Abstract:
A flexible sensing apparatus for soft and curving objects which can sense vital signals of the specified object and convert reflected signals into electrical signals. The flexible sensing apparatus includes a transmitting layer, a readout layer, and a receiving layer, arranged in that order. The transmitting layer generates ultrasonic waves. The receiving layer receives reflected ultrasonic waves and converts them into localized electric charges. The readout layer converts the localized electric charges into electrical signals to represent detected vital signs. The receiving layer is adjacent to the specified object, and the transmitting layer faces away from the specified object. The readout layer comprises a flexible thin film transistor (TFT) array. The flexible TFT array converts the localized electric charges generated by different positions of the third conductive structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Patent Application No. 201610593605.5 filed on Jun. 26, 2016, the contents of which are incorporated by reference herein. 
       FIELD 
       [0002]    The subject matter herein generally relates to a flexible sensing apparatus, especially to an ultrasonic sensing patch. 
       BACKGROUND 
       [0003]    Sensing apparatuses are widely used. Reflective type apparatus typically cooperates with a mobile phone or a watch to sense heart rates. A complementary metal-oxide-semiconductor (CMOS) sensor is used in the reflective type sensing apparatus for detecting heart rates. The CMOS sensor senses a light intensity difference based on a vasoconstriction, and transmits an output signal. The output signal of the CMOS sensor is calculated by a method of photo plethsmography (PPG) to obtain heart rates. However, the sensing apparatus is large in size, and adhesion of the sensing apparatus is poor. Thus, there is room for improvement in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0004]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0005]      FIG. 1  is an isometric view of a first exemplary embodiment of a flexible sensing apparatus, the flexible sensing apparatus comprising a readout layer. 
           [0006]      FIG. 2  is a planar view of the readout layer of  FIG. 1 . 
           [0007]      FIG. 3  is an isometric view of the flexible sensing apparatus applied to a specified object. 
           [0008]      FIG. 4  is an isometric view of a second exemplary embodiment of a flexible sensing apparatus, the flexible sensing apparatus comprising a readout layer. 
           [0009]      FIG. 5  is a planar view of the readout layer of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that the exemplary embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features. The description is not to be considered as limiting the scope of the exemplary embodiments described herein. 
         [0011]    The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the specified object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series, and the like. 
         [0012]    The present disclosure is described in relation to a flexible sensing apparatus, which may cooperate with other apparatus for detecting physiological parameters of specified objects. The specified object may be humans or animals. The flexible sensing apparatus may generate sensing signals. The flexible sensing apparatus may be integrated with the other apparatus, or used separately. The other apparatus may be, but is not limited to, a mobile device, a watch, a computer device, or any other apparatus which is capable of processing the sensing signals and generating a viewable result. 
         [0013]      FIG. 1  illustrates a first exemplary embodiment of a flexible sensing apparatus  100  applied on a curved surface or a rough surface. The flexible sensing apparatus  100  senses vital signs related to blood, for example, a heart rate, a pulse, a blood pressure, and so on. The flexible sensing apparatus  100  generates ultrasonic waves, receives the ultrasonic waves reflected by the specified object, and generates electrical signals representing the vital signs. In at least one exemplary embodiment, the flexible sensing apparatus  100  is a flexible sensing patch. 
         [0014]    The flexible sensing apparatus  100  includes a transmitting layer  110 , a receiving layer  120 , a readout layer  130 , a first flexible circuit board  140 , a second flexible circuit board  150 , a third flexible circuit board  160 , and two adhesive layers  170 . The transmitting layer  110  generates the ultrasonic waves. The receiving layer  120  converts the ultrasonic waves reflected by the specified object into localized electric charges, and transmits the localized electric charges to the readout layer  130 . The readout layer  130  converts the localized electric charges into electrical signals and outputs to an external circuit (not shown). The first flexible circuit board  140  provides a first specified voltage to the transmitting layer  110 . The second flexible circuit board  150  provides a second specified voltage to the transmitting layer  110 . The third flexible circuit board  160  transmits data to the receiving layer  120 . One of the adhesive layers  170  is attached to the transmitting layer  110  and the second flexible circuit board  150  together, and another of the adhesive layers  170  is attached to the receiving layer  120  and the readout layer  130  together. In other exemplary embodiments, the flexible sensing apparatus  100  can include another adhesive layer for pasting the flexible sensing apparatus  100  on the specified object. 
         [0015]    The transmitting layer  110  includes a transmitting element  111 , a first conductive structure  113 , and a second conductive structure  115 . The transmitting element  111  is between the first conductive structure  113  and the second conductive structure  115 . The first conductive structure  113  is between the transmitting element  111  and the second flexible circuit board  150 . The second conductive structure  115  is between the transmitting element  111  and the first flexible circuit board  140 . The first specified voltage is applied by the first conductive structure  113 , and the second specified voltage is applied by the second conductive structure  115 , a voltage difference between the first conductive structure  113  and the second conductive structure  115  drives the transmitting element  111  to generate the ultrasonic waves. In at least one exemplary embodiment, the transmitting element  111  is made of a piezoelectric material, for example, polyvinylidene fluoride (PVDF), BaiO 3 , PbiO 3 , Pb(Zri)O 3 , plumbum scandium tantalite (PST), quartz, (Pb, Sm)iO 3 , PMN(Pb(MgNb)O 3 )—PT(PbiO 3 ), and PVDF-TrFE. In at least one exemplary embodiment, the first conductive structure  113  and the second conductive structure  115  are substantially circular or elliptical in shape. In other exemplary embodiments, the first conductive structure  113  and the second conductive structure  115  can include a plurality of sensing electrodes separated from each other. Each of the sensing electrodes can be rectangular, a wave shape, or a serrated shape, not to be limited in shape. The first conductive structure  113  and the second conductive structure  115  may be formed on a surface of the transmitting element  111  by a vacuum sputtering manner, a painting manner, or a coated manner. In at least one exemplary embodiment, opposite surfaces of the transmitting element  111  can attach to the first conductive structure  113  and the second conductive structure  115  respectively by a conductive adhesive structure. 
         [0016]    The receiving layer  120  includes a receiving element  121  and a third conductive structure  123 . The receiving element  121  is between the third conductive structure  123  and the adhesive layer  170 . The receiving element  121  can receive the ultrasonic waves reflected by the specified object. The third conductive structure  123  is between the receiving element  121  and the third flexible circuit board  160 . The receiving element  121  can convert the reflected ultrasonic waves into localized electric charges. The third conductive structure  123  may control the localized electric charges of the receiving element  121  to be transmitted to the readout layer  130 . In at least one exemplary embodiment, strength of the reflected ultrasonic waves depends on a vasoconstriction within the specified object. In at least one exemplary embodiment, the receiving element  121  is made of piezoelectric material, for example, polyvinylidene fluoride (PVDF), BaiO 3 , PbiO 3 , Pb(Zri)O 3 , plumbum scandium tantalite (PST), quartz, (Pb, Sm)iO 3 , PMN(Pb(MgNb)O 3 )—PT(PbiO 3 ), and PVDF-TrFE. In at least one exemplary embodiment, the third conductive structure  123  is a bias electrode layer, and is substantially a plane. In other exemplary embodiments, the third conductive structure  123  can include sensing electrodes separated from each other, each of the sensing electrodes can be rectangular, wave shaped, or a serrated shape, but not to be limited thereto. The third conductive structure  123  can be formed on a surface of the receiving element  121  by a vacuum sputtering manner, a painting manner, or a coated manner. In at least one exemplary embodiment, the receiving element  121  can be pasted to the third conductive structure  123  by a conductive adhesive structure. 
         [0017]    Referring to  FIG. 2 , the readout layer  130  can convert the localized electric charges transmitted by the adhesive layer  170  into electrical signals, and transmit the electrical signals to a readout circuit (not shown) for calculating a vital sign. The readout layer  130  includes a one-piece readout unit  132 . The readout unit  132  includes a flexible thin film transistor (TFT) array, which receives the localized electric charges. The readout unit  132  is substantially rectangular. In at least one exemplary embodiment, the flexible TFT array can be high temperature polycrystalline TFT (HTPS-TFT), low temperature polycrystalline TFT (LTPS-TFT), amorphous silicon TFT (a-Si-TFT), or indium gallium zinc oxide TFT (IGZO TFT). In other exemplary embodiments, the readout unit  132  can be a triangle shape, an annular shape, or a polygon shape. 
         [0018]    The first flexible circuit board  140  and the second flexible circuit board  150  are electrically connected to the first conductive structure  113  and the second conductive structure  115  respectively. The first flexible circuit board  140  provides the first specified voltage to the second conductive structure  115 , and the second flexible circuit board  150  provides the second specified voltage to the first conductive structure  113  The second specified voltage is different from the first specified voltage. The third flexible circuit  160  transmits data to the third conductive structure  123 . In at least one exemplary embodiment, the first flexible circuit board  140 , the second flexible circuit board  150 , and the third flexible circuit board  160  are insulated from each other. In other exemplary embodiments, the first flexible circuit board  140 , the second flexible circuit board  150 , and the third flexible circuit board  160  may be electrically connected, and some of the first flexible circuit board  140 , the second flexible circuit board  150 , and the third flexible circuit board  160  may be integrated. 
         [0019]    One of the adhesive layers  170  is between the third conductive layer  123  and the readout layer  130 . The adhesive layer  170  is pasted on the receiving layer  120  and on the readout layer  130 . The other adhesive layer  170  is between the first conductive structure  113  and the second flexible circuit board layer  150 . The adhesive layer  170  is pasted on first conductive structure  113  and on the second flexible circuit board layer  150 . In at least one exemplary embodiment, the adhesive layer  170  is an anisotropic conductive film. 
         [0020]    As shown in  FIG. 3 , the flexible sensing apparatus  100  is pasted or held against the specified object, such as a wrists. The voltage difference between the first conductive structure  113  and the second conductive structure  115  cause the transmitting element  111  to vibrate and generate ultrasonic waves, the ultrasonic waves pass through the receiving layer  120  and the third flexible circuit board  160  to reach the specified object. The receiving element  121  receives and converts the ultrasonic waves reflected into the localized electric charges based on the reflected ultrasonic waves. The third conductive layer  123  controls the localized electric charges to be transmitted to the readout layer by passing through the adhesive layer  170 . The strength of the ultrasonic waves depends on a vasoconstriction in the specified object. The readout layer  130  converts the localized electric charges into electrical signals transmitted by the adhesive layer  170 . The specified object may be in direct contact with the third flexible circuit board  160 , or be spaced from the third flexible circuit board  160  for a specified distance. 
         [0021]    By using flexible circuit board, flexibility and adhesion of the flexible sensing apparatus  100  are improved. 
         [0022]      FIG. 4  illustrates a second exemplary embodiment of the flexible sensing apparatus  200 . The flexible sensing apparatus  200  according to the second exemplary embodiment is approximately the same as the sensing apparatus  100 . The differences between the flexible sensing apparatus  200  and the sensing apparatus  100  are hereinafter described. 
         [0023]    The flexible sensing apparatus  200  includes a transmitting layer  210 , a receiving layer  220 , a readout layer  230 , a first flexible circuit board  240 , a second flexible circuit board  250 , a third flexible circuit board  260 , and two adhesive layers  270 . 
         [0024]    The readout layer  230  can convert the localized electric charges transmitted from the adhesive layer  270  into electrical signals, and transmit the electrical signals to an external circuit (not shown) for calculating a vital sign of the specified object. Referring to  FIG. 5 , the readout layer  230  includes a plurality of readout units  232  arranged in a matrix. The readout units  232  are driven by different signals in turn. Each of the readout units  232  includes a flexible thin film transistor (TFT) array, which receives the localized electric charges. The readout unit  232  is substantially rectangular. In at least one exemplary embodiment, the flexible TFT array can be high temperature polycrystalline TFT (HTPS-TFT), low temperature polycrystalline TFT (LTPS-TFT), amorphous silicon TFT (a-Si-TFT), or indium gallium zinc oxide TFT (IGZO TFT). In other exemplary embodiments, the readout unit  232  can be a triangle shape, an annular shape, or a polygon shape. 
         [0025]    While various exemplary and preferred exemplary embodiments have been described, the disclosure is not limited thereto. On the contrary, various modifications and similar arrangements (as would be apparent to those skilled in the art) are intended to also be covered. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.