JP5012743B2 - Human body communication wireless audio output device - Google Patents

Description

  The present invention relates to a human body communication wireless audio output device that receives an audio signal transmitted from an audio reproduction device using a human body as a transmission medium, and outputs an audible audio generated based on the received audio signal.

  Conventionally, it is composed of a portable audio reproduction device and a headphone device. The audio signal is transmitted from the audio reproduction device using a wireless communication method such as infrared rays or radio waves, and the headphone device receives the audio signal received from the audio reproduction device. There is known a wireless headphone system that can output music audible to a user's ear without using a cable by outputting an audible sound generated by performing a conversion process such as demodulation or amplification.

  By the way, in this type of wireless headphone system, when a wireless communication system using infrared rays is used, a part of the user's body or outdoor natural light is obstructed and the optical path is interrupted, and the sound reproduction device is switched to the headphone device. There was a problem that audio signals could not be transmitted successfully. In addition, when using radio communication systems using radio waves, it is difficult to assign frequencies due to regulations in each country, and there is a possibility that interference may occur if there are multiple users within the communication range. there were.

For this reason, a human body capable of transmitting an audio signal regardless of the use environment and without using a cable by adopting a method (so-called human body communication method) for transmitting a signal through a part of the user's body. A communication wireless headphone system has been proposed (see, for example, Patent Document 1). Note that the human body communication method regards the human body as a conductor (cable) consisting mostly of salt-containing water, and exchanges with a weak current (for example, 1 mA or less) that does not affect the health of the human body. A signal is transmitted.
JP 2001-144661 A

  By the way, in a conventional human body communication wireless headphone system, a so-called overhead headphone device composed of a headband and an ear pad is used, and an audio signal (weak current) transmitted from the audio reproduction device via the human body is received. An input electrode is provided at the ear pad position.

  In the headphone device configured as described above, since the ear pad is only urged by the elastic force of the portion connected to the headband, the contact between the input electrode and the human body is not stable, and the audio signal is appropriately transmitted. There was a problem that it could not be received.

  In order to solve the above problems, an object of the present invention is to provide a human body communication wireless audio output device capable of stably outputting an audible sound based on an audio signal transmitted using a human body as a transmission medium.

  The human body communication wireless audio output device according to claim 1, which is an invention made to achieve the above object, wherein the input electrode unit receives an audio signal transmitted from an audio reproduction device using the human body as a transmission medium, The headphone unit is configured to convert an audio signal received via the input electrode unit into an audible sound and output the audible sound.

  Here, in the human body communication wireless audio output device, a curved ear hook portion that hangs on the ear shell in the human body is extended to the housing that houses the headphone portion, and the input electrode portion is the ear hook portion, The gist of the present invention is that it is provided at least at a position in contact with the base of the ear shell in the mounted state. The wearing state refers to a state where the ear hook portion is hung on the ear shell.

  That is, when the thus configured human body communication wireless audio output device is attached to a user (human body), the weight of the headphone unit together with the housing is placed in the direction of gravity in the portion of the ear hook unit connected to the housing. Since the input electrode is biased to the base part of the user's ear shell, the contact between the input electrode and the human body is stabilized (that is, the contact impedance is reduced), and the audio signal can be received appropriately. Become.

Therefore, according to the human body communication wireless audio output device of the present invention, it is possible to stably output audible audio based on an audio signal transmitted using the human body as a transmission medium.
The headphone unit may be provided at a position for outputting audible sound toward the lower jaw on the lower side of the ear shell when worn, as in a so-called bone conduction headphone. Thus, it may be provided at a position where audible sound is output toward the ear canal in the human body in the wearing state.

  According to another aspect of the human body communication wireless audio output device of the present invention, the hook support portion protruding from the housing supports the one end of the ear hook portion so as to be rotatable about the axis. And an urging mechanism for urging the ear hook portion in a direction in which the ear shell is sandwiched between the ear hook portion and the housing in the mounted state.

  That is, in the human body communication wireless audio output device configured as described above, the force (pressing force) that the housing presses against the ear shell can be increased, and the headphone portion can be uniformly adhered to the ear shell. For this reason, in addition to being able to efficiently transmit the sound (audible sound) output from the headphone unit to the user's inner ear, the contact between the input electrode and the base portion of the ear shell can be further stabilized.

  By the way, in the human body communication wireless audio output device of the present invention, as described in claim 4, the ear hook portion is made of a non-conductive resin material, and the input electrode portion is formed on the ear hook portion. It is desirable to consist of a conductive thin film.

In this case, the ear hook part can be easily processed (molded or the like), and the amount of the conductor used as the input electrode part can be reduced, so that the manufacturing cost can be suppressed.
In addition, as described in claim 5, the input electrode portion faces the neck portion side of the human body, the base side of the ear shell, and the neck portion of the ear shell in the mounted state on the outer peripheral surface of the ear hook portion. It is desirable to be provided at a position that covers the entire side (hereinafter referred to as the neck-opposing side).

  In this case, in the wearing state, the input electrode portion comes into contact with the base portion of the ear shell, and also comes into contact with at least one of the neck side or the neck facing side, and the contact area between the input electrode portion and the human body is wide. Since it is ensured, the contact impedance can be further reduced.

  According to a sixth aspect of the present invention, in the ear hook portion, a surface that contacts the human body in the mounted state is used as a hook contact surface, and the hook contact surface has a plurality of irregularities. It is desirable.

  In this case, the frictional resistance between the ear hook part and the base part of the ear shell increases in the wearing state, and the ear hook part becomes difficult to slip (that is, the headphone part becomes difficult to slip), thereby improving the user's wearing feeling. In addition to being able to do so, the contact between the input electrode and the human body can be further stabilized. Further, in addition to the headphone portion being less likely to be displaced, the contact area between the input electrode portion and the human body is ensured to be larger, so that the contact impedance can be further reduced.

  By the way, when the current crosses the interface between the input electrode part (conductor) and the human body (electrolyte), there is a problem that polarization voltage (noise) may be generated due to the formation of the electric double layer. Therefore, it is desirable that a dielectric insulating film for covering the input electrode portion is provided on the ear hook portion as described in claim 7.

  In this case, the input electrode portion and the human body are connected only by capacitive coupling, and transmission errors can be reduced. Note that even if the input electrode portion is made of metal, the metal does not directly touch the human body in the mounted state, so that it is possible to deal with users who have metal allergies.

Embodiments of the present invention will be described below with reference to the drawings.
<Configuration of headphone system>
FIG. 1 is a schematic diagram showing an outline of a headphone system to which the present invention is applied, and FIG. 2 is a block diagram showing a configuration of the headphone system.

  As shown in FIG. 1, the headphone system 1 includes a portable music player 10 as an audio reproduction device that transmits an audio signal using a part of a user's body (that is, a human body) as a transmission medium, and an audio reproduction device (music). It comprises a headphone device 20 as a human body communication wireless audio output device that receives an audio signal transmitted from the player 10) via a human body and outputs an audible audio generated based on the received audio signal.

  In the headphone system 1, the human body is regarded as a conductor (cable) made up of salt-containing water, and the music player 10 and the headphone device 20 are either directly on the user's skin (skin) or through clothing or the like. An audio signal (alternating current signal) is transmitted with a weak current (for example, 1 mA or less) that does not affect the health of the human body while being indirectly contacted.

<Configuration of music player>
Among these, as shown in FIG. 2, the music player 10 reads out audio data from a storage medium (not shown) such as a flash memory, a CD, or an MD, and a signal (IF) obtained by modulating a carrier wave with the read out audio data. Signal generator 11 that outputs a signal), a reference oscillator 12 that generates a reference signal having a predetermined reference frequency, and outputs from the signal generator 11 and the reference oscillator 12 are mixed to frequency-convert the IF signal. And a mixer 13.

  Further, the music player 10 selectively passes a signal that has been frequency-converted to a predetermined frequency band among signals (RF signals; corresponding to audio signals) output from the mixer 13 (hereinafter referred to as BPF). ) 14, an amplifier circuit 15 that amplifies the RF signal that has passed through the BPF 14, and an output electrode unit 10 a that transmits the RF signal amplified by the amplifier circuit 15. The amplifier circuit 15 is connected to the output electrode portion 10a via a capacitor (not shown).

<Configuration of headphone device>
On the other hand, the headphone device 20 receives an RF signal transmitted from the music player 10 through the human body, and converts the RF signal (audio signal) received through the input electrode unit 20a into an audible sound. And a headphone unit 2 for outputting.

  That is, the headphone unit 2 selectively passes only an amplifier circuit 21 that amplifies a signal received via the input electrode unit 20a, and a signal (RF signal) in a predetermined frequency band among outputs from the amplifier circuit 21. BPF 22, local transmitter 23 that generates a high-frequency signal for frequency conversion, mixer 24 that converts the received signal frequency by mixing the RF signal that has passed through BPF 22 and the output from local transmitter 23, and mixer 24 An amplifier circuit 25 that amplifies the signal (IF signal) output from the signal, a demodulator circuit 26 that demodulates the IF signal amplified by the amplifier circuit 25 into audio data, and the audio data demodulated by the demodulator circuit 26 is audible. And an audio output device 27 that converts the sound into an output.

Next, FIGS. 3A and 3B are a top view and a side view showing an outline of the headphone device 20.
As shown in FIG. 3A, the headphone device 20 is in contact with the housing 3 for housing the headphone unit 2 and the headphone unit 2 (audio output device 27) to output audible sound (that is, the headphone unit 2). , A sponge-like (e.g., low-resilience urethane) ear pad 4 arranged in the direction of sound emission, and a curved ear hook portion 5 extending to the housing 3 and hanging on the user's ear shell. .

  Of these, the housing 3 is in contact with the ear pad 4 to form a plurality of small holes (or slits) for sound emission, and a substantially hemisphere that is fixed to the contact part 6 and covers the headphone unit 2. The dome portion 7 has a shape, and a hook support portion 8 provided at a position protruding from the dome portion 7 and supporting the ear hook portion 5. Although not shown, a holding mechanism for attaching the headphone unit 2 by fitting is formed on the inner lower portion of the dome portion 7 so that the center of gravity inside the housing 3 is on the lower side. .

  The hook support portion 8 is provided with an insertion hole (not shown) having substantially the same diameter as one end of the ear hook portion 5, a rotation mechanism that supports one end of the ear hook portion 5 so as to be rotatable about an axis, and a leaf spring. By the elastic member (not shown) such as the ear hook portion 5 in the direction in which the user's ear shell is sandwiched between the ear hook portion 5 and the ear pad 4 (contact portion 6) in the mounted state (see FIG. 3B). And an urging mechanism for urging.

  As shown in FIG. 4, the wearing state refers to a state where the headphone device 20 is worn by the user by hanging the ear hook portion 5 on the ear shell. The hook support portion 8 includes a connection cord (not shown) for electrically connecting the input electrode portion 20a and the headphone portion 2 (receiver 21).

Here, FIG. 5 is a schematic view showing the position of the input electrode portion 20a with respect to the user's ear shell, and FIG. 6 is a schematic view for explaining a partial shape of the ear hook portion 5. FIG.
The ear hook portion 5 is made of a non-conductive resin material, has a round shape that matches the shape of a general ear shell, and a portion where the user's ear shell and the neck portion are connected (that is, the root of the ear shell). ) In the groove portion X (see FIG. 5 (a)) so as to be carried by the ear shell (see FIG. 5 (b)) so as to be inserted from above. In addition, as shown in FIG. 6, a surface of the ear hook portion 5 that comes into contact with the user's ear shell and neck when worn (that is, a surface that comes into contact with the groove portion X at the base of the ear shell; A plurality of wavy irregularities are formed along the groove portion X at the base of the ear shell.

  An input electrode portion 20a made of a conductive thin film formed by plating is provided on the inner side surface of the ear hook portion 5 including the hook contact surface 5a. In addition, as shown in FIG.5 (c), the input electrode part 20a of this embodiment is a user's state in mounting | wearing state among the edge parts (namely, outer peripheral surface) of the cross section along the axial direction of the ear hook part 5. As shown in FIG. It is provided at a position that covers all of the neck side, the base side of the ear shell, and the side of the ear shell that faces the neck (an area that covers the periphery of the cross section about 3/4 on the lower side).

  Furthermore, the ear hook part 5 is provided with a dielectric insulating film 5b that covers the input electrode part 20a. In general, when an electric current crosses a boundary surface between a conductor (input electrode portion 20a) and an electrolyte (human body), polarization voltage (noise) is generated due to the formation of an electric double layer. Therefore, an insulator (insulating film 5b) is used. By covering, the input electrode portion 20a is connected only by capacitive coupling with the human body, and transmission errors can be reduced.

<Effect of this embodiment>
As described above, in the headphone device 20 of the present embodiment, the input electrode portion 20a is the ear in the mounted state among the ear hook portions 5 that protrude from the housing 3 (dome portion 7) that houses the headphone portion 2. It is provided on the surface that contacts the groove portion X of the base of the shell.

  That is, when the headphone device 20 configured in this way is attached to a user (human body), the weight of the headphone unit 2 together with the housing 3 is reduced by gravity at a portion of the ear hook unit 5 connected to the dome unit 7. Since the input electrode portion 20a is biased by the groove portion X at the base of the ear shell, the contact between the input electrode portion 20a and the human body is stabilized (that is, the contact impedance is reduced), and the audio signal is appropriately Can be received.

Therefore, according to the headphone device 20 of the present embodiment, it is possible to stably output an audible sound based on an audio signal transmitted using the human body as a transmission medium.
In the headphone device 20, the headphone unit 2 is attached by the holding mechanism of the dome unit 7 so that the center of gravity in the housing 3 is on the lower side, so that the center of gravity of the headphone device 20 is lowered in the mounted state. . Further, the upper part of the user's ear shell is slightly inclined outward with respect to the neck. For this reason, even if a force is applied outward from the center of gravity of the headphone device 20 in the worn state, the ear hook portion 5 becomes difficult to come off from the ear shell, and as a result, the contact between the input electrode portion 20a and the human body can be further stabilized. it can.

  Furthermore, in the headphone device 20, since the connection cord for electrically connecting the input electrode portion 20 a and the headphone portion 2 (receiver 21) is included in the hook support portion 8, the connection cord is connected to the headphone device 20. It is possible to suppress the reception of noise from the outside and to suppress the emission of data (signal) to the outside, and to improve the noise resistance and security. it can. In addition, the length (distance) of the connection cord can be shortened, and communication loss can be suppressed.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it is possible to implement in various aspects.

  For example, the hook contact surface 5a of the above embodiment has a plurality of wavy irregularities formed along the groove portion X at the base of the ear shell. However, the present invention is not limited to this, and a plurality of protrusions are pointed. It may be formed in a shape.

  In the headphone device 20 of the above embodiment, the dielectric insulating film 5b covering the input electrode portion 20a is provided, but the output electrode portion 10a may be similarly covered with the dielectric insulating film 5b. Good.

  Further, the headphone device 20 of the above embodiment urges the ear hook portion 5 in a direction in which the user's ear shell is sandwiched between the ear hook portion 5 and the ear pad 4 by the urging mechanism of the hook support portion 8. However, the present invention is not limited to this. For example, instead of the urging mechanism of the hook support 8, an urging portion for urging the ear pad 4 in the direction of the lower jaw on the lower side of the ear shell is provided, so that audible sound is transmitted to the inner ear as so-called bone conduction. You may tell it directly.

  By the way, in the headphone system 1 of the above embodiment, the music player 10 is exemplified as the sound reproducing device, but the present invention is not limited to this, and for example, an AM / FM radio, a mobile phone, or the like may be used as the sound reproducing device.

  Further, the headphone system 1 of the above embodiment is configured to demodulate the audio signal digitally modulated by the music player 10 by the headphone device 20, but these modulation / demodulation methods are not limited. Absent. For example, an audio signal analog-modulated by the music player 10 may be demodulated by the headphone device 20. An amplifier circuit may be added on the headphone device 20 side.

1 is a schematic diagram showing an outline of a headphone system 1 to which the present invention is applied. 1 is a block diagram showing a configuration of a headphone system 1. FIG. FIG. 2 is a top view and a side view showing an outline of the headphone device 20. The schematic diagram for demonstrating a mounting state. Schematic which shows the position of the input electrode part 20a with respect to a user's ear shell. Schematic for demonstrating the partial shape of the ear hook part 5. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Headphone system, 2 ... Headphone part, 3 ... Housing, 4 ... Ear pad, 5 ... Ear hook part, 5a ... Hook contact surface, 5b ... Insulating film, 6 ... Contact part, 7 ... Dome part, 8 ... Hook Support unit, 10 ... music player, 10a ... output electrode unit, 11 ... signal generator, 20 ... headphone device, 20a ... input electrode unit, 27 ... audio output unit.

Claims (7)

An input electrode unit that receives an audio signal transmitted from an audio reproduction device using the human body as a transmission medium;
A headphone unit that converts an audio signal received through the input electrode unit into an audible sound and outputs the audible sound;
An ear hook portion having a curved shape that extends to a housing that houses the headphone portion and hangs on an ear shell of the human body;
A human body communication wireless voice output device comprising:
A state where the ear hook portion is hung on the ear shell is a wearing state,
The human body communication wireless audio output device according to claim 1, wherein the input electrode portion is provided in a portion of the ear hook portion that is in contact with at least a base of the ear shell in the mounted state.   2. The human body communication wireless audio output device according to claim 1, wherein the headphone unit is provided at a position for outputting the audible audio toward an ear hole in the human body in the wearing state. A hook support portion that protrudes from the housing and supports one end of the ear hook portion so as to be rotatable about an axis;
3. The hook support part according to claim 2, further comprising a biasing mechanism that biases the ear hook part in a direction in which the ear shell is sandwiched between the ear hook part and the housing in the mounted state. The human body communication wireless audio output device described. The ear hook part is made of a non-conductive resin material,
4. The human body communication wireless audio output device according to claim 1, wherein the input electrode portion is made of a conductive thin film formed on the ear hook portion. 5.   The input electrode portion includes all of the outer peripheral surface of the ear hook portion on the neck side of the human body in the mounted state, the base side of the ear shell, and the side of the ear shell that faces the neck portion. The human body communication wireless audio output device according to claim 4, wherein the human body communication wireless audio output device is provided at a covering position. Of the ear hook portion, a surface that contacts the human body in the mounted state is a hook contact surface.
6. The human body communication wireless audio output device according to claim 1, wherein a plurality of irregularities are formed on the hook contact surface.   7. The human body communication wireless audio output device according to claim 1, wherein a dielectric insulating film that covers the input electrode portion is provided on the ear hook portion. 8.