Two-way communications earset - Patent Review 5448637

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BACKGROUND OF THE INVENTION

The present invention relates to an earset for use in two-way voice communications which is worn in or at an ear canal of a user and which is operated hands-free. The earset of the present invention can transmit the user's voice and receive voice signals from another party simultaneously without causing feedback.

Modern wireless technologies have advanced to the extent that portable, wireless and mobile telephones have become small in size and are used widely. Such portable telephones typically include a handset requiring the use of at least one hand for communication.

A disadvantage of the handset type of telephone is that they are inconvenient to use in front of a computer or while driving a car. In such instances, the user must use a hand to hold the handset while typing at the keyboard, which is very difficult to do, or while holding the steering wheel of a car, which is dangerous. Alternatively, the user must hold the telephone handset to their ear with their shoulder, which is very uncomfortable.

In order to solve this drawback, hands-free telephones have been developed. A conventional two-way communications apparatus used with hands-free telephones comprises a headband including a speaker positioned in front of one ear and a boom attached to the headband with a small microphone at one end of the boom. With the boom connected to the headband, the microphone extends in front of the mouth of the user. However, this type of hands-free telephone is not convenient to use because it is cumbersome and because it disturbs the hair of the user.

Another conventional two-way communications system used with hands-free telephones includes a structure which hangs from the ear of the user. This type of communications system includes a speaker positioned in front of the user's ear and a boom having a microphone extending in front of the mouth of the user. Again, such a structure is not convenient for the user because it typically does not hang well at the ear and because it is bulky to carry owing to the boom.

Alternatively, as shown in FIG. 1, yet another conventional two-way communications system includes a receiver section 1 with a speaker la which is placed in the user's ear canal. Sound is transmitted to the user via an opening 1b in the back of the speaker 1a. The two way communications system also includes a transmitter section 3 which is located relatively close to the user's mouth. The transmitter section 3 includes a microphone 3a.

In the conventional two-way communications system shown in FIG. 1, however, the transmitter section 3 is attached to the receiver section 1 by a chord 2. The cord 2 also extends past the transmitter section 3 and is connected to a telephone terminal (not shown).

The two-way communications system shown in FIG. 1 does not require hands to operate. However, due to the connection of the transmitter section 3 by the cord 2, the microphone 3a dangles. With such a configuration, the microphone 3a must be omni-directional causing noise when the microphone 3a rotates at the chord 2. Additionally, with the two-way communications system shown in FIG. 1, the sound intake of the microphone 3a may be blocked by the face or clothing of the user, causing a decrease in the quality of the transmitted voice signals. Moreover, contact between the transmitter section 3 and the clothing of the user tends to cause noise.

Conventional two-way communications systems, such as those shown in FIG. 2 and FIG. 3 attempt to overcome the deficiencies described above with the two-way communications system shown in FIG. 1.

The conventional two-way communications earsets shown in FIGS. 2 and 3 integrate the speaker 1a and the microphone 3a into a single case 4. The L-shaped case 4 houses the speaker 1a in one leg and houses the microphone 3a in the other leg. In the embodiment shown in FIG. 2, the speaker 1a has a single opening 4a at a back portion thereof. Alternatively, as shown in FIG. 3, the speaker 1a may have a plurality of holes 4a'. The microphone 3a has an opening 4b through which signals are received. There is a chord 2 coming out from the lower part of the L-shaped case 4 which is connected to a telephone terminal (not shown).

By incorporating the speaker 1a and the microphone 3a in the case 4, conventional two-way communications earsets shown in FIGS. 2 and 3 solve many of the problems discussed above related to the communications system shown in FIG. 1. However, the two-way communications earsets of FIGS. 2 and 3 cause feedback because sound that leaks out from the opening 4a is fed into the microphone 3a though sound intake hole 4b. Therefore, in the communications earsets shown in FIGS. 2 and 3, either the sound volume of the speaker 1a has to be controlled below a certain level or the sensitivity of the microphone 3a has to be kept below a certain level to reduce the effects of feedback.

However, if the sound volume is maintained at a low level, the user may find it difficult to hear voice signals due to the presence of ambient noise. In an effort to reduce the effects of ambient noise, the user may cover his ear with his hand. Unfortunately, this significantly increases the acoustic coupling between the speaker and microphone, causing even more feedback.

In addition, with two-way communications earsets shown in FIGS. 2 and 3, voice signals of the user are picked up at the ear, which is about 14 cm away from the user's mouth. Conventional telephone handsets are designed to pick up voice signals directly in front of the user's mouth which are approximately 2.5 cm away from the microphone. At this distance, the level of the voice signal is approximately 94 dBSPL. Because the two-way communications earsets shown in FIGS. 2 and 3 receive voice signals further away from the mouth than conventional handsets, the signals are approximately 14 dBSPL (sound pressure level) lower than those received by a conventional telephone handset. Because the voice signals are received from further away, they require greater amplification. As a result, the systems shown in FIGS. 2 and 3 tend to pick up more ambient noise and room reverberation, both of which make the received voice signals less intelligible.

Accordingly, an object of the present invention is to provide an earset for use in two-way voice communications which is worn in or at an ear canal of the user and which is operated hands-free.

Another object of the present invention is to provide an earset which transmits the user's voice and receives voice signals from another party simultaneously without causing feedback caused by acoustic or mechanical coupling between the speaker and the microphone.

A further object of the present invention is to provide a two-way communications earset which delivers an adequate level of sound to the user without causing feedback, while also delivering an adequate level of sound to a receiver a the other end of the communication system.

A still further object of the present invention is to provide a two-way voice communications earset which is less sensitive to ambient noise at a level almost equal to a telephone handset and to room reverberation so that clear voice communications can be obtained.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

SUMMARY OF THE INVENTION

To achieve the objects in accordance with the purposes of the present invention, as embodied and described herein, the earset of the present invention comprises a one piece two-way simultaneous voice transmitting and receiving device comprising a receiver for emitting sound primarily to the ear canal of a user and a transmitter, coupled to the receiver, and located outside the ear canal, comprising a first microphone adapted to be located at a first position relative to the mouth of the user and outputting a first signal, a second microphone spaced a distance away from the first microphone and adapted to be located at a second position relative to the mouth of the user further from the mouth of the user than the first position, and outputting a second signal and means for detecting the first and second signals.

The earset of the present invention further comprises a one piece two-way simultaneous voice transmitting and receiving device comprising a receiver, emitting sound primarily to the ear canal of a user, and a transmitter, coupled to the receiver and located outside the ear canal, comprising a microphone with bi-directional directivity having two sound receiving ends, a cavity housing the microphone substantially at a central portion thereof and directed toward the mouth of the user and sound absorbing materials placed with the cavity and abutting the sound receiving ends of the microphone.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate the presently preferred apparatus of the present invention and, together with the general description given above and the detailed description of the preferred embodiments given below serve to explain the principles of the invention. In the drawings:

FIG. 1 is a sectional view of a conventional earset with a microphone attached to a cord;

FIG. 2 is a side sectional view of a conventional one piece earset adapted to be worn in a user's ear;

FIG. 3 is a side sectional view of another conventional one piece earset adapted to be worn in a user's ear;

FIG. 4 is a sectional view of a two-way communications earset according to a first embodiment of the present invention;

FIG. 5 is a side view of a second embodiment of a two-way communications earset according to the present invention placed in an ear of a user;

FIG. 6 is a sectional view of a two-way communications system according to a third embodiment of the present invention;

FIG. 7 is a side view showing the relative positioning of a sound source relative to the earset shown in FIG. 4;

FIG. 8 is a side view showing the relative positioning of a mouth relative to the earset shown in FIG. 4;

FIG. 9 is a side view showing the relative positioning of a speaker output relative to the earset shown in FIG. 6;

FIG. 10 is a side view showing the relative positioning of a sound source with respect to an alternative embodiment of the two-piece microphone;

FIG. 11 is a circuit diagram of conventional circuit that produces an electret microphone output;

FIG. 12 is a circuit diagram of circuitry used in the earset of the present invention for subtracting the outputs of two microphones when the microphones are in phase;

FIG. 13 is a circuit diagram of circuitry used in the earset of the present invention for adding the outputs of two microphones when the microphone outputs are out of phase;

FIG. 14 is a circuit diagram of circuitry used in the earset of the present invention for adding the outputs of two microphones when the microphones are mutually out of phase;

FIG. 15 is a side view of a two-way communications earset according to a fourth embodiment of the present invention;

FIG. 16 is a side sectional view of the earset according to the fourth embodiment of the present invention hung on the user's ear;

FIG. 17 is a sectional view of a two-way communications earset according to the fifth embodiment of the present invention;

FIG. 18 is a side view of the earset according to the fifth embodiment inserted in a user's ear canal;

FIG. 19 is a side view of the earset according to the fifth embodiment with an alternative ear insertion shape;

FIG. 20 is a back view of a two-way communications earset according to the sixth embodiment of the present invention;

FIG. 21 is a side sectional view of the earset according to the sixth embodiment hung on an ear of a user;

FIG. 22 is a block diagram of a circuit used in the earset of the present invention for reducing the degree of amplification of sound to less than 70 dBSPL; and

FIG. 23 is a graphical representation of the input-output characteristics of the circuit shown in FIG. 22.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4 is a sectional view of a two-way communications earset according to a first embodiment of the present invention. The embodiment shown in FIG. 4 comprises an earset 10 which has an L-shaped configuration. The earset 10 is preferably made of plastic and includes an enlarged portion 11a which is inserted in the ear of the user. The enlarged portion 11a includes an earset component portion 11b and an insertion portion 11c.

The enlarged portion 11a is placed in the user's ear auricle and the insertion portion 11c is inserted into the ear canal. The insertion portion 11c is preferably shaped so that the ear canal of the user will not be completely clogged by the earset 10 and so that the earset 10 will not be so loose as to cause feedback due to leaked sound.

A speaker 20 is housed in the earset component portion 11b and is supported by resilient material 30. The output of the speaker 20 is input to the insertion part 11c and is fed into the ear canal of the user through hole 11f. The speaker 20 can preferably be either a magnetic-type speaker or dynamic-type speaker. As shown in FIG. 1, the speaker 20 is situated in the earset component portion 11b. However, in accordance with the present invention, the speaker 20 can be placed in an alternate location, so long as the output from the speaker 20 is guided into the ear canal of the user.

The earset 10 also includes a cylindrical cavity 11d. At the ends of the cavity 11d are housing spaces 11d1 and 11d2. The housing spaces 11d1 and 11d2 are connected to the outside of the earset 10 through two respective holes 1e1 and 1e2. Two electret pieces 40 and 40' are respectively housed in the two housing spaces 11d1 and 11d2. Each of the electret pieces 40 and 40' is preferably a small and sensitive device.

Additionally, in a preferred embodiment of the present invention, the electret pieces 40 and 40' are preferably back-type electret so that they are immune to vibrations emanating from the earset 10 and from extraneous noise from the wires connecting the elements of the earset 10. Such wires may include the wire 50, which is substantially parallel to the cylindrical cavity 11d, and is led to the outside of the earset 10 and the wires coming from speaker 20 and electret pieces 40 and 40'.

The earset 10 shown in FIG. 4 also preferably includes a combination circuit 100 which combines the outputs of the electret pieces 40 and 40'. The combination circuit is explained in more detail below, but preferably is coupled to the output wires of the electret pieces 40 and 40' and has its output coupled to wire 50. As shown in FIG. 4, the combination circuit 100 is located within the cylindrical portion 11d. However, in accordance with the present invention, the combination circuit 100 may be located at any convenient place in the earset 10, so long as the outputs of the electret pieces 40 and 40' are input thereto.

FIG. 5 shows an earset according to a second embodiment of the present invention. As shown in FIG. 5, the earset has a two-piece construction including a two-way wireless communication device 52 connected to an earset 51. The communication device 52 includes a transmitter/receiver at the front portion of the ear lobe. The communication device 52 also includes an integrated circuit (not shown) that transmits voice signals from electret pieces 40 and 40' to a station and receives voice signals from the station, and a combination circuit 100 that combines the outputs of electret pieces 40 and 40'.

The communication device 52 also includes a battery cell located at the back portion of the ear lobe. The battery cell and the transmitter/receiver remain connected to the ear lobe by a pinching mechanism located therebetween. The earset 51, shown in FIG. 5, is substantially the same as that shown in FIG. 4.

FIG. 6 is a side sectional view of an earset according to a third embodiment of the present invention. The earset 60 includes a cylindrical cavity 61d which preferably has a slightly folded cylindrical shape. With such a shape, the lower electret piece 40' is situated closer the user's mouth than the upper electret piece 40. With such a configuration, the lower microphone 40' picks up more of the user's voice signals that does the upper microphone 40 and therefore the users voice can be amplified to a greater extent than when the earset shown in FIG. 4 is used.

The operation of the earset according to any of the embodiments shown in FIGS. 4-6 will be described below, specifically with respect to FIG. 4. The enlarged portion 11a of the earset 10 is inserted into the user's ear auricle and the insertion part 11c is inserted into the ear canal. The shape of the insertion part 11c is formed so that the insertion part 11c will not clog the ear canal. With such a shape, the user can hear sound coming from the outside and therefore finds the earset 10 safe to use.

Additionally, the shape of the insertion part 11c is formed so that the insertion part 11c will not leak much sound. As shown in FIG. 4, the speaker 20 is preferably situated in the earset component portion 11b. However, the speaker 20 can be located in other places within the earset 10 as long as the output of the speaker 20 is output to the user's ear canal.

With the earset 10 situated in the user's ear, the user can hear sound from the speaker 20 that is sent via the wire 50 from a duplex transmitting and receiving terminal (not shown). The output of the speaker 2 is led to the ear canal via a hole 11f of the insertion part 11c.

The voice signal from the user reaches the earset 10 via holes 11e1 and 11e2, and then respectively reaches the electret pieces 40 and 40'. The voice signals are converted into electrical signals by electret pieces 40 and 40' and are sent after being combined by the combination circuit 100 via the wire 50 to the duplex voice transmitting and receiving terminal (not shown).

The earsets according to the embodiments shown in FIGS. 4-6 have a higher sensitivity to the voice signal of the user than to noise signals coming from places distant from to the user's mouth. This is because the lower electret piece 40' is located closer to the user's mouth than the upper electret piece 40. Thus, when the combination circuit 100 combines the outputs of the electret pieces 40 and 40', the voice signal of the user is output and noise signals from distant sources are nulled.

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