Patent Publication Number: US-2021168539-A1

Title: Hearing aid device with biometric sensor

Description:
RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional patent Application No. 62/733,327 filed Sep. 19, 2018, the disclosure of which is incorporated herein by reference as if set forth in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to monitoring devices and, more particularly, to optical sensor devices. 
     BACKGROUND OF THE INVENTION 
     There is growing market demand for personal health and environmental monitors, for example, for gauging overall health and metabolism during exercise, athletic training, dieting, daily life activities, sickness, and physical therapy. However, traditional health monitors and environmental monitors may be bulky, rigid, and uncomfortable—generally not suitable for use during daily physical activity. 
       FIGS. 1A-1B and 2  illustrate a prior art ear worn fitness tracking device  10  having a biometric sensor assembly  12  and a speaker  14  in different locations. In  FIG. 1B  the housing of the device  10  is transparent to better illustrate the location of the biometric sensor assembly  12  and speaker  14 . As illustrated in  FIG. 2 , when the device  10  of  FIGS. 1A-1B  is worn, the housing of the device  10  generally fills the volume of the Concha Cavum and both the biometric sensor assembly  12  and speaker  14  are located outside of the auditory canal. The addition of the biometric sensor assembly  12  to the device  10  creates challenges to user comfort as well as to perceived overall size of the device  10 . 
     Referring to  FIGS. 3A-3B , the biometric sensor assembly  12  of the device  10  of  FIGS. 1A-1B  is illustrated. The illustrated biometric sensor assembly  12  includes a housing  16  having windows  18  formed therein. A printed circuit board  20  supporting an optical emitter  22  and optical detector  24  and related electronics is secured to the housing  16 . Light guides  26  are positioned within the windows  18  and are configured to guide light from the optical emitter through a respective window  18  and collect light through a respective window  18  and guide the collected light to the optical detector  24 . 
     In addition, other wearable fitness trackers are focused on wrist-worn form-factors that are used for sports and fitness applications rather than form-factors routinely used by those having health conditions. 
     SUMMARY 
     It should be appreciated that this Summary is provided to introduce a selection of concepts in a simplified form, the concepts being further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of this disclosure, nor is it intended to limit the scope of the invention. 
     According to some embodiments of the present invention, a hearing aid module configured to be inserted within the auditory canal of an ear of a subject includes an elongated housing, an optical sensor module positioned within the housing, an audio driver positioned within the housing adjacent the optical sensor module that is configured to provide sound to the subject, and first and second light guides. One or both of the first and second light guides may be supported by the audio driver in some embodiments. However, in other embodiments, one or both of the first and second light guides may be supported by the housing or one or more other components and do not contact the audio driver. 
     The module has a rectangular configuration with opposite first and second sides, opposite third and fourth sides, and opposite first and second ends. The first and second sides each include an opening, and an acoustic passage is formed through the housing first end. An ear tip is coupled to the housing at the first end and is configured to retain the module within the auditory canal. 
     In some embodiments, the housing includes front and rear sections that are joined together. In some embodiments, portions of the housing adjacent the first opening and/or the second opening are opaque. 
     The optical sensor module includes at least one optical emitter and at least one optical detector. The first light guide is configured to guide light from the at least one optical emitter through the opening in the housing first side and toward the skin of the auditory canal in a non-line of sight manner. The second light guide is configured to collect light from the skin of the auditory canal and direct the collected light to the at least one optical detector in a non-line of sight manner. 
     The module may include an opaque barrier or body positioned between the optical sensor module and the audio driver to prevent crosstalk between the at least one optical emitter and the at least one optical detector. In some embodiments, the opaque body has opposite first and second sides, opposite third and fourth sides, and opposite first and second end portions. The opaque body first end portion abuts the optical sensor module or is in close relationship thereto, the opaque body second end portion abuts an end portion of the audio driver or is in close relationship thereto, the opaque body first side abuts a portion of the first light guide or is in close relationship thereto, and the opaque body second side abuts a portion of the second light guide or is in close relationship thereto. In other embodiments, the opaque body may be a part of a housing of the audio driver. 
     The first light guide includes first and second sections. The first section has an elongated flat configuration with opposite first and second ends and opposite first and second surfaces. The second section extends outwardly from the second surface of the first section adjacent the first end of the first section. The second section is positioned near the at least one optical emitter and the first section second surface abuts or is located very close to a surface of the audio driver. Light from the at least one optical emitter passes into the first light guide through the second section and exits through the first section first surface. 
     The second light guide includes first and second sections. The first section has an elongated flat configuration with opposite first and second ends and opposite first and second surfaces. The second section extends outwardly from the second surface of the first section adjacent the first end of the first section. The second section is positioned near the at least one optical detector and the first section second surface abuts or is located very close to a surface of the audio driver. The second light guide collects light from the skin of the auditory canal through the first section first surface and directs the collected light into the at least one optical detector via the second section. 
     According to some embodiments of the present invention, a hearing aid device includes a first module comprising a power supply and a second module as described above configured to be inserted within an auditory canal of an ear of a subject. The first and second modules are electrically coupled via a cable. 
     It is noted that aspects of the invention described with respect to one embodiment may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which form a part of the specification, illustrate various embodiments of the present invention. The drawings and description together serve to fully explain embodiments of the present invention. 
         FIGS. 1A-1B  illustrate a prior art ear worn fitness tracking device. 
         FIG. 2  illustrates the device of  FIGS. 1A-1B  inserted within the ear of a person. 
         FIG. 3A  is a bottom perspective view of the biometric sensor assembly of the device of  FIGS. 1A-1B . 
         FIG. 3B  is an exploded side view of the biometric sensor assembly of  FIG. 3A . 
         FIG. 4  is a perspective view of a hearing aid device according to some embodiments of the present invention. 
         FIG. 5  illustrates the receiver-in-canal (“RIC”) module of the hearing aid device of  FIG. 4  inserted within an auditory canal of an ear of a person. 
         FIGS. 6A and 6B  are front perspective views of a RIC module for a hearing aid device according to some embodiments of the present invention. In  FIG. 6B , the housing of the RIC module is transparent to illustrate the components therewithin. 
         FIG. 7  illustrates the RIC module of  FIGS. 6A-6B  with the ear tip removed. 
         FIG. 8  is an exploded perspective view of the RIC module of  FIGS. 6A-6B . 
         FIG. 9  is an exploded perspective view of the housing of the RIC module of  FIGS. 6A-6B  illustrating the front section and rear section thereof. 
         FIG. 10A  is a front perspective view of the components housed within the housing of the RIC module of  FIGS. 6A-6B . 
         FIGS. 10B-10C  are exploded perspective views of the components illustrated in  FIG. 10A . 
         FIG. 11A  is a front perspective view of an optical sensor module having a printed circuit board supporting an optical emitter and detector on one side and an accelerometer on the opposite, side according to some embodiments of the present invention. 
         FIG. 11B  is a front perspective view of an optical sensor module having a printed circuit board supporting two optical emitters and an optical detector on one side and an accelerometer on the opposite side, according to other embodiments of the present invention. 
         FIG. 12  illustrates the optical sensor module of  FIG. 11B  with an opaque barrier positioned between the optical emitters and the optical detector to prevent crosstalk therebetween, according to some embodiments of the present invention. 
         FIGS. 13-22  are perspective views of various configurations and shapes of the light guides utilized in the RIC module of  FIGS. 6A-6B , according to some embodiments of the present invention. 
         FIG. 23A  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with a portion of the front section of the housing transparent to light to allow light from the optical emitter to pass therethrough, according to some embodiments of the present invention. 
         FIG. 23B  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to light to allow light from the optical emitter to pass therethrough, according to other embodiments of the present invention. 
         FIG. 23C  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to light to allow light from the optical emitter to pass therethrough, according to other embodiments of the present invention. 
         FIG. 23D  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to light to allow light from the optical emitter to pass therethrough, according to other embodiments of the present invention. 
         FIG. 23E  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front and rear sections of the housing opaque to light, and with selected portions of the front and rear sections of the housing transparent to light to light to allow light from the optical emitter to pass therethrough, according to other embodiments of the present invention. 
         FIG. 23F  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front and rear sections of the housing opaque to light, and with selected portions of the front and rear sections of the housing transparent to light to allow light from the optical emitter to pass therethrough, according to other embodiments of the present invention. 
         FIG. 24A  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to allow light to pass therethrough and reach the optical detector, according to some embodiments of the present invention. 
         FIG. 24B  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to allow light to pass therethrough and reach the optical detector, according to other embodiments of the present invention. 
         FIG. 24C  is a front perspective view of the RIC module of  FIGS. 6A-6B  with selected portions of the front section of the housing opaque to light, and with selected portions of the front section of the housing transparent to allow light to pass therethrough and reach the optical detector, according to other embodiments of the present invention. 
         FIG. 25  is a front perspective view of the RIC module of  FIGS. 6A-6B  with an opaque boundary positioned around a periphery of the front section of the housing to prevent crosstalk between the optical emitter and detector, according to some embodiments of the present invention. 
         FIG. 26  is an exploded perspective view of a RIC module according to other embodiments of the present invention. 
         FIG. 27  is a perspective view of the optical sensor module and light guides of  FIG. 26 , and wherein the optical detector is facing upwardly. 
         FIG. 28  is a perspective view of the optical sensor module and light guides of  FIG. 26 , and wherein the optical emitters are facing upwardly. 
         FIG. 29  is an exploded perspective view of a RIC module according to other embodiments of the present invention. 
         FIG. 30  is a perspective view of the optical sensor module, light guides, and audio driver of  FIG. 30 . 
         FIG. 31  is an exploded perspective view of a RIC module according to other embodiments of the present invention. 
         FIG. 32  is a perspective view of the optical sensor module, light guides, audio driver, and ear tip of  FIG. 30 . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying figures, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Like numbers refer to like elements throughout. In the figures, certain layers, components or features may be exaggerated for clarity, and broken lines illustrate optional features or operations unless specified otherwise. In addition, the sequence of operations (or steps) is not limited to the order presented in the figures and/or claims unless specifically indicated otherwise. Features described with respect to one figure or embodiment can be associated with another embodiment or figure although not specifically described or shown as such. 
     It will be understood that when a feature or element is referred to as being “on” another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being “directly on” another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being “connected”, “attached”, “coupled”, or “secured” to another feature or element, it can be directly connected, attached, coupled, or secured to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being “directly connected”, “directly attached”, “directly coupled”, or “directly secured” to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     As used herein, the terms “comprise”, “comprising”, “comprises”, “include”, “including”, “includes”, “have”, “has”, “having”, or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation “e.g.”, which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. The common abbreviation “i.e.”, which derives from the Latin phrase “id est,” may be used to specify a particular item from a more general recitation. 
     As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”. 
     As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.” 
     Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal” and the like are used herein for the purpose of explanation only unless specifically indicated otherwise. 
     It will be understood that although the terms first and second are used herein to describe various features or elements, these features or elements should not be limited by these terms. These terms are only used to distinguish one feature or element from another feature or element. Thus, a first feature or element discussed below could be termed a second feature or element, and similarly, a second feature or element discussed below could be termed a first feature or element without departing from the teachings of the present invention. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity. 
     The term “about”, as used herein with respect to a value or number, means that the value or number can vary, for example, by as much as +/−20%. 
     The terms “optical source” and “optical emitter”, as used herein, are interchangeable. 
     The term “monitoring” refers to the act of measuring, quantifying, qualifying, estimating, sensing, calculating, interpolating, extrapolating, inferring, deducing, or any combination of these actions. More generally, “monitoring” refers to a way of getting information via one or more sensing elements. For example, “blood health monitoring” may include monitoring blood gas levels, blood hydration, and metabolite/electrolyte levels, etc. 
     The term “physiological” refers to matter or energy of or from the body of a creature (e.g., humans, animals, etc.). In embodiments of the present invention, the term “physiological” is intended to be used broadly, covering both physical and psychological matter and energy of or from the body of a creature. However, in some cases, the term “psychological” is called-out separately to emphasize aspects of physiology that are more closely tied to conscious or subconscious brain activity rather than the activity of other organs, tissues, or cells. 
     The term “body” refers to the body of a subject (human or animal) that may wear a device incorporating one or more optical sensor modules, according to embodiments of the present invention. 
     The term “coupling”, as used herein, refers to the interaction or communication between excitation energy entering a region of a body and the region itself. For example, one form of optical coupling may be the interaction between excitation light generated from an optical sensor module and the blood vessels of the body of a user. In one embodiment, this interaction may involve excitation light entering the ear region and scattering from a blood vessel in the ear such that the intensity of scattered light is proportional to blood flow within the blood vessel. 
     The term “processor” is used broadly to refer to a signal processor or computing system or processing or computing method which may be localized or distributed. For example, a localized signal processor may comprise one or more signal processors or processing methods localized to a general location, such as to an earbud. Examples of a distributed processor include “the cloud”, the internet, a remote database, a remote processor computer, a plurality of remote processors or computers in communication with each other, or the like, or processing methods distributed amongst one or more of these elements. The key difference is that a distributed processor may include delocalized elements, whereas a localized processor may work independently of a distributed processing system. Microprocessors, microcontrollers, ASICs (application specific integrated circuits), analog processing circuitry, made-for Al (artificial intelligence) circuitry, and digital signal processors are a few non-limiting examples of physical signal processors that may be found in wearable devices. 
     The term “remote” does not necessarily mean that a remote device is a wireless device or that it is a long distance away from a device in communication therewith. Rather, the term “remote” is intended to reference a device or system that is distinct from another device or system or that is not substantially reliant on another device or system for core functionality. For example, a computer wired to a wearable device may be considered a remote device, as the two devices are distinct and/or not substantially reliant on each other for core functionality. However, any wireless device (such as a portable device, for example) or system (such as a remote database for example) is considered remote to any other wireless device or system. 
     Referring now to the drawings, some embodiments of the present invention are illustrated.  FIG. 4  illustrates a hearing aid device  100  having a receiver-in-ear (“RIC”) module  200  connected to a behind-the-ear (“BTE”) module  300  by cable  400 . In some embodiments, the BTE module  300  is adapted to be disposed behind an ear of a user during operation of the hearing aid device  100 . The BTE module  300  contains a power source which supplies power to the biometric sensor(s) within the RIC module  200  and to the audio driver  260  within the RIC module  200  via cable  400 . The cable  400  may be electrical wiring surrounded by a protective sheath, which may help prevent the electrical wiring from coming in unwanted contact with the body, moisture, or the like. 
     The BTE module  300  may also include various additional electronic components including, but not limited to, a signal processor, a wireless module for communicating with a remote device, a microphone, a speaker, an environmental sensor, a memory storage device, etc. The power source within the BTE module  300  may be a battery (such as a lithium polymer battery or other portable battery) or other power source sufficiently small to fit within the housing (such as an energy harvesting source). The power source may be charged via a charge port, such as a USB charge port, for example. In some embodiments, the BTE module  300  may include at least one biometric sensor, such as a PPG sensor, ECG sensor, inertial sensor, auscultatory sensor, or the like. In some embodiments, the BTE module  300  may include at least one sensor, such as a physiological (biometric) sensor, an environmental sensor, a motion sensor, or the like. Non-limiting examples of physiological (biometric) sensors may include sensors for measuring physiological properties such as vital signs (heart rate, respiration rate, blood pressure, SpO 2 , core body temperature, brain activity, and the like) or other biometrics. Non-limiting examples of environmental sensors may include an ambient light sensor, humidity sensor, ambient temperature sensor, or the like. Non-limiting examples of motion sensors may include accelerometers, gyroscopes, mechanical motion sensors, bone conduction sensors, Hall-effect sensors, optical sensors, acoustic sensors, or the like. 
     The RIC module  200  is configured to be inserted within the auditory canal of an ear of a person, as illustrated in  FIG. 5 . Referring now to  FIGS. 6A-6B, 7-9 and 10A-10C , the RIC module  200  includes a housing  202  having opposite first and second ends  202   a ,  202   b . In the illustrated embodiment, the housing  202  has a generally elongated rectangular shape, although other shapes are possible. As will be described below, the housing  202  contains an optical sensor module  240 , a light guide assembly  250 , and an audio driver  260  for providing sound to the wearer of the hearing aid device  100 . The housing first end  202   a  includes an elongated, generally cylindrical nozzle  204  extending outwardly therefrom that serves as a sound port. The nozzle  204  includes an acoustic passage  206  that is configured to direct sound from the audio driver  260  within the housing  202  to the ear of a wearer. In the illustrated embodiment, the acoustic passage  206  extends along a longitudinal centerline C ( FIG. 9 ) of the housing  202 . In other embodiments, the nozzle  204  may be configured such that at least a portion of the acoustic passage  206  extends along a non-centerline portion of the housing  202 . 
     An ear tip  210  is coupled to the nozzle  204  of the housing  202  and, in the illustrated embodiment, includes a body member  212  having opposite first and second ends  212   a ,  212   b , and an acoustic passage  214  extending therethrough from the first end  212   a  to the second end  212   b . A flange  216  having a generally conical or hemispherical shape extends outwardly over the body member  212  from the body member first end  212   a , as illustrated. The flange includes opposite outer and inner surfaces  216   a ,  216   b . The ear tip  210  is configured to comfortably retain the RIC module  200  within a user&#39;s auditory canal and, optionally, to substantially seal the auditory canal to attenuate external sounds and to provide a secure fit. The ear tip  210  is formed of a soft, conformable material, such as silicone, and may have a substantially uniform wall thickness between the inner surface  216   b  ( FIG. 4 ) and the outer surface  216   a . However, variable wall thicknesses may be utilized in some embodiments. Material for the ear tip  210  is not limited to silicone; various other soft, thermoplastic elastomers may be used, also. Although a hard ear tip  210  may be used with embodiments of the present invention, a non-compliant ear tip  210  may generate a pain response in the person wearing the device. 
     In some embodiments, the ear tip  210  is designed to be replaceable and can be removably secured to the nozzle  204  of the housing  202  such that a user can select and use an ear tip  210  that best fits the ear of the user. In the illustrated embodiment, the nozzle  204  is inserted within a receiving channel  212   c  of the ear tip body member  212 . The ear tip  210  may be secured to the nozzle  204  via a snug fit of the nozzle  204  within the receiving channel  212   c . In other embodiments, a snap fit configuration or other interlocking geometry between the nozzle  204  and the receiving channel  212   c  may be utilized. 
     In some embodiments the housing  202  is a plastic housing made from polycarbonate or a reinforced plastic such as a glass filled polyarylamide (e.g., IXEF® brand polyarylamide available from Solvay Group of Belgium). However, the housing  202  may be formed from various other materials. For example, the housing  202  may be formed from a metal or metallic material. 
     In the illustrated embodiment, the housing  202  includes a front section  220  and a rear section  222  configured to be secured together. The front section has a generally rectangular cross-sectional shape with opposite first and second sides  220   a ,  220   b , opposite third and fourth sides  220   c ,  220   d , and end portion  220   e . The rear section  222  has a generally rectangular cross-sectional shape with opposite first and second sides  222   a ,  222   b , opposite third and fourth sides  222   c ,  222   d , and end portion  222   e . The cable  400  enters the housing  202  via the end portion  222   e  in the illustrated embodiments. 
     The front section  220  includes a pair of openings  230 ,  232  in opposing sides  220   a ,  220   b  thereof that are configured to expose respective light guides  252 ,  256  located within the housing  202 . In the illustrated orientation of the housing front section  220 , one opening  230  is facing upwardly and the other opening  232  is facing downwardly. 
     An optical sensor module  240  is located within the housing  202  and includes a printed circuit board (PCB)  241  that supports a pair of optical emitters  242   a ,  242   b  and an optical detector  244  on one side and an accelerometer  246  on the opposite side. The active region of the illustrated optical detector is indicated as  245 . Each optical emitter  242   a ,  242   b  may be one or more light-emitting diodes (LED), laser diodes (LD), compact incandescent bulbs, micro-plasma emitters, IR blackbody sources, organic LEDs, or the like. The optical detector  244  may be one or more photodiodes, photodetectors, phototransistors, thyristors, solid state devices, optical chipsets, or the like. 
     Embodiments of the present invention are not limited to the illustrated configuration of the optical sensor module  240 . Various numbers of optical emitters, optical detectors, and motion sensors (e.g., accelerometers and the like), as well as other electronics, may be utilized in accordance with embodiments of the present invention. Moreover, various arrangements of optical emitters, optical detectors, and motion sensors on the PCB  241  may be utilized. For example,  FIG. 11A  illustrates an optical sensor module  240  with a single optical emitter  242   a  and a single optical detector  244 .  FIG. 11B  illustrates the optical sensor module  240  of  FIG. 8  with two optical emitters  242   a ,  242   b.    
     A light guide assembly  250  is located within the housing  202  adjacent the optical sensor module  240 . The light guide assembly  250  includes a pair of first and second light guides  252 ,  256  and an opaque barrier  259 . The first light guide  252  is configured to guide light from the optical emitters  242   a ,  242   b  into the skin of the auditory canal of a wearer of the device  100  in a non-line of sight manner. The second light guide  256  is configured to collect light from the skin of the auditory canal of a wearer of the device  100  and direct the collected light to the active region  245  of the optical detector  244  in a non-line of sight manner. The opaque barrier  259  is configured to prevent light from the optical emitters  242   a ,  242   b  from directly reaching the optical detector  244  (i.e., crosstalk). The opaque barrier  259  may comprise a material that is opaque and/or reflective in nature: a dark material with roughened surface, a metallic material, a dark or reflective coating, or the like. The opaque barrier  259  may be comprised of a reasonably solid material (such as plastic, acrylic, putty, wax, silicone, polycarbonate, glass, metal, semi-metal, or the like) for which light at the optical emission wavelength(s) cannot pass through. 
     The first and second light guides  252 ,  256  each have a flat configuration that allows them to fit closely against or near respective sides  260   a ,  260   b  of the audio driver  260  and thereby conserve space. In some embodiments, one or both of the first and second light guides  252 ,  256  may be supported by the audio driver  260 . However, in other embodiments, one or both of the first and second light guides  252 ,  256  may be supported by the housing  202  or one or more other components and, thus, do not contact the audio driver  260 . 
     The illustrated opaque barrier  259  has opposite first and second sides  259   a ,  259   b , opposite third and fourth sides  259   c ,  259   d , and opposite first and second end portions  259   e ,  259   f . The first end portion  259   e  of the opaque barrier  259  is configured to abut or be positioned closely to the optical sensor module  240 , and the second end portion  259   f  of the opaque barrier  259  is configured to abut or be positioned closely to an end portion  260   e  of the audio driver  260 . The opaque barrier first side  259   a  abuts or is positioned closely to the second section  254  of the first light guide  252 , and the opaque barrier second side  259   b  abuts or is positioned closely to the second section of the second light guide  257  as illustrated in  FIG. 10A . The first and second sides  259   a ,  259   b  of the opaque barrier  259  can have mating configurations with the respective second sections  254 ,  258  of the first and second light guides  252 ,  256 . As such, the light guides  252 ,  256 , opaque barrier  259  and audio driver  260  can be assembled compactly with very little wasted space. 
     The first light guide  252  includes first and second sections  253 ,  254 . The first section  253  has an elongated flat, rectangular configuration with opposite first and second ends  253   a ,  253   b  and opposite first and second surfaces  253   c ,  253   d . The second section  254  extends outwardly from the second surface  253   d  of the first section  253  adjacent the first end  253   a  of the first section  253 . When the optical sensor module  240  and light guide assembly  250  is assembled within the housing  202 , a surface  254   a  of the second section  254  of the first light guide  252  is configured to be positioned near the optical emitters  242   a ,  242   b  so as to receive light from the optical emitters  242   a ,  242   b . The first surface  253   c  of the first section of the first light guide  252  has an elongated flat configuration configured to direct light from the optical emitters  242   a ,  242   b  toward the skin of an auditory canal of a wearer of the device  100 . Thus, light from the optical emitters  242   a ,  242   b  enters the first light guide  252  at surface  254   a , passes through the second section  254  into the first section  253 , and then exits through the first surface  253   c  of the first section  253 . 
     The second light guide  256  includes first and second sections  257 ,  258 . The first section  257  has an elongated flat, rectangular configuration with opposite first and second ends  257   a ,  257   b  and opposite first and second surfaces  257   c ,  257   d . The second section  258  extends outwardly from the second surface  257   d  of the first section  257  adjacent the first end  257   a  of the first section  257 . When the optical sensor module  240  and light guide assembly  250  is assembled within the housing  202 , a surface  258   a  of the second section  258  of the second light guide  252  is configured to be positioned near the active region  245  of the optical detector  244 . The first surface  257   c  of the first section  257  of the second light guide  256  has an elongated flat configuration configured to collect light from the skin of an auditory canal of a person wearing the device  100 . Thus, light collected by the first surface  257   c  of the first section  257  passes through the first section  257  into the second section  258  and into the active region  245  of the optical detector  244  via the surface  258   a  of the second section  258 . 
       FIGS. 13-22  illustrate different configurations that the first and second light guides  252 ,  256  can have. For example, the first and second sections  253 ,  254  of the first light guide  252  and the first and second sections  257 ,  258  of the second light guide  256  can have various shapes and configurations that can be used to change how light is directed from the optical emitters  242   a ,  242   b  and to the optical detector  244 . In addition, the edges of the first and second light guides  252 ,  256  can have various shapes and configurations that can be used to change how light is directed from the optical emitters  242   a ,  242   b  and to the optical detector  244 . In some embodiments, the first and second light guides  252 ,  256  may have identical configurations. In other embodiments, the first and second light guides  252 ,  256  may have different configurations. 
     Furthermore, various surface coatings and finishes, such as textured surfaces and polished surfaces, can be utilized to change the index of refraction or surface reflectivity to further direct or disperse light as desired. For example, the light receiving surface  257   c  of the second light guide  256  may be smooth, whereas the light guiding surface  253   c  of the first light guide  252  may have be smooth or texturized or may have a combination of smooth and texturized. Having a texturized surface  253   c ,  257   c  may be helpful in guiding light evenly along the periphery of the respective first and second light guides  252 ,  256 . For example, a roughened surface may help scatter light more evenly across the surface. 
     In some embodiments, the second surface  253   d ,  257   d  of one or more of the first and second light guides  252 ,  256  may be textured. For example, in  FIG. 18 , the second surface  253   d ,  257   d  has a saw tooth configuration. Such a saw tooth pattern can help to generate a desirable optical beam shape or to guide light in a desirable direction. Alternatively, a microlens array may be integrated on the light guide surfaces  253   d ,  257   d  to facilitate optical beam shaping and/or light guiding. Alternatively, the light guides  252 ,  256  may comprise photonic crystalline structures or photonic metamaterials to facilitate optical beam shaping and/or light guiding. 
     The audio driver  260  is in acoustic communication with the acoustic passage  206  of the nozzle  204  and with the acoustic passage  214  of the ear tip  210  and is configured to deliver sound to the wearer of the device  100 . The illustrated audio driver  260  has a generally elongated rectangular cross-sectional configuration with opposite first and second sides  260   a ,  260   b , opposite third and fourth sides  260   c ,  260   d , and opposite end portions  260   e ,  260   f . The audio driver  260  typically has a sound outlet tube extending outward from a sound port (not shown) in end portion  260   f  which is in acoustic communication with the acoustic passage  206  of the nozzle  204  and with the acoustic passage  214  of the ear tip  210 . However, audio drivers that may be utilized in accordance with embodiments of the present invention may have various shapes and configurations and are not limited to the illustrated shape/configuration. 
     The audio driver  260  may be mounted within the housing  202  in various ways. In some embodiments, the audio driver  260  is secured to the housing front section  220 . In other embodiments, the audio driver  260  may mounted within the housing  202  in a flexible jacket or other resilient structure. Such an embodiment may help prevent or reduce vibrations to the audio driver  260 . In other embodiments, the audio driver  260  may be mounted on a flexible tube that connects the audio driver  260  to the nozzle  204 . Such an embodiment may also help prevent or reduce vibrations to the audio driver  260 . 
     Non-limiting exemplary audio drivers that may be utilized with embodiments of the present invention are available from Sonion, Roskilde, Denmark. 
     In some embodiments, at least a portion of the audio driver  260 , optical emitters  242   a ,  242   b , and optical detector  244  are encapsulated within a hydrophobic encapsulant material. 
     In some embodiments, an optical filter may be integrated within one or more of the first and second light guides  252 ,  256 . For example, a light guide  252 ,  256  may comprise a material having an optically filtering dye or a material which inherently filters one or more wavelengths of light. As one example, either or both of the first and second light guides  252 ,  256  may comprise, wholly or partially, a dye therewithin. As one specific example, a dye, such as an infrared dye designed to block visible wavelengths but pass IR wavelengths may be utilized. For example, a polycarbonate or acrylic light guide  252 ,  256 , dyed with Filtron® absorptive dye E800 (Gentex Corporation, Carbondale, Pa.), would facilitate both light-guiding and IR-pass filtering functionality. Alternatively, another example of such an integrated physical optical filter comprises absorptive dyes available from Sabic (Riyadh, Saudi Arabia) dispersed in polycarbonate and/or acrylic to create an edge or long-pass optical filter. At least one of the first and second light guides  252 ,  256  may be partially or wholly comprised of such a material, thereby facilitating the combinational purpose of light guiding and optical filtering. A few additional non-limiting examples of an inherently filtering material includes sapphire, which absorbs some infrared (IR) wavelengths, glass, which absorbs some ultraviolet (UV) wavelengths, and dyed glass (for which dye combinations can be applied to enable optical filtering that is low-pass, high-pass, band-pass, notching, and the like). However, various types of filtering material may be utilized, without limitation. 
     In some embodiments, an optical filter may be integrated with the optical emitter(s)  242   a ,  242   b  and/or the optical detector  244 . For example, a bandpass filter, such as an interference filter or the like, may be disposed on an optical emitter  242   a ,  242   b  and/or optical detector  20 . Alternatively (or additionally), an optical filter effect may be integrated within the semiconductor material comprising the optical emitter  242   a ,  242   b  and/or optical detector  244 , such as by depositing alternating optically-transparent layers (such as oxides and/or nitrides), selective ion implantation of certain regions within silicon, or by band-gap engineering within compound semiconductors, such as the AlInGaAs or AlInGaN system of semiconductor engineering. 
     In some embodiments of the present invention, the light-guiding material of one or more of the first and second light guides  252 ,  256  may comprise polarizing material. Exemplary polarizing material that can be used in accordance with embodiments of the present invention is available from American Polarizers, Inc., Reading, Pa., as well as Edmund Optics, Barrington, N.J. A key benefit of a cross-polarizing implementation, where the optical emitter polarizer is configured to be orthogonally polarized with respect to the optical detector polarizer, may be that unwanted specular reflection is attenuated such that the light beam collected by the optical detector comprises a higher percentage of photons that have passed through a blood flow region of the body. 
     According to embodiments of the present invention, various portions of the housing  202  may be configured to be opaque or transparent in order to improve the signal to noise ratio at the optical detector  244 .  FIGS. 23A-23F ,  24 A- 24 C and  25  illustrate various embodiments of opaque/transparent housing portions. For example,  FIG. 23A  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  230  for the first light guide  252  opaque as indicated by  220   x . In addition, a portion of the nozzle  204  on the same side as the window  230  is opaque as indicated by  204   x . As such, only the light leaving the surface  253   c  of the first light guide  252  illuminates the skin. Light is not allowed to illuminate the skin through the portions of the front section  220  adjacent the first light guide  252 . The remainder of the front section  220  and the nozzle  204  remain transparent to light. The rear section  222  of the housing  202  is entirely opaque. 
       FIG. 23B  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  232  for the second light guide  256  opaque as indicated by  220   x . In addition, a portion of the nozzle  204  on the same side as the window  232  is opaque as indicated by  204   x . The remainder of the front section  220  and the nozzle  204  remain transparent to light. As such, the entire upper portion of the front section  220  allows light to illuminate the skin. The rear section  222  of the housing  202  is entirely opaque. 
       FIG. 23C  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  232  for the second light guide  256  opaque and with selected portions of the front section  220  near the window  230  for the first light guide  252  opaque. The opaque portions of the front section  220  are indicated by  220   x . In addition, the entire nozzle  204  is opaque as indicated by  204   x . The remaining portions of the front section  220  remain transparent to light. As such, light from the surface  253   c  of the first light guide  252  and through portions of the front section  220  illuminates the skin. The rear section  222  of the housing  202  is entirely opaque. 
       FIG. 23D  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  232  for the second light guide  256  opaque and with selected portions of the front section  220  near the window  230  for the first light guide  252  opaque. The opaque portions of the front section  220  are indicated by  220   x . In addition, a portion of the nozzle  204  on the same side as the window  232  is opaque as indicated by  204   x . The remaining portion of the front section  220  and the nozzle  204  remain transparent to light. As such, light from the surface  253   c  of the first light guide  252  and through portions of the front section  220  and nozzle  204  illuminates the skin. The rear section  222  of the housing  202  is entirely opaque. 
       FIG. 23E  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  230  for the first light guide  252  opaque and with selected portions of the front section  220  near the window  232  for the second light guide  256  opaque. The opaque portions of the front section  220  are indicated by  220   x . The entire nozzle  204  is opaque as indicated by  204   x . The remaining portions of the front section  220  remain transparent to light. The rear section  222  of the housing  202  has portions that are opaque as indicated by  222   x . The remaining portions of the rear section  222  are transparent to light. As such, light from the surface  253   c  of the first light guide  252  and through the transparent portions of the rear section  222  illuminates the skin. 
       FIG. 23F  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with the portion of the front section  220  near the window  230  for the first light guide  252  opaque and with selected portions of the front section  220  near the window  232  for the second light guide  256  opaque. The opaque portions of the front section  220  are indicated by  220   x . The entire nozzle  204  is opaque as indicated by  204   x . The remaining portions of the front section  220  remain transparent to light. The rear section  222  of the housing  202  has portions that are opaque as indicated by  222   x . The remaining portions of the rear section  222  are transparent to light. As such, light from the surface  253   c  of the first light guide  252  and through the transparent portions of the rear section  222  illuminates the skin. 
       FIG. 24A  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with portions of the front section  220  near the window  232  for the second light guide  256  opaque and with the remaining portion of the front section  220  near the window  230  for the first light guide  252  opaque. The opaque portions of the front section  220  are indicated by  220   x . In addition, the entire nozzle  204  is opaque as indicated by  204   x . The remaining portion of the front section  220  remains transparent to light. The rear section  222  of the housing  202  is entirely opaque. As such, light can be collected through the second light guide  256  and through the transparent portions of the front section  220 . 
       FIG. 24B  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with portions of the front section  220  near the window  232  for the second light guide  256  opaque and with the remaining portion of the front section  220  near the window  230  for the first light guide  252  opaque. The opaque portions of the front section  220  are indicated by  220   x . In addition, a portion of the nozzle  204  on the same side as the window  230  is opaque as indicated by  204   x . The remaining portion of the front section  232  and the nozzle  204  remain transparent to light. The rear section  222  of the housing  202  is entirely opaque. As such, light can be collected through the second light guide  256  and through the transparent portions of the front section  220  and nozzle  204 . 
       FIG. 24C  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with a portion of the front section  220  near the window  232  for the second light guide  256  opaque as indicated by  220   x . The remaining portions of the front section  220  and the nozzle  204  are transparent to light. The rear section  222  of the housing  202  is entirely opaque. As such, light can be collected through the second light guide  256  and through the transparent portions of the front section  220  and nozzle  204 . 
       FIG. 25  illustrates the housing  202  of the RIC module  200  of  FIGS. 6A-6B  with the ear tip removed for clarity and with a peripheral portion of the front section  220  and the nozzle opaque as indicated by  220   p . The portion  220   p  prevents crosstalk between the optical emitters  242   a ,  242   b  and the optical detector  244 . 
     Referring back to  FIG. 12 , in some embodiments, an opaque barrier  247  may extend between the optical emitters  242   a ,  242   b  and the optical detector  244 . This opaque barrier  247  may be utilized with or without the various opaque housing embodiments described above. 
     Referring now to  FIGS. 26-28 , a RIC module  200 ′ according to other embodiments of the present invention is illustrated. The RIC module  200 ′ includes a housing  202  having a front section  220  and a back section  222 . Within the housing are an optical sensor module  240 ′, first and second light guides  252 ,  256 , and an audio driver  260 . The illustrated RIC module  200 ′ does not utilize a separate opaque barrier/body. Instead, the optical sensor module  240 ′ is rotated 90° relative to other embodiments such that the optical emitters  242   a ,  242   b  face the first opening  230  in the housing front section  220  and such that the active region  245  of the optical detector  244  faces the second opening  232  in the housing front section  220 . In this configuration, the PCB  241  serves as an optical barrier to prevent crosstalk between the optical emitters  242   a ,  242   b  and the optical detector  244 .  FIG. 27  illustrates the optical sensor module  240 ′ oriented such that the optical detector  244  is facing upwardly, and  FIG. 28  illustrates the optical sensor module  240 ′ oriented such that the optical emitters  242   a ,  242   b  are facing upwardly. The orientation of the optical sensor module  240 ′ in  FIGS. 26-28  allows for creating a “standard” backend of a RIC module that can be utilized with various front end configurations (i.e., audio driver configurations). 
     Because the optical emitters  242   a ,  242   b  face the first opening  230  the first light guide  252  guides light from the optical emitters  242   a ,  242   b  through the opening  230  and into skin of the auditory canal in a line of sight manner. Similarly, because the optical detector  244  faces the second opening  232 , the second light guide  256  collects light from the skin of the auditory canal and directs the collected light to the optical detector  244  in a line of sight manner. 
     The first and second light guides  252 ,  256  in  FIGS. 26-28  have a shorter length than the light guides  252 ,  256  of previous embodiments because of the orientation of the optical emitters  242   a ,  242   b  and optical detector  244 . However, it is understood that the light guides  252 ,  256  in  FIGS. 26-28  may be longer than illustrated and may have the same or similar lengths as the light guides  252 ,  256  in previously illustrated embodiments. 
     Referring now to  FIGS. 29-30 , a RIC module  200 ″ according to other embodiments of the present invention is illustrated. The RIC module  200 ″ is similar to the RIC module  200  illustrated in  FIGS. 8 and 10A , except the optical sensor module  240 ″ is positioned at the front end  260   f  of the audio driver  260 , the optical emitters  242   a ,  242   b  and optical detector  244  are oriented facing the rear section  222  of the housing (i.e., away from the ear tip  210 ), and the accelerometer  246  is secured to the rear end  260   e  of the audio driver  260 . 
     An opaque barrier  259  similar to the one illustrated in  FIGS. 8 and 10A  is utilized and has opposite first and second sides  259   a ,  259   b  and opposite first and second end portions  259   e ,  259   f . The first end portion  259   e  of the opaque barrier  259  abuts or is positioned closely to the optical sensor module  240 ″, and the second end portion  259   f  of the opaque barrier  259  abuts or is positioned closely to the front end portion  260   f  of the audio driver  260 . The opaque barrier first side  259   a  abuts or is positioned closely to the second section  254  of the first light guide  252 , and the opaque barrier second side  259   b  abuts or is positioned closely to the second section of the second light guide  257 . As with the embodiment illustrated in  FIGS. 8 and 10A , the light guides  252 ,  256 , opaque barrier  259  and audio driver  260  of  FIGS. 29 and 30  can be assembled compactly with very little wasted space. 
     Referring now to  FIGS. 31-32 , a RIC module  200 ′ according to other embodiments of the present invention is illustrated. The RIC module  200 ′″ is similar to the RIC module  200  illustrated in  FIGS. 8 and 10A , except the optical emitters  242   a ,  242   b  are positioned on the front end  260   f  of the audio driver  260  and face forward towards the ear tip  210 . The optical detector  244  is mounted on the rear end  260   e  of the audio driver  260  via an opaque barrier, and a single light guide  256  is utilized to collect light from the skin of the auditory canal and direct the collected light to the active region  245  of the optical detector  244  in a non-line of sight manner, as described above. The nozzle  204  and the ear tip  210  are formed at least partially from light guiding material and serve as a light guide to direct light from the optical emitters  242   a ,  242   b  into the skin of the auditory canal. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.