of the conventional vibration detection apparatus. It is a figure explaining the manufacturing method of the conventional vibration detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibration detection apparatus 2 Inner case 21 Thin part 22 Notch part 23 Rib 24 2nd accommodating part 25 1st accommodating part 26 Groove 27 Through-hole 28 Partition 3 Microphone element 33 Vibration film 4 Silicone 5 Outer case 51 Open end 52 Engagement part 53 engaging portion 54 third housing portion 6 mounting component 61 engaging portion 7 bottom cover C signal line s space 23a cover

<< First Embodiment >>
<Structure of vibration detector>
Hereinafter, a vibration detection apparatus to which the present invention is applied will be described with reference to the drawings.
FIG. 1 is a plan view of the vibration detection apparatus 1, and FIG. 2 is a cross-sectional view taken along the line II of FIG.

  As shown in FIGS. 1 and 2, the vibration detection device 1 includes an inner case 2 accommodated in a cylindrical outer case 5, and a microphone element 3 and silicone 4 accommodated in the inner case 2. . The upper portion of the microphone element 3 is filled with silicone 4, and the silicone 4 is in contact with the vibration film 33 of the microphone element 3. Further, a signal line C is wired below the microphone element 3. The signal line C is a cable for sending a detection signal from the vibration detection device 1 to the outside.

When the vibration detection device 1 is mounted on a mounting target device (for example, a mobile phone), a mounting component 6 for mounting the vibration detection device 1 on the mounting target device is used. That is, as shown in FIGS. 1 and 2, the vibration detection device 1 is housed in the mounting component 6.
The mounting component 6 is formed in a ring shape, and a plurality (three in this example) of convex engaging portions 61 are provided on the inner peripheral surface thereof at a predetermined interval in the circumferential direction. . Corresponding to these engaging portions 61, a concave engaging portion 53 is provided on the outer peripheral surface of the outer case 5 of the vibration detecting device 1.

The protruding width of the engaging portion 61 is set to be larger than the depth of the engaging portion 53, so that a gap is formed between the outer peripheral surface of the outer case 5 and the inner peripheral surface of the mounting component 6. That is, the vibration detection device 1 is supported with a gap between the outer surface of the outer case 5 and the inner surface of the mounting component 6.
As described above, the vibration detection device 1 is supported at a point (for example, supported at three points) with a gap between the outer surface of the outer case 5 and the inner surface of the mounting component 6. Vibration transmission between the cases 5 can be suppressed. In other words, the mounting component 6 and the outer case 5 are not in contact with each other at the surface but are in contact with each other, so that the contact area is reduced and vibration from the mounting target device is not easily transmitted to the vibration detection device 1. . As a result, external noise can be suppressed.
A bottom lid 7 is attached to the bottom surface of the mounting component 6.

  The inner case 2 is a resin molded product formed in advance in the shape shown in FIG. 3 using a synthetic resin such as ABS resin, polystyrene resin or acrylic resin, rubber, resinous hard silicone or the like as a material. In consideration of impact resistance, it is possible to use a metal having a high hardness instead of a resin, but it is preferable to use a resin in order to reduce the weight.

  As shown in FIG. 3, a second housing portion 24 for housing the microphone element 3 is formed at the lower center portion of the inner case 2. The second accommodating portion 24 has a diameter slightly smaller than the diameter of the microphone element 3, and when the microphone element 3 is press-fitted into the second accommodating portion 24, the microphone element 3 is fitted and fixed in the second accommodating portion 24. It is formed as follows. Further, the bottom surface of the second housing portion 24 is opened, and the microphone element 3 can be inserted through the opening.

  On the other hand, a first accommodating portion 25 having an opening on the upper end side is formed above the inner case 2. A partition wall 28 having a through hole 27 is provided between the second housing part 24 and the first housing part 25, and the second housing part 24 and the first housing part 25 communicate with each other through the through hole 27. The partition wall 28 functions as a locking member that locks excessive insertion from the second housing portion 24 to the first housing portion 25 when the microphone element 3 is inserted into the second housing portion 24.

  As shown in FIG. 2, the first accommodating portion 25 is filled with silicone 4 that is a vibration transmission medium and accommodated. The silicone 4 is also filled into the microphone element 3 side through the through hole 27, and adheres to the vibration film 33 of the microphone element 3 when the silicone 4 is cured.

  In addition, arched ribs 23 are stretched on the partition wall 28. As shown in FIG. 1, the ribs 23 are formed so as to be bridged at, for example, three points across the through hole 27. The rib 23 is embedded in the silicone 4 as shown in FIG. 2 when the silicone 4 is filled.

The 1st accommodating part 25 is formed in the mortar shape from which the internal diameter reduces toward the 2nd accommodating part 24 from the opening of an upper end side. In the present embodiment, an example of a mortar shape is shown, but a parabolic shape or a hemispherical shape whose inner surface is curved may be used.
The outer peripheral edge portion of the first accommodating portion 25 is formed thinner than the other portions. The thin portion 21 has a tip portion formed in a shape corresponding to the engaging portion 52 of the outer case 5 and functions as an engaging portion. Further, the width of the thin portion 21 in the radial direction of the first accommodating portion 25 is such that the tip end portion of the thin portion 21 is engaged with the engaging portion 52 (see FIG. 5) of the outer case 5 and the opening end of the outer case 5 51 (see FIG. 5) is set to a size such that a circumferentially continuous groove 26 is formed between the inner circumferential surface 51 (see FIG. 5).

The groove 26 is formed in this way to increase the adhesion between the inner case 2 and the silicone 4 by increasing the surface area of the inner surface of the inner case 2.
The thin portion 21 is provided with a plurality of (three in this example) cutout portions 22 at a predetermined interval in the circumferential direction. The notch 22 is provided to improve the fluidity of the silicone 4 into the groove 26. Although the number is not limited to three, it is preferable to determine in consideration of characteristics such as viscosity and curing speed of the silicone 4 in order to cause the silicone 4 to flow uniformly (rapidly).

  The silicone 4 is a vibration transmission medium whose surface becomes a contact surface with a soft tissue of a living body that is a vibration source, and conducts sound vibration transmitted from the soft tissue to the microphone element 3. Here, the soft tissue of a living body refers to an individual tissue having a certain degree of elasticity, such as skin tissue, muscle tissue, adipose tissue, and fat.

  As the material of the silicone 4, soft silicone having a relatively low hardness is applicable, and a material having an acoustic impedance substantially equal to that of a soft tissue of a living body serving as a sound vibration transmission medium is selected. The acoustic impedance is obtained by the product of the medium density ρ and the propagation velocity C. As long as the acoustic impedance of each substance differs between two adjacent substances, sound reflection occurs strongly at the boundary surface where the two substances contact. Therefore, in order to mediate the sound propagating through the soft tissue of the living body to the vibrating membrane 33 of the microphone element 3 without reflection attenuation as much as possible, it is only necessary to select one having an acoustic impedance equivalent to that soft tissue.

  It is known that the acoustic impedance of soft tissue shows almost the same value although there is a slight difference depending on the tissue. The specific acoustic impedance value of the soft tissue varies depending on the measurement environment, but the fat tissue is about 1.3 × 10 6 (kg / m 2 s). When actually selecting the material of the silicone 4, what has the best acoustic impedance may be selected experimentally and empirically.

The microphone element 3 is a vibration detection element that detects a vibration conducted through the silicone 4 filled in the first housing portion 25 and converts it into an electric signal.
FIG. 4 shows an enlarged cross-sectional view of the microphone element 3.
As shown in FIG. 4, the microphone element 3 is a capacitor-type microphone element in which a vibration film 33, a spacer 34, a back electrode 35, and an FET (Field Effect Transistor) 36 are housed in a cylindrical case 31. is there.

  The case 31 has an upper central portion opened in a circular shape, and a sound receiving hole 37 is formed. A washer 32 having the same hole diameter as the sound receiving hole 37 is provided inside the upper surface of the case 31, and a vibration film 33, a spacer 34, and a back electrode 35 are laminated and attached to the washer 32. Note that the diameter of the washer 32 may not be the same as long as it is smaller than the diameter of the sound receiving hole 37.

  A substrate 38 is provided above the bottom surface of the case 31 with a gap therebetween, and a spacer 39 is provided between the substrate 38 and the back electrode 35. The spacer 39 supports the washer 32 and the like attached to the vibration film 33. An FET 36 is installed in the inner hole of the spacer 39 on the substrate 38. The FET 36 is provided with three terminals, which are connected to the back electrode 35, the signal line C, and the ground line, respectively.

  The outer case 5 is a silicone molded product formed in advance into the shape shown in FIG. 5 using silicone as a material. Silicone has higher hardness than silicone 4 such as curable soft silicone, rubber-like, resinous hard silicone, etc. (for example, hardness (JIS A) relative to silicone 4 hardness (JIS A) 6). Apply a material that is less deformed by pressing. Further, silicone having an acoustic impedance different from that of the resin forming the inner case 2 is applied.

The outer case 5 has an opening at the upper end of the cylinder, and has a third housing portion 54 formed so that the shape of the inner surface thereof corresponds to the outer shape of the inner case 2. A concave engaging portion 52 corresponding to the thin portion 21 of the inner case 2 is provided on the inner surface of the third accommodating portion 54.
Moreover, the opening end 51 of the 3rd accommodating part 54 is shape | molded so that it may protrude from the surface of the said silicone 4 in the state with which the silicone 4 was filled, as shown in FIG.

  In this way, the opening end 51 is protruded because the surface of the silicone 4 becomes a contact surface to the soft tissue that is the vibration source. By bringing the opening end 51 into contact before the contact surface, the silicone 4 is interposed. This is to alleviate excessive pressing directly applied to the microphone element 3.

  In addition, the vibration detection device 1 is brought into contact with and pressed against the soft tissue, but the contact portion of the soft tissue with the vibration detection device 1 is hardened by the pressing at this time, and vibration transmitted from the soft tissue becomes difficult to be transmitted. There is. Therefore, the material of the outer case 5 that is in direct contact with the soft tissue is not a hard resin or metal, but a silicone having a low hardness, thereby reducing the pressure on the soft tissue and preventing the soft tissue from hardening. The vibration from the organization is easily transmitted.

  A concave portion is formed on the outer surface of the outer case 5 over the entire circumference in the circumferential direction to form an engaging portion 53 that engages with the mounting component 6. As described above, the concave shape of the engaging portion 53 is not the entire engagement of the convex portion of the engaging portion 61 provided corresponding to the mounting component 6 side, but the tip of the convex portion. It is formed so that it may engage with a part of. Thus, the outer case 5 is supported at three points so that a gap is generated between the outer surface of the outer case 5 and the inner surface of the mounting component 6 when the outer case 5 is stored in the mounting component 6. Become.

  The mounting component 6 is an outer member for mounting the vibration detection device 1 to a mounting target device. The mounting component 6 is a molded product that has been previously molded into the shape shown in FIG. As shown in FIG. 6, the mounting part 6 has a hollow inside the cylinder. This hollow portion is a fourth housing portion 62 for housing the vibration detection device 1. An engaging portion 61 that engages with the outer case 5 is formed on the inner wall. Further, a through hole for passing the signal line C of the microphone element 3 is provided in a part of the peripheral edge of the cylinder.

  The bottom lid 7 is a disk-shaped plate material.

<Method for Manufacturing Vibration Detection Device 1>
With reference to FIGS. 7, 8 </ b> A, and 8 </ b> B, a manufacturing method of the vibration detection device 1 will be described.
FIG. 7 is a diagram for explaining a method of assembling each member. The numbers in parentheses shown in FIG. 7 indicate the order of the assembly process.
First, the signal line C is wired to the microphone element 3 by soldering (see (1) in FIG. 7). It is preferable to wire the signal line C at the earliest possible stage. This is because the more the inner case 2, the outer case 5, and the like are covered, the more easily the heat during soldering is trapped in the cases 2 and 5, and as a result, the microphone element 3 may be destroyed by heat. . Another reason is that when soldering is performed after the silicone 4 is filled, the adhesion between the silicone 4 and the vibration film 33 of the microphone element 3 deteriorates due to the heat. If measures against heat are taken, soldering can be performed at the final stage.

Next, the microphone element 3 to which the signal line C is wired is inserted from the bottom opening of the inner case 2 that is a resin molded product.
This is inserted into the third housing portion 54 of the outer case 5, and the thin portion 21 of the inner case 2 is engaged with the engaging portion 52 of the outer case 5 (see (2) in FIG. 7).

Next, the first housing portion 25 of the inner case 2 is filled with silicone 4 (see (3) in FIG. 7).
The filling process of the silicone 4 will be described with reference to FIGS. 8A and 8B.
The filling amount of the silicone 4 is determined in advance so that the silicone 4 is filled up to a position serving as a filling reference. The position serving as the filling reference is determined to be a position (see FIG. 1) lower than the protruding portion, for example, 1 mm below the protruding portion of the opening end 51 of the first housing portion 25.

  At the time of filling, the silicone 4 is poured from the inclined portion of the inner surface of the first housing portion 25 so that the silicone 4 does not drop directly on the microphone element 3. At this time, as shown in FIG. 8A, the interface of the silicone 4 rises according to the amount of dripping, and gradually fills the first housing portion 25. When the interface reaches the notch 22, the silicone 4 flows into the notch 22 and enters the groove 26. Meanwhile, when the interface of the silicone 4 in the first housing portion 25 rises due to further filling, the silicone 4 filling the first housing portion 25 and the silicone 4 entering the groove 26 merge, and as shown in FIG. 8B It becomes a state.

Here, consider a case where the notch 22 is not provided.
When the silicone 4 reaches the boundary with the groove 26, the silicone 4 temporarily enters the groove 26 due to its surface tension. Furthermore, when the amount of dripping onto the silicone 4 is increased and a pressure equal to or higher than the surface tension is applied, the silicone 4 enters the groove 26. However, since the fluidity of the silicone 4 decreases around the groove, The surrounding silicone 4 is cured. As a result, there is a possibility that the curing of the silicone 4 in the first housing part 25 becomes non-uniform. Further, if excessive dripping is performed in order to exceed the surface tension, it is considered that when the groove 26 is filled with the silicone 4, the interface thereof exceeds the position that should be originally filled.

  However, since the inner case 2 in the present embodiment is provided with the notch 22 in the groove 26, the silicone 4 first enters the notch 22 at a position lower than the groove 26 as shown in FIG. 8A. It becomes. As a result, the surface tension of the silicone 4 is relaxed, and the silicone 4 that has entered from the notch 22 enters the groove 26, so that the fluidity of the silicone 4 generated by the formation of the groove 26 can be improved.

  Then, when all of the predetermined amount of silicone 4 is filled, this is left to cure and the silicone 4 is cured. The vibration detector 1 is completed by curing the silicone 4.

  Next, the completed vibration detection device 1 is inserted into the mounting component 6 from the bottom opening of the mounting component 6 as shown in FIG. 7 (step indicated by (4) in the figure). When the engaging portion 53 provided on the outer surface of the outer case 5 of the vibration detection device 1 is engaged with the engaging portion 61 provided on the inner surface of the mounting component 6, the bottom cover 7 is placed on the bottom surface of the mounting component 6. Is attached (step shown by (5) in the figure).

<Operation of Vibration Detection Device 1>
When using the vibration detection device 1, the user holds the outer surface of the mounting part 6 and brings the side where the silicone 4 is exposed into contact with the soft tissue of the living body. At this time, since the sensitivity of the vibration detection device 1 varies depending on the contact position, it is only necessary to find a position with good sensitivity empirically. Experimental results have shown that the area immediately below the mastoid, which is the back of the ear, is optimal.

  At the time of contact, the open end 51 of the outer case 5 protruding from the surface of the silicone 4 first comes into contact with the soft tissue. Next, the soft pressure tissue inside the open end 51 rises due to the contact pressure, and comes into contact with the surface of the silicone 4. The vibration transmitted from the soft tissue of the living body that is in contact is conducted to the microphone element 3 through the silicone 4. In the microphone element 3, an electric signal is generated by the FET 36 according to the vibration received by the vibration film 33, and this electric signal is sent to the outside through the signal line C.

A vibration detection apparatus 10 as shown in FIG. 9 was produced as a comparative example for the vibration detection apparatus 1 and the performance was evaluated by measuring the sensitivity characteristics, noise resistance, voice spectrum, and the like.
The vibration detection device 10 shown in FIG. 9 is a resin in which the microphone element 3 and the silicone 4 (the microphone element and the silicone 4 are the same as the vibration detection device 1 and will be denoted by the same reference numerals). The case 11 is housed. The vibration detecting device 1 is a point in which a mortar-shaped opening is formed at one end of the case 11 and the silicone 4 is accommodated therein, and a partition wall 28 via the silicone 4 accommodating portion and the through hole 27 is disposed at the other end side. Through which the accommodating portion of the microphone element 3 is formed, the silicone 4 and the vibrating membrane of the microphone element 3 are in contact, and the open end of the case 11 is formed so as to protrude from the surface of the silicone 4. The points are common in configuration. However, the vibration detection device 10 is different in that the case 11 is formed integrally with the exterior, the rib is not provided, and the mounting component 6 is not used.

<Experiment>
The material of the silicone 4 of the vibration detecting device 1 according to the present embodiment is the same as the material of the silicone 4 of the vibration detecting device 10 according to the comparative example, and the material of the inner case 2 of the vibration detecting device 1 and the case 11 of the vibration detecting device 10. As a result, the following measurements were performed.

(1) Measurement of sensitivity characteristics The vibration detection device 1 according to the example and the vibration detection device 10 according to the comparative example are brought into contact with an experimental vibration source, and the sensitivity (dB) is changed by changing the frequency of the sound from the vibration source. It was measured. The sensitivity is measured for two patterns in which the pressure per contact area is changed to 100 (g) and 200 (g).

(2) Measurement of noise tolerance The vibration detection device 1 according to the example and the vibration detection device 10 according to the comparative example are arranged at a distance of 5 (cm) from the experimental vibration source, and air conduction sound from the vibration source. Was treated as noise, and the sensitivity (dB) to the air conduction sound was measured. Sensitivity is measured by changing the frequency of the sound.

(3) Measurement of voice spectrum With the vibration detection device 1 and the vibration detection device 10 in contact with the soft tissue of the human body, the same phrase “human has twisted all reality toward himself” is uttered. Then, an audio spectrum was created based on detection signals from the vibration detection device 1 and the vibration detection device 10. The experiment was performed with respect to two patterns of proper pressing of the contact area and excessive pressing obtained by adding further pressing to the proper pressing, and respective sound spectra were obtained. Here, the appropriate pressure is a pressure included in a pressure range determined to have the best balance of signal detection at a low frequency (800 (Hz) or less) and a high frequency (800 (Hz) to 4 k (Hz)). Say. The experiment shows that the proper pressing range of the vibration detection device 10 is about 0 to 40 (g), and the proper pressing range of the vibration detection device 1 is about 0 to 200 (g). In particular, the vibration detection apparatus 1 had the best balance around 100 ± 50 (g).

<Evaluation>
(1) Evaluation of sensitivity characteristic As a measurement result of the sensitivity characteristic of the vibration detection apparatus 1, the result shown in FIG. 10 was obtained. In contrast, the vibration detection apparatus 10 obtained the results shown in FIG.
In FIG.10 and FIG.11, the sensitivity characteristic when the press at the time of contact is 100 (g) is shown by a solid line, and the sensitivity characteristic when it is 200 (g) is shown by a dotted line.

As shown in FIG. 10, in the vibration detection apparatus 1 according to the embodiment, there is no great difference in sensitivity characteristics between 100 (g) and 200 (g).
On the other hand, in the vibration detection apparatus 10, as shown in FIG. 11, in a region of a frequency of 4000 (Hz) or less, a difference of about 6 to 7 (dB) is applied when the pressure is 100 (g) and 200 (g). Has occurred. In particular, the human voice range is often included in a frequency band of about 100 (Hz) to 4 (kHz) (varies most depending on the language to be used), but the vibration detection device 10 according to the comparative example is intelligible. It can be seen that the sensitivity tends to vary due to pressing in a high frequency region of 2 to 4 (kHz), which has a large effect on (easy to hear).

(2) Evaluation of Noise Resistance FIG. 12 is a diagram showing measurement results of noise resistance of the vibration detection device 1 and the vibration detection device 10. In FIG. 12, the solid line indicates the noise sensitivity characteristic of the vibration detection device 1 according to the embodiment, and the dotted line indicates the noise sensitivity characteristic of the vibration detection device 10 according to the comparative example.
As shown in FIG. 12, it is clear that the vibration detection device 10 has a higher sensitivity to noise and lower noise resistance than the vibration detection device 1 at about 3.5 (kHz) or less.

(3) Evaluation of Audio Spectrum FIGS. 13A and 13B are diagrams showing the audio spectrum obtained by the vibration detection device 1. 14A and 14B are diagrams showing a sound spectrum by the vibration detection device 10. FIG. In these audio spectrums, the magnitude of the signal level is indicated by density, and the higher the density, the higher the signal level. FIG. 13A and FIG. 14A are audio spectrums when pressed against the human body with proper pressing, and FIGS. 13B and 14B are audio spectra when over-pressing.

  Comparing FIG. 13A and FIG. 13B, it can be seen that the signal is slightly attenuated in the frequency band of 500 (Hz) to 1 (kHz) when excessive pressure is applied (the region circled in FIG. 13B). The sound spectrum characteristics are almost the same. From this, it can be seen that the vibration detection apparatus 1 performs stable voice detection regardless of the magnitude of the pressure.

  On the other hand, comparing FIG. 14A and FIG. 14B, in the vibration detection device 10, the signal amount in the high frequency region increases due to excessive pressing, and the sound spectrum greatly changes. From this, it can be seen that the vibration detection device 10 cannot cope with the change in the pressure, and the sound detection becomes unstable. Further, since signal detection is performed over the entire frequency band, the frequency components (100 (Hz) to 4 (kHz)) of the sound that is the original detection target are diluted. Furthermore, since the input amount of the signal becomes excessive, the signal level exceeds the allowable input value. When the audio in this case is viewed, the sound becomes muffled and difficult to view.

The following is considered as a cause of obtaining the above evaluation.
As shown in FIG. 9, when the vibration detection device 10 is brought into contact with the soft tissue, the pressure due to the contact is directly applied to the vibration film of the microphone element 3 through the silicone 4. Therefore, it seems that the sensitivity varies depending on the pressure and the appropriate pressure range is narrowed.

  Further, when the pressure becomes excessive, there is a case where the vibration detection of the microphone element 3 is not normally performed. As shown in FIG. 15A, in order for the microphone element 3 to normally detect vibration, it is necessary that a gap exists between the vibration film 33 and the back electrode 35 of the microphone element 3. This is because the microphone element 3 can exhibit a capacitor function due to this gap. However, if excessive pressing is performed, the vibrating membrane 33 is pressed against the back electrode 35 as shown in FIG. 15B, and the gap is lost. When the gap is lost, the function as a capacitor cannot be achieved, and the detection operation of the microphone element 3 becomes abnormal.

  The case 11 of the vibration detection device 10 is a resin molded product having high hardness. Therefore, when the vibration detection device 10 is pressed against the soft tissue, the soft tissue portion in contact with the case 11 is hardened by the pressing, and vibration transmitted from the soft tissue to the vibration detection device 10 is suppressed. It is possible to end up. With this, vibration cannot be detected with high accuracy.

Furthermore, since the case 11 is integrally formed as an exterior, it has low resistance to external noise. This is because the vibration of noise transmitted to the case 11 from the outside causes the microphone element 3 to vibrate.
In addition, since the case 11 is not particularly structured to be fixed to a mounting part, vibration is detected by the mounting part, such as forming a mounting part so as to be fitted and fixed when housed in the mounting part. It is conceivable that the device 10 is sandwiched, but depending on the material, shape, etc. of the mounting parts, it may be a sound collecting plate and noise vibration from the outside is transmitted to the microphone element 3.

  Moreover, in the vibration detection apparatus 10, the fixing of the silicone 4 to the case 11 depends only on the adhesion between the case 11 and the silicone 4, and it cannot be said that the adhesion strength is high.

  With respect to such a problem, according to the vibration detection device 1 according to the present embodiment, the inner surface of the inner case 2, the contact surface with the vibration source (soft tissue) of the silicone 4 and the vibration film of the microphone element 3. The ribs 23 are stretched on the partition wall 28 between them and embedded in the silicone 4 in direct contact with the vibration source. When the silicone 4 is pressed, the repulsive force of the ribs 23 acts and the pressure received by the ribs 23 is dispersed in the inner case 2, so that excessive pressing on the microphone element 3 can be suppressed. Accordingly, the appropriate pressing range can be expanded, and pressing can be prevented until the vibrating membrane 33 comes into contact with the back electrode 35 side, and abnormal operation of the microphone element 3 can be prevented.

  Further, the repulsion of the rib 23 is small when the pressure is small, and conversely, the rebound is large when the pressure is large. Thus, since the repulsive force of the rib 23 is proportional to the pressure at the time of contact, the pressure applied to the microphone element 3 can be made substantially constant. Therefore, it becomes possible to always make the sensitivity characteristic of the microphone element 3 constant regardless of the pressing at the time of contact.

  Moreover, according to the vibration detection apparatus 1, the outer case 5 having the open end 51 that comes into contact with the soft tissue is formed of silicone. Thereby, when the vibration detection apparatus 1 is pressed against the soft tissue, the pressure applied to the soft tissue can be reduced. By reducing the pressure, it is possible to prevent the vibration transmission from the soft tissue from being hindered.

  In the vibration detection device 1, the case that houses the microphone element 3 has a separate configuration of the inner case 2 and the outer case 5 that have different acoustic impedances. As a result, vibration transmitted from the outside to the outer case 5 can be reflected at the boundary between the inner case 2 and the outer case 5, and noise resistance can be improved.

  Further, when the vibration detection device 1 is actually used, a mounting component 6 for mounting the vibration detection device 1 on the vibration source is required, but the outer case 5 is engaged with the mounting component 6. Since the portion 53 is provided, the position of the vibration detection device 1 can be fixed when the vibration detection device 1 is stored in the mounting component 6. Further, since the outer case 5 is engaged with the mounting part 6 by the three engaging portions 53 and 61 so that a gap is maintained between the outer case 5 and the mounting part 6, the outer case 5 and the mounting part 6 Can be minimized, and noise vibration transmitted from the mounting component 6 to the vibration detecting device 1 can be reduced.

  In the vibration detection device 1, the adhesion between the inner case 2 and the silicone 4 is high. This is because the silicone 4 is locked by the tension of the ribs 23. Further, the area in contact with the silicone 4 is increased by the surface area of the groove 26 and the rib 23 formed in the inner case 2, and the adhesion thereof is improved.

In addition, embodiment mentioned above is a suitable example to which this invention is applied, and is not limited to this.
For example, the rib 23 has a dome shape and is bridged at three points arranged at equal intervals in the communication portion between the first housing portion 25 and the second housing portion 24, as shown in FIGS. 16A and 16B. It is good also as extending | stretching the rib 231 which cross-links at four points by cross shape. FIG. 16A is a front view, and FIG. 16B is an enlarged cross-sectional view of the case 2 along the line II in FIG. 16A. The tensioning position is not the partition wall 28 but the inner surface of the inner case 2 and may be any position as long as it is between the contact surface of the silicone 4 with the vibration source and the vibration film 33.

  Moreover, in the said embodiment, although the concave engaging part 53 was provided in the outer surface of the outer case 5, if the shape respond | corresponds with the engaging part 61 of the components 6 for mounting, the shape will not be specifically limited. For example, a convex engaging portion 531 may be provided as shown in FIG. 17, or an engaging portion 532 having an umbrella-shaped cross section may be provided on the bottom surface of the outer case 5 as shown in FIG. In the case of the umbrella type, the engagement with the mounting component 6 can be further strengthened, and the vibration detection device 1 can be structured to be difficult to peel off from the mounting component 6.

  Further, in the above configuration, the signal line C is directly wired to the microphone element 3. However, as shown in FIG. 19, the microphone element 3 is connected to the terminal T1, the bottom cover 7 is connected to the terminal T2, and the terminal T2. A terminal T3 wired to C is provided, and when the bottom lid 7 is attached to the mounting component 6, the terminal T1 of the microphone element 3 and the terminal T2 of the bottom lid 7 come into contact with each other, so that wiring is possible. Good. That is, when the bottom cover 7 having the signal line C wired to the terminal T3 is attached to the mounting component 6, the terminal T1 of the microphone element 3 and the terminal T2 of the bottom cover 7 are in contact, and the terminal T2 is connected to the terminal T3. Therefore, wiring can be easily performed only by attaching the bottom lid 7. According to this configuration, it is not necessary to wire the signal line C directly to the microphone element 3, and the microphone element 3 can be protected from high heat due to soldering or the like during wiring.

<< Second Embodiment >>
In the second embodiment, an example will be described in which a space is provided between the vibration film and the vibration transmission medium to prevent the pressure from being directly applied to the vibration film through the vibration transmission medium due to contact with the vibration source.
<Structure of vibration detector>
FIG. 20 is a plan view of the vibration detection apparatus 1a according to the second embodiment, and FIG. 21 is a cross-sectional view taken along line XX of FIG. The vibration detection device 1a according to the second embodiment is such that a space is provided between the silicone 4 and the vibration film 33 of the vibration detection device 1 according to the first embodiment, and other configurations are the same. Therefore, the same reference numerals are given to the same components as those in the first embodiment, the description thereof is omitted, and components different from those in the first embodiment will be mainly described.

  As shown in FIGS. 20 and 21, the vibration detection device 1 a is provided with a space s between the silicone 4 and the vibration film 33. The boundary surface between the space s and the silicone 4 is formed in a dome shape along the shape of the rib 23. In this way, by providing the space s, the vibration film 33 can be separated from the silicone 4 that receives the pressure from the vibration source, and the pressure is not directly applied to the vibration film 33 via the silicone 4. Can do.

<Method for Producing Vibration Detection Device 1a>
With reference to FIGS. 22 and 23, a method of manufacturing the vibration detection device 1a will be described.
In producing the vibration detection device 1a, the shaft 8 and the shaft base 9 are used as shown in FIG. The shaft 8 has a convex cross section, and the tip of the convex portion is formed in a dome shape so as to coincide with the shape of the rib 23. The shaft base 9 is formed with an installation base for the outer case 5 in which the inner case 2 is accommodated in the upper part, and is configured to accommodate the shaft 9 therein.

  As shown in FIG. 22, first, the inner case 2 is assembled into the outer case 5, and this is installed on the upper part of the shaft base 9 (step (1) in FIG. 22). In this state, the shaft 8 is inserted from the lower part of the shaft base 9 into the shaft base 9 (step shown by (2) in FIG. 22). FIG. 23 is a view after the shaft 8 is inserted. As shown in FIG. 23, the shaft 8 is inserted until the tip portion of the convex portion contacts the rib 23. And the silicone 4 is filled in the 1st accommodating part 25 of the inner case 2 in the state which inserted the shaft 8 (process shown by (3) in FIG. 23). Since the filling method of the silicone 4 is the same as that of the first embodiment, the description is omitted here.

  When the filled silicone 4 is cured, the shaft 8 and the shaft base 9 are separated from the outer case 5. Then, the microphone element 3 to which the signal line C is wired from the bottom opening of the inner case 2 is inserted. After that, the vibration detecting device 1a is completed by attaching the mounting component 6 and the bottom lid 7 sequentially.

<Operation of Vibration Detection Device 1a>
Since the operation of the vibration detection device 1a is the same as the operation of the vibration detection device 1 in the first embodiment, the description thereof is omitted here.

For the vibration detection device 1a, the vibration detection device 1 was manufactured as a comparative example, and performance evaluation was performed by measuring the sensitivity characteristics, noise resistance, voice spectrum, and the like.
<Experiment>
(1) Measurement of Sensitivity Characteristics In the measurement environment shown in FIG. 24, the detection values in the vibration detection device 1a according to the present example and the vibration detection device 1 according to the comparative example were measured. As shown in FIG. 24, the measurement was performed in a state where a speaker was installed at one end of a cylindrical silicone pipe made of silicone of hardness 30 and the vibration detection devices 1a and 1 were installed on the side surface of the silicone pipe. The measurement is performed in two patterns: (i) when 20 to 20 (kHz) sweep sound (−20 dB) is output from the speaker, (ii) “Aiio, Sashisuseso” sound is output from the speaker. went.
In addition, a weight for pressing is arranged on the upper part of the vibration detection devices 1a and 1 in order to reproduce the pressing when contacting the vibration source. The silicone pipe has a thickness of 5 mm and a length of 100 mm, and the distance between the speaker and the vibration detection devices 1a and 1 is 50 mm. Further, a reference microphone for detecting sound vibrations as a reference for sensitivity evaluation is installed at the other end facing the speaker.

(2) Measurement of voice spectrum The vibration detection device 1 according to this example and the vibration detection device 1 according to the comparative example were attached to the attachment positions shown in FIG. 25, and "Aiueo, Sashisuseso" was uttered. And the audio | voice spectrum was created based on the detection signal by the vibration detection apparatuses 1a and 1.

<Evaluation>
(1) Evaluation of sensitivity characteristics FIG. 26A is a diagram showing a measurement result when (i) sweep sound is output, and FIG. 26B is a diagram showing a measurement result when (ii) sound is output. The measurement results according to the examples are indicated by solid lines, and the measurement results according to the comparative examples are indicated by dotted lines. As can be seen from FIG. 26A and FIG. 26B, it can be seen that the example and the comparative example have almost the same characteristics regardless of whether the sound is a sweep sound or a sound. That is, even when the space s is provided between the vibration film 33 and the silicone 4 as in the vibration detection apparatus 1a (example), the vibration detection apparatus 1 (comparative example) in which the vibration film 33 and the silicone 4 are in close contact with each other. It can be seen that a degree of sensitivity characteristic can be realized.

(2) Evaluation of audio spectrum FIG. 27A shows an audio spectrum according to the embodiment, and FIG. 27B shows an audio spectrum according to a comparative example. Since any sound has almost the same audio spectrum in the example and the comparative example, the vibration detection device 1a provided with the space s is also similar to the vibration detection device 1 provided with no space s. It can be seen that the characteristics are obtained.

  Although the space s is provided between the vibration film 33 and the silicone 4 as described above, the same sensitivity characteristic as that in the case where the space s is not provided can be realized because the contact surface between the space s and the silicone 4 is formed in a dome shape. It is thought that this is due to For example, when the contact surface has a planar shape as shown in FIG. 28, the vibration transmitted from the vibration source via the silicone 4 proceeds perpendicular to the contact surface. That is, vibration is transmitted to the vibration film 33 perpendicular to the surface of the vibration film 33. In this case, the vibration transmitted to the vibration film 33 is dispersed depending on the position where the vibration enters. On the other hand, in the case of the dome shape, the vibration enters the normal portion with respect to the curved surface of the dome, and therefore the vibration is likely to gather at the center portion of the vibration film 33. Therefore, the dome shape has better vibration transmission efficiency than the flat shape, and as a result, the detection accuracy increases.

  As described above, according to the second embodiment, since the space s is provided between the vibration film 33 and the silicone 4, the vibration film 33 and the silicone 4 are separated by the space s and the vibration detection device 1a is brought into contact with the vibration source. It is possible to prevent pressure from being directly applied to the vibration film 33 through the silicone 4 when it is applied. Therefore, a structure in which the vibration film 33 is not easily damaged can be obtained.

  In addition, the boundary surface between the space s and the silicone 4 has a dome shape. As a result, even when the space s is provided, it is possible to realize sensitivity characteristics comparable to those when the space s is not provided.

The second embodiment is merely a preferred example to which the present invention is applied, and is not limited to this.
For example, as shown in FIGS. 29 and 30, instead of the ribs 23, a dome-shaped cover 23a may be provided on the boundary surface between the silicone 4 and the space s. In this case, protection of the vibration film 33 can be strengthened.

  It can be used in the field of acoustic technology and can be applied to a microphone device of a mobile phone.

Claims (8)

A vibration transmission medium whose one surface can contact the vibration source;
A vibration detection element having a vibration film in contact with the other surface of the vibration transmission medium;
In a vibration detection apparatus comprising: the vibration transmission medium and an inner case that houses the vibration detection element;
An inner wall of the inner case that houses the vibration transmission medium, wherein a rib is stretched between the vibration film and a contact surface of the vibration transmission medium with a vibration source, and the rib is disposed in the vibration transmission medium. A vibration detecting device embedded in An outer case that houses the inner case;
The vibration detecting apparatus according to claim 1, wherein an engaging portion that engages with each other is provided on the outer case and the inner case.   The vibration detection apparatus according to claim 2, wherein the inner case and the outer case have different acoustic impedances.   The vibration according to claim 3, wherein the outer case is formed of silicone, and a part of the outer case is formed to protrude from a contact surface of the vibration transmission medium with a vibration source. Detection device. The outer case can be stored in the surrounding member,
An outer surface of the outer case is an engaging portion with the outer member, and holds a gap between the outer surface of the outer case and the inner surface of the outer member when engaged with the outer member. The vibration detecting device according to any one of claims 2 to 4, further comprising an engaging portion formed to support the outer case.   The vibration detection device according to any one of claims 1 to 5, wherein a space is provided between the vibration film and the vibration transmission medium.   The vibration detection apparatus according to claim 6, wherein a boundary surface between the space and the vibration transmission medium has a dome shape. A vibration transmission medium whose one surface can contact the vibration source;
A vibration detection element having a vibration film in contact with the other surface of the vibration transmission medium;
In a vibration detection apparatus comprising: the vibration transmission medium and an inner case that houses the vibration detection element;
A space is provided between the vibration film and the vibration transmission medium,
A vibration detection apparatus comprising a dome-shaped cover at an interface between the space and the vibration transmission medium, which is an inner wall of the inner case that houses the vibration transmission medium.

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