Patent Publication Number: US-2019183365-A1

Title: Capacitive accelerometer device and sensing method thereof

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application claims the benefit of priority to Taiwan Patent Application No. 106144210, filed on Dec. 15, 2017, and Taiwan Patent Application No. 107115245, filed on May 4, 2018. The entire content of the above identified application is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to an accelerometer device, and more particularly to a capacitive accelerometer device and sensing method thereof. 
     2. Description of Related Art 
     Due to technological advancement over the years, convenient sensing devices can now partially replace large medical devices, such as sensing heartbeats with smart bracelets. In recent years, multi-functional sensing devices have become more popular, and smart watches can be used to play music and sense heartbeat. However, a general sensing device does not have a function of comparing normal values with abnormal values, which lacks applicability. 
     SUMMARY OF THE INVENTION 
     A capacitive accelerometer device is provided according to an embodiment of the present disclosure, and applied to sense an arterial acceleration pulse wave of a user. The capacitive accelerometer device includes a capacitive accelerometer module, a display device and a signal line. The capacitive accelerometer module includes one or more capacitive accelerometers. Each of the capacitive accelerometers is used to sense the arterial acceleration pulse wave of the user. The display device includes a displayer and a speaker. The displayer is used to display the arterial acceleration pulse wave of the user. The speaker emits an audible signal according to a change value of the arterial acceleration pulse wave. The display device is connected to a fixing bracket via a connector. The fixing bracket has a clasp for snapping the display device on a wrist of the user. The display device is applied to a smart bracelet, a smart phone, a desktop computer, a laptop computer, a dedicated monitor or a tablet computer. The display device automatically senses the arterial acceleration pulse wave of the user and correspondingly generates the change value. The display device generates a prompt signal when the change value is equal to or larger than a predetermined value. 
     A sensing method is provided according to another embodiment of the present disclosure, used in a capacitive accelerometer device, and applied to sense an arterial acceleration pulse wave of a user. The sensing method includes: sensing the arterial acceleration pulse wave of the user in a contact manner by one or more capacitive accelerometers included in a capacitive accelerometer module; displaying the arterial acceleration pulse wave of the user by a displayer included in a display device; and emitting an audible signal according to a change value of the arterial acceleration pulse wave by a speaker included in a display device. The display device connects to a fixing bracket via a connector. The fixing bracket has a clasp for snapping the display device on a wrist of the user. The display device is applied to a smart bracelet, a smart phone, a desktop computer, a laptop computer, a dedicated monitor or a tablet computer. The display device automatically senses the arterial acceleration pulse wave of the user and correspondingly generates the change value. The display device generates a prompt signal when the change value is equal to or larger than a predetermined value. 
     For further understanding of the instant disclosure, reference is made to the following detailed description illustrating the embodiments of the instant disclosure. The description is only for illustrating the instant disclosure, not for limiting the scope of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a block diagram of a capacitive accelerometer device depicted in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  shows a block diagram of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure. 
         FIG. 3A  is a schematic view showing an appearance of a capacitive accelerometer device depicted in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 3B  is a schematic view showing an appearance of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure. 
         FIG. 3C  is a schematic view showing an appearance of rear side of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure. 
         FIG. 3D  is a schematic view showing an appearance of a display device depicted in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 4A  is an oscilloscope diagram taken before meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 4B  is an oscilloscope diagram taken 1 hour after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 4C  is an oscilloscope diagram taken 2 hours after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 4D  is an oscilloscope diagram taken 3 hours after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 5  shows a flow chart of a sensing method in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 6A  is an oscilloscope diagram taken before jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 6B  is an oscilloscope diagram taken 4 hours after jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 6C  is an oscilloscope diagram taken 7 hours after jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is made to  FIG. 1 , which shows a block diagram of a capacitive accelerometer device depicted in accordance with an exemplary embodiment of the present disclosure. 
     The capacitive accelerometer device  100  includes a capacitive accelerometer module  110  and a display device  120 . The capacitive accelerometer device  100  is used to sense an arterial acceleration pulse wave of a radial artery, a brachial artery, a carotid artery, a subclavian artery, a foot artery or a head artery of a user. The present disclosure is not limited to the types of artery disclosed herein. The capacitive accelerometer device  100  is used to sense the user. The capacitive accelerometer module  110  includes one or more capacitive accelerometers  111 . Each of the capacitive accelerometers  111  is used to sense the arterial acceleration pulse wave of the user in a contact manner. For example, the capacitive accelerometer module  110  can sense the arterial acceleration pulse wave of the carotid artery of the user. The capacitive accelerometer module  110  can sense the arterial acceleration pulse wave of the radial artery of the user. Furthermore, the capacitive accelerometers  111  can be a condenser microphone. The condenser microphone can be an electret condenser microphone or a micro-electromechanical condenser microphone. The electret condenser microphone or the micro-electromechanical condenser microphone used by the capacitive accelerometer device  100  of the present disclosure are used to increase a sensitivity of sensing the arterial acceleration pulse wave of the user and decrease manufacturing costs. The capacitive accelerometer device  100  can be applied to a mobile device. 
     The display device  120  includes a displayer  121  and a speaker  123 . The displayer  121  is used to display the arterial acceleration pulse wave of the user. The speaker  123  emits an audible signal according to a change value of the arterial acceleration pulse wave. The display device  120  connects to a fixing bracket via a connector (not shown). The fixing bracket has a clasp for snapping the display device  120  on a wrist of the user (not shown). Furthermore, the display device  120  further includes a signal line  130 , an analog-to-digital converter (not shown) and a central processor (not shown). The display device  120  electrically connects to the capacitive accelerometer module  110  via the signal line  130 . The analog-to-digital converter connects between the capacitive accelerometer module  110  and the central processor. The analog-to-digital converter converts an analog signal of the arterial acceleration pulse wave sensed by the capacitive accelerometers  111  of the capacitive accelerometer module  110  to a digital signal of the arterial acceleration pulse wave and transmits the digital signal to the central processor. The central processor has appropriate hardware, software and firmware with a function of feature extraction for converting the detected arterial acceleration pulse waves before and after a meal, a heart rate, a heart rate variability, a respiration rate, a blood pressure, a fatigue index, etc. Furthermore, the display device further includes a button. When the user presses the button, the displayer  121  correspondingly displays the heart rate, the heart rate variability, the respiration rate, the blood pressure and the fatigue index according to the detected arterial acceleration pulse wave before and after the meal. In addition, the capacitive accelerometer  111  can connect to the capacitive accelerometer module  110  by snap-fastening to increase a flexibility in replacing the capacitive accelerometer. Since the capacitive accelerometer senses the arterial acceleration pulse wave of the user in a contact manner, and the user&#39;s skin may have small amounts of bacteria, a replaceable capacitive accelerometer can increase a cleanliness of the capacitive accelerometer device  100 . 
     The display device  120  automatically senses the arterial acceleration pulse wave of the user and correspondingly generates the change value. The display device  120  generates a prompt signal when the change value is equal to or larger than a predetermined value. For example, the display device  120  can include a communication device (not shown). When the change value of the arterial acceleration pulse wave of the user is equal to or larger than the predetermined value, the communication device of the display device  120  transmits the prompt signal to a remote electronic device through the wireless communication mode, which is suitable for the home care of a patient, and informs remote relatives or the medical team that the health condition of the patient may be abnormal. In addition, the capacitive accelerometer device  100  may also sense an arterial acceleration pulse wave of an animal. The display device  120  may be applied to a smart bracelet, a smart phone, a desktop computer, a laptop computer, a dedicated monitor or a tablet computer. 
     Reference is made to  FIG. 2 , which shows a block diagram of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure. 
     The capacitive accelerometer device  200  includes a capacitive accelerometer module  110 , a display device  120  and a signal line  130 . Furthermore, the capacitive accelerometer module  110  further includes one or more finger sleevings  213 . Each of the finger sleevings  213  is used for being sleeved on a finger of the user. 
     Reference is made to  FIG. 3A , which is a schematic view showing an appearance of a capacitive accelerometer device depicted in accordance with an exemplary embodiment of the present disclosure. 
     The capacitive accelerometer module  310   a  has a finger sleeving  313   a , a signal line  330  and a circuit board  340 . The signal line  330  electrically connects to the circuit board  340 . The finger sleeving  313   a  is sleeved on a middle finger of the user. The capacitive accelerometer (not shown) is disposed on a side of the finger sleeving. For example, the capacitive accelerometer can be disposed on the other side of a contact point of the finger sleeving  313   a  and the circuit board  340  (a back side of the circuit board  340 ). The capacitive accelerometer senses the arterial acceleration pulse wave of the user through a pulse received by the finger sleeving  313   a.    
     Reference is next made to  FIGS. 3B and 3C .  FIG. 3B  s is a schematic view showing an appearance of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure.  FIG. 3C  is a schematic view showing an appearance of rear side of a capacitive accelerometer device depicted in accordance with another exemplary embodiment of the present disclosure. 
     The capacitive accelerometer module  310   b  has a finger sleeving  313   a , a finger sleeving  313   b , a finger sleeving  313   c , a signal line  330  and a circuit board  340 . The finger sleeving  313   a , the finger sleeving  313   b  and the finger sleeving  313   c  are used for being sleeved on an index finger, a middle finger and a ring finger of the user. The capacitive accelerometers  361  are disposed on a side of the finger sleeving  313   a , the finger sleeving  313   b  and the finger sleeving  313   c  and are separated by one finger gap from each other. For example, the capacitive accelerometers can be disposed on the other side of a contact point between the finger sleeving  313   a , the finger sleeving  313   b , the finger sleeving  313   c  and the circuit board  340  (a back side of the circuit board  340 ). The capacitive accelerometers sense the arterial acceleration pulse wave of the user through a pulse received by the finger sleeving  313   a , the finger sleeving  313   b  and the finger sleeving  313   c.    
     Reference is next made to  FIG. 3D , which is a schematic view showing an appearance of a display device depicted in accordance with an exemplary embodiment of the present disclosure. 
     The display device  320  includes a displayer  321  and a speaker  323 . The displayer  321  is used to display the arterial acceleration pulse wave of the user. The speaker  323  emits an audible signal according to a change value of the arterial acceleration pulse wave. For example, the audible signal may be a 3-second short tone. The display device  320  connects to a fixing bracket  350  via a connector (not shown). The fixing bracket  350  has a clasp  351  for snapping the display device  320  on a wrist of the user. 
     Reference is made to  FIGS. 4A, 4B, 4C and 4D .  FIG. 4A  is an oscilloscope diagram taken before meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure.  FIG. 4B  is an oscilloscope diagram taken 1 hour after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure.  FIG. 4C  is an oscilloscope diagram taken 2 hours after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure.  FIG. 4D  is an oscilloscope diagram taken 3 hours after meal as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
     The oscilloscope diagram of  FIG. 4A  includes a Q wave  410   a , a R wave  420   a , a S wave  430   a , a T wave  440   a , an U wave  450   a  and a V wave  460   a.    
     The oscilloscope diagram of  FIG. 4B  includes a Q wave  410   b , a R wave  420   b , a S wave  430   b , a T wave  440   b , an U wave  450   b  and a V wave  460   b.    
     The oscilloscope diagram of  FIG. 4C  includes a Q wave  410   c , a R wave  420   c , a S wave  430   c , a T wave  440   c , an U wave  450   c  and a V wave  460   c.    
     The oscilloscope diagram of  FIG. 4D  includes a Q wave  410   d , a R wave  420   d , a S wave  430   d , a T wave  440   d , an U wave  450   d  and a V wave  460   d.    
     In a comparison between the oscilloscope diagrams before a meal and 1 hour after meal, the R wave  420   b , the S wave  430   b  and the T wave  440   b  are significantly lower than the R wave  420   a , the S wave  430   a  and the T wave  440   a . The U wave  450   b  is significantly higher than the U wave  450   a.    
     In a comparison between the oscilloscope diagrams 1 hour after meal and 2 hours after meal, the R wave  420   c , the S wave  430   c  and the T wave  440   c  are significantly higher than the R wave  420   b , the S wave  430   b  and the T wave  440   b . The U wave  450   c  is significantly lower than the U wave  450   b.    
     In a comparison between the oscilloscope diagrams 3 hours after meal and before a meal, the Q wave  410   d , the R wave  420   d , the S wave  430   d , the T wave  440   d , the U wave  450   d  and the V wave  460   d  are similar to the Q wave  410   a , the R wave  420   a , the S wave  430   a , the T wave  440   a , the U wave  450   a  and the V wave  460   a . This comparison result represents that the arterial acceleration pulse wave of the user has approached a steady state at 3 hours after meal. 
     In an embodiment of the present disclosure, the condenser microphone is used to collect sound waveforms transmitted in the air, including the main sound and all ambient noise. The condenser microphone is adhered on the skin to sense the arterial acceleration pulse wave. Based on a distance variation principle of capacitor electrodes in a capacitive accelerometer, when the active diaphragm is changed by an external force shockwave to change a gap (d) between fixed electrodes, a capacitance value C is changed, where the capacitance value C=ε*S/d, ε=dielectric constant, S=electrode plate area, d=two electrode plate gap. The capacitance value changes according to the acceleration value. The condenser microphone and the capacitive accelerometer have the same operating principle and become a vibrating capacitive accelerometer, so as to convert and obtain an acceleration pulse wave that is resistant to environmental sound interference. In addition, the condenser microphone can also be used in a smart phone, a smart bracelet, an ear-hook detection device, a headset smart glasses, etc. When the capacitive accelerometer is applied to a smart phone, the smart phone can have a jack. For example, the jack may be a headphone jack, a USB jack, a micro USB jack, a type-C jack or a charging jack. The capacitive accelerometer module is connected to the jack of the mobile device, and each of the capacitive accelerometers is used to sense and recognize the arterial acceleration pulse wave of the user in a contact manner via a built-in program in the mobile device. In addition, the capacitive accelerometer module can be built-in in the mobile device or externally connected to the jack of the mobile device. 
     In an embodiment of the present disclosure, the condenser microphone is used to sense an arterial velocity pulse wave and convert it into an acceleration pulse wave. The acceleration pulse wave includes a baseline and six waves. Deviation of six waves from baseline reflects vascular physiological status. Blood glucose rising after a meal increases a blood viscosity and a blood viscosity coefficient. According to Poiseuille&#39;s law, a blood flow resistance R is equal to (8ηΔχ)/(πr 4 ), where η=blood viscosity coefficient, Δχ=vascular unit length, π=pi, r=vascular radius. The blood flow resistance in the vascular is proportional to the blood viscosity coefficient, which causes the blood flow velocity to decrease. The six waves of the arterial acceleration pulse wave vary with blood glucose fluctuations. 
     Reference is made to  FIGS. 4A-4D , first, a pulse wave before a meal with an empty stomach is measured as the user&#39;s basic acceleration pulse wave or the user&#39;s basic blood glucose level. Next, a pulse wave 1 hour after meal is measured as an acceleration pulse wave or a blood glucose 1 hour after meal. Next, pulse waves 2 hours after meal and 3 hours after meal are measured to individually obtain acceleration pulse waves 2 hours after meal and 3 hours after meal. The deviation and recovery of the six waves and the baselines of the acceleration pulse waves before a meal, 1 hour after meal, after 2 hours meal and 3 hours after meal are compared. Usually, the waves of the acceleration pulse wave 3 hours after meal will return to the waves of the acceleration pulse wave before a meal as the blood glucose fluctuation of a person. 
     In an embodiment of the present disclosure, the capacitive accelerometer device can be used to sense a blood pressure of the user to analyze the difference by waves of a systolic phase and a diastolic phase waveform deviating from the baseline. When the blood pressure rises, the heart rate will rise by more than 20%, and the R wave will shift upward and the S wave will shift downward. 
     In an embodiment of the present disclosure, the capacitive accelerometer device can be used to sense a vascular age of the user. The Q wave represents a starting point at a beginning of a ventricular systolic phase. The R wave represents a peak value of the systolic phase. The S wave represents a cut point of a reflected wave, which may also be referred to as a reflection point of a fine artery. The T wave represents a peak value of the reflected wave at the end of the systolic phase. The U wave represents an arterial notch as the end of the ventricular systolic phase. The V wave represents a peak value of the diastolic phase, and a raised wave at a beginning of a ventricular diastolic phase is a reflected wave of aortic valve closure. The interval from the Q wave to the next Q wave is a pulse heart rate. A period from the Q wave to U wave represents the ventricular systolic phase. A period from the U wave and the next Q wave rising at a starting point of the baseline represents the ventricular diastolic phase. 
     Reference is made to  FIGS. 1 and 5 .  FIG. 5  shows a flow chart of a sensing method in accordance with an exemplary embodiment of the present disclosure. The sensing method is applied to the capacitive accelerometer device  100  and used to sense the arterial acceleration pulse wave of the user. 
     In step S 510 , one or more capacitive accelerometers  111  of the capacitive accelerometer module  110  sense the arterial acceleration pulse wave of the user in a contact manner. 
     In step S 520 , the displayer  121  of the display device  120  displays the arterial acceleration pulse wave of the user. 
     In step S 530 , the speaker  123  of the display device  120  emits the audible signal according to the change value of the arterial acceleration pulse wave. The display device  120  connects to the fixing bracket via the connector, and the fixing bracket has a clasp for snapping the display device  120  on the wrist of the user. 
     In step S 550 , the display device  120  automatically senses the arterial acceleration pulse wave of the user and correspondingly generates the change value. The display device  120  generates a prompt signal when the change value is equal to or larger than a predetermined value. 
     In an embodiment, the display device  120  is used to sense the arterial acceleration pulse waves of the user before and after a meal. The display device  120  generates a heart rate signal, blood viscosity signal and vascular age signal according to the arterial acceleration pulse waves of the user before and after a meal. 
     Reference is made to  FIGS. 6A, 6B and 6C .  FIG. 6A  is an oscilloscope diagram taken before jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure.  FIG. 6B  is an oscilloscope diagram taken 4 hours after jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure.  FIG. 6C  is an oscilloscope diagram taken 7 hours after jogging as shown on a displayer in accordance with an exemplary embodiment of the present disclosure. 
     The oscilloscope diagram of  FIG. 6A  includes a Q wave  610   a , a R wave  620   a , a S wave  630   a , a T wave  640   a , an U wave  650   a  and a V wave  660   a.    
     The oscilloscope diagram of  FIG. 6B  includes a Q wave  610   b , a R wave  620   b , a S wave  630   b , a T wave  640   b , an U wave  650   b  and a V wave  660   b.    
     The oscilloscope diagram of  FIG. 6C  includes a Q wave  610   c , a R wave  620   c , a S wave  630   c , a T wave  640   c , an U wave  650   c  and a V wave  660   c.    
     Exercise redistributes the blood of limbs and organs of the human body, shrinks and expands the micro arteries and microvessels of muscle tissue and organs, thereby promoting a microcirculation to provide nutrients and promote metabolism. In a comparison between the oscilloscope diagrams before jogging and 4 hours after jogging, the S wave rising above the baseline represents promoting a vascular elasticity and delaying a reflected wave of the systolic phase. The T wave rises to the baseline. Amplitudes of the S wave and the T wave decreasing represent decreasing residual blood of the radial artery and increasing a blood perfusion of the micro arteries. Accordingly, the microcirculation is improved. 
     The capacitive accelerometer device of the present disclosure can sense the arterial acceleration pulse wave of the user before and after a medication, the exercise, etc., to illustrate changes of the arterial acceleration pulse wave of the user, where the changes of the arterial acceleration pulse wave of the user represent a change of the microcirculation of the user. 
     In summary, the condenser microphone used in the capacitive accelerometer device of the present disclosure can increase the accuracy of sensing the arterial acceleration pulse wave of the user and decrease the manufacturing costs. The capacitive accelerometer is connected to the capacitive accelerometer module by snap-fastening to increase the flexibility in replacing the capacitive accelerometer and the cleanliness in use. The display device sends the prompt signal when the arterial acceleration pulse wave automatically senses that a preset value is exceeded in a time range, so as to implement the function of remote medical detection. 
     The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.