Abstract:
A biometric sensor that measures biometric information and a biometric analysis system including the biometric sensor are provided. The biometric sensor may include: a light source configured to emit light toward a region of interest of an object under examination, the light being diffused at the region of interest; a collimator that includes a though-hole and is configured to collimate the diffused light received from the region of interest; and a spectrometer configure to analyze the diffused light transmitted by the collimator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from Korean Patent Application No. 10-2015-0029203, filed on Mar. 2, 2015 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Apparatuses and methods consistent with exemplary relate to biometric sensors and biometric analysis systems including the same, and more particularly, to biometric sensors detecting light that is reflected from an object under examination after being incident thereto and biometric analysis systems for analyzing information obtained from the biometric sensors. 
         [0004]    2. Description of the Related Art 
         [0005]    Due to technical developments, near-infrared spectrometers and Raman spectrometers have become smaller. In the related art, measurement of biometric information may be restricted to certain regions of a human body under examination. However, small-sized near-infrared spectrometers and Raman spectrometers may allow biometric information to be measured from various body parts. 
         [0006]    In order to obtain biometric information from an object under examination, light may be emitted onto the object so that the emitted light is reflected from the object, and biometric information is obtained from the reflected light. The light that includes biometric information may be diffused in all directions, and in a process of inputting the light that includes biometric information, light loss may be accompanied. Thus, in order to obtain a high efficiency spectrum and to increase a signal-to-noise ratio, there may be a need for minimizing loss of diffused light. For example, when Raman spectroscopy is used, since frequency of photons includes biometric information, it may be important to reduce loss of light caused by diffusion. 
       SUMMARY 
       [0007]    Exemplary embodiments address at least the above problems and/or disadvantages and other disadvantages not described above. Also, the exemplary embodiments are not required to overcome the disadvantages described above, and may not overcome any of the problems described above. 
         [0008]    One or more exemplary embodiments provide biometric sensors that transmit diffused light that includes biometric information to a spectrometer with reduced light loss. 
         [0009]    Further, one or more exemplary embodiments provide biometric analysis systems that include the biometric sensors. 
         [0010]    According to an aspect of an exemplary embodiment, there is provided a biometric sensor including: a light source configured to emit light toward a region of interest of an object under examination, the light being diffused at the region of interest; a collimator that comprises a though-hole and is configured to collimate the diffused light received via the through-hole; and a spectrometer configured to analyze the diffused light transmitted by the collimator. 
         [0011]    The biometric sensor may further include a focus lens configured to control a focal distance of the emitted light. 
         [0012]    The emitted light may have a wavelength in a range from about 0.7 μm to about 2.5 μm. 
         [0013]    The emitted light may be focused on the through-hole of the collimator by the focus lens. 
         [0014]    The biometric sensor may further include an optical path converter configured to control an optical path of the emitted light. 
         [0015]    The collimator may include an opening via which the emitted light is incident on the region of interest. 
         [0016]    The collimator may be a compound parabolic concentrator (CPC) type collimator. 
         [0017]    According to an aspect of another exemplary embodiment, there is provided a biometric analysis system including: a light source configured to emit light toward a region of interest of an object under examination, the light being diffused at the region of interest; a collimator that includes a through-hole and is configured to collimate the diffused light received via the through-hole; a spectrometer configured to analyze the diffused light transmitted by the collimator; and a controller configured to analyze biometric information of the object obtained from the analyzed diffused light. 
         [0018]    The controller may include: a signal processor configured to analyze the biometric information of the object based on a signal provided to the controller by the spectrometer; and a user interface configured to communicate with the signal processor. 
         [0019]    The user interface may include: an input unit configured to input a command during an analysis of the biometric information and a display configured to display a result of the analysis of the biometric information. 
         [0020]    The biometric analysis system may further include a storage configured to store the analyzed biometric information. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The above and/or other aspects will be more apparent by describing certain exemplary embodiments, with reference to the accompanying drawings, in which: 
           [0022]      FIG. 1  illustrates a biometric analysis system according to an exemplary embodiment; 
           [0023]      FIG. 2  is schematic view of a biometric sensor of a biometric analysis system according to an exemplary embodiment; 
           [0024]      FIG. 3  is a schematic view of a biometric sensor according to another exemplary embodiment; 
           [0025]      FIG. 4  is a schematic view of a biometric sensor according to another exemplary embodiment; 
           [0026]      FIG. 5  is a cross-sectional view of a structure that includes an optical sensor according to an exemplary embodiment; and 
           [0027]      FIG. 6  is a flow chart illustrating a method of biometric analysis by using a biometric analysis system according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Exemplary embodiments are described in greater detail below with reference to the accompanying drawings. 
         [0029]    In the following description, like drawing reference numerals are used for like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the exemplary embodiments. However, it is apparent that the exemplary embodiments can be practiced without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the description with unnecessary detail. 
         [0030]    In describing layer structures, when an element or layer is referred to as being “on” another element or layer, the element or layer may be directly on another element or layer or intervening elements or layers. 
         [0031]      FIG. 1  illustrates a biometric analysis system  100  according to an exemplary embodiment. 
         [0032]    Referring to  FIG. 1 , the biometric analysis system  100  may include a biometric sensor  11  and a control unit (e.g., controller)  14 . The biometric sensor  11  may emit light L 11  onto a region A 1  of interest of an object  10  under examination and acquire diffused light L 12  that is reflected from the region A 1  of interest. The control unit  14  may analyze biometric information of the object  10  by using the diffused light L 12  obtained from the biometric sensor  11 . The biometric sensor  11  may include a light source unit (e.g., light source)  12  that emits the light L 11  to the object  10  and a spectrometer  13  that measures the diffused light L 12  generated from the region A 1  of interest. The control unit  14  may include a signal processing unit (e.g., signal processor)  15  and a user interface  16 . Also, the biometric analysis system  100  may further include a storage unit (e.g., storage or memory)  18  that stores the biometric information of the object  10  that is processed in the signal processing unit  15 . 
         [0033]    The biometric sensor  11  used in the biometric analysis system  100  according to an exemplary embodiment is a non-invasive biometric sensor and may include the light source unit  12  and the spectrometer  13 , which will be described in detail below. The light L 11  may be emitted from the light source unit  12  of the biometric sensor  11  onto the region A 1  of interest of the object  10 . The type of the light L 11  may be selected in connection with biometric information to be obtained from the object  10  under examination. For example, the light source unit  12  may emit light of near infrared region having a wavelength in a range from about 0.7 μm to about 2.5 μm. A light source used in the light source unit  12  may include a light emitted diode (LED) or a laser diode. 
         [0034]    The light L 11  may collide with a surface and internal molecular structure of the object  10  under examination, and may become a diffused light L 12 , a wavelength of which is changed when the diffused light L 12  is re-emitted after being absorbed in the molecular structure. The diffused light L 12  may include various spectrums due to different degrees of wavelength transformation according to the state of molecules that constitute the region A 1  of interest of the object  10 . Accordingly, the diffused light L 12  emitted from the region A 1  of interest may include biometric information of the region A 1  of interest, and thus, biometric information (e.g., blood glucose contents) may be obtained by analyzing the diffused light L 12 . 
         [0035]    The light L 12  may be diffused in all directions, and thus, in order to correctly detect the biometric information of the object  10 , the diffused light L 12  may be required to be transmitted to the spectrometer  13  with minimum loss. Accordingly, a collimator may be included in the biometric sensor  11  to collimate the direction of the diffused light L 12  reflected from the object  10  in a constant direction towards the spectrometer  13 . An optical reflection material layer to reflect the diffused light L 12  towards the spectrometer  13  may be formed in the collimator, and the optical reflection material layer may have a compound parabolic concentrator (CPC) shape. The biometric sensor  11  according to an exemplary embodiment employs an optical system structure by which the light L 11  is emitted onto the region A 1  of interest and the diffused light L 12  reflected from the region A 1  of interest may be input to the spectrometer  13 . 
         [0036]      FIG. 2  is schematic view of the biometric sensor  11  of a biometric analysis system according to an exemplary embodiment. 
         [0037]    Referring to  FIG. 2 , the biometric sensor  11  may include a light source  22  that emits light L 21  onto a region A 2  of interest of the object  20  under examination and a collimator  26  that causes a travel direction of diffused light L 22  to be aligned in a certain direction. 
         [0038]    The light source  22  may emit light in a near infrared region having a wavelength in a range from about 0.7 μm to about 2.5 μm, and may include an LED or a laser diode. The travel direction of the diffused light L 22  may be collimated in a constant direction by the collimator  26 . An opening for exposing the region A 2  of interest of the object  20  may be formed on a region of the collimator  26 . A focusing element  24  may be disposed on an optical path via which the light L 21  emitted from the light source  22  is emitted onto the region A 2  of interest of the object  20  under examination that is exposed through the region of the collimator  26 . The focusing element  24  may be, for example, a focus lens. The light L 21  emitted from the light source  22  may be incident onto the region A 2  of interest through an appropriate focal distance control by the focusing element  24 . A window (e.g., through-hole)  28  may be formed on a side of the collimator  26  on the optical path of the light L 21  so that the light L 21  reaches the region A 2  of interest. The light L 21  emitted from the light source  22  may be focused on the window  28  of the collimator  26  by the focusing element  24 . 
         [0039]    In this manner, since the focusing element  24  and the window  28  are formed on the optical path, the light L 21  emitted from the light source  22  may be incident onto the entire region A 2  of interest, and thus, a maximum irradiation region may be ensured. Also, an excessive exposure of the region A 2  of interest to the light L 21  may be prevented by adjusting the light L 21  emitted to the region A 2  of interest. Accordingly, an optical loss may be prevented, high efficiency spectrums may be ensured, and a signal-to-noise ratio may be improved during a biometric information analysis. The light L 21  emitted onto the region A 2  of interest may collide with a surface and internal molecular structure, and may be emitted as a diffused light L 22 , a wavelength of which is changed when the diffused light L 22  is re-emitted after being absorbed in the molecular structure. The emitted diffused light L 22  may be collimated in a constant direction, for example, towards the spectrometer  13  of  FIG. 1  by the collimator  26 . 
         [0040]      FIG. 3  is a schematic view of a biometric sensor according to another exemplary embodiment. 
         [0041]    Referring to  FIG. 3 , a light source of the biometric sensor according to the current exemplary embodiment may include a light source  32  that emits light L 31  onto a region A 3  of interest of an object  30  under examination and a focusing element  34  that is formed on an optical path between the region A 3  of interest and the light source  32 . The biometric sensor may include a collimator  36  that adjust a travel direction of diffused light L 32  reflected from the object  30  to be aligned with a spectrometer. For example, the collimator  36  may cause the travel direction of the diffused light L 32  to be parallel to a lengthwise direction of the collimator  36 . A region of the collimator  36  may be opened to expose the region A 3  of interest to the outside. A window  38  may be formed on a side of the collimator  36  on the optical path via which the light L 31  emitted from the light source  32  is incident onto the region A 3  of interest. 
         [0042]    The light L 31  emitted from the light source  32  may be focused on the window  38  of the collimator  36  by the focusing element  34 . The window  38  may be an opening or a through-hole placed on a side of the collimator  36 , and may be a region on which the light L 31  emitted from the light source  32  is focused. A width of the window  38  may be appropriately controlled and is not specifically limited. In comparison to the optical sensor of  FIG. 2 , in the optical sensor of  FIG. 3 , an incidence angle of the light L 31  is almost 90° with respect to the region A 3  of interest. In this manner, the optical sensor according to the current exemplary embodiment may emit the light L 31  with various incidence angles to the region A 3  of interest, and an optical irradiation region and optical density with respect to the object  30  may be controlled. 
         [0043]      FIG. 4  is a schematic view of a biometric sensor according to another exemplary embodiment. 
         [0044]    Referring to  FIG. 4 , a biometric sensor according to the current exemplary embodiment may include a light source unit that includes a light source  42  that emits light L 41  onto an region A 4  of interest of the object  40  under examination and a focusing element  44  formed on an optical path between the light source  42  and the region A 4  of interest. The optical path between the light source  42  and the region A 4  of interest may be variously controlled. In order to control the optical path, the biometric sensor according to the current exemplary embodiment may further include an optical path converter  45 . In  FIG. 4 , as an example, the optical path converter  45  has a prism type. However, the optical path converter  45  may be a mirror having a flat panel type or a beam splitter. 
         [0045]    The biometric sensor may include a collimator  46  that induces the travel direction of diffused light L 42  towards a spectrometer  400 . A region of the collimator  46  may be opened to expose the region A 4  of interest. A window  48  may be formed on a side of the collimator  46  via which light, an optical path of which is changed by the optical path converter  45  after being emitted from the light source  42 , is incident onto the region A 4  of interest passing through the collimator  46 . The window  48  may be a region on which the light L 41  emitted from the light source  42  is focused. A width of the window  48  may be appropriately controlled, and is not specifically limited. An angle θ between the collimator  46  and a surface may be appropriately controlled to readily collimate the diffused light L 42  emitted from the region A 4  of interest to the spectrometer  400 , and the angle θ is not specifically limited. 
         [0046]    As described above, in the optical sensor according to the current exemplary embodiment, the optical path of the light L 41  emitted from the light source  42  may be converted by the optical path converter  45  to have various optical paths. Also, the light L 41  may be emitted onto the region A 4  of interest with various angles, and the control of an optical irradiation region and an optical density with respect to the object  40  under examination may be possible. 
         [0047]      FIG. 5  is a cross-sectional view of a structure that includes an optical sensor according to an exemplary embodiment. The structure of  FIG. 5  includes the biometric sensor of  FIG. 4 . 
         [0048]    Referring to  FIG. 5 , the structure may include a housing  500  and a light source  52  that emits light and a focusing element  54  located on an optical path of the light emitted from the light source  52  that are located within the housing  500 . The housing  500  may also include an optical path converter  55  that may change an optical path of the light emitted from the light source  52 . Here, a light source unit may include the light source  52 , the focusing element  54 , and the optical path converter  55 . 
         [0049]    A collimator  56  may be formed on a region of the housing  500 . An opening  51  may be formed on a region of the collimator  56  and the housing  500 . The opening  51  may be located on a region of interest of an object under examination. A window  58  may be formed on a side of the collimator  56  via which light emitted from the light source  52  enters the opening  51 . A spectrometer  59  at which diffused light emitted from the collimator  56  is collimated and focused may be formed on an edge of the collimator  56 . 
         [0050]    The housing  500  that surrounds the biometric sensor may be formed of various materials, for example, flexible materials. Also, the housing  500  may be formed of a material that blocks external light. The biometric sensor may be a wearable device to be worn on the object  10  under examination, for example, may be a bracelet type device that can be worn on a wrist. At this point, all of the constituent elements of the biometric analysis system  100  as depicted in  FIG. 1  may be included in the wearable device. Also, optionally, only the structure of the light source unit  12  may be mounted in the wearable device and a signal of the diffused light L 12  measured by the spectrometer  13  may be transmitted to an external device. Also, the light source unit  12  may be implemented as a wearable device and the control unit  14  may be embodied separately from the wearable device. 
         [0051]      FIG. 6  is a flow chart illustrating a method of biometric analysis by using a biometric analysis system according to an exemplary embodiment. 
         [0052]    Referring to  FIGS. 1 and 6 , the region A 2  of interest of the object  20  under examination may be determined to obtain biometric information from the region A 2  (operation S 1 ). For example, in order to measure a blood glucose content of a human body, a wrist portion may be designated as a region of interest. The light L 21  is emitted onto the region A 2  of interest from a light source of the light source unit  12  (operation S 2 ). While the region A 2  of interest is in contact with a boundary of an opening of a collimator, a laser light in a region of near infrared having a wavelength in a range from about 0.7 μm to about 2.5 μm may be emitted onto the region A 2  of interest from the light source unit  12 . When the light L 21  is incident onto the region A 2  of interest, diffused light L 12  that includes biometric information of the region A 2  of interest may be emitted from the region A 2  of interest. The diffused light L 12  is collimated by a collimator and is detected by the spectrometer  13  (operation S 3 ). 
         [0053]    The diffused light L 12  detected by the spectrometer  13  is transmitted to the control unit  14  where biometric information or biometric signal of the region A 2  of interest is analyzed (operation S 4 ). The control unit  14  may include a signal processing unit  15  that analyzes the biometric information of the object  10  under examination from the signal that is generated from the diffused light L 12  and is measured by the spectrometer  13 . The signal processing unit  15  may be driven by a microprocessor. The signal processing unit  15  may analyze properties of the object  10  under examination by using the Raman Spectroscopy or a method of analyzing a near infrared ray absorption spectrum. When the light L 21  is emitted into the object  10  under examination, the light L 21  is diffused in various directions after colliding with atoms or molecules in the object  10  under examination. The Raman Spectroscopy uses the diffusion, in particular, inelastic scattering of the light L 21  in various directions. Here, inelastic scattering denotes the emission of light after being absorbed by the atoms or molecules as opposed to merely a simple reflection at surfaces of atoms or molecules. The diffused light L 12  emitted from the object  10  under examination may have a relatively longer wavelength than that of the incident light L 21 , and a wavelength difference between the light L 21  and the diffused light L 12  may be approximately below 200 nm. Various properties, such as vibration of molecules and a structure of molecules in the object  10  under examination may be detected by analyzing a spectrum of the diffused light L 12 . The control unit  14  may further include the user interface  16 , and the user interface  16  may further include an input unit through which various commands are inputted in a process of analyzing biometric information and a display unit on which a biometric analyzing process and the result are visually displayed. 
         [0054]    Next, the analysis result of the biometric information of the object  10  under examination may be stored in the storage unit  18  by the control unit  14 . Optionally, after analyzing the biometric information of the object  10  under examination by the control unit  14 , a process for comparing the measured biometric information with biometric information of the object  10  under examination stored in advance may be performed. The results of the comparison and evaluation may be restored in the storage unit  18 . 
         [0055]    The biometric sensor according to an exemplary embodiment may prevent an optical loss of diffused light that is emitted from an object under examination after emitting the light from a light source onto a region of interest of the object under examination. 
         [0056]    Since a focusing element and a window are formed on an optical path of light that is emitted from a light source onto an object under examination, a required irradiation region may be ensured and an excessive exposure to light may be prevented. 
         [0057]    Also, a high efficiency spectrum may be ensured and a signal-to-noise ratio may be improved. 
         [0058]    The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting. The present teaching can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.