JPH06189388A - Ear set type handset - Google Patents

Abstract

PURPOSE:To avoid production of howling, to cancel noise and to attain clear transmission by allowing a transmitter to synthesize outputs between a microphone arranged near a mouth and a microphone arranged at a position apart from the mouth. CONSTITUTION:A swelling part 1a of a case 1 is fixed to an auricle and a sound emitting part 1c is inserted in an external auditory meatus. A transmitter is provided with a microphone 4' located near a mouth and a microphone 4 remote from the mouth and uses a subtractor to synthesize AC outputs of the two microphones 4, 4' so as to cancell with each other. An external radio wave is inputted through a bi-directional simultaneous radio communication device and a voice signal being an electric signal is inputted to a speaker 2 from a connection cord 5 and the sound signal is emilled in an external auditory meatus. Thus, even when the sound volume from the speaker is increased or the sensitivity of the microphone is increased, no howling nor noise is in existence and clear talking is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handset in a two-way simultaneous voice communication terminal, and more particularly to an earset type handset which can be transmitted and received while being worn on an auricle without using a hand.

[0002]

2. Description of the Related Art In recent years, a hands-free type has been developed which allows users to talk while writing in the office while talking and to make a call while driving safely without using hands. Handsets are commercially available. That is, the earpiece is attached to the auricle, and the transmitter is attached in the middle of the cord connecting the handset and the telephone.

A conventional hands-free type handset will be described below with reference to FIG. 1 is a receiver including a speaker 1a inserted into the auricle, and an air hole 1b is provided on the back side.
Are formed. Reference numeral 2 is a cord for connecting the handset to a telephone (not shown), and 3 is a transmitter including a microphone 3a connected in the middle of the cord 2.

In the hands-free type handset having the above-mentioned structure, the handset is attached to the auricle and the handset 3 is attached to the cord 2 near the mouth. However, if the cord 2 is twisted so that the sound collection port 3b of the microphone 3a faces away from the mouth of the speaker, the output level of the microphone 3a decreases and stable sound cannot be collected.

Therefore, if a non-directional microphone 3a is used, ambient noise is picked up and it becomes difficult for the other party to hear it. Further, when the sound collection port 3b of the transmitter 3 touches clothes, the fricative sound is transmitted to the other party as noise, which is also difficult to hear.

To solve these problems, the ones shown in FIGS. 22 and 23 have been developed. Hereinafter, this conventional example will be described. The difference between these two conventional examples and the above-mentioned conventional example is that the speaker 1a and the microphone 3a are housed in the same case.

That is, the speaker 1a is housed in the short tube side of the L-shaped case 4, the microphone 3a is housed in the middle of the long tube side, and the air hole 4 is formed in the back surface of the speaker 1a.
a and the sound collecting port 4 on the front of the microphone 3a.
b is opened. In addition, 2 is the speaker 1a and the microphone 3a derived from the lower end of the case 4.
It is a code that connects the and the telephone.

[Problems to be Solved by the Invention]

In the handset having the above structure,
Since the microphone 3a is integrally attached to the case 4 to be attached to the auricle, the problem as in the conventional example described above can be solved, but the sound wave emitted from the air hole 4a is collected from the sound collection port 4b. Sound waves leaking between the transmitter 1 and the auricle also enter the microphone 3a through the sound collection port 4b, and as a result, a howling phenomenon occurs when the volume is increased even a little.

Therefore, communication must be performed at a volume at which howling does not occur, which causes a problem that a sufficient volume is not transmitted to the other party and it becomes difficult to listen.
Furthermore, if the handset is covered with a hand during a call because it is difficult to hear due to ambient noise, acoustic coupling between the handset and the handset becomes high, and howling easily occurs. In addition, since sound is collected near the ears, there is a problem that reverberation sounds in a room or the like are more likely to be picked up and the intelligibility is lowered than when sound is collected in front of the mouth.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to increase the volume of sound from a speaker to a practically sufficient extent and to increase the sensitivity of a microphone. , Even when the handset is covered with the hand in the mounted state, howling does not occur, and even if the sensitivity of the microphone is increased, ambient noise is canceled, and clear sound can be transmitted without muffled sound. There is a set type handset available.

[0011]

The earset type handset of the present invention is intended to achieve the above-mentioned object, and the means has a structure in which the handset unit can emit sound only in the direction toward the ear canal. And, a sound shielding plate which is integrated with the receiver so that the transmitter is placed outside the external auditory meatus, or a sound shielding plate which is hooked on the upper side of the auricle of the ear and covers the auricle, and an inner surface of the sound shielding plate. A two-way earset type in which a receiver that is attached at a position corresponding to the ear canal and that can emit sound only in the direction toward the ear canal and a transmitter that is arranged on the outer surface of the sound shielding plate are integrated to enable two-way communication A handset comprising: a first microphone placed near the mouth;
The two microphones each including a second microphone disposed farther from the mouth than the other microphones, and a microphone output combining unit that electrically combines the AC outputs of the two microphones so as to cancel each other. Be prepared.

Further, in the transmitter, a microphone having bidirectionality and one sound receiving surface of the microphone having a length of 5
connected to a first pipe having a length of 5 cm or less, the other sound receiving surface is connected to a second pipe having a length of 5 cm or less, and the opening of the first pipe is directed toward the mouth, and the opening of the second pipe is opened. And a sound absorbing material provided on the sound receiving surface side of the microphone in the first and second pipes.

Further, the transmitter has two microphones each of which includes a first microphone arranged near the mouth and a second microphone arranged farther from the mouth than the first microphone. And a microphone output synthesizing means for electrically synthesizing the AC outputs of the two microphones so as to cancel each other out, and an output from the microphone output synthesizing means for a sound of 70 dBSPL or less near the entrance of the ear canal, And a non-linear gain amplifier that realizes amplification whose amplification gain is lower than the sound of 70 dBSPL or more.

Further, in the transmitter, a microphone having bidirectionality and one sound receiving surface of the microphone having a length of 5
connected to a first pipe having a length of 5 cm or less, the other sound receiving surface is connected to a second pipe having a length of 5 cm or less, and the opening of the first pipe is directed toward the mouth, and the opening of the second pipe is opened. The pipe is formed so that the portion faces the direction opposite to the mouth, the sound absorbing material provided on the sound receiving surface side of the microphone in the first and second pipes, and the output of the microphone is the inlet of the ear canal. A non-linear gain amplifier that realizes amplification of a sound with an amplification gain of 70 dBSPL or less in the vicinity thereof is lower than that of the sound with 70 dBSPL or more.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an earset type handset according to the present invention will be described below with reference to FIG. Reference numeral 1 denotes a case formed of a synthetic resin in a substantially L shape, and a bulging portion 1a having a size for entering an entrance of the ear canal is formed on a side of the receiver, which is a short piece side of the L shape, and this bulging portion. There is a vacant room 1 in 1a.
b is formed, and the sound emitting portion 1c is formed at the tip of the bulging portion 1a.
Are formed. It is desirable that the case 1 be formed as an integrally molded product of plastic such as ABS resin.

A vertically long cavity 1d is formed on the transmitter side, which is the long side of the case 1, and microphone housings 1d ₁ and 1d ₂ are formed at both ends of the cavity 1d. Further, small-diameter sound inlets 1e ₁ and 1e ₂ are opened in the outer closed portions of the microphone storage portions 1d ₁ and 1d ₂ .

Reference numeral 2 denotes an electromagnetic or dynamic speaker housed and fixed in a vacant chamber portion 1b of the bulging portion 1a by a support member 3 made of an elastic body, and the sound from the speaker 2 is emitted from the sound emitting portion 1c. Sound is emitted from the sound hole. The speaker 2 may be an open type speaker having an opening near the entrance of the ear canal. 4, 4'is the microphone storage unit 1
It is an electret type microphone (hereinafter, simply referred to as a microphone) housed and fixed in d ₁ and 1d ₂ .

Reference numeral 5 is a connecting cord from the speaker 2 and the microphones 4 and 4 ', which is led out to the outside through the outside of the hollow portion 1d in a state of being integrated into one. As the microphones 4 and 4 ', a compact and highly sensitive electret microphone is most suitable, and since contact noise of the connection cord 5 is also generated, it is preferable to use a back electret type which is hard to pick up vibrations transmitted directly.

Reference numeral 6 denotes a two-way simultaneous radio communication device in a wireless type earset type handset, which comprises a communication section designed to miniaturize a dedicated LSI with a button battery on the back of the earlobe, and the earlobe like an earring. It is installed by sandwiching it (Fig. 2). Although the hollow portion 1d of the case 1 is linear in the above-described embodiment, the hollow portion 1d may have a dogleg shape as shown in FIG.

Next, the operation of the earset type handset having the above configuration will be described. First, the bulging portion 1a of the case 1 is fixed to the auricle, and the sound emitting portion 1c is inserted into the ear canal. In this state, the sound emitting portion 1c has a shape that does not completely block the external auditory meatus, and there is little feeling of blockage, and external sound leaks, so there is no safety problem, and the sound from the sound emitting portion 1c is not heard. There are few leaks. In this embodiment, the speaker 2 is inserted into the vacant chamber 1b of the bulging portion 1a, but the speaker 2 is not placed at the entrance of the ear canal, and the sound pipe is used at another place. It is also possible to guide.

In this way, when the transmitter / receiver is set, when a radio signal from the outside is input to the speaker 2 as an electric signal from the connection cord 5 via the two-way simultaneous radio communication device, the speaker 2 The sound is emitted from. The sound emitted from the speaker 2 is emitted into the ear canal from the sound hole of the sound emitting section 1c.

On the other hand, the voice from the wearer is the voice intake 1
e, 1e 'is transmitted to the microphones 4, 4', and the microphones 4, 4 '
In 4 ', it is converted into an electric signal and is sent out as a radio wave from the connection cord 5 via the two-way simultaneous radio communication device 6.

By the way, in the earset type transceiver of the above-mentioned embodiment, only the voice of the wearer is picked up, and the external noise from the part far from the mouth is not picked up. For this purpose, the transmitter is provided with a microphone 4'closer to the mouth and a microphone 4 placed farther from the mouth than the microphone 4 ', and the AC outputs of the two microphones 4 and 4'cancel each other. It is provided with a microphone output synthesizing means that is electrically synthesized so as to meet each other.

As the microphone output combining means, a subtracter is used when the AC outputs of the two microphones 4 and 4'are in phase with each other.
If the phases are opposite to each other, an adder is used. As will be apparent from the following description, it is convenient and convenient to use two microphones 4 and 4'having the same shape and the same type. Since the audible frequency band for human beings is 50 Hz to 20 KHz, the DC component has no practical meaning in the region handling voice, so in the following description, all inputs and outputs are AC components unless otherwise specified. Will be shown.

First, in order to derive the general expression of the microphone combined output, the two microphones 4 and 4'have the same shape, the same type, and the outputs in phase with each other, and the microphone output combining means changes the output from the microphone 4 to the microphone. Consider the case of a subtractor that subtracts the output of 4 '.

Considering the relationship between the output V when the sound wave radiated from one sound source with sound pressure P is received by the microphone and the distance L to the sound source microphone input section, the sound pressure is attenuated in inverse proportion to the distance. However, since the microphone output is proportional to the sound pressure, the following relationship is generally established: V = k · P / L (k is a proportional constant peculiar to the microphone)

Therefore, the sound produced by a certain sound source P is
The microphone outputs when received by the two microphones 4 and 4'are V ₁ and V ₂ , respectively, the distances L ₁ and L ₂ between the sound source and the voice inlet of the microphone 4 and the voice inlet of the microphone 2, and the proportions of the microphones 4 and 4 '. When the constants are k ₁ and k ₂ , the output of the microphone 4 becomes the microphone 4 '
The combined transmitter output V _{0 from} which the output of ₁ is subtracted is expressed by the following equation. V ₀ = V ₁ −V ₂ = (k ₁ · P / L ₁ ) − (k ₂ · P / L ₂ ) ── (2)

Then, as described above, the two microphones 4,
Since 4'has the same shape and the same type, k ₁ = k ₂ =
It is considered to be k, and the equation (2) can be rewritten as the following equation. V ₀ = kP {(1 / L ₁ )-(1 / L ₂ )} = kP / L ₁ {1- (L ₁ / L ₂ )} ── (3)

The reason why ambient noise can be eliminated when the sound source P is at a distant position as shown in FIG. 4 will be described by using the general expression of the microphone combined output expressed by the equation (3). When the two distances between the microphone 4, 4 'and the L _3, if L ₁ and L ₂ is sufficiently large in proportion to L _3, with an approximately 10-fold or more values of L _3, i.e., the sound source P is If you're far enough,
L ₁ and L ₂ have almost the same value. Therefore, from the equation (3), V
₀ is approximately equal to zero.

This is a sound emitted from a sound source P far away,
That is, it means that the transmitter of the present invention produces almost no output with respect to ambient noise for the transmitter / receiver. Specifically, since the value of L ₃ can be set to about 5 cm, the specific value at a distance far enough to remove noise is about 50 cm or more, which is a very preferable value for practical use.

Next, as shown in FIG. 5, the reason why a synthesized output having a sufficient size can be obtained when the sound source P is the mouth of the wearer sufficiently close to the two microphones 4 and 4 '.
The distance between the center of the wearer's lip M and the entrance to the ear canal is approximately 14 cm.
Considering that L ₃ is 5 cm, the distance L ₁
And L ₂ becomes large, and L ₁ / L ₂ is sufficiently smaller than 1, V ₀ has a sufficiently large value as an output from the above equation (3).

This means that the mouthpiece of the present invention produces a sufficiently large output for speech emitted from the mouth. Further, in the structure as shown in FIG. 3 described above, L ₁ / L ₂ can be reduced and V ₀ can be increased by bringing the microphone 4 ′ as close to the mouth as possible and moving the microphone 4 away from the mouth.

Next, the reason why howling can be suppressed by the sound from the speaker when the sound source P is a built-in speaker as shown in FIG. 6 will be described. Even if the distance between the speaker 2 and the microphones 4 and 4'is small, it is located between the voice outlet of the receiver soaker 2, the voice inlet of the microphone 4, and the voice inlet of the microphone 4 ', and the voice outlet of the speaker 2 is the microphone 4 L ₁ and L ₂ are substantially equal to each other at a distance substantially equal to the voice inlet of, the expression (3) indicates that the output of the transmitter hardly leaks from the receiver.

This indicates that the sound leaking from the handset to the transmitter is amplified by the feedback from the transmitter to the receiver and the howling phenomenon in which the speaker as the receiver emits a ringing sound does not occur. As the microphones 4 and 4'in the above description, either omnidirectional or unidirectional microphones can be used, but a unidirectional microphone is used to direct the microphone 4'to the mouth. , By pointing the microphone 4'in the direction far from the mouth, the microphone sensitivity to the sound from the mouth can be further improved.

Next, as the microphones 4 and 4'shown in FIG. 7, electret microphones having open rear surfaces are attached to both ends of the hollow portion 1d of the case 1, and the hollow portion 1d is inserted in the middle portion of the hollow portion 1d. A description will be given of a case in which a voice inlet is formed so that the microphone voice outputs inside the cavity 1d are offset from each other, and only the difference in voice output from the outside of the cavity 1d is taken out as a transmitter output. .

That is, the electrode surfaces 4a, 4a '(rear surfaces) of the two microphones 4, 4'are arranged so as to face each other, and the sound inlet is inserted into the cavity portion 1d corresponding to the substantially central portion between the respective microphones 4, 4'. Open 1 g. The distance Lp ₁ from the voice intake 1g to the electrode surfaces 4a, 4a ′ of the microphones 4, 4 ′,
Since Lp ₂ is substantially equal and all external sounds reaching the electrode surfaces 4a and 4a 'pass through the sound intake port 1g, the distance Lp between the sound source P and the electrode surface sound entrances of the two microphones 4 and 4'. Correspond to each other.

Therefore, the electrode surfaces 4 of the two microphones 4 and 4 '
The microphone voice outputs from the a and 4a 'sides are substantially the same and cancel each other when they are subtractively combined. Therefore, the combined microphone output becomes a difference between the microphone outputs from the front side, and the sensitivity and directivity are reduced. It will be very advantageous.

The voice inlet 1g described above can be used together with the outlet for the connection cord 5. Further, by realizing the microphone output synthesizing means in the hollow portion 1d, it is possible to further reduce the size of the transmitter, reduce the number of lead wires, and increase the degree of integration.

Next, a method for constructing a microphone output synthesizing means by using two 4,4 'electret condenser microphones 4 and 4'having two terminal outputs will be described. To take out the output of this type of microphone, use the positive DC power supply + Vcc, load resistance RL, and DC cut capacitor C.
Is the most general method in which the AC output v is obtained via the capacitor C by connecting as shown in FIG. The microphone output synthesizing means used in the present invention is basically a microphone output v ₁ and a microphone output v ₂ individually extracted by using this method, and a subtracting means or an adding means is added.

In-phase microphone 4 used in the above description
As a typical example in the case where the AC outputs v ₁ and v _{2 of the} microphone 4'and the microphone 4'are in phase with each other, there is one using a subtracter D as shown in FIG. In the figure, + Vcc is a positive DC power source E, R _L1 and R _L2 are load resistances, C ₁ and C ₂ are DC cutting capacitors, and there are four calculation elements having a common resistance value R with the operational amplifier OP _1. The resistors R _A1 , R _A2 , R _A3 , and R _A4 form a subtractor D having a gain of 1, and a combined output v ₀ = v ₁ -V ₂ is taken out.

[0041] Here, RA ₁ is a sufficient large value of 20 times or more of R _L1 and R _L2, for C _1, C ₂ is to pass the AC above 50 Hz, from _{1 / 2πfcR A (fc = 50Hz} ) Use a large value. R _L1 and R _L2 are microphone 4 and microphone 4 '
Have the same shape and type, and have almost the same sensitivity,
For example, if the products are of the same type and the same production lot, R _L1 = R _L2 may be set. However, if there is a difference in sensitivity, one of the values may be adjusted to obtain an accurate difference. You can

On the other hand, depending on the structure of the microphone, 2
The AC outputs v ₁ and v ₂ of the two microphones 4 and 4 ′ can be made opposite in phase to each other. As a typical example of the output synthesizing means in this case, there is an adder S shown in FIG. 10.
_{+ Vcc, E, R L1,} R L2, C 1, C 2 is the same role as that of phase described above, five operational elements and the operational amplifier OP _2, OP ₃ have a common resistance value R _B resistance R _B1 Up to R _B5 form an adder S having a gain of 1, and the combined output v ₀ = v ₁ +
v ₂ is retrieved.

As in the in-phase case, R _B is R _L1 and R _L2
20 times or more, which is a sufficiently large value, and C ₁ and C ₂ are 1 /
And greater than 2πfcR _B (fc = 50Hz). R _L1 , R
The same can be said for _L2 .

However, when the outputs of the two microphones 4 and 4'are of the two-terminal type, that is, the reference potential terminal and the voltage output terminal, and the outputs of opposite phases are generated, the two microphones are used. By connecting the reference potential terminals of 4, 4'to each other, the microphone output synthesizing means can be configured. That is, as shown in FIG. 11, the combined output can be taken out only by the power source + Vcc, the load resistance R _L , and the DC cutoff capacitor C, just as in the case of the single microphone shown in FIG.

This method is a very simple and effective means when the shapes and types are the same and the sensitivities are substantially the same except that the microphones 4 and 4'generate alternating-current AC outputs. , Using the above-mentioned cavity 1d,
If the wiring is completed inside, it can be taken out as a two-terminal output to the outside of the cavity, and the number of connection cords 5 can be reduced.

The above description has been made on the assumption that the two microphones 4 and 4'have the same shape and the same type, and the sensitivities are substantially equal. However, in reality, two microphones 4 and 4'having the same shape and the same type are used. However, there is a slight difference in sensitivity, and the ambient noise elimination effect is reduced accordingly.

As a method of improving this point, the microphone output synthesizing means has means for adjusting the synthesizing ratio of the output of the microphone 4 or the output of the microphone 4 '. The simplest method for adjusting the composite ratio is the load resistance R _L1 shown in FIGS. 9 and 10.
Alternatively, one of R _L2 is replaced with a variable resistor, and the microphone AC output on the variable resistance side increases or decreases in proportion to the magnitude of the resistance value, so that the composition ratio can be adjusted.

Next, another embodiment will be described with reference to FIGS. 12 and 13. In this embodiment, the speaker 2 which is the receiver in the above embodiment is inserted into the ear canal together with the bulging portion 1a. However, some people dislike what is inserted into the ear canal, and some people feel pain when it is inserted for a long time.

Therefore, in this embodiment, the sound shielding plate 7 made of synthetic resin having the collar portion 7a hooked on the auricle upper side of the ear is manufactured, and when the sound shielding plate 7 is hooked on the auricle, The speaker 2 is arranged on the inner surface of the portion corresponding to the ear canal, and the pipe 8 having the microphones 4 and 4'mounted on both ends is directed to the microphone 4 toward the mouth and the microphone 4'to the opposite side from the mouth. It is attached to the outside of the sound shielding plate 7 so as to face it. It should be noted that 8a is a voice inlet and corresponds to 1g in FIG.

In this embodiment having such a configuration,
Since the speaker 2 and the microphones 4 and 4'are completely shielded acoustically, the sound from the speaker 2 does not flow into the microphones 4 and 4'and cause howling, and
It is easy to put on your ears and does not cause a feeling of strangeness.

Next, another embodiment of FIGS. 14 and 15 will be described. In this embodiment, instead of the two microphones 4 and 4'in the embodiment of FIG.
Microphone 9 such as two small electret microphones in case 1
It is characterized in that it is fixed to the substantially central portion of the vacant chamber portion 1d formed in the above, and the front and rear vacant chambers of the microphone 9 are filled with a fibrous sound absorbing material 10 such as Japanese paper or cotton. The structure of is the same as that of the previous embodiment.

The length of the pipe-shaped portion to which the microphone 9 of the case 1 is attached is optimally 10 cm or less in total length in consideration of stability of ear wearing. The microphone 9 is 5 cm from the center of the pipe, that is, from the openings at both ends.
It is fixed to the part inside. Further, the sound emitting portion 1c in the embodiment of FIGS. 14 and 15 is a type that is inserted into the ear canal and directly emits sound, whereas FIG. 16 is a type that is attached to the entrance of the ear canal and emits sound at the entrance of the ear canal. is there.

Next, another embodiment of FIGS. 17 and 18 will be described. In this embodiment, in place of the microphones 4 and 4 striking in the embodiment of FIGS. 12 and 13, one bidirectional microphone 9 is attached to the sound shielding plate 7 for pipe 8 (see FIGS.
It is characterized in that it is attached to the center of the pipe-like portion in the embodiment of FIG. 16 and is filled with the sound absorbing material 10.

Incidentally, 7b in FIG. 17 is the speaker 2
A sound absorbing material such as a sponge fixed in a ring shape on the outer periphery of the speaker is provided so that the sound from the speaker 2 is not emitted to the outside by coming into contact with the inner side of the auricle. Further, conductive plastic is used as the material of the sound shielding plate 7 so that static electricity is discharged through the conductive plastic when the wearer holds it in the hand to prevent discharge between the auricle at the time of wearing. Therefore, it is desirable to prevent the shock due to the discharge.

In the embodiments of FIGS. 14 to 18 thus constructed, the sound from the speaker 2 is made difficult to leak from the ear canal, and even if the leaked sound enters the microphone 9, the bidirectional characteristic is obtained. Since sound leaking from the direction orthogonal to the axis of is input, the sensitivity to the microphone 9 is low and howling can be avoided.

Further, in the above-mentioned embodiment, the sound path pipe 1 having a length of 5 cm or less is used in order to increase the sensitivity to the sound coming out of the mouth.
Since d and 8 are arranged so as to be oriented toward the mouth, the openings 1e ₁ and 1e _{2 of} the sound path pipes 1d and 8
The sound arriving at 8a reaches the microphone 9 through the sound path pipes 1d and 8 without being diffused thereafter, so that the microphone 9 is effectively
The distance between the mouth and the mouth is shortened. Furthermore, the sound absorbing material 10 can avoid resonance in the sound path pipes 1d and 8.

Further, since the ambient noise often arrives from a horizontal surface in practice, and the sound source is generally 10 times or more than the distance between the mouth and the microphone 9, the explanation of FIG. Similarly to the above, the input level of noise to the microphone 9 becomes low, and it is hardly affected by external noise.

However, in a normal telephone usage environment, 70
Since it can be assumed that the ambient noise is less than dBSPL, it can be virtually assumed that there is a difference in volume of 10 dBSPL or more between the sound from the mouth (around 80 dBSPL) collected near the ear and the ambient noise. However, since the human ear has a logarithmic sensitivity to the sound volume, at such a sound volume difference, when the ambient sound is interrupted by the talker, ambient noise is transmitted to the other party and sounds harsh.

Therefore, a circuit for suppressing the ambient noise is connected by making the output signal of the microphone 9 pass through a logarithmically non-linear amplifier so that the amplification factor of the ambient noise of 70 dBSPL or less is made lower than the amplification factor of the volume higher than that. . This circuit will be described below with reference to FIG.

In FIG. 19, 11 is a level detection circuit for detecting the level of the output signal from the microphone 9, and 12 is a non-linear signal generation circuit 1 described later for the output signal from the microphone 9.
A logarithmic amplifier that amplifies with an amplification factor according to the output level from 3, and 13 has a characteristic shown in FIG. 20 according to the signal input from the level detection circuit 11 (the amplification factor decreases from a broken line to a solid line at 70 dBSPL or less. ), A non-linear signal generating circuit for transmitting a voltage of a level based on the above), a distribution circuit 14 for distributing the output from the logarithmic amplifier 12, and an output 15 for amplifying the signal distributed by the distribution circuit 14 and outputting it to the speaker 2. It is an amplifier.

The operation of the microphone 9 will be described next.
Is output to the level detection circuit 11, and the level detection circuit 11 outputs an output corresponding to the output from the microphone 9. Then, this output signal is input to the non-linear signal generation circuit 13, and the output from the microphone 9 is 70 dBS.
When it is equal to or higher than PL, the output according to the level from the level detection circuit 11 is sent to the logarithmic amplifier 12. Also, microphone 9
If the output is less than 70 dBSPL, a lower output is sent to the logarithmic amplifier 12 as shown in FIG.

From the above, as for the output from the logarithmic amplifier 12, a low level signal such as ambient noise is hardly transmitted to the output amplifier 15 and the line 16 via the distribution circuit 14 when there is no voice of the caller. Therefore, since the ambient noise does not sneak into the speaker 2 and is not sent to the line 16, only the voice of the caller is amplified with a high gain, and the callability can be improved. Furthermore, since the sound is collected near the ears, the disadvantage that it is easier to pick up reverberant sounds in the room than when collected in front of the mouth is eliminated, and the clarity is increased.

It should be noted that as an earset type handset to which the above-mentioned circuit for suppressing the ambient noise is connected, FIG.
The application to the earset type handset shown in FIG. 18 has been described, but this circuit is shown in FIG. 1, FIG. 3 and FIG.
Even if it is applied to the earset type handset, the above-mentioned communication performance can be improved.

[0064]

As described above, the present invention provides a two-way voice communication device in which a transmitter is provided in a case arranged near the entrance of the ear canal and a receiver for emitting a sound is provided near the entrance of the ear canal. By arranging the speaker that is the handset in the case and the electret microphones at both ends of the cylindrical cavity, even if the volume of the speaker is increased to a practically sufficient level or the sensitivity of the microphone is increased, Howling does not occur even when the handset is covered with the handset in the mounted state, and ambient noise can be canceled and clear transmission can be performed even if the sensitivity of the microphone is increased.

Further, since the speaker is attached to the inner surface of the sound shielding plate that can be worn by hooking it on the upper side of the auricle of the ear, and the two microphones are attached to the outer surface, it is possible to prevent sound leakage from the speaker in addition to the above effects. The sound from the speaker does not wrap around to the microphone side, and thus howling can be prevented well.

Further, when there is no voice of the caller, the ambient noise is extremely small to be sent to the line, so that only the voice of the caller is clearly transmitted to the other caller and the ambient noise heard from the handset is also generated. Since it becomes extremely small, it has an effect that the voice of the caller can be clearly heard.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an earset type handset of the present invention.

FIG. 2 is a perspective view showing a state in which the earset type handset of the above is attached to the auricle.

FIG. 3 is a side view showing another embodiment.

FIG. 4 is an operation explanatory diagram when a sound source is located far away.

FIG. 5 is an operation explanatory diagram when a sound source is near.

FIG. 6 is an operation explanatory diagram when a speaker is a sound source.

FIG. 7 is an operation explanatory diagram of another embodiment.

FIG. 8 is a circuit diagram of how to take out an output of a microphone alone.

FIG. 9 is a circuit diagram of a microphone output synthesizing unit.

FIG. 10 is a circuit diagram of a microphone output synthesizing means of another embodiment.

FIG. 11 is a circuit diagram of a microphone output synthesizing means by wiring.

FIG. 12 is a rear perspective view of an earset type handset according to another embodiment.

FIG. 13 is a front perspective view of the above.

FIG. 14 is a sectional view of an earset type handset according to still another embodiment.

FIG. 15 is a side view of the above.

FIG. 16 is a side view of another embodiment of the above.

FIG. 17 is a rear perspective view of an earset type handset according to another embodiment.

FIG. 18 is a front perspective view of the above.

FIG. 19 is a block diagram of a transmitter circuit.

FIG. 20 is a characteristic diagram of the above circuit.

FIG. 21 is a side view of a conventional earset type handset.

FIG. 22 is a side view of another conventional example.

FIG. 23 is a side view of still another conventional example.

[Explanation of symbols]

 1 Case 1d Cavity 2 Speaker 4,4 'Microphone 5 Connection cord 7 Sound shield 8 Pipe 9 Bidirectional microphone 10 Sound absorbing material 11 Level detection circuit 12 Logarithmic amplifier 13 Nonlinear logarithmic amplifier

Claims (8)

[Claims] 1. An ear set which has a structure in which a receiver unit can emit sound only in a direction toward the ear canal, and which is integrated with the receiver so that the transmitter is arranged outside the ear canal. Type microphone, wherein the microphone is a first microphone arranged near the mouth and a second microphone arranged at a position farther from the mouth than the first microphone.
An earset-type handset including: two microphones including the microphones; and a microphone output synthesizing unit that electrically synthesizes AC outputs of the two microphones so as to cancel each other. 2. A two-way call ear set that is structured such that the earpiece portion can emit sound only in the direction toward the ear canal, and that the earpiece is integrated with the earpiece so that the transmitter is located outside the ear canal. The microphone is a bidirectional microphone, wherein one sound receiving surface of the microphone is connected to a first pipe having a length of 5 cm or less and the other sound receiving surface is long. A pipe connected to a second pipe having a length of 5 cm or less, the opening of the first pipe being directed toward the mouth, and the opening of the second pipe being directed away from the mouth; An earset type handset including a sound absorbing material provided on the sound receiving surface side of the microphone in the first and second pipes. 3. A two-way ear set having a structure in which a receiver unit can emit sound only in a direction toward the ear canal, and which is integrated with the receiver so that the transmitter is disposed outside the ear canal. Type microphone, wherein the microphone is a first microphone arranged near the mouth and a second microphone arranged at a position farther from the mouth than the first microphone.
Microphones composed of two microphones, a microphone output combining means for electrically combining the AC outputs of the two microphones so as to cancel each other, and an output from the microphone output combining means is near the entrance to the ear canal. 70 dB
The amplification gain is 70 dBSPL for sounds below SPL.
An earset type handset, comprising: a non-linear gain amplifier that realizes amplification lower than the above sound. 4. An ear set which has a structure in which a receiver unit can emit sound only in a direction toward the ear canal, and which is integrated with the receiver so that the transmitter is disposed outside the ear canal. The microphone is a bidirectional microphone, wherein one sound receiving surface of the microphone is connected to a first pipe having a length of 5 cm or less and the other sound receiving surface is long. A pipe connected to a second pipe having a length of 5 cm or less, the opening of the first pipe being directed toward the mouth, and the opening of the second pipe being directed away from the mouth; The sound absorbing material provided on the sound receiving surface side of the microphone in the first and second pipes and the output of the microphone are 70 dB near the entrance of the ear canal.
The amplification gain is 70 dBSPL for sounds below SPL.
An earset type handset, comprising: a non-linear gain amplifier that realizes amplification lower than the above sound. 5. A sound shielding plate that is hooked on the upper side of the auricle of the ear and covers the auricle, and is attached to a position corresponding to the outer ear canal on the inner surface of the sound shielding plate and can emit sound only in the direction toward the outer ear canal. A two-way earset type handset capable of two-way communication, wherein a handset having a structure and a handset placed on the outer surface of the sound shielding plate are integrated, and the handset is placed near the mouth. A first microphone and a second microphone arranged at a position farther from the mouth than the first microphone
An earset-type handset including: two microphones including the microphones; and a microphone output synthesizing unit that electrically synthesizes AC outputs of the two microphones so as to cancel each other. 6. A sound shielding plate that is hooked on the auricle upper side of the ear and covers the auricle, and is attached at a position corresponding to the external auditory canal on the inner surface of the sound shielding plate and can emit sound only in the direction toward the external auditory canal. A two-way earset type handset capable of bidirectional communication, wherein a handset having a structure and a handset arranged on an outer surface of the sound shielding plate are integrated, wherein the handset is a bidirectional microphone. And one sound receiving surface of the microphone is connected to a first pipe having a length of 5 cm or less, and the other sound receiving surface is connected to a second pipe having a length of 5 cm or less, and an opening of the first pipe And a sound absorbing member provided on the sound receiving surface side of the microphone in the first and second pipes, the pipe being formed so that the portion faces toward the mouth and the opening of the second pipe facing away from the mouth. Earset type handset characterized by having a material. 7. A sound shielding plate having a shape that is hooked on the auricle upper side of the ear and covers the auricle, and is attached to a position corresponding to the outer ear canal on the inner surface of the sound shielding plate and can emit sound only in the direction toward the outer ear canal. A two-way earset type handset capable of two-way communication, wherein a handset having a structure and a handset placed on the outer surface of the sound shielding plate are integrated, and the handset is placed near the mouth. A first microphone and a second microphone arranged at a position farther from the mouth than the first microphone
Two microphones that are composed of
Microphone output synthesizing means for electrically synthesizing the AC outputs from the two microphones so as to cancel each other, and the output from the microphone output synthesizing means has an amplification gain for a sound of 70 dBSPL or less near the entrance of the ear canal. 70 dB
An earset type handset, comprising: a non-linear gain amplifier that realizes amplification lower than a sound above SPL. 8. A sound shielding plate that is hooked on the upper side of the auricle of the ear and covers the auricle, and is attached to a position corresponding to the outer ear canal on the inner surface of the sound shielding plate and can emit sound only in the direction toward the outer ear canal. A two-way earset type handset capable of bidirectional communication, wherein a handset having a structure and a handset arranged on an outer surface of the sound shielding plate are integrated, wherein the handset is a bidirectional microphone. And one sound receiving surface of the microphone is connected to a first pipe having a length of 5 cm or less, and the other sound receiving surface is connected to a second pipe having a length of 5 cm or less, and an opening of the first pipe And a sound absorbing member provided on the sound receiving surface side of the microphone in the first and second pipes, the pipe being formed so that the portion faces toward the mouth and the opening of the second pipe facing away from the mouth. Material and the output of the microphone near the entrance of the ear canal 0dB
The amplification gain is 70 dBSPL for sounds below SPL.
An earset type handset, comprising: a non-linear gain amplifier that realizes amplification lower than the above sound.