Abstract:
A device and method for non-invasively measuring analytes and physiological parameters by measuring terahertz radiation emitted though biological tissue. Terahertz pulses are emitted from a miniaturized quantum cascade laser to a fiber optic array into the wrist of the user. A corresponding sensor on the opposite side of the wrist receives the terahertz signals that have been modified by interacting with organic molecules. The data from the sensor is compiled and analyzed on a RAM chip and logic chip, where a program uses an algorithm to compare measurements to a library of existing measurements and topographic maps generated when the user first dons the device. Once the algorithm has parsed all the data points, a value, such as blood glucose level, appears on a display of the device. The device may be equipped with a gasket to reduce ambient light from contacting the sensor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application No. 61/891,903, filed on Oct. 17, 2013, hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present invention relates to a non-invasive device and method for measuring analytes and physiological parameters in a biological being. More particularly, the device and method measure glucose concentration by sensing the absorption of terahertz waves emitted through human tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    Diabetes (type I and II) is potentially life threatening, but with studious management, a person living with the disease can live a full, normal and active life. However, current technologies for the daily monitoring of the disease are often cumbersome, painful and invasive. The standard procedure is for the diabetic person to break his or her skin, draw blood, capture blood on a strip, and insert the strip into a measuring device. Not only is measuring glucose in this way painful, but it is also difficult and expensive to perform constant monitoring of one&#39;s own blood glucose level. 
         [0004]    There have been several attempts to monitor glucose levels non-invasively using various methods and devices, but these attempts have been met with challenges and have not been proven to be very successful. Some current non-invasive devices require direct contact with skin, use electric current, and/or use adhesives. These devices and methods often produce a skin irritating effect and are inaccurate. Other ways to measure blood glucose non-invasively have included: shining light through skin or body tissues, using ultrasound, blood viscosity testing, and measuring infrared radiation emitted by the body. Some technologies measure glucose and other analytes by measuring reflection and/or of absorption of electromagnetic waves in the terahertz range (approximately 0.3 to 3.0 terahertz). By measuring reflection or absorption of terahertz radiation by organic molecules, and comparing these measurements with a database of known reflection/absorption values for concentrations of organic molecules can be determined. Some technology used to measure blood glucose levels are disclosed in the following patents and patent applications: 
         [0005]    U.S. Pat. No. 6,188,648 to Olsen discloses a diabetic care watch that signals the wearer of the watch for a need to test blood glucose levels. Here, the wearer manually calculates carbohydrates counts and blood glucose levels are not directly measured. 
         [0006]    U.S. Pat. No. 7,174,199 to Berner discloses a method and device for measuring blood glucose levels transdermally using iontophoresis. 
         [0007]    U.S. Pat. No. 8,135,450 to Esenaliev discloses a non-invasive method and system to detect blood glucose levels based on the change of tissue dimensions, which correlate to blood glucose concentration. 
         [0008]    U.S. Pat. No. 8,698,085 to Ouchi discloses an apparatus to measure analytes in a gas (not within human tissue) using terahertz or infrared radiation. 
         [0009]    U.S. Patent Application Pub. No. 20070255122 to Vol discloses a device to measure analytes. The device uses at least two spaced apart electrodes for providing a bio-potential measurement to determine physiological parameters. 
         [0010]    U.S. Pat. No. 6,675,030 to Ciurczak discloses an individualized modeling equation for predicting a patient&#39;s blood glucose level generated as a function of non-invasive spectral scans of a body part and an analysis of blood samples from the patient. 
         [0011]    U.S. Pat. No. 6,645,142 to Braig discloses a glucose monitoring instrument having network-based communication features that provide a link between patient and practitioner. 
         [0012]    U.S. Pat. No. 6,723,048 to Fuller discloses an apparatus for non-invasive detection and quantification of analytes, such as blood glucose, by employing an amplifier that uses high-gauss permanent magnets to permit an RF signal to be transmitted through a sample. The concentration of the analyte can be determined from the magnitude of the reduction in the amplitude of the radio-frequency (RF) signal at a characteristic frequency. 
         [0013]    U.S. Patent Application Pub. No. 20080068932 to Mosley discloses a watch for monitoring diabetes, which includes an alert system, and includes measurement by a transdermal sensor mounted to the back of a wristwatch. 
         [0014]    U.S. Pat. No. 6,923,763 to Kovatchev discloses a non-linear model and implementation for hypoglycemia that uses predictive algorithms for determining the onset of hypoglycemia. 
         [0015]    U.S. Patent Application Pub. No. 20130289370 to Sun discloses a method and device using an electromagnetic absorption constant. 
         [0016]    International Patent Application Pub. No. WO2007071092 to Artley discloses a non-invasive blood glucose sensor that uses terahertz radiation to detect blood glucose levels by measuring reflected radiation. 
         [0017]    Patents and patent applications that teach hardware and software implementation are generally known, and are disclosed in U.S. Pat. No. 4,858,207 to Buchner, U.S. Pat. No. 5,371,687 to Holmes, U.S. Pat. No. 5,678,571 to Brown, and U.S. Pat. No. 5,701,894 to Cherry. 
         [0018]    Despite the advances in non-invasive glucose monitoring, all suffer from one or more drawbacks in accuracy, comfort, convenience, features, and price. Therefore, there is a continuing need for new devices and methods that accurately and non-invasively measure physiological parameters and analytes, such as blood glucose. 
       BRIEF SUMMARY OF THE PRESENT INVENTION 
       [0019]    The present invention provides a device and method for measuring analytes and physiological parameters in a biological being. Analytes in blood that are desirous of measuring, include, but are not limited to: glucose, urea, lactate amino acids, enzyme substrates, and products indicating a disease state or condition. 
         [0020]    In one aspect of the present invention, the invention provides a device that allows an individual, parent, guardian, or medical professional, a consistent, non-invasive way to continuously, or nearly continuously monitor blood glucose levels in children or dependent elders with type I or type II diabetes. The device may be in the form a wristband or wristwatch, which enables a user to be alerted to dangerously high or low levels of glucose. These and other objects are accomplished using a combination of the following: (a) a miniaturized quantum cascade laser (QCL) designed to emit a plurality of pulses of terahertz radiation that are tuned to the resonant frequency of the analyte (e.g. glucose) being sampled, (b) an emitter unit operatively connected to the miniaturized quantum cascade laser where emitter unit emits the terahertz radiation from a fiber optic emitter array that has an array of field emission points arranged two-dimensionally on the fiber optic emitter array, (c) a sensor unit, preferably comprising a photo-conductive indium antimonide sensor array that is adapted to detect terahertz radiation generated by the QCL, (d) a display unit adapted to display at least one measurement of an analyte measured by the device, and (e) a processing unit (such as a CPU) that has a stored programmable memory and a random access memory. The processing unit is configured to process signals received by the sensor, and determine the concentration of analytes, or measure other physiological parameters. The processing unit may be connected to programmable memory, a random access memory, the QCL, the sensor unit, and display unit. Analytes such as glucose may be specifically measured when the terahertz frequency is tuned to a frequency that excites specific analytes, and produces a unique optical excitation spectra that can be analyzed. The processing unit compares readings from the sensor to an onboard database of similar body types and compositions, and uses an algorithm to determine the concentration of the analyte by comparing data from a user to database of optical spectra of various analytes, similar body types, and compositions. The measurements may be shown to the user on a display (such as the face of a wristwatch), and may also be transmitted to a third party. 
         [0021]    In one aspect of the device, the miniaturized quantum cascade laser is operatively connected through fiber optic array that has approximately 350 terahertz fiber optic emission points. The fiber optic array is aligned to a corresponding indium antimonide sensor on the opposite side of the user&#39;s tissue (e.g. wrist). 
         [0022]    In another aspect of the device, the fiber optic sensor is surround by a comfortable opaque material (such as a neoprene gasket, which may have inflatable features) to reduce ambient light form contacting the sensor, and provides a secure fit. 
         [0023]    In another aspect of the device, the device includes a universal serial bus (USB) connector so that data from the device can be retrieved and the device can be charged via the same connector. 
         [0024]    In another aspect of the device, the device includes a wireless transmitter capable of transmitting data to third party. 
         [0025]    In another aspect of the invention, the present invention provides a non-invasive method for detecting the concentration of an analyte or physiological parameter. The method includes steps of: (a) generating electromagnetic waves in a terahertz range using a device comprising a miniaturized quantum cascade laser (QCL), (b) emitting electromagnetic waves in a terahertz range via a fiber optic array having plurality of field emission points arranged two-dimensionally, (c) transmitting electromagnetic waves in the terahertz range through a biological tissue, (d) measuring transmitted electromagnetic waves on a photo-conductive sensor array, wherein the photo-conductive sensor array comprises a plurality of individual photo-conductive sensors arranged two-dimensionally, and wherein the photo-conductive sensor array is positionally arranged parallel to the fiber optic array on opposite sides of the biological tissue, and (e) calculating a value of an analyte from the transmitted waves by determining a frequency energy received by the photo-conductive sensor having a plurality of photo-conductive sensors. 
         [0026]    In other aspects of the invention, the method includes emitting the electromagnetic waves only when the device is relatively flat and still, and the sensor is relative dark, in order to prevent erroneous due to momentum, motion, and shifting of internal tissues, and ambient light that that may lead to compromised results. 
         [0027]    In yet another aspect of the method, the method includes a step of calibrating the device to account for discrepancies that may occur due to non-blood tissues near the emitter (e.g., bone, tendons, etc.). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1   a  is a perspective view of a wristband used to house a glucose detection device. 
           [0029]      FIG. 1   b  is a top cross sectional view of the wristband of  FIG. 1   a.    
           [0030]      FIG. 2   a  is a perspective view of an engine and housing for a glucose detection emitter array. 
           [0031]      FIG. 2   b  is the bottom view of engine and emitter array of  FIG. 2   b.    
           [0032]      FIG. 3  is an exemplary view of a cascade quantum laser and array embedded within the wristband. 
           [0033]      FIG. 4  is an exemplary view of sensor array embedded within a wristband that shows an individual photo-conductive sensor within the array. 
           [0034]      FIG. 5  is cross sectional exemplary view of the glucose detection device within a wristband around a user&#39;s wrist. 
           [0035]      FIG. 6  is a cross sectional view of a wristband having a gasket to block ambient light from contacting the sensor. 
           [0036]      FIG. 7  is a system diagram of the glucose monitoring device. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0037]    The following discussion addresses a number of embodiments and applications of the present disclosure. Reference is made to the accompanying drawings that form a part hereof, and are shown by way of illustration of specific embodiments in which the disclosure may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present disclosure. It is to be understood that the present disclosure is not limited to such specific application and that numerous implementations of the present disclosure may be realized. 
         [0038]    The beneficial features of the present disclosure will be evident from the described embodiments. All references to patents, patent applications, and non-patent publications in the background and description are hereby incorporated by reference, in their entireties. 
         [0039]    In one embodiment of the invention, a glucose detection device is in the form of a wristband  10  and more specifically a wristwatch, as shown in  FIG. 1   a  and  FIG. 1   b . Other embodiments may include the technology incorporated in a ring, earring, or other wearable device. The wristband  10  includes an upper strap  4 , a lower strap  6 , and adjustable strap  8 . Connecting upper strap  4  and lower strap  6  is a pocket  12  that has a top surface  14  and a bottom surface (not shown). The engine  20  (See  FIGS. 2   a  and  2   b ) of the device is placed within the pocket  12 . Defined here, the engine  20  comprises the internal software and some hardware of the device, such as the sensor unit  84  and display  94 . The engine  20  may operate independently of the band so that the user can remove the engine  20  from the wristband  10  if he or she desires. The engine  20  may be worn once fully assembled into the wristband  10 . The engine  20  is small enough so that it may discreetly fit inside a purse, wallet, pocket, or keychain, where the user may manually check blood sugar levels whenever he or she pleases. The engine  20  may be made out of a variety of materials such as anodize aluminum, or metallic microlattice, and may have a glass curved touchscreen  94 . The engine  20  may securely connect to the band via a variety of means, and is illustrated as a hook  22 , or other type of protrusion near the first end  54  of the upper strap  4 . The protrusion  22  is designed to latch onto a fastening, or shackle  26  of the engine  20 . The hook may be made from any sturdy material, but preferably steel. The bottom surface of the pocket  12  has a hole  28  so that when the engine  20  is placed in the pocket  12 , the bottom surface of the engine  20  is placed in direct contact with the user&#39;s skin, or may be slightly raised from the user&#39;s skin. The engine  20  may also have a plurality of protrusions  64  that align with indentations  62  located on the top surface  14  of the pocket in order to help lock in the position of the engine  20  within the pocket  12 . 
         [0040]    The lower strap of the watch  6  has a USB port (male)  34  at a first end  32 , and a USB port (female)  36  at its second end  38 . The adjustable strap  8  has a USB port (female)  40  at its first end  42  and insertion hole  46  to insert the second end  44  of the upper strap  4 . A plurality of adjustment protrusions  48  along the length of the top surface of the upper strap  4  corresponds in size and shape to an adjustment hole  50  on the second end  52  of the adjustment strap  8 . The wristband  10  can therefore vary in length depending on which protrusion  48  is secured to the adjustment hole  50 . To secure the entire wristband  10  around the user&#39;s wrist, the USB port (male)  34  of the lower strap  6  is inserted into the USB port (female)  40  of the adjustment strap  8 . The upper strap  4 , lower strap  6 , and adjustable strap  8  may include various ornamental features such as aluminum bands  98  along one or more regions of the straps. 
         [0041]    Referring now to  FIGS. 2   a  and  2   b , the engine  20  includes a miniaturized quantum cascade laser (QCL)  60  capable of emitting radiation of terahertz frequency (shown in  FIG. 3 ). The use of QCLs for emitting terahertz radiation is known in the art. (See “Continuous Glucose Monitoring by Means of Fiber-Based, Mid-Infrared Laser Spectroscopy,” Labrecht, et al., Applied Spectroscopy 60, 729-736 (2006)). Terahertz radiation has also been used to detect a variety of polycrystalline structures. (See “Far-infrared Vibrational Modes of Polycrystalline Saccharides” Upadhya, et al., Vibrational Spectroscopy, 35, 129-143 (2004)). In the present embodiment, the engine  20  has an emitting unit  84  that is connected to the miniaturized QCL  60 . The emitting unit  84  may have a tuning module  114  connected to a controller or processor  108  that allows the wavelength of the terahertz radiation emitted by the laser  60  to be controlled within a range of frequencies. The operative connections between various components of the device are illustrated in  FIG. 7 . By default, the device will be set to detect glucose at or around 1.4 terahertz (or a close range, such as between 1.3 and 1.5 terahertz). The laser  60  can be tuned to emit and detect other substances if desired. For example, to detect fructose, the laser  60  can be tuned to approximately 1.7 terahertz, well within the QCL&#39;s operating range. 
         [0042]    In operation, the beam of the laser is guided through the terahertz equivalent of fiber optic strands  66  and the terahertz waves are emitted at the end of each strand on fiber optic emission points  72 , which are mounted to an array  68  or grid of individual emitting cells  70 . The array  68  may be in the form of a mounting lattice made of a flexible, insulating material. The lattice may be comprised of a nylon-polycarbonate material, such as those manufactured by Taulman 3D, LLC. Array lattices made from a nylon-polycarbonate hybrid have advantages in that they exhibit both strong insulating and flexion qualities and they may be manufactured additively (i.e. 3D printing). The array  68  may be of a variety of sizes and shapes. In a preferred embodiment, the emitter array  68  is a size that comfortably lies substantially flat on the top of a user&#39;s wrist  116  or other body part. In a preferred embodiment the array  68  is approximately 0.57 inches (1.45 cm) in length, and 1.00 inches (2.54 cm) in width. The size of the array  68  may be doubled (1.04 in. by 2 inches) or halved (0.29 in. by 0.50 in.) without detracting from the comfort or utility of the device. However, any size that would fit comfortably on the user&#39;s wrist would work equally well. Preferably, the size of each emitting array cell  70  on the array  68  is approximately 1 mm×1 mm, but sizes that are double of half of the preferred size would likewise not detract from the comfort or utility of the device. Each cell  70  of the array is operatively connected to a fiber optic strand  66 . An exploded view of a single emitting cell  70  is shown in  FIG. 3  as well as a sample of numerous fiber optic strands  66  attached to the array  68 . 
         [0043]    Within wristband  10  is a sensing unit  86  that connects a sensor array  74  via serial cables  90  to a voltage detecting unit  92  (shown in  FIG. 4 ). The sensor array  74  has the same dimensions and same number and size of cells as the emitter array  68 . The individual photo-conductive sensors  76  on the array  74  are arranged two-dimensionally, and each comprises a positive terminal  78 , a negative terminal  80 , and a disc  82  of photo-conductive indium antimonide mounted between the positive and negative terminals  78 ,  80 . Depending on the frequency of the terahertz radiation received, more or less current may pass through each sensor. Other photoconductive materials may be used in the sensor, such as: indium arsenide, mercury telluride, cadmium mercury telluride, lead telluride, gallium arsenide, aluminum arsenide, aluminum nitride, aluminum phosphide, boron nitride, boron phosphide, boron arsenide, gallium antimonide, gallium nitride, gallium phosphide, indium phosphide, cadmium zinc telluride, and alloys and/or mixes of the above. Indium antimonide sensors and sensors other of semi-conductive sensor arrays are known in the art and disclosed in U.S. Pat. No. 7,026,602 to Dausch, U.S. Pat. No. 5,580,795 to Schimert, U.S. Pat. No. 8,324,660 to Lochtefeld, U.S. Pat. No. 7,864,326 to Cox, and U.S. Pat. No. 8,809,106 to Cheng. 
         [0044]    The sensor unit  86  may be embedded in the strap so that the sensing array  74  lies directly on the skin of the user. In a preferred embodiment, in order to reduce interference on the array from dead skin cells, dirt, sweat, or other matter, the sensor array  74  may be slightly recessed from the surface of upper wristband  10  so that the sensor array  74  in not direct contact with the user&#39;s skin when the wristband  10  is wrapped around the user&#39;s wrist  116 . 
         [0045]    Since the glucose measurement device is wearable, this enables a user to be immediately alerted to dangerously high or low levels of glucose. Alerts may be accomplished using a variety of methods. The alert may be an audible alarm on the device that signals the user to dangerously high or low glucose levels. The glucose measurements may be shown to the user on a display  94  (such as the face of a wristwatch) and may also be transmitted to a third party, wirelessly via blue-tooth, RF, 3G, 4G, Wi-Fi other known wireless technology. 
         [0046]    In a preferred embodiment there are features of the device that prevent outside ambient light from exciting the sensor array  74 , which would cause the sensor&#39;s photoconductivity to spike, essentially blotting out the desired reading from the sensor array  74 . A set of darkening tracks, which may be in the form of a gasket  100 , trace the edges of the wristband  10 , as illustrated in  FIG. 6 . The gasket  100  may be made from a microfiber wrapped around a core of neoprene or similar material that has a hollow air channel in its center, which allows air to inflate within the gasket  100  and the air pressure is used to tighten or loosen the wristband  10  against the user&#39;s wrist. The gasket  100  is connected to piping that is connected to a small pump that pumps air into the gasket  100 . Air may be pumped into the gasket material itself, or in some embodiments the gasket  100  is in the form of a closed hollow rectangular, circular, or doughnut shape where air can be pumped inside of the hollow region. The gasket  100  prevents air from leaking out from the edges of the wristband  100  due to the airtight features of the gasket material and wristband  10  material against the user&#39;s skin. In another embodiment, water may be pumped in the piping instead of air, which has the added benefit of eliminating interference from any environmental terahertz radiation. The gasket feature is preferable to traditional clinching because of the need for symmetrical positioning of the emitter array and the sensor array. Inflatable technologies have been used in other devices to measure pulse, such as the pump band disclosed in U.S. Pat. No. 5,509,423 to Bryars and physiological sensing device in U.S. Pat. No. 6,491,647 to Bridger. Before the measuring device takes a glucose reading, ambient light should be below a threshold so that the essential reading is not blotted out by the presence of excessive ambient light. 
         [0047]    The power to pump air into the gasket  100 , and power the device in general, may be through an integrated cable through which the unit may be charged and also charge a pair of miniaturized air pumps. By pumping air into the gasket, not only is ambient light preventing from contacting the sensor  74 , but the emitter  68  and sensor  74  are stabilized into a more fixed position on the user&#39;s wrist, which provides for more accurate readings. 
         [0048]    The device as a whole is preferably powered by a lithium ion battery  110  or similar battery, which can be recharged via the built-in USB connection  96  in the same manner as a smart phone. The device preferably may be charged while fully assembled, and may also be charged by connecting the device to a wall outlet. The engine  20  of the device may also connect to a charger separately. 
         [0049]    The display  94  of the engine  20  can be a LED or LCD display similarly found on any digital watch. The display  94  would also have a three-digit area to display blood glucose levels. Other areas could display measurements of other physiological parameters (such as other analytes, body temperature, blood pressure, etc.). The display  94  may have ancillary functions as desired, and may be a touchscreen display controlled by an operating system. The screen can also serve as an interface for calibrating the watch, setting up readings, reporting frequencies, and tuning the QCL to detect other analytes besides glucose. Multiple wireless communication options (Bluetooth, Wi-Fi, 3G, 4G, 5G, LTE, RF radio, etc.) could be embedded within device to wirelessly transmit the recorded physiological parameters from the device to another user via a transmitting module  107 . The device may be equipped with components so that data can be sent by SMS/MMS, send information to a calendar/messenger, or send alerts/conventional alarms. As the final readings take very little storage space, the device can potential archive years of data onboard, however, a back up is preferred. 
         [0050]    The device may have an embedded system on a chip (SoC)  108  such as an A8 chip, or similar chip known in the art. It may include a microcontroller, a microprocessor, a DSP core, memory blocks (ROM, RAM  112 , flash memory), and interfaces for USB, Firewire, or Ethernet. Preferably, there is at least 2 GB of RAM. Preferably there is a separate module to tune the QCL&#39;s frequency tuning mechanisms such as those disclosed by Lu et al. in “Widely-tuned room-temperature terahertz quantum cascade laser sources” SPIE Proceedings, Vol. 8631, p. 863108-1, Photonics West, San Francisco, Calif., by Lu et al. (Feb. 3, 2013), and “Widely tuned room temperature terahertz quantum cascade laser sources based on difference-frequency generation” in Applied Physics Letters, Vol. 101, No. 25, p. 251121-1 (Dec. 17, 2012). 
         [0051]      FIG. 5  illustrates a cross-sectional view of the device on a user&#39;s wrist. The wrist comprises various bones  104 , and soft tissue  106 , which may includes blood, adipose, and adipose. The emitting array  68  is aligned with the sensing array  74  on the opposite side of the user&#39;s wrist  102 . When the arrays  68 ,  74  are aligned, the device can detect the amount of glucose or other analyte by detecting the absorption of terahertz radiation at specific frequencies emitted from the emitting array  68  and detected by the sensor  74 . In another embodiment, instead of a single emitting array  68  and sensor array  70 , the device may have several emitting and sensor arrays interspersed along the wristband  10 . This may have the added benefit of obtaining more readings and it would not limit the terahertz beams from necessarily having to traverse the entirety of the wrist, but instead the sensor may measure reflected excitation of terahertz radiation from organic molecules, instead of measuring transmitted radiation. In some embodiments the sensor cells may be arranged in a pattern of tessellated hexagons approximately 1 mm in diameter with terahertz fiber optic emission points threaded trough vertices. This would allow the individual sensors  76  to measure the interactions of the terahertz radiation at the sub-dermal layer without the need to transverse the full thickness of the wrist. 
         [0052]    In order to prevent compromised readings the device may be equipped with one or more than one of an accelerometer  103 , gyroscope and level  105 . Since motion and orientation of the emitter and sensor may affect readings, the device should detect levelness and stillness within a certain predetermined tolerance before taking a glucose measurement. These additional detection hardware components of the device are operative connected to the processing unit and known generally in the art such as the accelerometer, gyroscope and level disclosed in U.S. Pat. No. 8,075,499 by Nathan et al., and U.S. Patent Application Pub. No. 20060212097 to Varadan et al. 
         [0053]    The internal software and/or firmware of the device would include code having the ability to save and recall data, view at-a-glance glucose measurements in real-time (highs and lows), alarms for meals or snacks, easy-to-read recommendations, arrows showing trends of the user&#39;s blood glucose levels, scroll-though graphs for patterns of the user&#39;s blood glucose level, customizable predictive alerts for oncoming highs and lows by flashing icons or audible alarms (even if the device is set to a vibrate only mode), telecommunication updates, emergency related information, automated 911 calling, and the like. The device may also be connected to cell phones and could be activated by voice command, such as through Apple&#39;s Siri® or other voice recognition software. Additional features would include some standard features found in other watches or cell phones, such as time, day, date, a calendar, battery life, satellite location, weight, body temperature, climate, weather, atmospheric pressure, various languages the watch could display or understand, and control of brightness. 
       Method 
     Sampling Process and Algorithmic Processing 
       [0054]    The device described above has the ability to accurately detect and measure glucose and other substances by using an algorithm that sorts, compares, and derives a measurement from samples. Preferable, the emitter unit  84  sends pulses to the sensing unit  86  at 30 terahertz pulses per second if the sensing array  68  is sufficiently still and dark. 
         [0055]    In one embodiment of the method, the device only detects analytes if the following conditions are met: 1) the sensor unit  86  must read a light pollution at or near zero (i.e. below a certain threshold), 2) the orientation of the sensor unit  86  is level or perpendicular, or within a certain threshold angle (such as within five degrees or less of the horizontal or perpendicular plane of the device), and 3) the accelerometer detects motion below a certain latent threshold. 
         [0056]    If the above conditions are met, the quantum cascade laser  60  emits a pulse at or approximately the resonant frequency of the analyte to be detected. In a preferred embodiment, the quantum cascade laser  60  emits a pulse at or approximately 1.4 terahertz, per the resonant frequency of glucose. (See “Far-infrared vibrational models of polycrystalline saccharides” by Upadhya et al, Vibrational Spectroscopy 35.1 (2004): 129-143, for resonant frequencies of various saccharides such as glucose, mannose, galactose, fructose, maltose, lactose, which could also be detected using the same device and methods). 
         [0057]    As the terahertz waves pass through the tissue of the user, analytes absorb some energy from the terahertz waves but allows some energy to pass through the wrist  116 , The terahertz waves that pass through the tissue excite the individual indium antimonide sensors  76  on the sensor array  74 . Depending on the excitation level of the individual sensors  76 , the composition of the sensor becomes conductive. The excitation jump of specific molecules known to be excited at a specific resonant frequency will cause each individual sensor  76  paired with the emitting cell  70  on the emitting array  68  to allow a certain amount of voltage through, which is communicated to the CPU  108  or other type of logic chip or system on a chip. The measuring of the voltages of each individual sensor  76  can then be synthesized into a graph (preferably 14×25 2d graph) of voltages, which shows their positions, and how close the resonant frequency of the substance being sought is. By measuring the voltage of individual sensors  76 , the frequency energy received by a given sensor  76  from its paired emitter  70  can be deduced, and from this, the values of the concentration of the analytes can be deduced. 
       Calibration 
       [0058]    The user calibrates the device by holding the device perpendicular so that the device can detect the presence and positioning of wrist bones  104 , tendons, etc., and can account for their respective attenuation tendencies.  FIG. 5  illustrates the device wrapped around a user&#39;s wrist. Initial detection is performed by the quantum cascade laser  60  sweeping through a range of known body tissue frequencies to assess tissue makeup and construct a plethysmographic map of body structures. This map construction may take between three and five seconds. The onboard RAM  112  of the device stores a database of similar body topographies (along with attendant traditional baseline readings for glucose and/or other analytes to be detected). A cluster of topographies that are most similar to the user&#39;s will be saved from this initial plethysmographic scan. The database of similar body topographies (with attendant traditional baseline readings) as used in the previous phase will then be used for comparison of individual terahertz pulses to determine if any of the pulses are compromised on any given individual sensor  76 . Sensors with the least obstructed, highest fidelity reception of the terahertz pulse, per the body topography map, are given priority, while sensors showing interference are given a lower priority due to low fidelity of the measured signal. 
         [0059]    To establish a preliminary reading of the analyte, measurements of individual cells of the sensors showing the highest fidelity are added. Sensor cells not having the highest fidelity, in order of the algorithm&#39;s confidence in their usefulness, are compared to known instances of that same preliminary reading and its attendant outliers. A combined measurement using both the highest fidelity and lower fidelity sensor cell  76  readings are added, leading to either a higher or lower measurement of the analyte. 
         [0060]    In other embodiments, the QCL may perform a broader and deeper sweep through frequencies associated with the analyte being sought. This allows the device to calculate the presence of a sought analyte from near misses, reflections, refractions, and other similar interference noise, in addition to the obvious resonant jumps in excitation. A control library of common yields from such sweeps and their attendant patterns will be stored in the onboard memory of the device will work in conjunction with the plethysmograph created at initial calibration. 
       Alignment Offset Parsing Phase 
       [0061]    Although the user will align the emitting array  68  with the sensor array  74  across their wrist or other body part, an exact alignment may not be possible. To mathematically pair each photo-conductive sensor  76  with the proper emitting sensor  70 , the sensing unit  84  will determine the positioning of the emitting array  68  relative to the sensor array  74 . This is accomplished by determining the x-position of the furthest edges of the sensor array  68  and measuring which photo-conductive sensors  76  are activated by beams from the QCL  60  (within a specified margin of error). Photo-conductive sensors  76  that are inactive for this sampling cycle and will store that cell count as a potential margin of error and compare subsequent sampling cycles to it until the watch is taken off. The positional offset of the emitter array  68  with the sensor array  70  will likely be offset by a different amount each time the user places the device on him or herself owing to differences in both the user&#39;s body and the variable sin exact positioning/angles/tightness of the band. 
       Aggregation of the Sensor Readings 
       [0062]    Sensors receiving the highest fidelity terahertz pulses are weighted in order of the algorithm&#39;s confidence and outlier readings from sensors having the least fidelity are compared to past distributions of outliers received from a set of measurements with a similar preliminary reading. This aggregation is performed because anatomical parts (e.g. a wrist) are not homogenous and the nature of determining topography with multiple terahertz pulses requires that several readings of terahertz pulses should be combined to form a reliable plethysmograph. Readings from the outliers are stored for the following step of the aggregation of signals. Certain outlier patterns will be given more weight, depending on the plethysmograph and how it compares to the outlying signals received in similar cases from the onboard database. Other outliers will be discarded from analysis as relegated to interference noise relative to the signal represented by the range of the composite. Based on the aggregation, the net reading will be adjusted higher or lower, depending on which weighting of the two readings is used and comparing the user to the stored cluster most similar to the user. 
       Final Output 
       [0063]    The net readings are averaged and compared to the device&#39;s library of known readings. The filtered outlier set is averaged and added to the average net readings. The result yields a compositional and volumetric analyte reading, which is extrapolated to account for the user&#39;s body volume/composition and saved in the memory of the device. The analyte measurement may be displayed on the screen of the device or transmitted to one or more than one other device such as device that a parent, guardian, physician, or emergency responder might have. The final output may be transmitted wirelessly via a transmitting module connected to the processing unit, logic chip, or system on a chip  108 . 
       Adaptability to Monitor Other Organic Molecules 
       [0064]    Most organic molecules are structured in such a way that they resonate somewhere in the terahertz spectrum. A Quantum Cascade Laser can be tuned to any of the respective resonant frequencies of an organic molecule. The same algorithm used to calculate glucose may be used to determine the concentration of other analytes in blood using essentially the same algorithm described. Further embodiments of the method and devices include detecting multiple organic compounds simultaneously during the same reading. For example, glucose and ethanol would be a useful combination of analytes to be measured simultaneously.