Abstract:
An in-ear microphone allowing assessment of sound pressure level directly of an individual&#39;s ear canal without intervening conduits between the sound source (i.e., ear canal) and the microphone is provided. Sound from an in-ear communications device may also be isolated from ambient noise using an in-line noise detector For recording the noise from the in-ear communications device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to US provisional application No. 62/316,005, filed Mar. 31, 2016, and hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a noise dosimeter for assessing exposure to noise levels, for example, to determine occupational noise exposure. 
         [0003]    Measuring noise is an important element of programs to prevent hearing loss caused by noise exposure. Such measurements are normally conducted with a noise dosimeter that can be used to measure environmental noise. Such dosimeters provide a sensitive broad-spectrum microphone that may be calibrated to a standard and include circuitry for calculation of sound pressure levels including, for example, peak sound pressure level and time average sound pressure levels. The circuitry may include filtering to provide different weightings conforming to sound exposure safety standards. 
         [0004]    Current noise dosimeters can be lightweight and portable, for example, to be attached to a person&#39;s clothing at the shoulder near the ears for continuous environmental noise monitoring. 
       SUMMARY OF THE INVENTION 
       [0005]    Currently available dosimeters do not allow noise measurement in the ear canal. The present inventors have determined that this can be a significant shortcoming when the individual is wearing an earpiece or headset of a type that may introduce sound, for example, from an audio transducer, directly into the ear canal. For example, during lab testing, a difference of approximately 1-13 decibels of sound pressure level was measured between a shoulder-measured sound dose and sound dose in the ear when an earpiece or headset was being used for radio communication. Field tests indicate a 2-27 dB difference in sound pressure level between these two measurement points. 
         [0006]    These differences in sound pressure level, between the ear canal and shoulder, can have significant implications for hearing health. For example, increasing a noise by 6 decibels of sound pressure level is roughly equivalent to doubling of intensity. Adding a 10 decibel sound pressure level is roughly equivalent to doubling of perceived loudness. Levels above the OSHA action level of about 85 decibels of sound pressure level were measured during field testing. 
         [0007]    The present invention accordingly provides a microphone adapter allowing assessment of the sound pressure level in an individual&#39;s ear canal while using shoulder, level dosimeters, Different versions of the invention accommodate a range of common earpieces and headsets. 
         [0008]    The present invention also provides an in-ear microphone allowing assessment of sound pressure levels directly from an individual&#39;s ear canal without intervening conduits between the sound source (i.e., ear canal) and the microphone. In this manner, sound will not be distorted through travel through tubes or pipes. The present inventors have found that even short distances of travel through a conduit may affect the measurement of sound at the microphone due to physical properties of the sound transmission such as conduit length, diameter, mass and stiffness. These physical properties tended to affect the frequency of noise resonated and propagated to the microphone, e.g., high frequencies were more affected than low frequencies. 
         [0009]    The present invention also provides that sound from an in-ear communications device may be isolated from ambient noise using an in-line noise detector for recording the noise from the in-ear communications device. 
         [0010]    In one embodiment of the present invention, a system for making in-ear measurements of sound pressure levels may be provided comprising an ear piece sized to fit within an ear canal of the human user: and a microphone coupled to the ear piece at a location within the ear canal and adapted to receive sound pressure signals from within the ear canal wherein the sound pressure signals are communicated to a sound monitor. 
         [0011]    It is thus a feature of at least one embodiment of the present invention to position the microphone within the ear canal so that sound pressure signals may be received directly within the inner ear. 
         [0012]    The ear piece may have a tubular stub extending into the car canal acid the microphone is coupled to an exterior surface of the tubular stub. 
         [0013]    It is thus a feature of at least one embodiment of the present invention to detect sound levels from both transmitted sounds from the two way transmitter and ambient noise. 
         [0014]    The microphone may be installed within a pocket nested within the tubular stub. The microphone may be substantially flush with the exterior surface of the tubular stub. 
         [0015]    It is thus a feature of at least one embodiment of the present invention to maintain comfort to the user when wearing the earpiece. 
         [0016]    The microphone may be positioned adjacent to a posterior wall of the ear canal. The microphone may be mounted on a printed circuit board. The microphone maybe a MEMS microphone. 
         [0017]    It is thus a feature of at least one embodiment of the present invention to place the microphone within the ear canal to produce more accurate representations of sound levels. 
         [0018]    The ear piece may have a rim sized to fit within a concha of an outer ear of the human user 
         [0019]    It is thus a feature of at least one embodiment of the present invention to allow for vented two way communication while using the microphone device. 
         [0020]    The tubular stub may receive an audio signal from a remote transducer. The remote transducer may be a two-way radio. 
         [0021]    An audio recording device may be installed between the remote transducer and the connector and recording the audio signal. The audio recording device may be simultaneously outputted to the tubular stub. The audio recording device may convert the audio signal to a MP3 file. 
         [0022]    It is thus a feature of at least one embodiment of the present invention to isolate the sounds from the two way transmitter from the ambient noise. 
         [0023]    In an alternative embodiment of the present invention, a system for making in-ear measurements of sound pressure levels may be provided comprising an ear piece disposed within the ear canal and having a connector communicating with a flexible conductor extending to a location outside of the car canal; and an external dosimeter coupled to an opposite end of the flexible tubular conductor and adapted to receive sound pressure signals from within the ear canal. 
         [0024]    It is thus a feature of at least one embodiment of the present invention to provide improved sound level measurement within the ear when using standard shoulder level portable noise dosimeters. 
         [0025]    The external dosimeter may have a microphone for receiving the sound pressure signals. 
         [0026]    An adapter receiving the sound pressure signals from the ear canal and conformed to fit over the microphone of the dosimeter. 
         [0027]    These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a simplified depiction of a commercial shoulder-mounted noise dosimeter adapted for use in-car canal measurements using the present invention; 
           [0029]      FIG. 2  is a detailed fragmentary view of the noise dosimeter showing an adapter cup fitting over the dosimeter microphone to attach it to a flexible tube leading to the ear canal; 
           [0030]      FIG. 3  is an exploded perspective view of an ear-adapter of the present invention for use with in-ear molds; 
           [0031]      FIG. 4  is a figure similar to that of  FIG. 3  showing an adapter for use with earbuds having a portion inserted into the ear canal; 
           [0032]      FIG. 5  is a figure similar to  FIGS. 3 and 4  showing an adapter for use with a headset supported by an ear hook; and 
           [0033]      FIG. 6  is a perspective view of an in-ear mold having a built-in microphone; 
           [0034]      FIG. 7  is a rear exploded perspective view of the in-car mold of  FIG. 6  showing a printed circuit board and sensor inserted into a canal portion of the in-ear mold; 
           [0035]      FIG. 8  is a figure similar to  FIG. 7  showing the printed circuit board and sensor installed into the canal portion of the in-ear mold; 
           [0036]      FIG. 9  is a simplified depiction of an in-line recording device installed between remote audio transducer and the in-ear mold; and 
           [0037]      FIG. 10  is a figure similar to that of  FIG. 6  showing a hearing aid having a built-in, microphone. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In-Ear Adapter for Shoulder Dosimeter 
       [0038]    Referring now to  FIGS. 1 and 2 , an individual  10  may wear a portable noise dosimeter  12  on their shoulder, for example, as held by a clip  14  attached to clothing  16  of the individual at shoulder height. The dosimeter  12  may have a microphone  20  extending upward and forward from the top of the dosimeter  12 . Dosimeters of this type are commercially available from the 3M Company of St. Paul, Minn., under the tradename of Edge Noise Dosimeter, for example, model EG5-D; Cirrus Research of the United Kingdom, under the tradename of doseBadge, for example, model doseBadge 5 : Larson Davis of Depew, N.Y., under the tradename Spark, for example, model 703+, 705+, 706RC; Casella CEL Inc. (subsidiary of Ideal Industries) of Buffalo, N.Y., under the tradename of dBadge and dBadge 2, and other commercially available noise dosimeters. 
         [0039]    An adapter  18  may provide for a sleeve conforming to and fitting over a cylindrical microphone  20  of the dosimeter  12 , the sleeve having an internal tapered channel allowing for sound to be communicated to the microphone  20  from a smaller diameter flexible tubing  22  attached to an upper end of the adapter  18 . The tubing  22  may lead to an ear-adapter  24  in the ear  19  of the individual  10  for measurement of sound in the ear canal of the individual  10 . 
         [0040]    The tubing  22  will impart its own audio characteristics to the measured sound conducted from the car canal including attenuation caused by the tube length and frequency spectrum modification caused by the distributed transmission properties of the tubing  22 . These modifications may be accommodated by software adjustment of the processing of the sound by the dosimeter  12 . In this regard, the dosimeter  12  may include an internal microcontroller (not shown) having an analog-to-digital converter reading electrical signals produced by the microphone  20  and processing those signals according to a stored program to provide display outputs  23  or possibly audio alerts. Such processing may, for example, include spectral analysis and filtering time integration and peak detection as is generally understood in the art. Control buttons  25  on the dosimeter  12  may be used to change formats of the displayed output  23  and to indicate that the adapter system of the present invention is employed so that suitable calibration changes may be made in producing the display outputs  23 . 
         [0041]    Referring now to  FIG. 3 , the ear ear-adapter  24  may include an ear mold  26  having a rim  28  fitting in the concha of the outer ear of the individual  10  to support the ear mold relative to the ear canal  30 . The ear mold  26  may include a short tubular stub  32  extending into the ear canal  30  and presenting arm outer hole  34  normally receiving a tube  44  communicating sound from a remote audio transducer (such as an electromagnetic speaker or piezoelectric transducer) on radio or the like. 
         [0042]    In the depicted embodiment, a three-way connector  36  provides a manifold of three mutually intercommunicating tubes including a first tube  38  that may be received in the hole  34 , a second tube  40  that may attach to the tubing  22  leading to the dosimeter  12  and a third tube  42  that may attach to the tube  44  from the audio speaker of a radio or the like such as normally would be connected directly to the hole  34 . In this way the three-way connector  36  provides a tap of the sound delivered to the ear that may be diverted to the dosimeter  12  for measurement. 
         [0043]    Referring now to  FIG. 4 , an alternative embodiment of the invention provides for a ring adapter  50  having a central opening  52  sized to approximate the diameter of the ear canal  30  and supporting at its edge a tubular conduit  54  having a first portion that may extend into the ear canal  30  and a second portion extending downward from the ring adapter  50  to receive tubing  22 . Elastomeric supports  56  may attach around the ring adapter  50  to stabilize the ring adapter  50  in alignment with the ear canal  30  against the concha. An ear bud  60  having an in-ear portion  62  may then be inserted through the central opening  52  and a corresponding end-aligned opening in the elastomeric supports  56  to fit along the side of the conduit  54  in the ear canal  30  thereby sampling sound pressure level directly in the ear canal to be sent to the dosimeter  12 . 
         [0044]    Referring now to  FIG. 5 , in an alternative embodiment a right angle adapter  64  may provide a downwardly extending tube  66  that attaches to tubing  22  The tube  66  communicates with a right angle connection  68  that may be attached to a small flexible silicone tube  70  that may fit within the ear canal  30 . The right angle adapter  64  may include a tie point  71  that allows it to be attached to an ear hanger  72  that may curve around the outside of the external ear to support the right angle adapter  64 . This same hanger  72  may support an earpiece  74  that either may fit over the ear canal  30  sandwiching the right angle adapter  64  between it and the ear canal  30  or may have an in-ear portion that may share the volume of the ear canal  30  with the tubing  70 . The earpiece  74  may, for example, be an audio transducer. Again the tubing  22  allows for sampling of in-ear sound pressure levels by the dosimeter  12 . 
       In-Ear Microphone Dosimeter 
       [0045]    Referring now to  FIGS. 6 through 8 , an individual  10  may wear a two-way communication device  80  having an earpiece  82  or headset communicating with a remote audio transducer  84  (see  FIG. 9 ), for example, a radio, phone, MP3 player, etc. The earpiece  82  may be “vented” so that ambient noises may also be heard. The two-way communication device  80  is commonly worn by police officers. firefighters, construction workers, as a way to communicate with other professionals. However, when ambient noise is at a high level, the individual  10  may increase the volume levels on their remote audio transducer  84 , It is desired to measure the noise levels within the ear canal accounting for both the ambient noise and the two-way communication. 
         [0046]    A microphone  86  is adapted to be installed within the earpiece  82  to measure noise from the remote audio transducer  84  and ambient noise from the individual&#39;s  10  surroundings. The microphone  86  may be a micro electrical mechanical system (MEMS) microphone  86  having a sensor and an integrated circuit interface. As is understood in the art, the sensor may be a silicon capacitor consisting of two silicon plates or surfaces. One plate is fixed and the other is movable on one end while being bonded on another end (i.e., cantilevered). The fixed plate is covered by an electrode to make it conductive and includes acoustic holes which allow sound to pass through. A ventilation hole allows the membrane to move back and forth within the pressure chamber. When sound waves pass through the capacitor, the integrated circuit converts the change in capacitance to a digital or analog output. 
         [0047]    The MEMS microphone  86  may be enclosed within a housing  88  having a sound inlet hole or top port  90  placed at the top of the housing  88 . The housing  88  may be a plastic package having wails conforming to an enclosed box having a top wall, a bottom wall and sidewalls. The top wall may hold the top port  90  for the acoustic energy to reach the sensor. The bottom wall may be a substrate on which the sensor and integrated circuit are fixed or bonded and which include the electrical connections. The MEMS microphone  86  may have three electrical connections: ground, output signal, and a voltage supply pin delivering a voltage to the MEMS microphone  86 . 
         [0048]    The MEMS microphone  86  is bonded to a printed circuit hoard  92  accepting the three electrical connections of the MEMS microphone  86 . For example, the MEMS microphone  86  may be stacked on the printed circuit board  92  such that the bottom wall of the housing  88  contacts the printed circuit board  92 . The printed circuit board  92  may have a larger surface area than the MEMS microphone  86  such that the printed circuit board  92  extends past the MEMS microphone  86 . The printed circuit board  92  may be a breakout board breaking out each conductor to a terminal that can accept a hook up wire for distribution. 
         [0049]    The MEMS microphone  86  and printed circuit board  92  are installed on an ear mold  26  having a rim  28  fitting in the concha of the outer ear of the individual  10  to support the ear mold relative to the ear canal  30 . The rim  28  may be between 0.7 and 1.3 inches, or about 1 inch. 
         [0050]    The ear mold  26  may include a short tubular stub  32  extending into the car canal  30 . The tubular stub  32  may be between 0.5 and 1 inch. The tubular stub  32  may present an outer hole  34  normally receiving a tube  44  communicating sound from the remote audio transducer  84  to the outer hole  34  and through a passage within the tubular stub  32  to an inner hole at the other end of the passage. It is understood that the tubular stub  32  may have an outer diameter that is less than an inner diameter of the ear. 
         [0051]    In one embodiment, the tube  44  may be a skeleton style tube with one end connected to the outer hole  34  and an opposite end having an adapter for connection to a connector of the remote audio transducer. In an alternative embodiment the outer hole  34  may receive an analog signal from an electrical connector communicating sound from the remote audio transducer  84 . 
         [0052]    The tubular stub  32  may include a hollow, mounting pocket  94  extending within the outer surface  96  of the tubular stub  32 . The mounting pocket  94  may be sized, and shaped to receive the printed circuit board  92  and may have a depth that less than a total thickness of the wall of the tubular stub  32 . The mounting pocket  94  may have a depth that is substantially equal to a height of the printed circuit board  92  and MEMS microphone  86 . 
         [0053]    The mounting pocket  94  may be oriented such that the mounting pocket  94  is adjacent a posterior wall of the ear canal when the ear mold  26  is inserted into the individual&#39;s  10  ear. In an alternative embodiment, the mounting pocket  94  may be oriented such that the mounting pocket  94  is adjacent an anterior wall of the ear canal. 
         [0054]    The printed circuit board  92  and MEMS microphone may be installed within the mounting pocket  94  such that the printed circuit board  92  lies within the mounting pocket  94  and the MEMS microphone  86  extends outwardly from the mounting pocket  94  and the top port  90  is exposed to the exterior surroundings. The MEMS microphone  86  may be substantially flush with the outer surface  96  of the tubular stub  32  to eliminate discomfort to the individual  10  and prevent the MEMS microphone  86  from falling out. It is understood that the MEMS microphone  86  may extend&#39;within the ear canal without substantial contact with the inner walls of the ear canal  30 . 
         [0055]    A connector  98  may provide communication between the printed circuit board  92  and a noise dosimeter  12  (see  FIG. 1 ). The connector  98  may extend from the printed circuit board  92  to a front of the ear mold  26  and be further connected to the remote audio transducer  84 . In an alternative embodiment, the noise dosimeter  12  may be a sound monitoring device that is built into the ear mold  26  or in-ear device such as a hearing aid. 
         [0056]    When worn, the ear mold  26  may be placed within the concha of the outer ear of the individual  10  with the short tubular stub  32  extending within the ear canal  30 . The MEMS microphone  86  extends into the ear canal and directly senses the noise received through the tubular stub  32  from the remote audio transducer  84  as well as ambient noise. 
         [0057]    Although the MEMS microphone  86  is shown being used with the ear mold  26  as seen in  FIG. 3 , it may also be incorporated into other in-ear devices shown in  FIGS. 4 and 5  without departing from the spirit of the present invention. 
         [0058]    As seen in  FIG. 4 , the tubular conduit  54  of the ring adapter  50  may be inserted into the ear canal  30  with the MEMS microphone  86  supported by the tubular conduit  54  and communicating with a connector  98  extending, from the ear to a noise dosimeter  12 , e.g., an external dosimeter  12  or one built into the ear piece. An ear bud  60  may fit along the side of conduit  54  in the ear canal  30  such that the MEMS microphone samples the sound signals coming from the ear bud  60 . In this embodiment, it is understood that the tubular conduit  54  may not need to be a tube transmitting sound pressure to an external dosimeter since the MEMS microphone detects the sound directly from the inner ear. In one embodiment, the ear bud  60  may be an in-ear hearing aid device. 
         [0059]    As seen in  FIG. 5 , the small flexible silicone tube  70  of the ring angle adapter  64  may be inserted into the ear canal  30  with the MEMS microphone  86  supported by the silicone tube  70  and communicating with a connector extending from the ear to a noise dosimeter  12 , e.g., an external dosimeter  12  or one built into the ear piece. An earpiece  74  may fit over the ear canal  30  or share the volume of the ear canal  30  with the silicone tube  70 . In this embodiment, it is understood that the silicone tube  70  may not need to be a tube transmitting sound pressure to an external dosimeter since the MEMS microphone detects the sound directly from the ear canal. In one embodiment, the earpiece  74  may be an in-ear hearing aid device. 
         [0060]    Referring to  FIG. 10 , the MEMS microphone  86  may be built into a hearing aid device  114 . The hearing aid device  114  may have an external microphone  116  receiving external sound waves and an amplifier/speaker  118  for amplifying the external sounds waves and delivering them through an in-ear tube  120  to the ear canal  30 . The in-ear tube  120  may support the MEMS microphone  86  within the ear canal  30  for recording the sound signals directly from the ear canal  30  and communicating the sound signals to a noise dosimeter  12 , e.g., an external dosimeter or one built into the hearing aid device  114 . 
       In-Line Sound Recorder 
       [0061]    Referring to  FIG. 9 , it may be desired to isolate the ambient noise received within the ear canal  30  and the noise received from the remote audio transducer  84 . An in-line device  100  may be installed between the remote audio transducer  84  and the earpiece  82  or headset in, order to record the audio output from the remote audio transducer  84  and store the audio signals for later evaluation. 
         [0062]    The in-line device  100  may include an audio recorder  102  for recording the audio output communicated from the remote audio transducer  84 . Audio recorders  102  of this type are commercially available from the Sony Corporation of Tokyo Japan, for example, model Sony 1CD PX333. 
         [0063]    The audio recorder  102  may receive the audio output through an auxiliary input connector  104  from the remote audio transducer  84 . The connection may be made through a flexible conductor  106 , for example, a 3.5 mm audio cord, connecting the remote audio transducer  84  to the audio recorder  102 . The audio recorder  102  records the incoming sound signal and saves the signal as, for example, a MP3 file or WAV file. The audio recorder  102  may collect the sound signal with a minimum sampling frequency of 44.1 kHz and may store data for at least eight hours or a normal workday. The sound signal is logged and saved by the audio recorder  102 . 
         [0064]    Simultaneous to the recording, the sound signal is outputted from the audio recorder  102  through an auxiliary output connector  108  to the earpiece  82  where it is communicated, to the individual  10  as it would if the audio recorder  102  was not installed in-line. The connection may be made through a flexible conductor  110 , for example, a 3.5 mm audio cord, connecting the audio recorder  102  to the earpiece  82 . A tube  44  with an adaptor may be installed between the audio recorder  102  and earpiece  82  for transmission of the sound signal through the earpiece  82 . 
         [0065]    The audio output may be evaluated by occupational noise specialists who will compare the log data with known characteristics of the earpiece  82  to determine the noise exposure to the individual  10 . The automatic audio file may be converted into arrays of data providing voltage data that can be used to analyze sound exposure levels. For example the MP3 file may be converted to a CSV file so that the data is compatible with data normally received by the dosimeter  12  and which logs exposure data for later evaluation. 
         [0066]    The in-line device  100  may be protected by a waterproof or water resistant case  112  holding the in-line device  100  therein but allowing communication cables to extend from the ease  112  for connection. The case  112  may include a clip so that the individual  10  may conveniently where the in-line device  100  on their clothing. 
         [0067]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”. “lower”, “above”. and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made dear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0068]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0069]    References to “a microprocessor” and “a processor” or “the microprocessor” and “the processor,” can be understood to include one or more microprocessors that can communicate in a stand-alone and/or a distributed environment(s), and can thus be configured to communicate via wired or wireless communications with other processors, where such one or more processor can be configured to operate on one or more processor-controlled devices that can be similar or different devices. Furthermore, references to memory, unless otherwise specified, can include one or more processor-readable and accessible memory elements and/or components that can be internal to the processor-controlled device, external to the processor-controlled device, and can be accessed via a wired or wireless network. 
         [0070]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications are hereby incorporated herein by reference in their entireties.