WO2015030832A1

WO2015030832A1 - Integrated optoelectronic module for physiological measurements and methods of use of the module

Info

Publication number: WO2015030832A1
Application number: PCT/US2013/057748
Authority: WO
Original assignee: Pandata Research Llc
Priority date: 2013-08-31
Filing date: 2013-08-31
Publication date: 2015-03-05

Abstract

The disclosure addresses the structure and operation of devices including a plurality of optical sensors configured to obtain physiological measurements of a user. The sensors are of a size and configuration that can facilitate their inclusion in a suitably compact package that they may be conveniently worn by a user without interfering with normal activities. The optical sensors can be of many forms depending on the measurements desired, but will often include one or more of a photoplethysmograph, a sensor for performing attenuated total reflectance (ATR) spectroscopy, and an optical temperature sensor. The measurement device containing such optical sensors can also include one or more conventional sensors, such as, accelerometers, electrical sensors, acoustic sensors, etc.

Description

INTEGRATED OPTOELECTRONIC MODULE FOR PHYSIOLOGICAL MEASUREMENTS AND

METHODS OF USE OF THE MODULE

[0001] The present invention relates generally to methods and apparatus for measuring physiological quantities, and more particularly relates to such methods and apparatus in a portable device having various sensor assemblies for measuring the physiological properties.

BACKGROUND OF THE INVENTION

[0002] Many forms of devices are known for providing monitoring of one or more physiological properties of a user. One class of such devices is intended for use by an individual for monitoring activities, either while exercising or on a continuing basis, such as throughout at least a substantial portion of a day. Current such devices are limited in the physiological measurements that can be made. Typically, most such devices use one or more sensors to monitor a limited number of properties, for example, one or more accelerometers to monitor movement, and in some cases, electrodes to monitor heart rate. To this point, optical sensors have not found their way into consumer-type devices, though they could facilitate measurements beyond those that can be achieved through other forms of sensors, such as electrical sensors, pressure sensors, etc.

SUMMARY OF THE DISCLOSURE

[0003] The disclosure addresses methods and apparatus facilitating use of a plurality of optical sensors to obtain physiological measurements of a user. In some examples, the sensors are of a size and configuration to be retained in a suitably compact package that they may be conveniently worn by a user without interfering with normal activities.

[0004] In some examples, at least one of the optical sensors will be a

photoplethysmograph, as is known for use in measuring the oxygenation of a user's blood, and as can also be used to determine the user's pulse rate. In some examples, at least one of the optical sensors will be configured to perform attenuated total reflectance (ATR) spectroscopy. Such spectroscopy can measure one or more parameters of a person's skin, and in some configurations as described herein, can measure properties beneath the skin surface of a user. As one example, such a detector may be used to evaluate body hydration. As described herein, in some example systems other optical detectors may be used, such as, for example, an optical temperature sensor (typically through use of a thermopile detector). In measurement device containing such optical sensors can also include one or more conventional sensors, such as, for example accelerometers, electrical sensors, acoustic sensors, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figures 1A-B each depict perspective view of an example measurement device being worn on a wrist of a user, depicted in Figure 1A on the underside of the wrist; and in Figure IB on the top side of the wrist.

[0006] Figure 2 is a side-view cross-sectional drawing of an example configuration of the wearable measurement device of Figure 1.

[0007] Figure 3 is a front-view schematic drawing of the configuration of Figure 2.

[0008] Figure 4 is a front-view schematic drawing of an alternative configuration for the measurement device of Figure 1.

[0009] Figure 5 is a side-view schematic drawing of one channel of the configuration of Figure 4, shown with an example configuration of additional optical components.

[0010] Figure 6 is a side-view schematic drawing of an alternative configuration of a channel that may be used with the measurement device of Figure 4.

[0011] Figure 7 is a front-view schematic drawing of a further alternative configuration for the measurement device of Figure 1.

[0012] Figures 8A-D depict a plurality of example portable electronic devices as may be used, in some example systems, in combination with a measurement device as described herein.

[0013] Figure 9 depicts an example flow chart for making physiological measurements through use of a measurement device as described herein.

[0014] Figure 10 is a block diagram view of an example measurement device, depicting example functional modules that may be associated with the sensors in a measurement device. DETAILED DESCRIPTION

[0015] The following description refers to the accompanying drawings that depict various details of examples selected to show how the present invention may be practiced. The discussion addresses various examples of the inventive subject matter at least partially in reference to these drawings, and describes the depicted embodiments in sufficient detail to enable those skilled in the art to practice the invention. Many other embodiments may be utilized for practicing the inventive subject matter than the illustrative examples discussed herein, and many structural and operational changes in addition to the alternatives specifically discussed herein may be made without departing from the scope of the inventive subject matter.

[0016] In this description, references to "one embodiment" or "an embodiment," or to "one example" or "an example" mean that the feature being referred to is, or may be, included in at least one embodiment or example of the invention. Separate references to "an embodiment" or "one embodiment" or to "one example" or "an example" in this description are not intended to necessarily refer to the same embodiment or example; however, neither are such embodiments mutually exclusive, unless so stated or as will be readily apparent to those of ordinary skill in the art having the benefit of this disclosure. Thus, the present invention can include a variety of combinations and/or integrations of the embodiments and examples described herein, as well as further embodiments and examples as defined within the scope of all claims based on this disclosure, as well as all legal equivalents of such claims.

[0017] The optical sensors as described herein all operate through detection of electromagnetic radiation that radiates from, reflected by, or transmitted through a user. In the provided examples, this electromagnetic radiation will be within the visible and invisible wavelength bands of electromagnetic radiation as are commonly referred to collectively as "light" by those skilled in the art, including, the IR band (including near-IR, mid-IR, and far-IR sub-bands), the visible light band, and the UV band. Such radiation will be identified herein either as "light" or a "beam."

[0018] Additionally, some of the optical sensors described herein will operate through use of light which is collimated. For some sensors, such as those performing ATR measurements, all light directly intersecting the sample for purposes of the measurement will preferably be essentially fully collimated; that is, fully collimated to the understanding of persons skilled in the art who recognize the impacts of system configuration (beam path length, intervening optical elements, etc.) which cause deviation from a theoretically ideal collimation. For some measurements, a less than fully collimated beam may be adequate for the measurements, so long as the beam includes a collimated component, for example, in the context of an ATR measurement, for which the angle of incidence may be controlled and the reflection resulting therefrom may be measured.

[0019] Referring now to Figure 1, the figure depicts an example measurement device 100 being worn on the left wrist of a user. During operation, the device 100 may be worn or held by a user, so that a measurement face of the device 100 may contact the skin of the user. In some cases, the measurement device may be of a form factor to be held by a user; and in other examples may be formed as an accessory module that may be attached to a portable device capable of providing processing, display, storage, and/or communication of measurements received from the measurement device. For example, such an accessory module may be configured to mechanically and/or electrically engage a cell phone, table, or other portable device, as discussed in reference to Figures 8A-D herein. In some examples, there may be no direct electrical engagement, but the accessory device may communicate with the portable device through a suitable communication protocol, for example, through Wi-Fi, Bluetooth, near field communications ("NFC"), or one or more of many other suitable protocols as may be recognized by those skilled in the art.

[0020] Although many locations on the body of the user may be used, for measurement devices configured to make measurements based on blood flow or blood constituents, such as, for example, a heart rate measurement, a particularly desirable location is on the wrist of the user, so that the measurement face of the device 100 faces the ulnar artery at the volar wrist. For example, the ulnar artery at the volar wrist is relatively close to the skin, and is particularly well-suited for measurement at that location. In addition, the device 100 may have an optional display 102 facing away from the skin, which may easily be viewed by a person during a workout or during other physical activity.

[0021] In this example, the size of the device 100 is relatively small, so that it may be worn during a workout or while performing a particular task during which physiological measurements are performed. Preferably, the device 100 will be sized and otherwise configured such that it may be worn on a wristband without significantly impeding any motion of the arm or hand.

[0022] In many examples, measurement device 100 will be configured to perform multiple measurements. For purposes of the present description, measurement device 100 will be discussed in the context of a device configured to take measurements that may be considered related to health and/or fitness; though as will be apparent to persons skilled in the art having the benefit of this disclosure, these measurement devices may also be useful in other applications. In this example, measurement device 100 is configured to make a plurality of optically sensed measurements, and therefore includes one or more optical emitters and/or detectors, as well as a power source and appropriate control functionality for controlling the sensors and obtaining data signals therefrom; and potentially for processing the received data signals and, optionally, for communicating with an external processor unit or network, such as the internet.

MEASUREMENT FACE CONSTRUCTION AND MATERIALS

[0023] Referring now to Figure 2, that figure depicts a block diagram representation of an example measurement device 200 as would be provided within a housing 202. In this example, housing 202 is elongated along a longitudinal axis A. Housing 202 may be formed from any suitable material for the application, such as, plastic, metal, or another suitable material or combination of materials. In circumstances where measurement device is intended in the subjected to varying conditions, for example by being worn or otherwise carried about by a user, housing 202 may be relatively rugged, so that the device is not damaged by shock or vibration during such use. For many such applications, housing 202 will be relatively impermeable to moisture, so that normal or prolonged exposure to a user's skin or at least humid conditions, will not damage the device.

[0024] The device 200 includes a measurement face 204, which is placed into contact with a particular location on the user's skin during use, such as the ulnar artery at the volar wrist. The measurement face 204 protects the emitters and detectors located below the measurement face 204. For convenience of identification in this disclosure, an x, y, z coordinate system is established around the measurement face 204 of the device 200, so that measurement face 204 is within the x-y plane. Measurement face 204 has a surface normal SN₂o₄ that extends along the z-axis.

[0025] In some examples, measurement face 204 will be planar; while in other examples measurement face 204 will have a curved exterior surface, such as with a concave curvature, in order to better locate the device on the user's anatomy, or to ensure relatively improved contact between the measurement face and the corresponding location on the skin of the user. For purposes of the present example, measurement face 204 is formed as a sheet, having parallel sides facing into and out of the device 200. In most examples, the side of measurement face 204 that faces the user is smooth, so that it may be cleaned easily. In some examples, the side of measurement face 204 facing away from the user is smooth in some areas, and may include one or more features in particular areas that are used to couple light into and out of the measurement face 204. These features are discussed below, with reference to Figures 5 and 6. Example materials for forming measurement face 204 will be discussed later herein.

[0026] In examples which are configured to be at least partially self-contained, measurement device 200 will include a power source 212, such as one or more batteries. In some such examples, measurement device 200 will include circuitry or other components for recharging the one or more of the batteries, either through a dedicated port that contacts a mating conductive element, or through an inductive portion that can be coupled to a corresponding inductive charger. In some examples configured to be worn by a user, the housing 202 includes one or more slots or notches that can be used to attach a wristband or strap to the housing 202.

MEASURED QUANTITIES

[0027] In the depicted example, measurement device 200 includes first and second optical sensors forming photoplethysmographs 206, 210 (denoted as "PPG" in the Figures) each of which can measure the dynamics of blood flow; and further includes optical sensors for measuring both body temperature and hydration, indicated generally at 208 (denoted as "T/H" in the Figures). These optical sensors will typically include emitters, detectors and other circuitry or other processing devices configured to perform the relative measurements of these optical sensors in measurement device 200. [0028] Measurement device 200 also includes a processing unit 214. As will be appreciated from the present disclosure, processing unit 214 may be of a variety of different configurations, depending in large part on the extent to which measurement device 200 is intended to be self-contained. For example, in some cases measurement device 200 will be configured to rely upon an external device, such as a portable electronic device, as addressed further later herein, for at least some portion of the control of the sensors and/or for receiving the sensor data signals, as well as for processing the sensor data to yield physiological measurements. In many examples, even if such reliance upon an external device is anticipated, the measurement device will include some degree of internal processing functionality, for example, sufficient processing functionality to facilitate communication with an external device. While in other examples, the processing unit may be relied upon for performing most or all of the actions required to receive measurements, as described herein.

[0029] In most examples, processing unit 214 will include one or more processors, in combination with additional hardware as needed (volatile and/or non-volatile memory; communication ports; I/O device(s) and ports; etc.) to provide the desired functionality. Whatever functionality may be desired of an example measurement device, the intended functions may be implemented by separate processing units, as desired.

[0030] As noted above, when sensors are intended to measure blood flow or constituents, it will typically be preferable for the sensors to be placed in a location providing relative to proximity of arterial blood flow, of which the ulnar artery is one example. The example configuration schematically depicted in Figure 2 may offer particular benefits when the device is to be worn as a wristband, and to measure flow in the ulnar artery, because the configuration assists in the device being functional when worn on the wrist in either of two orientations. The ulnar artery is not centered on the user's arm, but is on the palm side of the arm, and relatively displaced to the side of the little finger. As a result, using two photoplethysmographs at opposing longitudinal ends of the device 200 may ensure that one of the two photoplethysmographs is placed generally proximate the ulnar artery to a sufficient degree to obtain a meaningful measurement, regardless of the orientation of measurement device 200 on the wrist. [0031] During a typical operation, the optical elements in both photoplethysmographs 206, 210 are energized, at least initially, but only one of the two photoplethysmographs will have a sufficient signal to produce a measurement, while the other of the two

photoplethysmographs will not have a sufficient signal to produce a measurement. In that situation, in some example systems, the measurement device will automatically select the photoplethysmograph measurement from the photoplethysmograph having the sufficient signal. In some examples, the measurement device might make a determination to disable the other photoplethysmograph at least until after passage of a period of time or until the reaching of a trigger selected for reenergizing the photoplethysmograph.

[0032] In some examples, the optical sensors 206, 208, 210 are separated spatially from each other in the housing 202, in order to reduce optical crosstalk among the various sensors. For example, if optical sensors 206, 208, 210 are located too close together, there may be crosstalk of the light (or other electromagnetic radiation) between the sensors, or potentially of electrical signals from the sensors, degrading one or more of the

measurements. In some examples, solid or optical barriers or electromagnetic shielding may be used between sensors, or otherwise as needed, to minimize risk of crosstalk or other signal degradation.

FIRST AND SECOND PHOTOPLETHYSMOGRAPHS

[0033] Referring now to Figure 3, the figure depicts a schematic layout for a

measurement device 300 that may be constructed generally in accordance with the measurement device of Figure 2. A photoplethysmograph measures the change in the volume of blood in a particular volume or under a particular area under optical examination. For the example measurement device 300, which is configured such that it may be worn on the wrist, the most likely placement would be for it to be worn such that at least one of two photoplethysmographs 306, 310 can optically examine the blood in the ulnar artery, and thereby identify the change in volume of blood in the ulnar artery with each beat of the heart.

[0034] In this example, the first photoplethysmograph 306 includes an emitter chip 312 and a detector chip 318, each having suitable circuitry and suitable active areas to emit or detect light. The emitter chip 312 has two distinct emitter areas on it, one emitter area 314 emitting red light and the other emitter area 316 emitting infrared (IR) light.

[0035] In many examples, the red light has a wavelength of about 660 nm, and the infrared light has a wavelength of about 905 nm; as these two wavelengths are commonly used for oximeter probes. At 660 nm, the extinction coefficient of oxygenated hemoglobin is significantly less than that of deoxygenated hemoglobin (i.e., deoxygenated absorbs more at 660 nm). At 905 nm, the extinction coefficient of oxygenated hemoglobin is slightly greater than that of deoxygenated hemoglobin (i.e., oxygenated absorbs slightly more at 905 nm). By illuminating an artery with known amounts of both wavelengths, detecting the amount of light reflected at both wavelengths, and forming a ratio of reflected light at one wavelength divided by reflected light at the other wavelength, one may use the ratio to sense the amount of oxygen in the blood. As the heart pulses, the sensed ratio shows spikes.

[0036] An example of a suitable emitter chip is a GaAIAs High Power infrared (IR) light emitting diode (LED) Emitter (660/905 nm), with part number PDI-E832, which is

commercially available from Advanced Photonix, Inc. of Camarillo, CA. This part produces light at red emitter area 314 with a peak wavelength of 661 nm +/- 3 nm, and produces light at IR emitter area 316 with a peak wavelength of 905 nm +/- 10 nm. The outer dimensions of this example chip are 6.35 mm wide (along the x-direction) and 4.24 mm tall (along the y- direction), where the red 314 and IR 316 emitter areas are separated by 1.04 mm. Note that all the numerical values for the PDI-E832 are provided as examples, and that other suitable numerical values for other suitable parts may also be used. For example, an alternative suitable IR emitter is the model PY0626 IR Emitter Die by Pyreos of Edinburgh, UK.

[0037] Regarding the beam output from the example PDI-E832 part, if the red 314 and IR 316 emitter areas were left bare, the output from each emitter area 314, 316 would be generally Lambertian, with the most light exiting along the z-axis, and monotonically decreasing light output for increasing angles away from the z-axis. The light distribution from such a Lambertian distribution falls to zero at an angle of ninety degrees with respect to the z-axis. In practice, the PDI-E832 part is produced with both emitter areas 314, 316 being encapsulated within the same ball of transparent material. The ball reduces the divergence of the output patterns of both wavelengths, so that they are slightly narrower than true Lambertian.

[0038] In the example first photoplethysmograph 306 of Figure 3, adjacent to the emitter chip 312 is a detector chip 318, which is sensitive to light at the wavelengths emitted by the emitter chip 312. The detector chip 318 has a detector area 320 that can receive light and convert the received light to a suitable electrical signal. The detector chip 318 also includes suitable circuitry for outputting the electrical signal into a form useable by the remainder of the measurement device or capable of being communicated to another device, processing unit, network, or the internet.

[0039] An example of a suitable detector chip 318 is a Photodiode in Plastic Surface Mount Package, with part number PDV-C173SM, which is commercially available from Advanced Photonix, Inc. of Camarillo, CA. This part is a blue-enhanced PIN silicon photodiode, with a responsivity (in amps per watt) greater than 0.4 in the spectral region of about 750 nm to about 1050 nm. The outer dimensions of this example chip are 5 mm wide (along the x-direction) and 4 mm tall (along the y-direction). The active detector area 320 of this example detector chip is square, measuring 2.77 mm on a side. The above numerical values for the PDV-C173SM are provided as examples only, and other suitable numerical values for other suitable parts may also be used.

[0040] Detector chip 318 also has sensitivity with an angular dependence, much like that of the emitter chip 312. In general, the angular sensitivity is Lambertian, with a maximum sensitivity at normal or near-normal incidence (i.e., for light arriving parallel to the z-axis), and the dependence falling to zero at an angle of ninety degrees with respect to the z-axis. Because both the emitter 312 and the detector 318 show performance effects that depend on direction, the first photoplethysmograph 306 is most sensitive when positioned directly over the ulnar artery. If the device 300 is translated laterally so that the emitter areas 314, 316 and the detector area 320 are positioned away from the ulnar artery, the sensitivity decreases.

[0041] In some examples, it may be desirable to leave some area between the red 314 and IR 316 emitter areas of the emitter chip 312 and the detector area 320 of the detector chip 318, in order to avoid spurious signals that arise from light traveling directly from the emitter to the detector, without interacting with the skin and tissue of the user. [0042] The second photoplethysmograph 310 is generally the same in structure and function as the first photoplethysmograph 306, but at an opposite longitudinal end of the housing 302 from the first photoplethysmograph 306, and optionally flipped in x- and/or y- dimensions. The second photoplethysmograph 310 also includes an emitter chip 322 with red 324 and IR 326 emitter areas, and a detector chip 328 with a detector area 330. The emitter chip 322 and detector chip 329 may also be similar in structure and function to those used in the first photoplethysmograph 306.

[0043] In practice, blood flow measurements may be taken from both

photoplethysmographs 306 and 310, with the device 300 selecting the measurement corresponding to the detector having the stronger (or only) signal. The

photoplethysmographs 306 and 310 can measure a pulse or heart rate (HR), a heart rate variability (HRV), a central aortic systolic pressure (CASP), and/or an ambulatory blood pressure (ABP). These measurements may rely on the same emitters, sensors, and electronics, possibly with varying degrees of calculations, and may therefore be made in sequence and/or simultaneously by either or both photoplethysmographs 306 and 310. Note that the configuration of the photoplethysmographs 306 and 310 may be used in each of the following three example system configurations.

TEMPERATURE/HYDRATION MONITOR - EXAMPLE #1

[0044] While the elements in the photoplethysmographs 306 and 310 are configured to operate in the visible and/or near-infrared portion of the spectrum, the elements in the temperature/hydration monitor 308 are configured to operate in the mid-infrared portion of the spectrum. For the water-related measurements, an infrared emitter produces light and directs it toward the skin and tissue sample, and a suitable detector detects the reflected light from the sample. For the temperature measurement, no external emitter is needed, as the human body produces detectable infrared light as a natural consequence of having a body temperature of about 37 degrees Celsius. To detect body temperature, a suitable sensor need only sense the infrared light emitted by the sampled portion of a user's body, without requiring an external source to illuminate the sample.

[0045] The same class of detectors may be used for sensing both hydration and body temperature, since both are generally in the same wavelength range in the mid-infrared portion of the spectrum. The temperature/hydration monitor 308 of Figure 3 may include multiple detectors of the same class or type, but with different functions for each. It is understood that the detectors themselves may be positioned and oriented to receive either the reflected light that originated with an external emitter, for the hydration measurement, or the light originating from the sample with little or no contribution from the external emitter, for the body temperature measurement.

[0046] For the body temperature measurement, a detector chip 344 may be used to sense light in the mid-infrared portion of the spectrum. The detector chip 344 has a detector area 346 that can receive light in the mid-infrared portion of the spectrum and convert the received light to a suitable electrical signal. An example of a suitable detector chip 344 is an Infrared Thermopile Sensor in Chip-Scale Package, with part number TMP006, which is commercially available from Texas Instruments of Dallas, TX. This part has a device size of 1.6 mm by 1.6 mm, and is specified as having a Wafer Chip-Scale Package (WCSP) Device (DSBGA). The digital output of this device is specified as having a sensor voltage of 7 microvolts per degree Celsius, for a local temperature of -40 degrees Celsius to 125 degrees Celsius. The TMP006 uses wavelengths in the range of 4 μιη to 8 μιη. The TMP006 is commonly sold with a printed circuit board (PCB) layout being square and having a dimension of 7.62 mm on a side, but significantly smaller circuit boards may also be used. For this part, the manufacturer provides guidelines for thermally isolating the detector chip 344 from the rest of the circuit board. The numerical values for the TMP006 are provided as examples, and other suitable numerical values for other suitable parts may also be used.

[0047] For a thermopile detector, the thermopile absorbs the infrared energy emitted from the object being measured and uses the corresponding change in thermopile voltage to determine the object temperature. The temperature is calculated from the electric signals corresponding to measured voltage, and a series of well-known algebraic equations that include constants specific to the specific chip, such as the TMP006. The equations and constants are typically provided by the chip manufacturer, as well as calibration routines that adjust for part-to-part variations.

[0048] As with the detector chip 318, the sensitivity of the detector chip 344 also has an angular dependence, which is also typically Lambertian, with a maximum sensitivity at normal or near-normal incidence (i.e., for light arriving parallel to the z-axis), and the dependence falling to zero at an angle of ninety degrees with respect to the z-axis.

[0049] Referring now to the hydration measurement, the temperature/hydration monitor 308 includes an emitter 332, preferably located away from the detector chip 344, so that light from the emitter 332 does not appreciably affect the temperature

measurement from the detector chip 344. In the example layout of Figure 3, in which both the emitter 332 for hydration and the sensor 344 for temperature directly face the sample at normal incidence or near-normal incidence, the lateral separation (along the y-direction) between the hydration emitter 332 and the temperature sensor 344 is especially useful for reducing or preventing the leakage of light from one to the other.

[0050] An example for a suitable emitter chip 332 is an infrared (IR) broadband emitter, with an emitter area 334. Such a broadband source produces a range of wavelengths, and relies on one or more spectral filters downstream to select one or more wavelengths of interest.

[0051] There are commercially available broadband infrared sources in which a current is passed through a thin film, which heats the thin film to a relatively high temperature. The heated thin film emits light as if it were a blackbody emitter with a temperature equal to that of the thin film. The emitted blackbody radiation extends over a relatively wide range of wavelengths, so that filtering the output can produce a useable amount of light over a relatively wide range of wavelengths.

[0052] An example of a commercially available thin film broadband infrared source is sold by HawkEye Technologies, LLC of Milford, CT, with a model number IR-5x. The IR-5x is a MEMS technology infrared emitter, which uses a thin film resistor of diamond-like nanostructured amorphous carbon. The IR-5x has a square active area measuring 1.7 mm on a side. The temperature of the thin film can be adjusted by adjusting the voltage and/or current. At a voltage of 4 volts, either AC or DC, the current is 80 mA, the source consumes 0.32 watts of power, and has a temperature of 450 degrees Celsius. At a voltage of 5.5 volts, AC or DC, the current is 110 mA, the source consumes 0.6 watts of power, and has a temperature of 600 degrees Celsius. At a voltage of 6.7 volts, AC or DC, the current is 134 mA, the source consumes 0.9 watts of power and has a temperature of 750 degrees Celsius. The IR-5x can be optionally packaged with a parabolic reflector to produce a generally collimated output.

[0053] In general, light from a blackbody radiator follows the well-known Planck Law, which provides a value of radiated power density (in watts per cubic meter), as a function of wavelength and blackbody temperature. The output at a particular temperature has a peak at a particular wavelength, which is found from the well-known Wien's Displacement Law. For the numerical example above, in which the thin film operates at a temperature of 600 degrees C, or about 875 K, the wavelength at which the radiant intensity peaks is 3.32 μιη; a significant amount of light is emitted on either side of this peak, so that the light output from the thin film emitter may be considered to be relatively broadband.

[0054] Because measuring hydration may utilize detection of the sample reflectivity at two or more wavelengths, the temperature/hydration monitor 308 may use two or more detectors, with each detector being associated with a particular wavelength. The two detectors comprise detector chips 336, 340 and corresponding detector areas 338, 342.

[0055] In some examples, one or more of the detectors will have a spectral filter associated with it, which transmits light in a relatively narrow pass band about a center wavelength, while reflecting and/or absorbing light outside the pass band. In some examples, the spectral filters can be applied as thin-film coatings to respective areas of the measurement face 304, preferably on the side of the measurement face 304 facing the detectors and facing away from the sample. For the configuration of Figure 3, where the two hydration detector chips 336, 340 are relatively square, and the corresponding detector areas 338, 342 are also relatively square, the spectral filter coatings may subtend a relatively square area on the measurement face 304, roughly the same size slightly larger than the corresponding detector chips 336, 340. As an alternative, the spectral filter coatings may be applied onto the detector areas 338, 342 or onto dedicated cover glasses that are placed in front of the detectors 336, 340.

[0056] The hydration detectors 336, 340 may be thermopiles, which may be similar in structure and function to the example thermopile used for measuring temperature. For the device 300 shown schematically in Figure 3, a typical size of the device 300 may be as small as 8 mm tall (along the y-direction) by 15 mm wide (along the x-direction), although other suitable dimensions may also be used. TEMPERATURE/HYDRATION MONITOR - EXAMPLE #2

[0057] Note that for the configuration of Figure 3, the hydration emitter chip 332 and the hydration detector chips 336, 340 all have areas 334, 338, 342 that are generally parallel to the measurement face 304 and face the skin of the user at generally normal incidence. Such a configuration may be suitable for measurement of hydration on the skin surface, but may present difficulty measuring hydration beneath the skin surface, within the tissue of the sample.

[0058] ATR spectroscopy, when performed in the region at and near the critical angle is suited to measuring quantities beneath a surface of a sample. This type of ATR

spectroscopy is discussed in U.S. Patent Application No. 12/865,698, titled "Methods, Devices and Kits for Peri-Critical Reflectance Spectroscopy," published as U.S. Patent Application Publication No. 2011/0001965 on January 6, 2011, and in U.S. Patent

Application No. 13/263,386, titled "Peri-Critical Reflection Spectroscopy Devices, Systems and Methods," published as U.S. Patent Application Publication No. 2012/0088486 on April 12, 2012.

[0059] An important feature of this form of ATR spectroscopy is that the reflectance from the tissue sample is measured in the angular region at or near the critical angle, rather than at normal incidence (as is done in the configuration of Figure 3). This angular region is sometimes referred to as being "peri-critical." In this peri-critical region, the incident light produces an evanescent wave inside the tissue sample that penetrates into the tissue sample to a significantly larger depth than at other incident angles. As a result, this peri- critical region is particularly well-suited to measure properties that are below the surface of the sample. For instance, the peri-critical region of incident angle may be well suited to measure the presence and/or concentration of a constituent in a user's blood, which may be at a significant depth beneath the user's skin.

[0060] A difference between the configuration of Figure 3 and one that allows for ATR is that for ATR, the incident angle of the light from the broadband emitter on the sample is controlled to have a single value or a plurality of well-defined values at or near the critical angle. In contrast, the incident angles in the configuration of Figure 3 are distributed in a continuous angular range that includes normal incidence. [0061] In order to control the incident angle from the broadband emitter in a manner as described above, the light from the broadband emitter is coupled into the measurement face so that it propagates at a particular angle. The light inside the measurement face reflects off the sample at an angle at or near the critical angle. A relatively small fraction of the light couples into the sample through an evanescent wave and is absorbed. This absorbed portion shows up as a small drop in the amount of reflected light. The reflected light is then coupled out of the measurement face and is directed to a suitable detector.

[0062] The coupling into and out of the measurement face may be performed by features on or near the bottom side of the measurement face (i.e., the side facing away from the sample). Figure 4 shows a front view of an example measurement device 400 having IR elements 410, some of which are configured to use ATR for measuring the tissue sample.

[0063] The IR elements 410 of Figure 4 include one thermopile detector chip 432 having a detector area 434 facing the tissue sample, which is used for measuring body temperature in the same manner as described above for Figure 3. The IR elements 410 further include a series of emitters 436, 442, 448, 454 that couple light into a plurality of waveguides, 440, 446, 452, 458, wherein the light is directed within the waveguide to a depicted measurement face of the waveguide. Each waveguide is configured to direct light of a selected wavelength to the measurement face 440A, 446A, 452A, 458A at a desired angle. The incident light interacts with the tissue sample, which is in contact with the respective measurement faces 440A, 446A, 452A, 458A, and reflects to form reflected light. The reflected light is coupled out of each waveguide to strike a respective detector 438, 444, 450, 456.

[0064] The emitters 436, 442, 448, 454, the waveguides 440, 446, 452, 458 and the respective detectors 438, 444, 450, 456 may be said to form a series of channels. There are four such channels shown in Figure 4, although more or fewer than four channels may also be used. The channels of Figure 4 are shown as being perpendicular to the longitudinal axis of the housing 402, but they may alternatively be parallel to the longitudinal axis, or may be angled at any suitable orientation with respect to the longitudinal axis.

[0065] The four channels may be configured to accomplish different tasks. For instance, two of the channels may have spectral filters that select one wavelength, while the other two channels have spectral filters that select another wavelength. As another example, two of the channels may couple light at a single wavelength into the measurement face 404 at respective incident angle on the sample, while the other two channels couple light into the measurement face 404 at a different incident angle. In this manner, a variety of wavelengths and incident angles may be selected.

[0066] The channels as described herein may or may not have physical boundaries between them. In the configuration of Figure 4, the channels occupy different portions of the measurement face 404, so that the lateral separation between adjacent channels is sufficient to keep any undesirable crosstalk between the channels suitably low. In other configurations, there may be actual physical features that separate the channels, such as trenches, walls, light absorbing coatings, or other delimiting features on or between waveguides 440, 446, 452, 458.

[0067] Example measurement device 400 also includes a housing 402, and includes first and second photoplethysmographs 406, 410, with corresponding emitter chips 412, 422 having red 414, 424 and IR 416, 426 emitting areas, and corresponding detector chips 418, 428 having detector areas 420, 430. For the example device 400 of Figure 4, a typical size of the device 400 may be as small as 8 mm tall (along the y-direction) by 20 mm wide (along the x-direction), although other suitable dimensions may also be used.

[0068] Measurement device 400 also includes one or more additional sensors that are non-optical sensors. In the example, measurement device 400 includes a pair of electrodes 460, 462 as might be used, for example, to measure skin conductivity. Other types of electrically sensed measurements may be used, as well as other types of sensors including acoustic sensors, pressure sensors, etc. Thus, some measurement devices may include both optical and non-optical sensors for making physiological measurements.

[0069] Referring now to Figure 5, the figure schematically depicts an example configuration of a waveguide 502 and other components forming an example channel 500 as identified relative to Figure 4. Other channels have a similar layout, optionally with different numerical values for the various parameters.

[0070] Light propagates along an optical path P, which comprises an incident beam extending from a light source 504 to waveguide 502, an internal beam extending through the waveguide 502, and an external beam extending from the waveguide 502 to a detector 514. The optical path P includes a reflection off the measurement face 510 at an incident angle of Θ. The sample interface includes at least a portion of each measurement face from the multiple waveguides within the device. Preferably, the light is collimated along the optical path P.

[0071] For convenience of identification in this disclosure, an x, y, z coordinate system is established around the measurement face 510 of the waveguide 502, so that the measurement face 510 is within the x-y plane, and a longitudinal axis of the waveguide 502 is parallel to the y-axis. The incident and exiting beams, which direct light into and out of the waveguide 502 through a rear face 508 of the waveguide 502 can, in many examples, be cooperatively arranged with waveguide 502 to propagate along the +z-axis and the -z-axis, respectively.

[0072] In this example, the light source 504 produces a collimated incident beam, which in the depicted example is directed parallel to the +z-axis. The incident beam refracts through a back face 508 of the waveguide 502 and propagates as the internal beam inside the waveguide 502.

[0073] Note that for the directions that describe the optical path P, it is intended that the terms "parallel," "perpendicular," and "normal incidence" are intended to provide angular relationships that are satisfied to within typical manufacturing and alignment tolerances. Angular descriptions used throughout this document also include typical manufacturing and alignment tolerances. The term "near-normal incidence" is intended to include a deliberate misalignment between a beam and a surface normal, typically on the order of +/- 1 degree or less, which in some cases may reduce undesirable interference fringing effects in the beam. Use of such near-normal incidence is well-known to those skilled in the art.

[0074] The transmission through the back face 508 of the waveguide 502 will preferably be as complete (i.e., as close to 100%) as is practical. An anti-reflection coating, applied to the back face 508 of the waveguide 502 in an area that is expected to fully subtend the incident beam (for example, close to the light source 504), may eliminate reflections at the surface, or reduce the reflections down to a sufficiently low level. The anti-reflection coating is intended to work at normal incidence or near-normal incidence, at either a single wavelength or a plurality of wavelengths. A simple example of anti-reflection coating is a single, quarter-wave-thick layer, having a refractive index equal to the square root of the product of the refractive index of waveguide 3 and the refractive index of air. For example, for a waveguide 502 made from ZnSe, with a refractive index of about 2.4, a quarter-wave anti-reflection layer should have a refractive index of about 1.55. Another example is a two-layer coating known as a "V-coat," which can achieve especially good performance at a single wavelength, at the expense of typically worse performance than the single quarter-wave layer at wavelengths far from the single wavelength. Another example is a three-layer coating known as a "W-coat" or a "broadband AR coating," which can achieve a very low reflection at two distinct wavelengths. In general, these and other anti- reflection coatings are well-known to those skilled in the art, and may be readily designed using common software without undue experimentation. Other suitable anti-reflection coatings may be used, or the back face 508 may remain uncoated in the region that receives the incident beam (i.e., near the light source 504).

[0075] A first inclined reflective face 506 receives the internal beam from the back face 508. The first inclined reflective face 506 has a surface normal SN₅₀6 that lies in the y-z plane, and is angled away from the z-axis by (Θ / 2). In the example of Figure 1, the first inclined reflective face 506 is directly adjacent to the measurement face 510 on the waveguide, with the first inclined reflective face 506 adjoining the measurement face 510 along a line that extends along the x-axis. The angle formed in air between the first inclined reflective face 506 and the measurement face 510 is 180 degrees plus (Θ / 2). The incident angle at the first inclined reflective face 506 (with respect to the surface normal SN₅₀6) is (Θ / 2), which is half the incident angle Θ at the measurement face 510. Light reflects off the first inclined reflective face 506 with an exit angle (with respect to the surface normal SN₅₀6) of (Θ / 2).

[0076] Typically, the reflection off the first inclined reflective face 506 is preferred to be as complete (i.e., as close to 100%) as is practical. A high-reflectance coating, applied to the first inclined reflective face 506 of the waveguide 502 in an area that is expected to fully subtend the internal beam, may increase reflections up to a sufficiently high level. The high- reflectance coating is intended to work at an incident angle of (Θ / 2), at either a single wavelength or a plurality of wavelengths. An example of a high-reflectance coating may be a single metallic layer, such as of gold. Another example of a high-reflectance coating may be a thin-film structure having alternating layers of dielectric materials with relatively high and relatively low refractive indices. In general, these and other high-reflection coatings are well-known to those skilled in the art, and may be readily designed using common software without undue experimentation. Other suitable high-reflection coatings may be used, or the first inclined reflective face 506 may remain uncoated in the region that receives the internal beam.

[0077] The back face 508 receives the light reflected from the first inclined reflective face 506, and reflects it toward the measurement face 510. The reflection off the back face 508 is at a high enough incident angle so that the internal beam undergoes total internal reflection at the back face 508. In most examples, there is no reflective coating on a central portion of the back face 508 for this reflection, since 100% of the light is reflected through total internal reflection. (Portions near the longitudinal ends of the back face 508 may optionally be anti-reflection coated for entry and exit of the beam though the back face 508 of the waveguide 502; such anti-reflection coatings are not needed in the central portion of the back face 508 away from the longitudinal ends.)

[0078] The measurement face 510, which is parallel to the back face 508, receives the light reflected from the back face 508. The measurement face 510 lies in the x-y plane and has a surface normal SN₅i₀ that lies along the z-axis. The incident angle at the measurement face 510 (with respect to the surface normal SN₅i₀) is Θ. In many applications, such as ATR- IR spectroscopy, Θ will be at or near the critical angle formed between the waveguide 502, with refractive index n_Wa_Veguide, and the sample 518, with refractive index n_sampie- Mathematically, the critical angle is given by the numerical value of sin ¹ (n_sampi_e / n_waveguide)- In most cases, the reflectivity from the measurement face 510 will be close to 100%, with the drop from 100% being caused by absorption of a transmitted evanescent wave by the sample 518. Light reflects off the measurement face 510 with an exit angle (with respect to the surface normal SN₅i₀) of Θ.

[0079] The back face 508 receives the light reflected from the measurement face 510, and again reflects it through total internal reflection. The back face 508 may again be uncoated in the area that is expected to fully subtend the internal beam at this reflection.

[0080] A second inclined reflective face 512 then receives the internal beam reflected from the back face 508. The second inclined reflective face 512 has a surface normal SN₅i₂ that lies in the y-z plane, and is angled away from the z-axis by (Θ / 2) but in the opposite direction as the first inclined reflective face 506. In the example of Figure 5, the second inclined reflective face 512 is directly adjacent to the measurement face 510 on the waveguide, with the second inclined reflective face 512 adjoining the measurement face 510 along a line that extends along the x-axis. The angle formed in air between the second inclined reflective face 512 and the measurement face 510 is 180 degrees plus (Θ / 2). The incident angle at the second inclined reflective face 512 (with respect to the surface normal SN512) is (Θ / 2). Light reflects off the second inclined reflective face 512 with an exit angle (with respect to the surface normal SN₅₀6) of (Θ / 2). The reflected light from the second inclined reflective face 512 travels along the -z-axis. The reflection off the second inclined reflective face 512 will preferably be as great (i.e., as close to 100%) as is practical. The second inclined reflective face 512 may have a high-reflectance coating, similar in function and construction to that on the first inclined reflective face 506.

[0081] The back face 508 of the waveguide 502 receives the light from the second inclined reflective face 512 at normal incidence or near-normal incidence. The back face 508 may have an anti-reflection coating in an area that is expected to fully subtend the internal beam received from the second inclined reflective face 512. Such an anti-reflection coating may be similar in function and construction to that on the back face 508 face in the area adjacent to the light source 504. The internal beam strikes the back face 508, refracts through the back face 508 and forms the exiting beam, which propagates away from the waveguide 502 along the -z-axis. The exiting beam passes through a spectral filter 514 and strikes a detector 516, where it is converted into an electrical signal for communication to a processing unit 520.

[0082] The waveguide has a thickness denoted by T, which is the separation along the z-axis between the measurement face 510 and the back face 508. For this thickness T, a rough approximation of the center-to-center spacing along the y-axis between the incident and exiting beams is (4T tan Θ), where Θ is the incident angle at the measurement face 510. Such an approximation is helpful for estimating component sizes for a variety of operating conditions.

[0083] In the example of Figure 5, the entire optical path P, from light source 504 to detector 516, remains generally in the y-z plane, to within typical manufacturing, assembly and alignment tolerances. In other examples, the system may be configured with one or more beam paths deviating from such a plane.

[0084] As noted previously, in some cases the waveguide 502 will be configured to direct the beam sufficiently close to the critical angle that the evanescent wave extends beneath the surface of the sample to a desired degree. Using the example of intersecting the sample at the critical angle, the waveguide 502 should have a refractive index close to, but greater than that of the sample 518. For water-based samples, such as human or animal tissue, the refractive index is typically between about 1.15 and about 1.5 over a wide range of wavelengths, from about 0.2 μιη to about 11 μιη. At wavelengths in the mid-infrared spectrum (about 3.5 μιη to about 13 μιη), a reasonable approximation for the refractive index of water, and therefore also of tissue, is about 1.33.

[0085] In many examples, the emitter may be configured to include a lens and/or mirror that produces a collimated output. Specifically, the emitters 436, 442, 448, 454 all have collimated outputs, and are useful for obtaining measurements below the surface of the user's skin. In contrast, the broadband emitter 332 of Figure 3 does not have any collimating optics, and produces a diverging beam that is useful for obtaining measurements at the skin surface.

[0086] In some examples, the light produced by the emitter 506 may include a broader range of wavelengths than would be desired. Thus, in such cases, the optical path P will include a spectral filter 512 between the emitter and the waveguide 502 to block all but a relatively narrow band of wavelengths. The narrow band of transmitted wavelengths may be referred to as a "pass band," which is commonly specified by a center wavelength and a bandwidth. In some examples, the spectral filter 512 is located in the optical path P between the emitter 506 and the grating 508 at the measurement face 502, as is shown in Figure 5. Such spectral filters 512 are known as notch filters, and are well-known to those skilled in the field of optics. In some cases, the spectral filters are discrete elements in the optical path P, as is shown in Figure 5 (and Figure 6).

[0087] The detector 514 may be a thermopile, as discussed above, or may be another suitable type of IR detector, such as a LiTa0₃ pyroelectric or a PZT pyroelectric. These detectors are commercially available in a range of sizes and configurations, and may be readily adapted to particular packaging aspects of miniaturization. [0088] Referring now to Figure 6, therein is depicted an alternative configuration for a waveguide 602 and channel 600 suitable for use in a measurement device such as that depicted in Figure 4. In contrast to the embodiment of Figure 5, channel 600 configured to use a relatively broadband emitter 606. Channel 600 includes a waveguide 602 having one or more associated diffraction gratings 608, 610. In some examples, these diffraction gratings may be integrally formed in waveguide 602, or otherwise may be placed and/or secured in association with the waveguide 602.

[0089] In some examples of this configuration, light is coupled into and out of the waveguide 602 by a pair of matched diffraction gratings 608, 610, each in the form of a blazed grating (or "echelette grating"), as known in the art. These gratings may be formed on the bottom surface of the waveguide 602 in respective areas at opposite ends of the channel location. The gratings 608, 610 may be formed over areas that are expected to fully subtend the incident and exiting beams, respectively. Light incident on the incident diffraction grating 608 may be transmitted into several diffracted orders, where the location of each order is determined by the well-known grating equation. By creating the grating with a blaze, nearly all the incident light may be coupled into a single diffracted order, which is then directed toward the sample 604 with incident angle Θ. The exiting diffraction grating 610 may be formed in a similar manner, but with a blaze in the opposite direction as the incident diffraction grating 608.

[0090] In some cases, spectral filters may be deposited or grown directly on the back face of the gratings 608, 610 on the side of the waveguide 602 that faces away from the tissue sample 604. In some examples, the spectral filters may be disposed directly onto the gratings, may be made integral with the measurement face, may be made separately and attached to the measurement face, may be made separately and disposed adjacent to the measurement face, or made be made integral with the gratings and disposed adjacent to the measurement face. Alternatively, a separate spectral filter 612 may be interposed between waveguides 602 and detectors 614.

[0091] In some examples, light from a relatively broadband emitter may be directed through one or more grating prisms, known in the art as "grisms." Each grism is similar to the blaze grating discussed above, but includes a tilt to the grating surface. Each such grism receives light from the relatively broadband emitter and bends the light a given amount. On the source side of the measurement face, the grism thereby establishes a particular angle of incidence at the measurement face (similar to the configuration of Figure 5), and directs the reflected light toward a particular detector or group of detectors 614.

TEMPERATURE/HYDRATION MONITOR - EXAMPLE #3

[0092] Figure 7 shows an example device 700 having a housing 702, a measurement face 704, first and second photoplethysmographs having respective emitters 708, 720 and detectors 706, 718, and temperature/hydration monitor elements. Body temperature is measured with thermopile detector 710, as described above.

[0093] While the example configuration of Figure 4 measures hydration by using a separate emitter 436, 442, 448, 454 for each channel, the example configuration of Figure 7 uses a single emitter 712 to illuminate all the channels. Any suitable number of emitters may be used to illuminate the channels, ranging from one emitter for all the channels, to one emitter per channel. The emitter 712 may be an IR broadband emitter, as described above.

[0094] Light from the emitter 712 is directed onto a plurality of combination grating prisms 714, as discussed above. To facilitate efficient delivery of the light while reducing or minimizing light directed to other locations on or through the measurement face 704, the angular distribution from the emitter 712 may be tailored to the geometry of Figure 7. For instance, if the thin film of the broadband infrared source is left bare, then the source emits into a Lambertian distribution, centered about a surface normal with respect to the plane of the thin film, which is typically parallel to the z-axis. As an alternative, the thin film of the emitter 712 may be embedded within an encapsulating lens, which can narrow the angular distribution from the emitter 712. As a further alternative, the emitter 712 may include a collimating lens or mirror, which may produce a generally collimated output. In some examples, the emitter 712 includes an anamorphic lens that collimates light along one axis, while partially collimating along the other axis or having no optical power along the other axis. Other beam-shaping options may be used for the emitter 712, as needed. The various grisms or grism pairs may allow for simultaneous use of various angles of incidence on the sample, as was discussed with respect to Figure 4. [0095] The detectors 716 may be laid out in a square array as shown in Figure 7, may be laid out in a rectangular or irregularly shaped array, or may be formed as pixels in a multi-pixel detector. For a multi-pixel detector, light from a particular grism 714 may subtend one pixel or more than one pixel. In some cases, there are suitable spectral filters present in the respective optical paths, so that a particular pixel or group of pixels is used to detect only a single wavelength or a relatively narrow spectral band about a particular center wavelength.

[0096] It should be noted that although the emitter 712, grisms 714, and detectors 716 are shown as all being laterally separated along the length of the measurement face 704, in practice some of the elements 712, 714, 716 may be stacked above or below each other, similar to the orientations shown in Figure 5.

[0097] In this manner, a range of incident angles on the sample and wavelengths may be used. In most examples, the incident angles are predetermined and are selected during the design phase of the device, and are varied from channel to channel. In most examples, the wavelengths are predetermined during the design phase of the device and are varied by spectral filters that cover particular pixels, groups of pixels, or suitable regions on the grisms.

[0098] The detectors 716 may be thermopiles, as discussed above, or may be another suitable type of IR detector, such as a LiTa0₃ pyroelectric or a PZT pyroelectric. These detectors are commercially available in a range of sizes and configurations, including multi- pixel configurations, and may be readily adapted to particular packaging aspects of miniaturization.

[0099] For the device 700 shown schematically in Figure 7, it is envisioned that a typical size of the device 700 may be as small as 5 mm tall (along the y-direction) by 12 mm wide (along the x-direction), although other suitable dimensions may also be used.

[00100] Referring now to Figures 8A-D, that figure depicts example portable devices that may, in some example systems, be used to obtain physiological measurements through use of a measurement device as described above. A portable device comprises, but is not limited to, a mobile telephone or smart phone 800, a portable tablet 850, an audio/video device 870, a personal computer 890 such as a laptop or netbook, any variety of mobile devices that include a touch sensor panel, or the like. In these examples, each of the mobile telephone/smart phone 800, portable tablet 850, audio/video device 870, and personal computer 890 includes a touch sensor panel 802 (also referred to as a touch sensitive display, touch sensitive screen, or a touchpad) and a controller assembly 804. The touch sensor panel 802 includes an array of pixels to sense touch event(s) from a user's finger, other body parts, or objects. Examples of touch sensor panel 802 includes, but is not limited to, capacitive touch sensor panels, resistive touch sensor panels, infrared touch sensor panels, and the like. The controller assembly 804 is configured to provide processing capabilities for the portable device. While many such portable devices will include a touch screen, such is not necessarily required (see for example, computer 890 having a display, but not a touch screen). In Figure 8, the example touch screens 802 and controller assemblies 804 have been numbered similarly, though as will be readily apparent to those skilled in the art, such numbering is not intended to suggest that such structures will be identical to one another, but merely that the identified elements generally correspond to one another. Each of the mobile telephone/smart phone 800, portable tablet 850, audio/video device 870, and personal computer 890 may also include a power button, a menu button, a home button, a volume button, a camera, a light flash source for the camera, and/or other components to operate or interface with the device.

[00101] As indicated earlier herein, the described measurement devices may be either self-contained, or configured for use with a portable electronic device such as those depicted in Figures 8A-D. The measurement device may be placed in communication with such a portable electronic device by any appropriate mechanism, for example by either a wired or wireless connection. In some cases, wherein power is to be supplied by the portable electronic device, a wired connection may be used. Where the connection with a portable electronic device is primarily to the received data signals for either display, processing or further transmission, the communication may typically be by any of a number of suitable wireless technologies, including, for example, Wi-Fi and/or Bluetooth^® protocols, or other protocols known to those skilled in the art.

[00102] Also as noted above, each portable electronic device includes a controller assembly (804). Accordingly, when a portable device is used in combination with the measurement device, the functionality for controlling the sensors (i.e., activating the emitters, receiving data, processing the data, etc.) can be performed through any desired apportionment of functionality between the measurement device (and the processing unit therein) and the portable electronic device (and the controller assembly therein).

[00103] Figure 9 illustrates an exemplary flow diagram 900 for obtaining physiological measurements using a portable device in accordance with some embodiments. The operations of flow diagram 900 provide an example of operations which may be

apportioned between the measurement device and a communicatively coupled portable electronic device, which alternatively can all be performed by the measurement device. At block 902, an optional calibration may be performed. Such a calibration might be a onetime event for a user, or might be performed routinely. Next at block 904, information might be displayed to a user to facilitate some forms of measurements. For example, for some types of measurements, it may be preferred that the user remains generally stationary; while such may not be required for other measurements, for example

measurement of a pulse rate. In some example systems, many physiological conditions will be monitored generally continuously (in reality, in most examples, at periodic intervals suitable for the measurement being performed).

[00104] At block 906, one or more of the sensors in the measurement device will be controlled to obtain physiological measurements represented by sensor output signals. The most be remembered that while the present disclosure emphasizes the use of different forms of optical sensors, and other types of sensors may also be employed, such as electrical sensors, such as for measuring skin conductivity and/or pressure sensors as may be used to sense blood flow, etc. These other sensors may be used independently, or may be used in combination with one or more of the optical sensors to facilitate determination of appropriate physiological measurements. Where a sensor operates through use of providing a stimulus to the body, this operation will control the timing and duration of that stimulus, as well as of any controls needed to facilitate a subsequent detection responsive to that stimulus.

[00105] As noted previously, in some cases, some or all of the sensor signals may be processed within the measurement device to provide physiological measurements; while in other cases, some or all of the sensor signals may be communicated, as indicated at optional block 908, to another device, such as a portable electronic device for further processing. At block 910, the sensor signals will be processed; and at block 912, physiological measurements will be calculated based upon the measured physiological parameters represented by the sensor signals.

[00106] Once the physiological measurements are determined, then in many example systems, they will be displayed to a user, as indicated at 914. Again, in some examples some, or all, such measurements will be displayed to a user through a display associated with the measurement device; while in other examples, the signals will be displayed through use of a portable electronic device in communication with the measurement device.

Similarly, in most examples, the physiological measurements will be saved, or will be transmitted to another device for saving, as indicated at block 916.

[00107] Referring now to Figure 10, that figure depicts a block diagram showing modules configured to facilitate the process of flow diagram 900. For purposes of this example, the block diagram of a controller assembly will be presumed to be that of a controller assembly located within the measurement device. As will be apparent to those skilled in the art, some of these functional modules may be contained within the measurement device, while others are contained at least in part within an associated portable electronic device.

[00108] The modules of Figure 10 comprise conceptual modules representing functionality to be performed. In many examples, this functionality will be achieved through use of instructions encoded in a computer readable storage device. When the instructions encoded in the computer readable storage device are executed by the controller assembly 804, computer system or processor, it causes one or more processors, computers, or machines to perform certain operations as described herein. In some cases, some of these operations may be performed through use of hardware, which would form a portion of the described modules.

[00109] In this example, both the computer readable storage device and the processing hardware/firmware to execute the encoded instructions stored in the storage device are described as components of an example measurement device 1000 having a plurality of sensors, as indicated at 1002, which sensors will preferably include a plurality of optical sensors, as described earlier herein. Although the modules shown in Figure 10 are shown as distinct modules, it should be understood that they may be implemented as fewer or more modules than illustrated. It should also be understood that any of the modules may communicate with one or more components external to the measurement device via a wired or wireless connection.

[00110] As shown in Figure 10, the measurement device may include a physiological parameter detection module as indicated at 1004. This physiological parameter detection module will, in many examples include control functionality sufficient to appropriately actuate each of the provided sensors as may be required to obtain particular measurements from each such sensor, and also to obtain data signals from each sensor as to the sensed physiological parameters. A physiological measurement calculation module 1006 is configured to receive the data signals representative of the sensed physiological parameters and to perform such calculations as may be necessary to generate physiological

measurements are useful to a user. As noted elsewhere herein, in some cases these measurements may be determined solely through analysis of the data signals from a single sensor; or in other examples may be determined through use of correlation of data signals from multiple sensors. An information display module 1008 may be implemented to display one or more of the determined physiological measurements to a user, either on the display associated with the measurement device itself, or through use of a display of a

communicatively coupled portable electronic device, as described above.

[00111] Additionally, a post-calculation module 1010 may be used for other handling of the determined physiological measurements, including storage of the measurements and/or transmission of the measurements to another electronic device. As will be apparent to those skilled in the art having the benefit of this disclosure, additional actions may be taken with respect to either in the sensed physiological parameters, or the signals representative thereof, or the determined physiological measurements. For example either of such types of information may be communicated to external devices for further processing, tracking, or other analysis.

[00112] Many additional modifications and variations may be made in the techniques and structures described and illustrated herein without departing from the spirit and the scope of the present invention. Accordingly, the present invention should be clearly understood to be limited only by the scope of the claims and equivalents thereof.

Claims

What is claimed is:

1. A physiological measurement device, comprising:

a plurality of optical sensors, including,

an ATR sensor, including,

a waveguide having a measurement face configured to engage a portion of a user's body, the waveguide further configured to receive light and to direct at least one wavelength of light internally to intersect the measurement face at a selected incident angle;

a light emitter cooperatively arranged to direct light into the waveguide; and a light detector configured to receive reflected light from the waveguide; and a second optical sensor configured to measure at least one of body temperature, body hydration, and pulse rate;

2. The physiological measurement device of claim 1, wherein the second optical sensor comprises a photoplethysmograph which functions to provide measurements including pulse rate.

3. The physiological measurement device of claim 1, wherein the measurement device further comprises a power source.

4. The physiological measurement device of claim 1, wherein the device comprises an I/O port configured to facilitate at least selective communication of measurement data to a portable electronic device.

5. The physiological measurement device of claim 4, wherein the I/O port is configured to provide wireless communication with the portable electronic device.

6. The physiological measurement device of claim 1, wherein the device comprises an optical body hydration sensor and an optical body temperature sensor

7. A physiological measurement device, comprising:

a housing;

a first optical detector forming a photoplethysmograph disposed within the housing;

a second optical detector disposed within the housing, the second optical detector including a body thermometer; and

a third optical detector disposed within the housing. .

8. The physiological measurement device of claim 7, wherein the housing is configured to engage a selected portion of a user's body.

9. The physiological measurement device of claim 7, further comprising a fourth optical detector in the hosing, the fourth detector forming a second photoplethysmograph.

10. The physiological measurement device of claim 7, further comprising

at least one processor; and

one or more machine-readable storage devices containing instructions that, when executed by at least one such processor, cause operations comprising taking at least one measurement through at least one of the optical sensors.

11. The physiological measurement device of claim 10, wherein the operations further comprise:

receiving measurement data from a plurality of the sensors in the device; and

processing the received measurement data to determine at least one physiological property of the user.

12. The physiological measurement device of claim 11, wherein the operations further comprise at least one of:

displaying the determined physiological property to the user; and

transmitting the determined physiological property to another electronic device.

13. The physiological measurement device of claim 7, wherein at least one of the optical sensors comprises a thermopile sensor.

14. The physiological measurement device of claim 7, wherein at least one of the optical sensors comprises an infrared broadband emitter, a spectral filter, and a detector.

15. The physiological measurement device of claim 7, wherein one of the optical sensors comprises a hydration detector

16. The physiological measurement device of claim 7, wherein at least one of the optical sensors comprises:

a waveguide having a measurement face configured to engage a sample, the waveguide configured to direct an incident light beam to the measurement face at a desired angle;

an emitter assembly configured to direct coherent light to the waveguide as the incident beam; and

a detector cooperatively arranged with the waveguide to receive reflected light from the waveguide.

17. A system for making physiological measurements of a user, comprising:

a physiological measurement device, comprising:

a plurality of optical sensors, including,

an ATR sensor, including,

a waveguide having a measurement face configured to engage a portion of a user's body, the waveguide further configured to receive light and to direct at least one wavelength of light internally to intersect the measurement face at a selected incident angle, a light emitter cooperatively arranged to direct light into the waveguide, and a light detector configured to receive reflected light from the waveguide; and a second optical sensor configured to measure at least one of body

temperature, body hydration, and pulse rate; and an I/O port configured to communicated with a portable electronic device; and

a portable electronic device having wireless communication capability, wherein the

physiological measurement device and the portable electronic device are configured for communication with one another.

18. The system of claim 17, wherein the second optical sensor comprises a

photoplethysmograph configured to provide measurements including pulse rate.

19. The system of claim 17, wherein the I/O port is configured to provide wired communication between the physiological measurement device and the portable electronic device.

20. The system of claim 17, wherein the I/O port is configured to provide wireless communication between the physiological measurement device and the portable electronic device

21. A method of making physiological measurements of a user's body, comprising: contacting the user's body with a housing assembly comprising:

a plurality of optical sensors, the optical sensors comprising,

a first sensor that includes either of,

a photoplethysmograph, comprising,

a plurality of optical emitters, one emitter of visible light and one emitter of infrared light, and

at least one detector; and

an ATR sensor, comprising,

a waveguide having a measurement face configured to engage a portion of a user's body, the waveguide further configured to receive light and to direct at least one wavelength of light internally to intersect the measurement face at a selected incident angle, a light emitter cooperatively arranged to direct coherent light into the waveguide at the selected incident angle, and

a light detector configured to receive reflected light from the

waveguide; and

a second optical sensor configured to measure at least one of body temperature, body hydration, and pulse rate;

controlling the optical sensors to obtain a plurality of optical measurements of the user's body; and

processing the obtained optical measurements to identify a plurality of physiological

measurements of the user.

22. The method of claim 21, further comprising the act of transmitting at least one obtained optical measurement to a portable electronic device for processing thereof.

23. The method of claim 22, wherein the act of controlling the optical sensors to obtain optical measurements is performed at least in part by the portable electronic device.