Abstract:
There has been no sufficient study to address an issue caused in the use of an open-air type audio device. Therefore, provided is an audio device with an actually useful organism sensor. In particular, the audio device includes an audio unit  10  to externally abut on the ear without being inserted thereinto, and an organism sensor unit  70  to be inserted into the ear.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to an audio device with an organism sensing function. 
       BACKGROUND 
       [0002]    Lately, an audio device having an earphone with a sensor for measuring a volume of blood flow, a blood pressure and the like has been developed. Also, there has been known an open-air type hearing aid. 
       CITATION LIST 
     Patent Literatures 
       [0003]    PLT 1: US2008220535A1 
         [0004]    PLT2: US2012283578A1 
         [0005]    PLT3: JP2006304147A 
       SUMMARY 
       [0006]    However, there has been no study to address an actual issue of the earphone and the like having an organism sensor mounted therein. 
         [0007]    For example, an issue caused in using an open-air type audio device has not been sufficiently studied. 
         [0008]    Therefore, it could be helpful to provide an audio device with an organism sensing function that is actually useful. 
         [0009]    The audio device according to the present disclosure includes an audio unit to externally abut on the ear without being inserted thereinto and an organism sensor unit to be inserted into the ear. 
         [0010]    The audio device according to the present disclosure considers actual issues and thus is useful. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    In the accompanying drawings: 
           [0012]      FIG. 1  is an external view of an audio device according to one embodiment; 
           [0013]      FIG. 2  is a schematic diagram illustrating curve of a panel of the audio device and a piezoelectric element; 
           [0014]      FIG. 3  is a block diagram of the audio device; 
           [0015]      FIG. 4  is a diagram illustrating a cross-sectional view of an audio unit and a housing unit of the audio device in a thickness direction and a bottom view of the audio unit; 
           [0016]      FIG. 5  is a cross-sectional view and an appearance view of an organism sensor unit of the audio device; 
           [0017]      FIG. 6  is a cross-sectional view and an appearance view of another organism sensor unit of the audio device; 
           [0018]      FIG. 7  is a cross-sectional view and an appearance view of an organism sensor unit according to another embodiment; 
           [0019]      FIG. 8  is a diagram illustrating a state of wearing the audio device; and 
           [0020]      FIG. 9  is a diagram illustrating measured data of acoustic characteristics. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Hereinafter, an embodiment will be described. 
         [0022]    An audio device according to one of the embodiment is, for example, a hearing aid or a headphone and generally includes an audio unit  10 , an organism sensor unit  500 , and a support  60  for supporting the audio unit  10  and the organism sensor unit  500 . 
         [0023]    The audio unit  10  includes a piezoelectric element  101  that curves and a panel  102  that vibrates when directly bent by the piezoelectric element  101 .  FIG. 2  is a diagram schematically illustrating a state of the panel  102  bent by the piezoelectric element  101 . The panel  102 , when directly bend by the piezoelectric element  101 , vibrates and widely curves in a central area thereof in a manner protruding from both ends thereof. The audio unit  10  functions to provide a user with a human body vibration sound caused mainly by vibration. Depending on a size of the panel, an air conduction sound may be generated. The air conduction sound is a sound that is delivered to the user&#39;s auditory nerve when air vibration caused by vibration of a substance travels through the external ear canal and vibrates the ear drum. The human body vibration sound is a sound that is delivered to the user&#39;s auditory nerve via a part of the user&#39;s body (for example, the cartilage of the external ear) in contact with a vibrating substance. The human body vibration sound may contain a component that changes from the vibration to the air conduction inside the external ear canal. We have preliminarily found in a research that, even when the panel  102  is small, vibration of the ear causes at least a 6th harmonic sufficiently higher than a background noise at least at three positions in the panel. When the harmonic components are provided together, regardless of the size of the panel  102  (for example, a rectangular shape of 3 cm in length and 1 cm in width or smaller), the sound becomes enough loud to be heard. The human body vibration sound contributes especially to articulation and thus is suitable for a person with geriatric defective hearing who has a difficulty in hearing a high pitch sound. 
         [0024]    The piezoelectric element  101  is an element that, upon application of an electric signal (a voltage), contracts or curves (bends) according to an electromechanical coupling factor of a material thereof. The piezoelectric element  101  is directly attached to the panel  102  via a double-sided tape. The piezoelectric element may be made of, for example, ceramics or crystal. The piezoelectric element  101  may be a unimorph, a bimorph, or a laminated piezoelectric element. The laminated piezoelectric element includes a laminated unimorph element in which the unimorphs are laminated (for example, approximately 16 to 100 layers thereof) or a laminated bimorph element in which the bimorphs are laminated (for example, approximately 16 to 48 layers thereof). The laminated piezoelectric element includes a plurality of dielectric layers made of, for example, PZT (lead zirconate titanate) and electrode layers disposed therebetween. In response to the application of the electric signal (the voltage), the unimorph contracts, while the bimorph bends. 
         [0025]    The panel  102  is made of, for example, a hard material such as glass and sapphire, or a synthetic resin such as acryl and polycarbonate. Preferably, the panel  102  is in a plate shape, and hereinafter the panel  102  is assumed as such. For example, the panel is approximately 2 cm to 5 cm in length and 0.5 cm to 2 cm in width. The piezoelectric element  102  is directly attached to the panel  102  via the double-sided tape and the like. 
         [0026]    The microphone  20  collects a sound from a sound source, in particular, a sound that reaches near the user&#39;s helix. Since the microphone  20  is behind the helix and thus unlikely to collect a sound leaking from the external ear canal (i.e., unlikely to cause howling), the microphone  20  may easily reproduce a natural sound to the user. 
         [0027]    One microphone unit may be provided to the audio unit  10  on both a left side and a right side. One microphone may generate a signal to be shared by the audio units on the left side and the right side. 
         [0028]    Note that the microphone is not necessary when an audio device does not need a function to collect and provide an ambient sound. It is a matter of course that the microphone may be used for an input of a telephone call. An exterior audio signal or an audio signal stored in an internal storage area needs to be input to a controller  30 . 
         [0029]      FIG. 3  illustrates an example of a block diagram. The controller (IC)  30  carries out various control of the audio device  1 . The controller  30  applies a predetermined electric signal (a voltage according to a sound signal) to the piezoelectric element  101 . In particular, the controller  30  controls an A/D converter  31  to convert the sound signal collected by the microphone unit  20  into a digital signal. Then, a signal processing unit  32 , based on information on volume and sound quality provided from a volume adjustment interface unit  40  and also on information stored in a storage unit  50 , outputs a digital signal for driving the audio unit  10 . A D/A converter  33  converts the digital signal into an analogue electric signal, which is then amplified by a piezoelectric amplifier  34  and applied to the piezoelectric element  101 . The voltage applied to the piezoelectric element  101  by the controller  30  may be higher than, for example, an applied voltage of an air conduction earphone speaker for delivering the air conduction sound. Thereby, the panel  102  generates sufficient vibration and thus the human body vibration sound that is delivered via a part of the user&#39;s body. A level of the voltage to be applied may be appropriately adjusted according to fixing strength of the panel  102  or performance of the piezoelectric element  101 . When the controller  30  applies the electric signal to the piezoelectric element  101 , the piezoelectric element  101  curves in a longitudinal direction thereof. 
         [0030]    At this time, the panel  102  having the piezoelectric element  101  attached thereto deforms according to the contraction or bend of the piezoelectric element  101  and vibrates. The panel  102  curves due to the contraction or bend of the piezoelectric element  101 . The panel  102  is directly bent by the piezoelectric element  101 . Here, “the panel  102  is directly bent by the piezoelectric element  101 ” is different from a phenomenon in which, as employed by a conventional panel speaker, inertial force of a piezoelectric actuator having the piezoelectric element  101  disposed inside a casing vibrates a particular area of the panel  102  and deforms the panel  102 . “The panel  102  is directly bent by the piezoelectric element  101 ” is a phenomenon in which the contraction or bend (curve) of the piezoelectric element  101  directly bends the panel  102  via a joining member. 
         [0031]    As described above, since the panel  102  vibrates, when the panel  102  is in contact with the tragus, the human body vibration sound is generated via the tragus. Preferably, the panel  102  vibrates having areas near both ends thereof functioning as a joint and the center thereof as the flat, in such a manner that an area near the center of the panel  102  abuts on the tragus and the antitragus. Thereby, the vibration of the panel  102  may be efficiently delivered to the tragus and the antitragus. 
         [0032]    As illustrated in  FIG. 1 , the support  60 , at both ends thereof, supports a housing unit  70 . Further, the housing unit  70  supports the audio unit  10  at a position opposite to the ear. 
         [0033]    The support  60  supports the audio unit  10  and the organism sensor unit  500 . Thereby, the audio unit  10  abuts on the ear. Here, on the user&#39;s ear, the audio unit  10  may abuts on, for example, the tragus or the antitragus. According to the present embodiment, hereinafter, it is assumed that the audio unit  10  abuts on the tragus. The organism sensor unit  500  is supported by a joint portion  604  extending from a bottom of the housing unit  70  at a position blocking the user&#39;s ear shell. The joint portion  604  is constituted by using a member such as a flat spring having appropriate elasticity. The joint portion  604  may be made of metal or resin, as a matter of course. Inside the joint portion  604 , a wire  510  is provided to supply an output signal from the organism sensor unit  500  and supply power to the organism sensor unit  500 . 
         [0034]    The support  60  includes an arm portion  601  in a semicircular shape extending along the user&#39;s occipital region. The arm portion  601  may be designed to allow adjustment of pressure approximately between 0.1 N to 10 N when the housing unit  70  abuts on, for example, the tragus. The arm portion  601  may be made of a metal spring curved into a predetermined shape and coated with resin, or a resin spring and the like, and has appropriate elasticity. 
         [0035]    The support  60  includes a pair of ear hooking portions  602  formed continuously from the arm portion  601 . The ear hooking portions  602 , as illustrated in  FIG. 8 , curve to hang on a part of the user&#39;s helix. The ear hooking portions  602  may be integrally formed with the arm portion  601 . 
         [0036]    Each of the ear hooking portions  602  of the support  60  is provided with the microphone  20 . Although it is preferable that two microphones are provided for each of the left ear and the right ear, one microphone may be provided for either one of the ears. The signal from the microphone  20 , through a signal wiring (not shown) disposed inside the support  60  (the ear hooking portions  602  and a support portion  603 ), is input to the controller  30  described later. 
         [0037]    The support  60 , at a distal end of the ear hooking portion  602 , is provided with the support portion  603  for supporting the housing unit  70 . The support portion  603  supports the housing unit  70  in such a manner that the panel  102  disposed on the housing unit  70  abuts on the user&#39;s ear. 
         [0038]    The housing unit  70  is supported by the support portion  603  of the support  60  and includes a substrate  702  and the like thereinside. The following is a detailed description of the housing unit  70  and the audio unit  10  with reference to  FIG. 4  by way of example. 
         [0039]      FIG. 4  is a cross-sectional diagram of the audio unit  10  and the housing unit  70  viewed in a thickness direction. As described above, the audio unit  10  includes the piezoelectric element  101  and the panel  102 . Preferably, the piezoelectric element  101  is in a panel shape as illustrated in  FIG. 4 . 
         [0040]    The piezoelectric element  101  is attached to the panel  102  via a joint member  103   x.  The joint member  103   x  is provided between a principal plane of the piezoelectric element  101  and a principal plane of the panel  102 . The joint member  103   x  is preferably a non-thermosetting adhesive or the double-sided tape. The double-sided tape may be, for example, a cloth impregnated with adhesive resin. 
         [0041]    Preferably, the principal plane of the panel  102  is in size 0.8 to 10 times larger than the principal plane of the piezoelectric element  101 . When the size of the principal plane of the panel  102  is within a range of 0.8 to 10 times of the size of the principal plane of the piezoelectric element  101 , the panel  102  may deform according to the contraction or bend of the piezoelectric element  101  and, also, a sufficient area to come into contact with the user&#39;s ear may be ensured. More preferably, the size of the panel is, for example, 0.8 to 5 times of the size of the piezoelectric element. 
         [0042]    Also, the panel  102 , on the principal plane on an ear side, may have a concave shape. Thereby, the panel  102  may be more easily contact the tragus that is protruding, in comparison with the panel  102  with a flat principal plane. That is, the panel  102  having the concave shape is effective in preventing displacement thereof. 
         [0043]    On a rear side of the panel  102  (on a side opposite to the housing unit  70 ), a pair of double-sided tapes  103   y  are attached. These double-sided tapes  103   y  attach the panel  102  to a principal plane of the housing unit  70 . Thereby, the panel  102  is attached to the housing unit  70 . The double-sided tape  103   y  is provided at either end of the piezoelectric element  101 . Since the double-sided tape  103   y  is not provided to the piezoelectric element  101  at any other positions including the center area than each end of the piezoelectric element  101 , sufficient vibration of the piezoelectric element  101  with low power consumption may be ensured at the center thereof. Note that, when the piezoelectric element  101  sufficiently strongly vibrates, the double-sided tape  103   y  may be provided in the entire area of the panel  102  in order to attach the panel  102  to the housing unit  70 . 
         [0044]    Preferably, the double-sided tape  103   y  is attached in a U-shape or a C-shape along three ends of the piezoelectric element  101 , from a viewpoint of reinforcing the adhesion while efficiently using the small area of the panel  102 . Thereby, the double-sided tape  103   y  is unlikely to inhibit the bend of the panel  102 . 
         [0045]    On a rear side (on a side opposite to the housing unit  70 ) of the piezoelectric element  101 , a pair of solders  104  are formed, to which a wire  704  is joined connecting to the substrate  702  in the housing unit  70  described later. 
         [0046]    The housing unit  70  includes a housing  701 , the substrate  702 , a battery  703 , the wire  704 , and a screw  705 . Further, the housing  70  includes the controller (IC)  30  built therein. 
         [0047]    The housing  701  is made of, for example, plastics. In particular, the housing  701  is obtained by molding a resin material such as polycarbonate resin and amine-based resin. Alternatively, a material in which synthetic resin having glass fiber weaved therein (for example, Reny (registered trademark) produced by Mitsubishi Gas Chemical Company, Inc.) may be used. The material of the housing  701  needs to be as light as possible so as ease the burden on the helix, as well as to be sufficiently strong against an impact of falling and the like. However, when the material is too light and thin, a resonance is easily generated, causing energy loss. Accordingly, a material and weight of the housing  701  is determined in consideration of both lightness and strength. That is, from a viewpoint of vibration, a material having rigidity as high as possible is preferably used. From this point of view, the housing  701  may be made of thick metal. 
         [0048]    The housing  701  is one casing made up of a pair of members bolted together using screws  705 . When the battery  703  is not rechargeable, the members are preferably bolted together, rather than being bonded together, so as to allow replacement of the battery  703 . 
         [0049]    The substrate  702  inside the housing  701  is electrically connected to the controller  30  and the piezoelectric element  101  via the solders  104  and the wire  704 . Also, the substrate is provided with the battery  703  mounted thereon. 
         [0050]      FIG. 8  is a diagram illustrating a state in which the user is wearing the audio device  1  according to one embodiment on the ear. According to the audio device  1 , the audio unit  10  externally abuts on the ear near the user&#39;s tragus and antitragus and delivers the vibration thereto, thereby providing the sound to the user. In an example illustrated in  FIG. 5 , the audio unit  10  externally abuts on the user&#39;s tragus. It is a matter of course that the audio unit  10  may abuts on either one of, or both of, the ears. 
         [0051]    Preferably, the audio unit  10  applies a pressure of 0.1 N to 3 N to the user&#39;s ear. When the audio unit  10  applies a pressure within a range of 0.1 N to 3 N, the vibration of the audio unit  10  is sufficiently delivered to the ear. Also, when the pressure is equal to or lower than 3 N, the audio device  1  hardly makes the user feel tired after wearing the audio device  1  for many hours and is capable of maintaining wearing comfort. Further, the tragus being slightly flattened does not block the external ear canal and thus is less likely to cause an ear-stuffed feeling. 
         [0052]    Now, acoustic characteristics of the audio device  1  according to one embodiment will be described with reference to  FIG. 9 .  FIG. 9  illustrates measured data of acoustic characteristics of the audio unit  10  on the right side of the audio device  1 .  FIG. 9  illustrates data of  12  samples and a mean value thereof. As can be seen in the figure, with respect to an external input at 15 dBV, sufficiently good acoustic characteristics are shown in each frequency band from 200 Hz to 8 kHz. Especially between 3 kHz and 4 kHz, a high sound pressure was obtained, which is effective also for a hearing-impaired person who speaks a language other than Japanese, such as English and the like. Further, the audio device  1  has a wide coverage of the frequency band and thus may be preferably used as the earphone. Note that the audio device  1  illustrated in  FIG. 6  employs a low-pass filter for gradually attenuating a signal at 8 kHz or over. 
         [0053]    When the low-pass filter or the like is not employed, the piezoelectric element  101  may vibrate in response to a sound in an ultrasonic frequency band such as, for example, 40 kHz. Therefore, the audio device  1  may also function as an audio device for generating various ultrasonic waves. 
         [0054]      FIG. 3  illustrates a block diagram of the organism sensor unit  500 . The organism sensor unit  500  according to the present embodiment, as illustrated in  FIG. 5  and  FIG. 6 , by using organic sensors SOIL and  501 R (a light reception unit  508  and a light emission unit  507 ) mounted in a housing  504  to be inserted into the ear, measures, for example, a user&#39;s pulse. The light emission unit  507  and the light reception unit  508  of the organic sensors  501 L and  501 R are arranged in parallel having a light shielding wall therebetween inside the housing  504 . A light transmission panel  505  is disposed on the organic sensors for a protective purpose, whereby the housing  504  is sealed. 
         [0055]    In order to measure the pulse, the light emission unit  507  uses a blue (a wavelength: 400 to 430 nm) or a green (the wavelength: 500 to 550 nm) LED or laser. The blue light and the green light with wavelengths described above are easily absorbed by hemoglobin. Therefore, an amount of the light absorbed increases in proportion to a volume of blood flow, and an output to the light reception unit  508  becomes weaker in proportion thereto. Alternatively, a red light (the wavelength: 630 to 650 nm) LED or the laser may be used. In this case, since the hemoglobin reflects an infrared light, an amount of the light reflected increases in proportion to the volume of blood flow, and the output to the light reception unit  508  becomes stronger in proportion thereto. As the light reception unit  508 , a photodiode corresponding to the wavelength is used. 
         [0056]    In order to measure the volume of blood flow, on the other hand, for example, red (the wavelength: 1.31 μm or 1.55 μm) laser is used so as to detect a relative volume of blood flow from a phase difference of the frequency caused by a Doppler shift. 
         [0057]    The housing  504  includes the substrate  506  and the controller  502  therein. The controller  502  mounted on the substrate  506  may include a determination unit for controlling light emission timing of the light emission unit  507  to the light reception unit  508  as well as for determining an error or a noise signal based on a signal of the light reception unit  508 , and also a calculation unit for calculating the pulse and the volume of blood flow. Sampling is carried out at intervals of 0.005 to 0.1 second. The determination unit determines that an error has occurred when detecting a high frequency that cannot be generated in the human body. 
         [0058]    When the organism sensor unit  500  according to another embodiment is a sensor for measuring the volume of blood flow, the laser for emitting, for example, the red light (the wavelength: 1.31 μm or 1.55 μm) is used to detect the relative volume of blood flow from the phase difference of the frequency caused by the Doppler shift. 
         [0059]    The controller  502  provided inside the housing  504 , similarly to the sensor for measuring the pulse, controls the light emission timing of the light emission unit  507  to the light reception unit  508  as well as for determining an error or the noise signal based the signal of the light reception unit  508 , and the calculation unit for calculating the volume of blood flow. Sampling is carried out at intervals of 0.005 to 0.1 second. 
         [0060]    When both a sensor for measuring the pulse and a sensor for measuring body temperature are provided, for example, the organism sensor  501 L and an organism sensor  501 R may function as a pulse sensor and a body temperature measurement sensor  511 , respectively. It is a matter of course that a combination of the blood flow sensor and the pulse sensor or a combination of the blood flow sensor and the body temperature sensor may be used. The body temperature measurement sensor  511  measures the body temperature by, for example, detecting the infrared light travelling from the external ear canal toward outside the ear. Similarly to the example described above, the housing  504  includes the substrate  506  and the controller  502  therein. The controller  502  mounted on the substrate  506  controls an operation of the light reception unit for measuring the body temperature and manages data of the body temperature. 
         [0061]    Biometric data from each of the organism sensors are stored in the storage unit  503 . Although the storage unit  503  is provided separately from the storage unit  50  that is used for the audio function in  FIG. 3 , the storage unit  50  may also function as the storage unit  503 . The biometric data stored in the storage unit  503  may be externally provided as necessary via a communication unit  1001  or the like. 
         [0062]    Next, with reference to  FIG. 7 , another variation of a configuration of the sensor will be described. 
         [0063]    In  FIG. 7 , the organism sensor unit  500  includes an insertion unit  509  to be inserted into the external ear canal, which is different from the embodiment illustrated in  FIG. 5  and  FIG. 6 . Therefore, the housing  504  is provided with an engaging unit  504 ′ that is engaged with an engaged portion  509 ′ provided to the insertion unit  509 . The insertion unit  509  is made of rubber with Shore hardness of, for example, approximately  30  to  60 . Alternatively, the insertion unit  509  may be made of a molded hard polyimide resin. The housing  504  may have a vent (an air hole)  512  so as to reduce the ear-stuffed feeling. 
         [0064]      FIG. 8  illustrates a diagram of an example of the wearing state of the audio device  1 . 
         [0065]    The housing  504  of the organism sensor  500  is placed in such a manner as to face the concha inside the ear. The light emission unit  507  emits the light toward the concha. The light is unlikely to leak outside. A rear side of the housing  504  (outside the ear) abuts on a rear side of the tragus and a rear portion of the antitragus, whereby the housing  504  is held inside the ear. On the other hand, a front side of the housing  504  faces the concha (and may abut on the concha). A space surrounded by the concha and the front side of the housing  504 , because of a peripheral portion of the housing  504 , is unlikely to receive external light. Therefore, the external light is unlikely to reach the light reception unit  508 , and reliability of the measurement of the sensor may be easily improved. 
         [0066]    Also, the audio unit  10  abuts on the tragus and, by vibrating the internal wall of the external ear canal, may deliver the air conduction sound. At this time, when the audio unit  10  and the organism sensor  500  sandwich the tragus from inside and outside the ear, the delivery of the vibration is more likely to be ensured. 
         [0067]    Next, an example of use when the organization sensor unit  500  includes a combination of the body temperature sensor and the pulse sensor will be described. 
         [0068]    First, power of the sensors is turned on, and the pulse and the body temperature are measured simultaneously or in series. Next, the organism sensors obtain the data. Then, it is determined that whether the body temperature is at a threshold or higher (for example, 38° C. degrees or higher) and, simultaneously, whether the pulse is at a threshold (for example, 10% of, or lower than, the pulse in a wakeful state) or less. In this case, the audio unit  10 , for example, may issue notification of a possibility of heat stroke. When the audio device includes the communication unit  1001 , the communication unit  1001  may transmit, to a registered particular receiver, notification of that the measured person is having the heat stroke or various measured organism data (the pulse, the temperature, and the volume of blood flow). The registered particular receiver may be a user&#39;s doctor or nurse and the like. 
         [0069]    The communication unit  1001  may employ a conventionally known communication method such as, for example, one in accordance with LTE and the like or Wi-Fi. Although in  FIG. 1  the communication unit  1001  is disposed on the rear side of the support  60 , i.e., at a position opposite to the occipital region, the location of the communication unit  1001  is not limited thereto. 
         [0070]    Also, although in the present embodiment the audio device  1  is the hearing aid, the audio device  1  is not limited thereto. For example, the audio device  1  may be a music player, in which case the microphone  20  may be omitted. Also, the audio device  1  may reproduce music based on music data stored in an internal memory thereof, or based on music data stored in an external server via the network. Further, the audio device  1  may store a synthesized voice or an alarm sound for warning about the heat stroke as described above by way of example. 
         [0071]    Although the present disclosure has been described based on the figures and the embodiment, it is to be understood that various modifications and changes may be implemented based on the present disclosure by those who are ordinarily skilled in the art. Accordingly, such modifications and changes are included in a scope of the present disclosure. For example, a function and the like included in each means, unit and the like may be rearranged without logical inconsistency, so as to combine a plurality of means or units together or to divide them.