Patent Publication Number: US-2011060250-A1

Title: Device for detecting vibration in living body and device for examining physiological state of the living body using the same

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for detecting a vibration in a living body using for detecting mainly physiological signals, for instance, respiration, pulsation, cough, snore, an eyeball movement, a body movement, a jaw movement, and turn over from a vibration caused by a change in a part, especially a head of a subject, and a device for examining physiological state of the living body using the same. 
     Patent document No. 1 discloses a device for respiration state which comprises an air mat arranged under a body of a subject lay down and pressure sensors for detecting pressure fluctuation inside this air mat and extracts and records physiological signals such as respiration frequency, heart rate and snoring signals and the like due to respiration movement in breathing muscle from output signals from the pressure sensors. 
     Patent document No. 2 discloses a panel for measuring physiological information. This panel has a floor plate part flexible elastically arranged under a subject and sensors for detecting distortion are installed on the floor plate part. In the state that the floor plate part is arranged under the subject, distortion of the floor plate part generated with physiological activity of the subject is detected by the sensors for detecting distortion. Besides, the floor plate part is put between elastic layers. 
     Patent document No. 1: JP 2000-271103 A 
     Patent document No. 2: JP 2006-43445 A 
     DISCLOSURE OF THE INVENTION 
     Problem to be Solved by the Invention 
     The device for detecting respiration state disclosed in the patent document No. 1 has a problem such that minute pressure variation cannot be detected because of detecting pressure variation of air inside the air mat arranged under the body of the subject. Besides, there is a problem such that it is difficult to maintain air pressure constantly inside the air mat. 
     Furthermore, in the device disclosed in the patent document No. 2, as the sensors for detecting distortion are arranged at both sides of the floor plate part put between the elastic layers with specific elastic force, minute variation is absorbed into the elastic layers, so that there is a problem such that only large vibration or variation can be detected. 
     Thus, the present invention is to provide a device for detecting a vibration in a living body using for detecting mainly physiological signals, for instance, respiration, pulsation, cough, snore, an eyeball movement, a body movement, a jaw movement, and turn over from a vibration caused by a change in a part, especially a head of a subject, and a device for examining physiological state of the living body using the same. 
     Means for Solving Problem 
     Accordingly, the device for detecting a vibration in a living body is to be constituted of a housing on which a specific part, especially a head part of a subject is placed, a distortion plate provided on an inner upper surface of the housing so as to be in contact with the inner upper surface of the housing, a means for detecting distortion being in contact with the distortion plate, and a supporting plate at least constituted of a contact part being in contact with an inner lower surface of the housing and a supporting plate extending form the contact part in order to support both side ends of the distortion plate. 
     Due to this constitution, it is gone away to depend on a state of an installation surface where the means for detecting distortion is placed, and constant detection sensitivity can be obtained in long time usage of year unit. Besides, it is preferred that the means for detecting distortion is arranged on a middle part of the distortion plate, but preferably a plurality of means for detecting distortion are arranged along a longitudinal direction of the distortion plate. Furthermore, it is desirable that the means for detecting distortion is constituted of an electronic circuit board provided in the housing. 
     Besides, the distortion plate may have slit parts extending from an edge of the distortion plate to proximity of the means for detecting distortion. 
     Furthermore, the means for detecting distortion may be a piezo element (PZT, polyvinylidene fluoride) or a strain gauge, it is desirable that a material for collision prevention comprising an elastic material is arranged on the contact part of the supporting plate where the piezo element or the strain gauge faces. 
     Moreover, a device for detecting a vibration in a living body is constituted of at least a housing on which a head part of a subject is placed, a distortion plate is provided on an inner upper surface of the housing so as to be in contact with the inner upper surface of the housing, a first electrode fixed on the distortion plate, a supporting plate comprising a contact part being in contact with an inner lower surface of the housing and supporting parts extending from the contact part and supporting both edge parts of the distortion plate, and a second electrode provided on the contact part of the supporting plate on which the first electrode faces. Besides, it is desirable that capacitance is constituted of the first and the second electrodes. 
     Furthermore, a device for examining physiological state according to the present invention is to comprise a device for detecting a vibration in a living body according to the present invention, a means for detecting physiological signals sampling at least respiration waves, pulsation waves, snoring waves, body movement waves, eye movement waves, chewing movement waves or the like from vibration waves detected by the device for detecting a vibration in a living body, a means for judging apnea from the respiration waves and/or the snoring waves and further judging REM sleep from the chewing movement s waves and the eye movement waves. 
     Moreover, it is desirable that the distortion plate is made of resin or metal, and that the distortion plate has width within a range from 5 to 600 mm. length within a range from 10 to 1000 mm and thickness within a range from 0.1 to 30 mm. Besides, it is desirable that the supporting plate is provided with material and size corresponding to the distortion plate. 
     EFFECT OF THE INVENTION 
     According to the device for detecting a vibration in a living body of the present invention, since the distortion plate being in contact with the upper surface of the housing on which the head of the subject is put is supported by the supporting plate being in contact with the lower surface of the housing, an effect such that minute vibration of the head of the subject can be transmitted to the means for detecting a vibration can be achieved. 
     Besides, because it becomes possible that the means for detecting a vibration can detect a minute vibration, it becomes possible to sample the waves showing respiration, pulsation, cough, snoring, body movement, eye movement, chewing movement or the like from the detected waves, and thus, it becomes possible to detect fine physiological state, especially apnea or REM sleep. 
    
    
     
       BRIEF EXPLANATION OF DRAWINGS 
         FIG. 1  This is a cross-sectional view of a device for detecting a vibration in a living body according to a first embodiment of the present invention; 
         FIG. 2  This is a plan view showing one example of constitution of a supporting plate in the device for detecting a vibration in a living body according to the first embodiment of the present invention; 
         FIG. 3  This is a plan view showing constitution of a distortion plate in the device for detecting a vibration in a living body according to a first example of the present invention; 
         FIG. 4  This is a plan view showing constitution of a distortion plate in the device for detecting a vibration in a living body according to a second example of the present invention; 
         FIG. 5  This is a plan view showing constitution of a distortion plate in the device for detecting a vibration in a living body according to a third example of the present invention; 
         FIG. 6  This is a schematic diagram of an amplifier circuit, 
         FIG. 7  This is a schematic diagram of a device for examining physiological state according to the present invention, 
         FIG. 8  This is an illustration showing one example of signal treatment in MPU, 
         FIG. 9  This is a flow chart diagram showing an operation performed in MPU, and 
         FIG. 10  This is a cross-sectional view of a device for detecting a vibration in a living body according to a second embodiment of the present invention. 
     
    
    
     EXPLANATIONS OF LETTERS OR NUMERALS 
     
         
           1  DEVICE FOR DETECTING A VIBRATION IN A LIVING BODY 
           2  HOUSING 
           3  DISTORTION PLATE 
           4  SENSOR FOR DETECTING DISTORTION 
           5  SUPPORTING PLATE 
           6  ELECTRONIC CIRCUIT SUBSTRATE 
           10  SLIT PART 
           20  AMPLIFIER CIRCUIT 
           30  DEVICE FOR EXAMINING PHYSIOLOGICAL STATE 
       
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, the preferred embodiments are explained along the drawings. 
     First Embodiment 
     A device for detecting a vibration in a living body  1  according to a first embodiment of the present invention is, for instance as shown in  FIG. 1 , constituted of at least a housing  2  on which a specific part, especially a head part of a subject is put, a distortion plate  3  provided on an inner upper surface  2 A so as to be in contact with the inner upper surface  2 A, a sensor for detecting distortion (concretely, a piezo element or distortion gauge)  4  fixed in an approximately middle part in the distortion plate  3 , a supporting plate  5  supporting both end edge parts of the distortion plate  3 , and an electronic circuit substrate  6  provided on the distortion plate  3  adjacent to the sensor for detecting distortion  4 . 
     The supporting plate  5  is, for instance as shown in  FIG. 2 , a contact part  5 A fixed or put in a middle of an inner lower surface  2 B of the housing and supporting parts  5 B extending from both sides of the contact part  5 A to both end edge parts  3 A of the distortion plate  3 , and both edge parts  3 A of the distortion plate  3  and fixed parts fixed by screws  8  or the like are formed on both end parts of the supporting parts  5 B. Besides, a collision prevention material  7  made of an elastic material is arranged opposite to a sensor for detecting distortion  4 . Furthermore, this supporting plate  5  is formed availably and selectively corresponding to a material and a shape of the following distortion plate  3 . 
     In a first example as shown in  FIG. 3 , the distortion plate  3  is formed in an approximately square shape similar to a shape of the inner upper surface  2 A of the housing  2  and formed of a material availably selected from groups consisting of metals such as aluminum, steel, stainless, brass, copper alloy, iron alloy, or the like, resins such as substrate for print wiring, plastics or the like, glass, and cloths, or a compound consisting of those materials, and it has a size that a head or a pillow can be put on, for instance, having width within a range from 5 mm to 600 mm, length within a range from 10 to 1000 mm of length and thickness within a range from 1 mm to 30 mm. Furthermore, in a first embodiment shown in  FIG. 3 , the sensor for detecting distortion  4  is fixed on an approximately center in a lower side surface of the distortion plate  3  and an electronic circuit substrate  6  corresponding to the sensor for detecting distortion  4  is arranged near the sensor for detecting distortion. 
     In a second example shown in  FIG. 4 , a plurality of sensors for detecting distortion  4  (three sensors in this embodiment) are arranged along a longitudinal direction of the distortion plate  3 , more minute detection against a position of the head of the subject (not shown in figures) becomes possible. 
     In a third example shown in  FIG. 5 , slit parts  10  extending from side edges of longitudinal direction of the distortion plate  3  to proximities of the sensor for detecting distortion  4  respectively are provided. Thus, because strength of proximity of the sensor of detecting distortion  4  is decreased, it becomes easy to detect more minute vibration. 
     An amplifier circuit  20  as shown in  FIG. 6  is provided in the electronic circuit substrate  6 . This means that physical vibration on the distortion plate  3  is changed into electrical signals by the sensor for detecting distortion, amplified in the amplifier circuit  20  and output. This amplifier circuit  20  has well-known constitution. 
     In the device for detecting a vibration in a living body having the above constitution, because the hard distortion plate  3  is supported by the supporting plate  5  and thus specific tension applies to the distortion plate  3 , a vibration generated from the head of the subject put on the housing  2  can be transmitted to the distortion plate  3  efficiently. 
     In a device for examining physiological state using the above mentioned device for detecting a vibration in a living body, for instance as shown in  FIG. 7 , a detecting wave ( FIG. 8A ) output form an electrical circuit  21  of the device for detecting a vibration in a living body constituted of the sensor  4  and the amplifier circuit  20  is transmitted to a micro processor unit (MPU)  32  via an A/D converter  31 . In MPU  32 , an operation, for instance, shown in a flowchart diagram in  FIG. 9  is performed. Besides, the device for examining physiological state comprises at least a power source circuit  35 , a memory device  33  and a communication device  34 . 
     At step  100  in  FIG. 9 , the detected wave shown in  FIG. 8A  is changed to a digital signal via the A/D converter  31  in order to input into the MPU  32 , and then signal treatment is performed as shown in  FIG. 8B  to pick up a respiration wave firstly as physiological signal wave. Similarly, at step  120 , a snoring wave is picked up due to amplitude of the respiration wave or the like, and then at step  130 , a pulsation wave is picked up as shown in  FIG. 8C . Similarly, a body movement wave is picked up from amplitude of the detected wave, a variation period thereof and the like (step  140 ), a chewing movement wave is picked up from amplitude of the detected wave corresponding to jaw movement of the subject, a variation period thereof and the like (step  150 ), and further, an eye movement wave is picked up from more minute variation thereof (step  160 ). 
     Moreover, in the picked-up physiological signal waves, frequency of respiration and low frequency of respiration are detected from the respiration wave and the snoring wave at step  170 , and it is detected at step  180  whether the subject is in apnea state or not. Besides, in this embodiment, it is detected whether the subject is in REM sleep due to the chewing movement wave and the eye movement wave or not. 
     The physiological data such as picked-up signal waves (the respiration wave, the snoring wave, the pulsation wave, the body movement wave, the chewing movement wave and the eye movement wave), calculated data (frequency of respiration, low frequency of respiration or the like) and the detected subject state (apnea, REM sleep) are output into the memory device  33  (step  200 ) and stored in it. Furthermore, the physiological data are output to the communication device  34  periodically (step  210 ) and then they are transmitted to necessary places such as an attending doctor&#39;s computer, a hospital, a caring center and the like. 
     Second Embodiment 
     A device for detecting a vibration in a living body according to a second embodiment of the present invention shown in  FIG. 10  comprises at least a housing  2  on which a head of a subject is put, a distortion plate  3  provided on an inner upper surface  2 A of the housing  2  so as to be in contact with the inner upper surface  2 A, a first electrode  4 A fixed on the distortion plate  3 , a supporting plate  5  comprising a contact part  5 A being in contact with an inner lower surface  2 B of the housing  2  and supporting parts  5 B extending from the contact part  5 A and supporting both end edge parts  3 A of the distortion plate  3 , and a second electrode  4 B provided on the contact part  5 A of the supporting plate  3  opposite to the first electrode  4 A. 
     In this embodiment, by detecting variation of capacitance between the first electrode  4 A and the second electrode  4 B by the vibration of the distortion plate  3 , the vibration can be detected as variation of an electrical signal. Also in this embodiment, the same operation as the first embodiment in the device for examining physiological state  30  is possible.