JP5305857B2 - Bone conduction transducer - Google Patents

Description

  The present invention relates to a bone conduction speaker that converts sound information into mechanical vibration and a bone conduction transducer that includes a directional microphone that is highly sensitive to a specific direction.

  Conventionally, bone conduction speakers have been researched and developed as a means for transmitting sound information to persons with disabilities in the sound transmission part of the outer ear and the inner ear, and as a means for clearly transmitting sound information in a noisy environment. The bone conduction speaker is a conversion device that converts sound information into mechanical vibration and transmits the vibration to the human head. This mechanical vibration is transmitted to the auditory organ through the bone of the human head and is sensed as sound. Conventionally, a cellular phone and a transmission / reception apparatus provided with such a bone conduction speaker have been devised (for example, Patent Documents 1 and 2). In addition, a method using a directional microphone having high sensitivity in a specific direction has been proposed in order to enable a clear call in a noisy place (for example, Patent Document 3).

JP 2003-348208 A JP 2000-341778 A Japanese Patent Laid-Open No. 10-290491

  When a cellular phone or a transmission / reception device provided with a bone conduction speaker proposed in Patent Document 1 and Patent Document 2 is used in a noisy environment, it is effective for listening to sound information clearly (receiving), There is an effect to ensure the reception. However, regarding the transmission of sound information spoken by the user to the other party (transmission), the microphone picks up the surrounding noise as part of the sound information. It has become.

  The directional microphone as proposed in Patent Document 3 for enabling a clear call in a noisy environment makes it difficult to pick up ambient noise due to its directivity, and the user's Since the voice is strongly picked up, the other party can easily hear the voice of the user.

  As described above, if a directional microphone is used for the bone conduction transmitter / receiver, at least the ambient noise included in the voice transmitted to the other party can be reduced, and the user can comfortably transmit / receive the speech. However, when a bone conduction speaker is used as a speaker for reception in the bone conduction transmitter / receiver, there arises inconvenience different from the case where a general air conduction speaker is used as a speaker for reception.

  Bone-conducting speakers have an order of magnitude greater mechanical vibrations transmitted to the housing than ordinary air-conducting speakers, so mechanical vibrations are also transmitted to the surrounding structure of the directional microphone inside the housing. Sound waves are generated by mechanical vibration, and the level at which the directional microphone picks up the mechanical vibrations and sound waves increases.

  In this way, if the directional microphone picks up the mechanical vibrations transmitted to the housing and the sound waves generated by the vibrations, the sound information sent from the other party may return to the other party's speaker as it is. Occur. Such a phenomenon is called echo back.

  In order to reduce the echo back, various proposals have been conventionally made. For example, mechanical vibrations transmitted to a directional microphone by holding the directional microphone and the structure holding the directional microphone through a soft vibration-proof structure and with a contact surface that is as small as possible. A structure that reduces this is considered.

  However, as described above, the echo back is generated not only by the mechanical vibration directly transmitted to the directional microphone, but also by a sound wave generated inside the housing by vibrating the surrounding structure. As a result of intensive studies by the present inventors, a condenser-type small microphone that is often used in recent portable communication devices, including a directional microphone, is more sensitive to mechanical vibrations that are directly transmitted to the microphone. It was found that the sensitivity to sound waves generated inside the body was much greater. In the holding structure using the above-mentioned soft vibration-proof structure with a small contact surface, high-frequency mechanical vibrations are difficult to be transmitted, but the sound collection part of the microphone is not high, so it occurs inside the housing. The sonic wave goes around the sound collection space of the microphone, and the microphone picks up the sound.

  Furthermore, if the microphone is held by a soft vibration-proof structure, the microphone will not vibrate when mechanical vibration from the bone conduction speaker occurs, but the housing will vibrate. And, since the distance between the inner wall of the housing and a small space changes relatively due to mechanical vibration from the bone conduction speaker, the sound pressure changes in the space facing the sound collection surface of the microphone, Sound waves are generated. For this reason, the microphone picks up the sound wave generated by the mechanical vibration from the bone conduction speaker, and the echo back is further generated.

  In addition, the directivity microphone support structure often affects the directivity performance. This is due to the reason described below. A directional microphone is generally made to have the most ideal directivity when placed alone in a sound wave space. In a product having only a single microphone function, the directional microphone element can be held with a surrounding structure with relatively few obstacles to sound waves, so that the directivity of the directional microphone can be ensured. However, when a directional microphone element is assembled in a product having a comprehensive function of communication means such as a cellular phone, the appearance design of the product, economics of manufacturing, protection of the microphone element, and space with other internal components There are many conditions that need to be adjusted, such as general distribution, and it is difficult to make a directional microphone holding structure that has no obstacle to sound waves (low propagation resistance) around the directional microphone. For this reason, due to structural balance and the like, it is necessary to devise a device that does not disturb the directivity of the directional microphone as much as possible.

  The present invention has been made in view of such problems, and its technical problem is to reduce the echo back, ensure the directivity of the directional microphone, and perform bone conduction that allows comfortable transmission and reception even in a noisy environment. It is to provide a transmission / reception device.

The present invention relates to a bone conduction speaker that converts sound information into mechanical vibration, a main body outer case that houses the bone conduction speaker, a plate-shaped directional microphone that has sound collection holes on both sides that serve as a sound collection surface, and A bone conduction transmitter / receiver device including a flip that houses the directional microphone and is held by the main body outer case, and forms a storage space for storing the directional microphone at a substantially central position on an inner wall of the flip. A cylindrical rib structure, an L-shaped and plate-like shape having a notch on the center side of the storage space, and one surface serving as a sound collection surface of the directional microphone ; A plurality of holding members that hold a side surface adjacent to one surface serving as a sound collection surface in the notch are integrally formed, and the cylindrical rib structure and the holding member have rigidity equal to or higher than that of the flip. Have The storage space is a space that is partitioned by the tubular rib structure and has no spatial connection with the other spaces in the flip, and is omnidirectional with respect to the outer shape of the directional microphone. Each of the sound collecting surfaces of the directional microphone faces each other in a state where the directional microphone is housed in the housing space, and the two small spaces are formed by the directional microphone. A bone conduction transmitter / receiver characterized by having a spatial connection by a space facing a side surface of a portion not held by the holding member.

  Further, according to the present invention, at least one through hole for collecting sound that communicates between the storage space and the outside is provided in two opposing inner walls of the flip forming the storage space, and each of the flips The bone conduction receiver is characterized in that the total area of the through holes in the inner wall is larger than the total area of the sound collecting holes of the directional microphones facing each other.

  According to the present invention, the housing space for the directional microphone is sealed, and the mutual position between the directional microphone and the casing or the surrounding structure is relatively difficult to change, thereby enabling the bone conduction speaker machine. The effect of air vibration inside the flip generated by mechanical vibration is blocked, and the generation of sound waves in the sound collection space of the directional microphone due to mechanical vibration of the bone conduction speaker can be reduced, and the echo back is reduced. In addition, the structure of the small space before and after the directional microphone and the structure of the side space, and the total area of the through holes for capturing sound waves provided in the flip are designed in a balanced manner, ensuring the directivity of the directional microphone. It is possible to provide a bone conduction transmission / reception apparatus that can perform comfortable transmission / reception.

  Embodiments of a bone conduction transmitter / receiver according to the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a configuration of a bone conduction transmitter / receiver according to the present invention. The bone conduction transmitter / receiver device 1 according to the present embodiment complies with a predetermined wireless communication standard, and operates as a slave unit of the mobile phone while performing wireless communication with a mobile phone (not shown). . In the present embodiment, it is assumed that the bone conduction receiver 1 conforms to the Bluetooth (registered trademark) standard.

  As shown in FIG. 1, a bone conduction transmitter / receiver device 1 of the present invention includes a bone conduction speaker 2, a call button 3, a volume switch 4, a light emitting diode (hereinafter abbreviated as LED) 5, a body case 8, and a flip. 9 is provided.

  The bone conduction speaker 2 converts a radio signal transmitted from a mobile phone by Bluetooth communication into mechanical vibration. The call button 3 is a button for performing an operation input such as a call start and a call end of the bone conduction transmitting / receiving apparatus 1. The volume switch 4 is an operation switch for adjusting the volume of the bone conduction speaker 2. The LED 5 is provided to notify the user of the state of the apparatus, for example, to notify an incoming call by blinking.

  The main body case 8 is a housing of the bone conduction transmitter / receiver 1. The body case 8 is provided with a bone conduction speaker 2, a call button 3, a volume changeover switch 4, and an LED 5. Although not shown, the main body case 8 also stores a circuit board for controlling wireless communication and the like, and switches for switching a microphone to be used between a directional microphone and an omnidirectional microphone.

  The flip 9 is a case different from the main body case 8 connected to the main body case 8 via the hinge portion 10 which is a part of the main body case 8. The hinge portion 10 pivotally supports the flip 9 on the main body case 8 so as to be rotatable. When the bone conduction transmitter / receiver 1 is not used, the flip 9 is housed in the recess of the main body case 8 in which the call button 3 and the LED 5 are disposed. Is moved to a position as shown in FIG. The flip 9 accommodates a directional microphone, an omnidirectional microphone, and the like, which will be described later, and is provided with a sound wave capturing hole 11a for the directional microphone and a sound wave capturing hole 11f for the omnidirectional microphone. ing.

  Note that the bone conduction transmitter / receiver device 1 according to the present embodiment is generally used in a state where the bone conduction speaker 2 is placed near the user's ear and the flip 9 is located near the user's mouth. Is.

  Next, the internal structure of the flip 9 will be described. 2 to 7 show the internal structure of the flip 9. FIG. 2 is an exploded perspective view of the flip according to the present invention. FIG. 3 is an inside perspective view on the flip according to the present invention. FIG. 4 is an enlarged view of part A of FIG. FIG. 5 is an inner perspective view under the flip according to the present invention. 6A and 6B are diagrams showing the structure of a flip according to the present invention. FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view taken along the line BB of FIG. FIG. 7 is an enlarged view of a portion C in FIG.

  As shown in FIG. 2, the flip 9 includes a flip upper 11 and a flip lower 12 as a housing, and the flip 9 is formed by these two. At the time of use, the flip top 11 faces the user side, and the flip bottom 12 faces the opposite. As shown in FIGS. 2 and 3, a directional microphone 6, an omnidirectional microphone 7, two dustproof sheets 13, and an antenna are included in the flip 9 formed by the flip upper 11 and the flip lower 12. The antenna mounting board 14 and the flip stopper 15 are accommodated.

  The directional microphone 6 and the omnidirectional microphone 7 pick up the user's voice. As shown in FIG. 2, the directional microphone 6 has a disc shape, and sound collecting holes are formed on both circular surfaces, and both surfaces are sound collecting surfaces. Although not shown, the directional microphone 6 has thirteen sound collecting holes with a diameter of 0.4 mm on the circular surface on the flip upper 11 side, and has a diameter on the circular surface on the flip lower 12 side. Two 0.6 mm sound collecting holes are provided. The upper flip 11 and the lower flip 12 are provided with sound wave capturing holes 11 a and 12 a for the directional microphone 6, respectively. The omnidirectional microphone 7 is also disk-shaped, and the sound collection surface is provided only on the circular surface on the flip 11 side.

  The dustproof sheet 13 is for protecting the directional microphone 6 from foreign matters such as dust mixed from the outside. The antenna and antenna mounting substrate 14 are an antenna for Bluetooth communication and a substrate on which the antenna is mounted. The flip stopper 15 is a cushioning material for relaxing the collision sound with the main body case when the flip 9 is closed.

  Further, as shown in FIGS. 3 and 4, on the inner wall of the upper flip 11, there are three directional microphone holding ribs 11b, an inner cylindrical rib 11c, and an outer cylinder as a structure for holding the directional microphone. A cylindrical rib 11g for holding the omnidirectional microphone is provided as a structure for holding the omnidirectional microphone. Further, as shown in FIG. 5, a cylindrical rib 12 b is provided on the lower flip 12.

  Further, the inner cylindrical rib 11c and the outer cylindrical rib 11d on the upper flip 11 are provided with lead wire takeout notches 11e, and the lead rib takeout notch 12c is provided on the cylindrical rib 12b below the flip. Is provided. The lead wire of the directional microphone 6 is taken out from a lead wire take-out port constituted by lead wire take-out notches 11e and 12c provided on the upper flip 11 and the lower flip 12.

  The arrangement of the components when the flip 9 is assembled will be described with reference to FIGS. As shown in FIGS. 6 and 7, the directional microphone 6 includes an inner cylindrical rib 11 c and an outer cylindrical rib 11 d provided on the upper flip 11, a cylindrical rib 12 b provided on the lower flip 12, and a flip It is stored in a directional microphone storage space 17 formed by the inner wall of the upper 11 and the inner wall of the lower flip 12. The omnidirectional microphone 7 has a cylindrical omnidirectional shape formed by a cylindrical rib 11g for holding an omnidirectional microphone provided on the upper flip 11, an inner wall of the upper flip 11, and an inner wall of the lower flip 12. It is stored in the microphone storage space 18.

  The directional microphone 6 is joined to three L-shaped directional microphone holding ribs 11b integrally formed on the flip top 11 and the inner wall of the inner cylindrical rib 11c. They are arranged so as to float in the microphone storage space 17. The directional microphone 6 and the directional microphone holding rib 11b are coupled with high rigidity with an epoxy adhesive or the like.

  As shown in FIG. 7, the directional microphone storage space 17 is formed by fitting the inner cylindrical rib 11c, the outer cylindrical rib 11d, and the cylindrical rib 12b, and the directional microphone storage space 17 is flipped. It is separated from the inner space. That is, since there is no spatial connection between the directional microphone storage space 17 and the flip inner space, the propagation of the sound waves between each other is blocked. Therefore, the sound waves generated in the flip inner space due to the mechanical vibration of the bone conduction speaker being transmitted to the flip 9 are prevented from propagating to the directional microphone storage space 17 and being picked up by the directional microphone 6.

  It is desirable to fill the gaps between the ribs of the fitting portion 16 of the inner cylindrical rib 11c, the outer cylindrical rib 11d, and the cylindrical rib 12b and the gap around the lead wire outlet with an adhesive. In this way, ventilation between the directional microphone storage space 17 and the flip inner space can be more effectively blocked, so that sound waves generated in the flip inner space wrap around the sound collection surface of the directional microphone 6. It is possible to more surely prevent it from coming out. Further, by inserting an adhesive into the fitting portion 16, the rigidity of the entire holding structure of the directional microphone 6 can be increased.

  The inner cylindrical rib 11c, the outer cylindrical rib 11d, and the directional microphone holding rib 11b are integrally formed with the upper flip 11, and the cylindrical rib 12b is integrally formed with the lower flip 12. Further, the upper flip 11 and the lower flip 12 are formed of the same material. Therefore, these ribs (the inner cylindrical rib 11c, the outer cylindrical rib 11d, the directional microphone holding rib 11b, the cylindrical rib 12b) and the flip (flip upper 11, flip lower 12) are materials having equal or higher rigidity. Is used to form a highly rigid holding structure. Rigidity and rigidity can be evaluated by referring to the Young's modulus of the resin used for a structure such as a flip or rib.

  For the flip and rib described above, it is desirable to use a resin that is lightweight and has a high Young's modulus. Furthermore, thermoplastic resins and thermosetting resins used in molding methods such as injection molding and transfer molding suitable for mass production. It is desirable to use For example, as a thermoplastic resin, acrylonitrile butadiene styrene resin (ABS), polycarbonate resin (PC), polybutylene terephthalate resin (PBT), polyphenylene sulfide resin (PPS), liquid crystal polymer resin (LCP), polystyrene resin (PS) And acrylonitrile styrene resin (AS) and the like, and examples of the thermosetting resin include a phenol resin, an epoxy resin, an unsaturated polyester resin, and the like. In addition, as in this embodiment, when the flip as the exterior part of the product and the rib as the internal structure are integrally formed, the ABS, taking into consideration chemical resistance, heat resistance, high mechanical strength, etc. PC, PC and ABS composite materials are particularly preferably used, and ABS is used in this embodiment.

  As described above, the directional microphone 6 and the surrounding structure including the inner cylindrical rib 11c of the upper flip 11, the outer cylindrical rib 11d of the flip upper 12 and the cylindrical rib 12b of the lower flip 12 are the directional microphone. It is held by a highly rigid joint via the holding rib 11b. As described above, if the holding structure having a high rigidity is used, the relative distance between the sound collection surface of the directional microphone 6 and the inner walls of the flip upper 11 and the flip lower 12 due to mechanical vibration of the bone conduction speaker. Fluctuations are suppressed and sound waves are not easily generated. Therefore, even when the mechanical vibration of the bone conduction speaker is transmitted to the inner walls of the upper flip 11 and the lower flip 12, the sensitivity of the microphone to the sound wave is higher than the sensitivity to the mechanical vibration. Thus, the echo back phenomenon is reduced.

  When the directional microphone 6 is stored, two small spaces facing the sound collection surface (front surface and rear surface) of the directional microphone 6 are formed in the directional microphone storage space 17. As these two small spaces are made as small as possible, the relative variation in the distance between the sound collection surface of the directional microphone 6 and the inner wall of the upper flip 11 and the inner wall of the lower flip 12 becomes smaller. Generation of sound waves in the directional microphone storage space 17 due to mechanical vibration is suppressed. However, if the inner wall of the upper flip 11 or the inner wall of the lower flip 12 contacts the sound collecting surface of the directional microphone 6 and the sound collecting hole of the directional microphone 6 is blocked, the directivity of the directional microphone 6 is reduced. Therefore, the sound collecting hole of the directional microphone 6 must be blocked.

  Due to the holding structure of the directional microphone 6 as described above, the sound wave generated in the flip inner space due to the mechanical vibration of the bone conduction speaker 2 does not reach the sound collection surface of the directional microphone 6 and is directional. Since the generation of sound waves in the directional microphone storage space 17 is also suppressed, it is possible to prevent the occurrence of echo back.

  The structure for preventing the occurrence of echo back has been described above for the directional microphone holding structure. Next, the structure for ensuring the directivity of the directional microphone will be described.

  As shown in FIGS. 3 and 4, a plurality of through-holes 11a for sound wave acquisition are provided in a substantially central portion of the inner wall of the upper flip 11 that forms the directional microphone housing space together with the inner cylindrical rib 11c. ing. In addition, a sound wave capturing hole 11f, which is a through hole, is provided at the substantially central portion of the inner wall of the upper flip 11 where the cylindrical rib 11g for holding the omnidirectional microphone is formed. The sound wave capturing hole 11a is a sound wave capturing hole for a directional microphone, and the sound wave capturing hole 11f is a sound wave capturing hole for a non-directional microphone. On the other hand, as shown in FIG. 5, a plurality of through-holes for sound waves 12a, which are a plurality of through holes, are provided in the substantially central portion of the inner wall of the lower flip 12 that forms the directional microphone housing space together with the cylindrical rib 12b. . The sound wave capturing hole 12a is a sound wave capturing hole for a directional microphone.

  The directional microphone collects sound not only on one surface (front surface) of the sound collecting surface but also on the other surface (rear surface), and obtains directivity characteristics by this differential. Therefore, a balance between the structure of a small space facing the front and rear surfaces of the sound collection surface and the amount of sound waves taken into this small space is also required. Therefore, it is necessary to have a structure that satisfies the above-described conditions for preventing the occurrence of echo back and ensures the directivity of the directional microphone.

  In order to properly maintain the directivity of the directional microphone, it is necessary to consider the balance of sound waves taken into the sound collecting holes provided on both sound collecting surfaces of the directional microphone. Ideally, there are no structures (holding members such as flips or directional microphone holding ribs on the outer wall) that obstruct sound wave reception around the directional microphone. In order to protect the directional microphone from the manufacturing cost, pressure applied from the outside, impact, and mischief, the outer wall and the holding member must be provided. As a result of optimizing these contradictory conditions, the following directional microphone holding structure, the structure of two small spaces where the sound collection surface of the directional microphone faces each flip, and the sound collection hole and flip of the directional microphone are used. The relationship of the total area of the sonic wave taking holes provided was adopted.

  In a directional microphone storage space consisting of two small spaces where both sound collection surfaces of the directional microphone and each flip face each other, and a space facing the side surface of the directional microphone that connects the two small spaces, the directional microphone is It is partially held by three directional microphone holding ribs. With this configuration, the side space of the part where the directional microphone is not held is spatially connected to the two small spaces facing the sound collection surface of the directional microphone, and directivity in a state where the propagation resistance of sound waves is low. A microphone can be installed.

  Furthermore, in order to improve directivity, the total area of the sound wave taking holes provided in the flip is preferably large, but in order to protect the microphone, it is necessary to make the total area as small as possible. Accordingly, as a condition for ensuring good directivity, it is desirable that the total area of the sound wave capturing holes is larger than the total area of the sound collecting holes of the opposing directional microphones. In this embodiment, the total area of the sound collecting holes of the directional microphone is 1.63 square mm on the front surface (13 holes with a diameter of 0.4 mm) and 0.57 square mm on the rear surface (0.6 mm in diameter). 2 holes). On the other hand, the total area of the sound-acquisition holes above and below the opposing flip is 3.68 square mm (13 holes with a diameter of 0.6 mm) of the sound-acquisition holes on the flip facing the front surface. The sonic wave taking holes under the flip facing the rear surface are 1.41 square mm (5 holes having a diameter of 0.6 mm), which is sufficiently large.

  As described above, in the design of the surrounding structure of the directional microphone and the total area of the sound wave acquisition holes provided in each flip, the directivity of the directional microphone is ensured from among the conditions that can be practically designed, In addition, as an optimum condition for effectively protecting the directional microphone, the two small spaces and the space facing the side surface of the directional microphone are connected in a state where the propagation resistance of sound waves is low, and the two small spaces are connected to the directional microphone. The sound collecting holes on both sound collecting surfaces are made as small as possible so as not to be blocked, and a sound wave taking hole is provided in each flip to sufficiently take sound waves from the outside into these two small spaces. The total area of the holes was designed to be larger than the total area of the sound collecting holes of the opposing directional microphones. With these structures, a good directivity close to the directivity of the directional microphone alone can be obtained.

  The echo back and directivity of the bone conduction transmitter / receiver of the present invention described above were evaluated.

  FIG. 8 shows an evaluation result of echo back. The echo back was evaluated as follows. Amount of directional microphones picking up mechanical vibrations generated from bone conduction speakers and sound waves generated by propagation to the case by inputting a 300mVp-p (peak to peak) sine wave from the function generator to the bone conduction speakers Was measured as an echo level and frequency analysis was performed. The higher the echo level, the greater the echo back. The unit of the echo level is indicated by dBVr in which the measured output voltage (effective value) of the microphone is displayed as a sound pressure level. At this time, a soft rubber sheet (silicon rubber having a thickness of 2 mm) was attached to the bone conduction speaker to reproduce a state in which the bone conduction speaker was in pseudo contact with human skin.

  As Comparative Example 1, the inner cylindrical rib 11c, the outer cylindrical rib 11d, and the cylindrical rib 12b shown in FIGS. 4 and 5 are not provided, and the directional microphone 6 is attached to the directional microphone holding rib 11b with an epoxy adhesive. A fixed one was produced. That is, Comparative Example 1 has a structure in which the directional microphone storage space and the flip inner space are not separated.

  FIG. 9 shows the directivity evaluation results. The directivity was evaluated as follows. A speaker was installed at a position 50 mm away from the directional microphone built in the bone conduction transmitter / receiver, and a 1 kHz sine wave sound wave was output from the speaker at a magnitude of 75 dB (A characteristic). The position of the speaker was rotated 360 degrees around the directional microphone, and the amount of sound waves generated from each angle picked up by the directional microphone was measured as the microphone sensitivity level. The unit of the microphone sensitivity level is indicated by dBVr in which the measured output voltage (effective value) of the microphone is displayed in the sound pressure level.

  As Comparative Example 2, measurement with a directional microphone alone was also performed. The single directional microphone is designed so that the sensitivity is good on the front surface (around 0 ° position) of the microphone, and the sensitivity is low on the rear surface (around 180 ° position) of the microphone. By approaching the characteristics of the single directional microphone, it can be determined that the directivity is good. Further, as Comparative Example 3, in this embodiment, the directional microphones have three L-shaped directional microphone holding ribs 11b provided on the flip top 11 and the inner wall of the inner cylindrical rib 11c shown in FIG. In Comparative Example 3, a directional microphone holding rib is provided on the entire inner wall of the inner cylindrical rib 11c, and the entire periphery of the directional microphone is fixed with an epoxy adhesive. Produced. That is, Comparative Example 3 has a structure in which there are two small spaces in which the directional microphone and the flip face each other, but no space facing the side surface of the directional microphone that connects the two small spaces is provided.

  As is apparent from FIGS. 8 and 9, there is provided a bone conduction transmitter / receiver device that secures good directivity of the directional microphone and suppresses echo back by adopting the surrounding structure of the directional microphone of the present invention. It was confirmed that it was obtained.

  In the present embodiment, it has been described that the directional microphone is sealed and stored in the directional microphone storage space. However, the omnidirectional microphone is also sealed and stored in the omnidirectional storage space. Of course it is good.

  In this embodiment, the bone conduction transmitter / receiver is a handset of a mobile phone. However, the present invention is not limited to this, and the bone conduction transmitter / receiver may be a handset of a landline phone. May be a mobile phone, a transceiver, or the like. In addition, the bone conduction transmitter / receiver may be preferentially connected to the host device or may be a landline telephone receiver.

  In this embodiment, since the disc-shaped directional microphone is adopted, the rib as the structure for holding it is cylindrical, but the shape of the rib (structure) is the shape of the directional microphone. Of course, it can be changed as appropriate. For example, if the directional microphone is a rectangular plate, the shape of the rib may be a rectangular frame.

As described above, according to the present invention, a directional microphone is assembled to the bone conduction transmitter / receiver to improve the transmission performance in a noise environment by ensuring good directivity, and to reduce the echo back. it can. That is, it is possible to provide a bone conduction transmission / reception device including a directional microphone that can perform comfortable transmission / reception even in a noisy environment.

  It is more effective when used as a voice information communication means in a noise environment such as a construction site or a station platform as well as a person with a disability in the sound transmission part of the outer ear and the inner ear.

The external appearance perspective view which shows the structure of the bone conduction transmission / reception apparatus which concerns on invention. The disassembled perspective view of the flip which concerns on this invention. The inside perspective view on the flip which concerns on this invention. The A section enlarged view of FIG. The inside perspective view under the flip concerning the present invention. The figure which shows the structure of the flip which concerns on this invention, Fig.6 (a) is a top view, FIG.6 (b) is the BB sectional drawing of Fig.6 (a). The C section enlarged view of FIG. Echoback evaluation result. Evaluation result of directivity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bone conduction transmitter / receiver 2 Bone conduction speaker 3 Call button 4 Volume switch 5 LED
6 Directional microphone 7 Non-directional microphone 8 Body case 9 Flip 10 Hinge part 11 Flip upper 12 Flip lower 11a, 11f, 12a Sound wave capturing hole 11b Directional microphone holding rib 11c Inner cylindrical rib 11d Outer cylindrical rib 11e, 12c Notch for taking out lead wire 11g Cylindrical rib 12b for holding omnidirectional microphone 12b Cylindrical rib 13 Dustproof sheet 14 Antenna and antenna mounting board 15 Flip stopper 16 Fitting portion 17 Directional microphone storage space 18 Nondirectional microphone storage space

Claims (2)

A bone conduction speaker that converts sound information into mechanical vibration, a main body exterior case that houses the bone conduction speaker, a plate-shaped directional microphone that has sound collection holes on both sides that serve as a sound collection surface, and the directivity A bone conduction transmission / reception device comprising a microphone and a flip held by the main body outer case, and a cylindrical rib forming a storage space for storing the directional microphone in a substantially central position on the inner wall of the flip A structure,
The cylindrical rib structure is L-shaped and plate-like having a notch on the center side of the storage space, and one surface that becomes the sound collection surface of the directional microphone and one surface that becomes the sound collection surface A plurality of holding members are integrally formed, and the cylindrical rib structure and the holding member are made of a material having a rigidity equal to or higher than that of the flip.
The storage space is a space that is partitioned by the cylindrical rib structure and has no spatial connection with other spaces in the flip, and is larger in all directions than the outer shape of the directional microphone, In the state where the directional microphone is stored in the storage space, the sound collecting surface of the directional microphone has two small spaces facing each other, and the two small spaces are holding members of the directional microphone. A bone conduction transmitter / receiver characterized by having a spatial connection by a space facing a side surface of an unheld portion.   At least one through hole for collecting sound that communicates between the storage space and the outside is provided in two opposing inner walls of the flip that form the storage space, and the through hole in each inner wall of the flip The bone conduction transmitter / receiver according to claim 1, wherein the total area of each is larger than the total area of the sound collecting holes of the directional microphones facing each other.

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