JPH0112469Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a vibration detection microphone that is used in contact with the cheek, mastoid region of the temporal region, etc., and is used in various communications equipment, audio equipment, etc. used for.

[Conventional technology]

Hands-free voice control type transceivers are used for conversations between multiple people located far apart at construction sites, workplaces, group activities at schools, etc., and foreign language learning devices are used to A handset with a headphone and a microphone attached to a headband is used to communicate between a specific learner and a teacher through a child's device.

As shown in FIG. 5, such a handset has an interactive microphone c attached to one end of the headband a via an arm b, and a headphone (not shown) attached to the other end. A headphone is placed in front of the person's mouth and outputs the sound from the other party, and is used with one ear covered.

However, in such a handset, all external noises existing in the external environment are input together with the voice generated from the mouth to the microphone c, so it is difficult for the side receiving the voice input to hear the voice input mixed with noise. You will hear the audio.

For this reason, for example, at a work site where industrial machinery or civil engineering machinery is in operation, the above-mentioned handset has the disadvantage that it cannot function satisfactorily for business-related conversations. Furthermore, even if such a handset is attached to a motorcycle rider, at speeds of 30 km/h or higher, wind noise will significantly interfere with the conversation, making it impossible to talk, and even at high-place construction sites, it will be difficult to communicate at wind speeds of 8 m/h or higher. It has been confirmed that this occurs.

On the other hand, in response to this, ear plug-type bone conduction microphones that are inserted into the external ear canal have been provided.

The bone conduction microphone uses an encapsulating body with an insert that receives sound vibrations in the ear canal to transmit bone vibrations to a piezoelectric element, and polarizes the piezoelectric element via a lead wire in response to the generation of strain caused by this vibration. A voltage is obtained, this voltage is reproduced as sound via an amplifier, etc., the necessary sound quality correction is performed, and the sound is output to earphones or headphones for listening.

Therefore, external noise is not input to this bone conduction microphone together with the audio signal.

However, when an earplug-type bone conduction microphone like the one above is assembled into a handset together with a headphone like the one above, the headphone and bone conduction microphone end up blocking the left and right ear holes, respectively. When used for such purposes, external sounds and other on-site work noises will not directly enter the ears, which is extremely dangerous. Furthermore, when a bone conduction microphone is used for a long period of time, the ear canal feels tender, causing various hygiene problems.

On the other hand, it is placed in contact with the temporal mastoid process behind the ear or the lower edge of the temporal bone without blocking the ear, so it is not bothered by external sounds and noises, and only clear sounds can be converted into sound. Bone conduction microphones are also available (see Utility Model Application No. 59-31885).

The bone conduction microphone 6 is shown in FIG. In the figure, reference numeral 8 denotes a synthetic resin housing having a U-shaped cross section, and a flexible diaphragm 9 is stretched over the open end on the side of the housing 8 so as to close it. At the center of the inside of this flexible diaphragm 9,
A piezoelectric element 10 is attached which causes distortion in the crystal when subjected to vibration. Reference numeral 11 denotes a lead wire that is polarized by the above distortion of the piezoelectric element 10 and takes out the polarized voltage generated between the diaphragm 9 and the piezoelectric element 10 to the outside via a resistor or other impedance conversion element. Reference numeral 12 denotes a sensing projection protruding from the outside of the central portion of the diaphragm 9. Further, the housing 8 is attached to the headband 5 with screws 13.

In such a bone conduction microphone 6, sound vibrations transmitted to the mastoid process etc. during vocalization are transmitted to the piezoelectric element 10 via the flexible diaphragm 9, and the piezoelectric element 1
0, a polarization voltage is generated between the diaphragm 9 and the diaphragm 9, and the change in the polarization voltage can be extracted to the outside as a change in the audio signal. This audio signal undergoes necessary sound quality correction and is output to an external headphone or the like so that it can be listened to.

[Problem that the invention attempts to solve]

However, in such a conventional bone conduction microphone structure, the ends of the sensing protrusions 12 are attached to the center of the flexible diaphragm 9 whose periphery is fixed as shown in FIG. When an external force is applied to the sliding adjustment rod 5 or the sensing protrusion 12, the stress concentrates on the center of the flexible diaphragm 9, causing the center to bend significantly, causing the piezoelectric element attached here to bend. There was a problem that I was losing money.

However, in order to solve this problem, the flexible diaphragm 9
A method of increasing the rigidity or reinforcing it by increasing the wall thickness has been considered, but in this case, new problems such as an increase in the external size and a change in vibration frequency characteristics have arisen.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is designed so that the sensing protrusions of the vibration sensing plate directly transmit vibrations to two locations other than the area where the piezoelectric element is provided on the flexible diaphragm. The stress generated in the flexible diaphragm due to an applied external force is dispersed around the piezoelectric element so that it is not directly applied to the piezoelectric element, thereby reliably preventing breakage or damage to the piezoelectric element.

[Effect]

In this invention, a flexible diaphragm is installed in the opening of the housing, and two sensing protrusions integrated with a vibration sensing plate that comes into contact with the human body are coupled to the outer surface of the flexible diaphragm. In addition, since a piezoelectric element is attached to the inner surface of the flexible diaphragm corresponding to the intermediate portion of the two sensing protrusions, external force acting on the vibration sensing plate can be absorbed by the attachment of the piezoelectric element. The piezoelectric element is efficiently dispersed in the flexible diaphragm except for parts thereof, and destruction of the piezoelectric element due to deformation of the flexible diaphragm is reliably prevented.

〔Example〕

1 and 2 show an embodiment of the vibration detection type microphone of the present invention. In the same figure, 21
is a highly rigid cylindrical casing made of synthetic resin or metal molding, and both ends of a flexible diaphragm 22 are held on the inner periphery of one open end of the casing. For this holding, any means among fitting, adhesion, and fastening using other fastening members is selectively used.

The flexible diaphragm 22 has a curved shape, for example, an inverted S-shape as shown in the figure (a simple S-shape is also the same)
, and its total length is set to ₁ . This can be obtained by punching a metal plate with high vibration transmission sensitivity.

Reference numeral 23 denotes a drip-proof cover that seals the open end of the housing 21 to prevent sweat and raindrops from entering the housing 21, and its peripheral portion fits into the outer surface of the housing 21.

Reference numeral 24 denotes a vibration sensing plate that comes into contact with the cheeks and the mastoid part of the temporal region, and two sensing protrusions 25 protruding from the inside thereof at a certain distance apart penetrate through the drip-proof cover 23. , and is further fixed through two mounting holes 26 of the flexible diaphragm 22. In other words, the vibration sensing plate 24 is supported by the flexible diaphragm 22 at two points.

27 is a flexible diaphragm 2 between two sensing protrusions 25
2. It is a piezoelectric element attached by pasting it on the inside.

28 is an electronic circuit board installed in the center of the housing 21, and electronic circuit components 29 placed on this electronic circuit board 28 include resistors, impedance conversion elements, etc.
It is connected to the piezoelectric element 27 by a lead wire 30.

31 is a lead wire that leads the impedance-converted signal voltage to the outside.

A cover plate 32 closes the opening at the other end of the housing 21, and prevents the electronic circuit component 29 and the piezoelectric element 27 from being damaged by direct mechanical external force.

Reference numeral 33 denotes a rubber cover that collectively covers the outer circumference of the case 21, the outer circumference of the drip-proof cover 23, the outer surface of the cover plate 32, and the vicinity of the case attachment part of the external lead wire 31. This effectively prevents vibrations, the sound of hair or clothing contacting the headband or the external lead wire 31, or wind noise from propagating to the housing 21.

34 is a Magic Fastener (registered trademark) affixed to the side surface of the rubber cover 33, so that it can be detachably engaged with another Magic Fastener (registered trademark) affixed to the arm at the end of the headband or the inside of a motorcycle rider's helmet. It's getting old.

FIG. 3 shows how the vibration detection type Microon d is used. This is at one end of headband a,
A microphone d is attached via an arm b, and the microphone d is used as a cheek-contact type microphone that lightly presses against the cheek of the user's face. In this case, the arm c is short as a whole and bent into a dogleg shape. Note that a headphone (not shown) is attached to the other end of the headband a.

Further, FIGS. 7 to 9 show other usage situations of the vibration detection type microphone d of the present invention.

FIG. 7 shows the device used in a telephone handset 41, which has a main body 42 with a speaker section 43 at one end and a vibration detection microphone d of the present invention at the other end. ing. The main body 42 is moderately curved, and when the speaker part 43 is brought into contact with the ear part, the vibration detection microphone d
is pressed against the cheek.

FIG. 8 shows a transceiver 44 used, which includes a main body 45, an antenna 46, a panel section 47, and a transmit/receive switch 4.
8, a speaker section 49, and a vibration detection type microphone d of the present invention. The front surface 50 of the main body 45 is moderately curved, and the speaker section 49
and a vibration detection microphone d are brought into contact with or pressed against the ear and cheek, respectively.

FIG. 9 shows a hand microphone 51 used for a radio device, and the hand microphone 51 for a radio device is equipped with an ordinary microphone 52 for detecting air vibrations of voice.
A vibration detection microphone d of the present invention is also provided. 53 is a transmission/reception changeover switch, and 54 is a microphone changeover switch. When there is noise in the surroundings, the noise can be reduced by pressing the vibration detection microphone d against the cheek or the like, and when there is no noise in the surroundings, the microphone changeover switch 54 can be switched to use the normal microphone. If 52 is used, transmission with particularly good sound quality can be achieved.

When the vibration detection microphone d having the above configuration is used in contact with the cheek as described above, air vibrations generated in the throat and oral cavity are directly propagated to the cheek flesh. The vibration is immediately propagated through the vibration sensing plate 24 that is in contact with the outer surface, and the vibration is further propagated to the flexible diaphragm 22 via the sensing projections 25. Since the piezoelectric element 27 is provided on the flexible diaphragm 22, the piezoelectric element 27 receives this vibration, and a polarization voltage is generated between the piezoelectric element 27 and the flexible diaphragm 22. Therefore, after impedance conversion is performed on this polarization voltage, it is taken out via the external lead wire 31, subjected to necessary processing, and then sent out.

By the way, the sensing protrusion 25 of the vibration sensing plate 24
As shown in FIG. 4a, is mounted on the flexible diaphragm 22 on the opposite side so as to straddle the piezoelectric element 27. Therefore, even if some external pressure acts on the vibration sensing plate 24 and the sensing protrusions 25 transmit an impact to the flexible diaphragm 22, the portion where the flexible diaphragm 22 is deformed by the impact is 4
As shown in FIG. b, this is the peripheral area excluding the mounting surface of the piezoelectric element 27. Therefore, no force is applied directly to the piezoelectric element 27 itself. In addition, since the stress is dispersed at two points around the area, the conventional
It is possible to alleviate the concentration of force that would occur in the case of point support, and the flexible diaphragm 22 can be protected.

Further, the flexible diaphragm 22 is as shown in the second diagram.
The structure is bent in an inverted S shape instead of a straight line, so the space it occupies can be kept small.
In addition to being able to be housed in a small housing 21, it is also easy to select the resonance frequency of vibration.

Note that the vibration detection type microphone d can be used as a bone conduction type microphone. In this case, bone conduction in the outer ear is used, so the air vibrations of the voice in the throat and oral cavity are propagated in a complex manner through many bone and cartilage areas in addition to the flesh, making it possible to produce high-pitched sounds necessary for conversation. Partial voices tend to attenuate, and the clarity deteriorates somewhat. On the other hand, when using it as a cheek-contact microphone, the sound mainly passes through only the flesh, so
Attenuation in the treble range is relatively small, making it possible to transmit speech with high clarity throughout the audible frequency range.

[Effect of idea]

The present invention shares the external force acting on the vibration sensing plate between the two locations of the acoustic diaphragm by connecting the sensing protrusions of the vibration sensing plate to two locations on the acoustic diaphragm other than the location where the piezoelectric element is installed. Because it can be propagated by
Stress concentration on the acoustic diaphragm can be prevented, and local bending of the acoustic diaphragm can therefore be avoided. Therefore, damage to the piezoelectric element due to this bending can be prevented.

Further, since the sensing protrusion is not provided at a position where external force is directly transmitted to the piezoelectric element, there is no problem that the impact input to the sensing protrusion directly damages or breaks the piezoelectric element.

Furthermore, since the outer periphery and outside of the microphone other than the vibration sensing plate is covered with a rubber cover,
It can absorb various external noises and effectively reduce noise input.

Experiments have confirmed that with this vibration-detecting microphone, motorcycle riders can communicate clearly even at speeds of 120 km/h with an S/N ratio of over 30 dB.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of the vibration detection microphone of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is an explanatory diagram showing its usage condition, and Figs. 4 a and b are flexible vibrations caused by the sensing element. An explanatory diagram showing the situation before and after the plate is deformed, Fig. 5 is an explanatory diagram showing the usage state of a conventional handset, Fig. 6 is a cross-sectional view of a conventional bone conduction microphone, and Fig. 7 is a vibration detection system of the present invention. FIG. 8 is an explanatory diagram showing another usage state of the microphone, and FIG. 9 is an explanatory diagram showing still another usage state. 21... Housing, 22... Flexible diaphragm, 24...
... Vibration sensing plate, 25 ... Sensing protrusion, 27 ... Piezoelectric element, 33 ... Rubber cover.

Claims (1)

[Claims for Utility Model Registration] (1) A flexible diaphragm is installed in the opening of the housing, and on the outer surface of the flexible diaphragm there are two vibration sensing plates that come into contact with the human body. In addition to combining the sensing protrusions,
A vibration detection type microphone characterized in that a piezoelectric element is attached to the inner surface of the flexible diaphragm other than the part where these two sensing protrusions are attached. (2) Utility model registration claim No. 1, in which a piezoelectric element is attached to the inner surface of a flexible diaphragm, which is the middle part of the part where two sensing protrusions are attached.
The vibration detection microphone described in .