JP2005351781A - Vibration detector and human body detector, and bed system mounting them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the sensitivity of a piezoelectric sensor for a vibration detector and a human body detector using a simple constitution. <P>SOLUTION: Piezoelectric sensors 9 are provided which are arranged facing a surface, where acceleration is added and generate outputs according to the acceleration and a deciding means 13 for deciding the wheare abouts of a human body from the outputs of the piezoelectric sensors. The piezoelectric sensors 9 are made of long scale soft lines and are human body detector forming a multitude of bends 14 under tension toward the surface. By increasing the length and contact density with a multitude of bends under tension, the sensitivity as a whole is increased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention detects vibrations through movements of an object, a person, and a heartbeat or breathing from a human body by deformation of a pressure sensor such as a piezoelectric sensor, and detects vibrations of objects, persons, etc., and places such as a seat and a bed The present invention relates to a human body detection device for detecting whether a person is present or absent and a bed device using the same.

  A conventional vibration detection device uses an acceleration sensor, and the acceleration sensor is fixed to a vibrating object, becomes in the same vibration state as the vibration of the object, generates an output corresponding to the acceleration at that time, and detects the vibration. It was.

  Further, in the conventional human body detection device, as shown in FIG. 13, when the human body is seated on the seat 50, the piezoelectric element 51 disposed under the surface cloth of the seat 50 is deformed by the movement of the human body and generates a voltage due to the piezoelectric effect. To do. A specific frequency component of the voltage is filtered by the filter 52, further amplified by the signal amplifying means 53, smoothed by the smoothing means 54, and input to the determining means 55 to determine whether there is an object or a person. (See, for example, Patent Document 1).

  That is, the output signal waveform of the smoothing means 54 inputted to the judging means 55 is as shown in FIG. 14, and in the case of rough body movement such as sitting, movement of limbs, and sitting, it is an operation over the whole body. A large signal waveform appears from the smoothing means 54 in response to the deformation. However, if the seated person is in a resting state, a signal waveform having a relatively low level such as the S portion is generated due to minute body movements propagated by the heart activity and respiratory activity of the human body.

  When an object is placed on the seat, a large signal waveform appears at that time, but since there is no heart activity or respiratory activity like a person, the object does not have a low signal waveform like the S part thereafter. . By using such a difference in signal waveform, a person is distinguished from an object.

  However, in the conventional vibration detection device, when the vibration is weak, the acceleration is very small, and the output of the acceleration sensor is amplified by the signal amplifying means, but the amplification factor needs to be a very large value such as several thousand times. There was a limit to the detection of weak vibrations.

  Further, in the conventional human body detection device, when detecting the presence or absence of a person by detecting a relatively low level signal while the person is still on the seated seat, the vibration of the human body is very weak. Therefore, the output of the piezoelectric element is also a very weak signal on the order of several mv. Accordingly, the amplification factor of the signal amplifying means for amplifying the output of the piezoelectric element needs to be very large, which complicates the circuit and is susceptible to noise.

  Therefore, in order to improve such problems, in another conventional human body detection apparatus, as shown in FIG. 15, a polymer piezoelectric material such as polyvinylidene fluoride (PVDF) is formed into a thin film and flexible on both sides. The vibration detecting means 60 is configured by sandwiching the piezoelectric element 56 having an electrode film attached thereto in the middle with a vibration input section 57 and a vibration amplifying means 59 having a plurality of convex portions 58 in contact with the piezoelectric element 56. Yes.

  When the object 61 comes into contact with the vibration input unit 57 and vibration (acceleration) is transmitted, the vibration is transmitted to the vibration amplifying means 59 through the piezoelectric element 56. Thereby, when the vibration amplifying means 59 vibrates, the vibration is transmitted to the piezoelectric element 56 through the convex portion 58. As a result, the piezoelectric element 56 is alternately pressed by both the object 61 and the vibration amplifying means 59. In particular, in a state where the vibration amplifying means 59 presses the piezoelectric element 56 most, the plurality of convex portions 58 are as shown in FIG. Each of the piezoelectric elements 56 is greatly deformed, and the piezoelectric elements 56 generate a larger voltage than when there is no convex portion.

However, in this human body detection device, even if a small vibration is easily detected, in order to amplify the vibration of the object 61 and apply it to the piezoelectric element 56, a complicated structure is added to which the vibration amplification means 59 is added. In addition, it is conceivable that various restrictions are imposed on the application development of products.
Japanese Patent Laid-Open No. 7-244168

  In view of the above-described problems of the conventional technology, the problem to be solved by the present invention is to provide a vibration detection device, a human body detection device, and a human body detection device that improve the sensitivity with a simple configuration without adding another member. It is to provide a bed apparatus using the bed.

  The present invention includes a pressure-sensitive sensor that generates a signal in response to deformation by a vibration source, and a determination unit that determines a vibration source based on the signal from the pressure-sensitive sensor, the pressure sensor facing a surface to be deformed. It is a vibration detection device that is arranged and has a long and flexible line shape and has a large number of curved portions.

  The present invention further includes a piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor facing a surface on which the acceleration of the human body is applied. It is a human body detecting device which is arranged in a long and flexible line shape and has a large number of curved portions.

  By each of the above means, the pressure-sensitive sensor or piezoelectric sensor increases the contact density due to the increase in the length of the vibration source of the object or human body, and partially increases the sensitivity, detects more vibrations and improves the output. To do. Therefore, the ratio of the sensitivity improvement portion in the pressure-sensitive sensor or the piezoelectric sensor is increased, and the sensitivity as a whole is improved.

  Furthermore, the present invention is a bed device equipped with the vibration detection device or the human body detection device of the above-described means, and can detect the presence or absence of a bed-rider with certainty.

  The vibration detection device or the human body detection device of the present invention can improve the sensitivity of the pressure sensor or the piezoelectric sensor as a whole with a simple configuration without providing any special vibration amplification means.

  Moreover, the bed apparatus of the present invention can be easily installed, as well as reliably detecting the presence or absence of a bedridden person using a vibration detection apparatus or a human body detection apparatus.

  A first invention includes a pressure-sensitive sensor that generates a signal in response to deformation caused by a vibration source, and a determination unit that determines a vibration source based on an output of the pressure-sensitive sensor, the pressure sensor facing a surface to be deformed. The vibration detecting device is arranged in a long and flexible line shape and has a large number of curved portions.

  As a result, the pressure sensor is increased in length and contact density by a large number of curved portions with respect to the vibration source (thing, human body). In addition, the pressure-sensitive sensor detects more vibrations regardless of the vibration direction of the vibration source by increasing the number of vibration directions that can be sensed by a large number of curved portions. Furthermore, the pressure sensor has a large number of curved portions, so that the total amount of displacement due to vibration increases and the elongation rate when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement part in the pressure sensor increases, and the sensitivity as a whole improves, and the sensitivity of the pressure sensor with a simple configuration without using special vibration amplification means. Can be improved easily.

  According to a second aspect of the present invention, there is provided a piezoelectric sensor that generates a signal in accordance with an acceleration of a human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor facing a surface on which the acceleration of the human body is applied. It is a human body detecting device which is arranged in a long and flexible line shape and has a large number of curved portions.

  As a result, the piezoelectric sensor increases in length and contact density due to a large number of bent portions with respect to the human body. In addition, the piezoelectric sensor detects a greater number of vibrations regardless of the direction of vibration of the human body due to the increased number of vibration directions that can be sensed by a large number of curved portions arranged on the surface to which acceleration is applied. Further, the piezoelectric sensor has a large number of curved portions, so that the total amount of displacement due to vibration acceleration increases, and the elongation when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor increases, the overall sensitivity is improved, and the sensitivity of the piezoelectric sensor can be simplified with a simple configuration without using a special vibration amplification means. Can be improved.

  According to a third aspect of the present invention, there is provided a piezoelectric sensor that generates a signal according to the acceleration of the human body and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor facing a surface of the human body where acceleration is applied. It is a human body detecting device that is arranged in a long and flexible line shape and has a shape in which a large number of curved portions are continuous.

  As a result, the piezoelectric sensor increases the length and contact density of the human body with a large number of curved portions and a shape in which the curved portions are continuous. In addition, the piezoelectric sensor detects a greater number of vibrations regardless of the direction of vibration of the human body due to the increased number of vibration directions that can be sensed by a large number of curved portions arranged on the surface to which acceleration is applied. Further, the piezoelectric sensor has a large number of curved portions, so that the total amount of displacement due to vibration acceleration increases, and the elongation when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor increases, the overall sensitivity is improved, and the sensitivity of the piezoelectric sensor can be simplified with a simple configuration without using a special vibration amplification means. Can be improved.

  According to a fourth aspect of the present invention, there is provided a piezoelectric sensor that generates a signal in accordance with an acceleration of a human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor. This is a human body detection device that is arranged in a long and flexible line shape, in which a large number of curved portions are made continuous and further meandered.

  Accordingly, the piezoelectric sensor has a shape in which a large number of curved portions and the curved portions are continuous with respect to the human body, and the length and contact density increase due to the meandering shape. In addition, the piezoelectric sensor can detect more vibrations regardless of the direction of vibration of the human body due to the increase in the number of vibration directions that can be sensed by a large number of continuous curved portions. Further, the piezoelectric sensor has a large number of curved portions, so that the total amount of displacement due to vibration acceleration increases, and the elongation when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor increases, the overall sensitivity is improved, and the sensitivity of the piezoelectric sensor can be simplified with a simple configuration without using a special vibration amplification means. Can be improved.

  According to a fifth aspect of the present invention, there is provided a piezoelectric sensor that generates a signal in accordance with an acceleration of a human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor facing a surface on which the acceleration of the human body is applied. This is a human body detection device that is arranged in a long and flexible line shape, in which a large number of S-shaped curved portions are continuous and further meandered.

  As a result, the piezoelectric sensor has a large number of S-shaped curved portions and a shape in which the curved portions are continuous with respect to the human body, and the length and contact density increase due to the meandering shape. In addition, the piezoelectric sensor has a shape in which a large number of S-shaped curved portions arranged on the surface to which acceleration is applied is continuous, and the meandering shape of the continuous S-shaped curved portions increases the vibration direction that can be detected. More vibrations are detected regardless of the direction of vibration. Further, the piezoelectric sensor has a large number of curved portions, so that the total amount of displacement due to vibration acceleration increases, and the elongation when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor increases, the overall sensitivity is improved, and the sensitivity of the piezoelectric sensor can be simplified with a simple configuration without using a special vibration amplification means. Can be improved.

  According to a sixth aspect of the present invention, there is provided a piezoelectric sensor that generates a signal in accordance with an acceleration of a human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, wherein the piezoelectric sensor is an acceleration of a human body such as a seat or a floor. This is a human body detection device that is arranged to face the surface to be added and has a long and flexible linear shape, in which a large number of S-shaped curved portions are continuous and further meandered. .

  As a result, the piezoelectric sensor has a large number of S-shaped bent portions and a shape in which the bent portions are continuous with respect to the human body, and further increases in length and contact density due to the meandered shape. In addition, the piezoelectric sensor has a continuous shape of a number of S-shaped curved parts arranged on the surface to which acceleration is applied, such as a seat and a floor, and the meandering shape increases the vibration direction that can be sensed and the vibration direction of the human body. It detects more vibrations in any orientation. Further, the piezoelectric sensor has a large number of curved portions, so that the total amount of displacement due to vibration acceleration increases, and the elongation when displaced due to vibration increases.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor increases, the overall sensitivity is improved, and the sensitivity of the piezoelectric sensor can be simplified with a simple configuration without using a special vibration amplification means. Can be improved.

  According to a seventh aspect of the present invention, there is provided a piezoelectric sensor according to any one of the second to sixth aspects, wherein the piezoelectric element material is formed by covering the center electrode in the center in the axial direction, the periphery of the center electrode, and the piezoelectric element material. An outer electrode provided on the outer periphery of the outer electrode and an outer sheath such as vinyl chloride coated on the outer periphery of the outer electrode.

  As a result, the piezoelectric sensor can be formed as a long and flexible linear cable, and a curved portion or a curved portion is formed continuously, or a number of S-shaped curved portions are continuously formed. Furthermore, it is possible to easily form each of the meandering shapes and arrange them.

  An eighth invention is a bed apparatus on which the vibration detecting apparatus according to the first invention or the human body detecting apparatus according to any one of the second to seventh inventions is mounted.

  Thereby, the effect by the vibration detection apparatus of 1st invention or the human body detection apparatus of any one of 2nd invention to 7th invention is obtained as a bed apparatus, and the presence or absence of a bedridden can be detected reliably.

  The object of the present invention can be achieved by using the first to eighth aspects of the present invention as the main part of the embodiment, so the details of the embodiment corresponding to each claim will be described below with reference to the drawings. It will be described and the best mode for carrying out the present invention will be described. The present invention is not limited to the present embodiment. Further, in the description of the present embodiment, the same reference numerals are given to the same configurations and the effects and the same description is not repeated.

(Embodiment 1)
FIG. 1 is a configuration diagram of a vibration detection device or a human body detection device according to Embodiment 1 of the present invention, FIG. 2 (a) is a plan view of a piezoelectric sensor sheet of the detection device, and FIG. FIG. 4 is a perspective view of the main part of the piezoelectric sensor in the detection device, FIG. 5A is a view of a load applied to the piezoelectric sensor, and FIG. FIG. 6A is a diagram of the output voltage of the piezoelectric sensor with respect to the load shown in FIG. 6A. FIG. 6A is a diagram of the bed apparatus used for medical use, nursing care, etc. equipped with the vibration or human body detection apparatus in the first embodiment. It is a schematic perspective view, (b) is a principal part disassembled perspective view of a bed apparatus.

  The vibration detection device or human body detection device of the present invention is composed of a rectangular piezoelectric sensor sheet 1 and a determination unit 2. The piezoelectric sensor sheet 1 and the determination unit 2 are connected to the determination unit 2 by detachably connecting the connector 3a of the cable 3 derived from the signal processing unit 4 disposed at the end of the piezoelectric sensor sheet 1. The piezoelectric sensor sheet 1 is a reclining type bed device equipped with a vibration detection device or a human body detection device in order to detect the presence or absence (also referred to as presence / absence) of the bedridden. FIG. 6 (a) (b) The back-raised floor 5 and the knee-raised floor 6 shown in FIG.

  The piezoelectric sensor sheet 1 is a long and flexible linear piezoelectric sensor disposed on a thin flexible support 7 that is disposed opposite to a surface that is subject to acceleration of a human body, which is a vibration source. 9. The long flexible linear piezoelectric sensor 9 is arranged to face the surface of the vibration source to which acceleration is applied, and generates a voltage as an output signal in accordance with the acceleration.

  The determination unit 2 includes a determination unit 13 configured by a microcomputer (hereinafter referred to as a microcomputer) and its peripheral circuits, and a determination result display unit (not shown), and a signal processing unit 4 based on an output signal of the piezoelectric sensor 9. Based on the output signal, the determination algorithm provided in the microcomputer determines the object and human body and the presence / absence of the bedridden person and displays them.

  The determination algorithm obtains the maximum value and the minimum value of the output signal of the signal processing unit 4 every 2 seconds, calculates the difference, and states that the difference is equal to or greater than the threshold value V1 a predetermined number of times every 2 seconds. If you continue N1, you will be in bed. In the presence determination state, the state in which the difference is equal to or less than the threshold value V2 is configured to be absent if N2 continues for a predetermined number of times every 2 seconds.

  Further, the determination unit 2 includes the determination means 13 integrally in the signal processing unit 4, sends a determination signal to the determination unit 2 by the cable 3 a, displays the determination result, and determines the determination signal wirelessly from the signal processing unit 4. You may make it the form which sends and displays to the unit 2. FIG.

  The signal processing unit 4 includes a signal amplifying unit 10 that amplifies the output signal of the piezoelectric sensor 9 and a filter 11 that filters a necessary frequency component from the amplified output signal. It should be noted that smoothing means may be provided when the signal required by the filter 11 cannot be sufficiently extracted.

  Further, the piezoelectric sensor 9 of the piezoelectric sensor sheet 1 is arranged in a specific shape on the surface to which the acceleration of the vibration source is applied in order to improve the output sensitivity so that an output signal can be generated according to the small acceleration of the vibration source. Yes.

  In other words, the piezoelectric sensor 9 is formed in a long and flexible line shape, and is disposed so as to face the surface of the vibration source where the acceleration is applied substantially in parallel, and a large number of tensioned S-shaped curved portions 14 are continuously provided. Further, the piezoelectric sensor sheet 1 is formed to meander to the left and right of the entire piezoelectric sensor sheet 1 with the above shape.

  Therefore, the piezoelectric sensor 9 has a length on the surface to which the acceleration is applied due to a shape in which a number of tensioned S-shaped curved portions 14 are continuous and a shape meandering the whole with the shape. It becomes long and it is comprised so that sensor amount (part which functions as a sensor) may increase.

  In addition, since the piezoelectric sensor 9 has a large number of S-shaped curved portions 14 arranged on the surface to which the acceleration of the human body is applied and tension is applied thereto, the sensitivity of the continuous S-shaped curved portions increases. In addition, the number of vibration directions that can be sensed is increased, and no matter what direction the vibration direction of the human body is, more vibration is detected and the output is improved.

  In addition, the piezoelectric sensor 9 has a large number of S-shaped curved portions 14 that increase the total amount of displacement due to vibration acceleration, and the elongation when displaced due to vibration is, for example, that of a piezoelectric sensor to which no tension is applied. The configuration is larger than that of the straight line portion.

  The sensor terminal portion 15 of the piezoelectric sensor 9 is electrically insulated with a heat shrinkable tube (not shown) or the like so that the center electrode 22 and the outer electrode 24 of the piezoelectric sensor 9 shown in FIG. The shrinkable tube and the vicinity thereof are covered with a shield member (not shown) connected to the outer electrode, and further covered with another heat shrinkable tube (not shown) for protection. If it is verified that the disconnection of the piezoelectric sensor 9 does not occur by performing a reliability test such as a strength test in accordance with the actual usage, the configuration of the sensor terminal 15 is used, and the center electrode of the piezoelectric sensor 9 is configured. Although it is not necessary to use a resistance for disconnection detection that connects the outer electrode 22 and the outer electrode 24, the resistor is connected in order to further improve the accuracy.

  In the present embodiment, the piezoelectric sensor 9 is arranged with a specific shape as shown in FIG. 1 and FIG. 2A, but the curved portion 14 is not made continuous, but FIG. ), A shape in which a large number of curved portions 14 and curved portions 14 are joined together by a straight portion 16 as shown in FIG. 2C, and as shown in FIG. The bent portion 14a as a curved portion having a very small radius of curvature than the tip portion (the upper and lower portions of the rounded portion) of the curved portion 14 shown in FIG. Is.

  In addition, the piezoelectric sensor 9 of the piezoelectric sensor sheet 1 shown in FIGS. 2A, 2B, 2C, and 2D has an overall arrangement with respect to the piezoelectric sensor sheet 1 in a meandering shape to the left and right. 2 (e) may be used, and the curved portion 14 shown in FIG. 2 (f) may be continuous in the vertical direction, and the whole may be made to meander up and down, and a piezoelectric sensor sheet is used. The shape of the piezoelectric sensor 9 is changed according to the product to be detected and the purpose of vibration detection. As described above, various shapes can be considered within the scope of the object of the present invention.

  The fixing thread 17 is one of the fixing tools for maintaining the piezoelectric sensor 9 in an arrangement having a specific shape for improving the sensitivity, and for improving the sensitivity by rationalizing the members and relaxing the movement of the piezoelectric sensor 9. The sewing machine automatically sews only the upper surface of one support 7 along the shape of the long flexible linear piezoelectric sensor 9 with a fixing thread 17 composed of an upper thread and a lower thread.

  Such a piezoelectric sensor sheet 1 is installed between the upper surface of the back-up floor portion 5 provided reclining on the bed base frame 19 of the bed apparatus and the lower surface of the mattress 20 as shown in FIGS. 3 and 6. . The back-raised floor 5 and the knee-raised floor 6 are provided with uneven grooves 8 along the longitudinal direction on the upper surface facing the lower surface of the mattress 20. Therefore, the piezoelectric sensor 9 of the piezoelectric sensor sheet 1 disposed between the upper surface of the back-up floor portion 5 and the lower surface of the mattress 20 has a form orthogonal to the groove 8, and the piezoelectric sensor 9 is easily deformed by the unevenness of the groove 8. Thus, the sensitivity is improved.

  When there is a mattress cover (not shown), the entire piezoelectric sensor sheet 1 and the mattress 20 disposed on the lower surface of the mattress 20 are covered with the mattress cover and disposed on the upper surface of the back-up floor portion 5. is there. The electric motor 21 drives the back raising floor 5 and the knee raising floor 6 up and down.

  Next, a specific configuration of the piezoelectric sensor 9 will be described. As shown in FIG. 4, the piezoelectric sensor 9 has a coiled or single-wire center electrode 22 as a signal derivation electrode at the center in the axial direction, and a piezo element material 23 is coated around the center electrode 22, and The outer electrode 24 is arranged on the outer periphery, and the outermost periphery is covered with a jacket 25 such as vinyl chloride.

  This piezoelectric sensor 9 uses a resin system having a heat resistance originally developed by the present applicant that can be used at a temperature of up to 120 ° C. for the piezo element material 23, and a conventional typical polymer piezo element material (uniaxially stretched). Polyvinylidene fluoride), chloroprene, and piezoelectric ceramic powder piezo element materials have characteristics that can be used in a temperature range higher than 90 ° C. (120 ° C. or lower), which is the maximum use temperature.

  The piezoelectric element material is composed of a flexible resin and a piezoelectric ceramic, and a coil-shaped metal is used as the center electrode 22 and a film-like flexible electrode is used as the outer electrode 24. Has the same flexibility.

  Furthermore, the piezoelectric sensor 9 is as sensitive as a polymer piezo element material, and the decrease in sensitivity is small even in a low frequency region (10 Hz or less) in which the movement of the human body is detected.

  The piezo element material 23 is composed of a composite of a resin material and a piezoelectric ceramic powder of 10 μm or less, and vibration detection characteristics are realized by ceramic, and flexibility is realized by resin.

  The piezo element material 23 uses chlorinated polyethylene as a resin-based material to achieve high heat resistance (120 ° C.) and flexibility that can be easily formed, and enables a simple manufacturing process that does not require crosslinking. Is.

  The piezoelectric sensor thus obtained does not have piezoelectric performance when the piezoelectric element material is molded. Therefore, by applying a DC voltage of several Kv / mm to the piezoelectric element material, the piezoelectric performance can be improved in the piezoelectric element material. It is necessary to perform a process to be applied (polarization process). This polarization process is performed by forming a center electrode 22 and an outer electrode 24 on a piezoelectric element material and then applying a DC high voltage to both electrodes.

  In the polarization method as described above, if a small defect such as a crack exists in the piezo element material 23, the center electrode 22 and the outer electrode 24 are easily discharged at the defect portion, and the two electrodes are easily short-circuited. A sufficient polarization voltage cannot be applied.

  In order to solve this problem, for example, after forming the piezo element material 23 around the center electrode 22 by extrusion molding, the piezo element material so that the outer periphery of the piezo element material 23 is in contact with a plurality of auxiliary electrodes one after another. A unique polarization method was established in which a direct current high voltage was applied between the center electrode 22 and the auxiliary electrode while performing the polarization.

  By this construction method, a minute defect such as a crack is inherent in a part of the piezoelectric element material 23, and a discharge occurs between the auxiliary electrode and the center electrode 22 in contact with the part, and sufficient polarization cannot be performed. However, a DC high voltage is applied between the other auxiliary electrode and the center electrode 22 in contact with another portion of the piezoelectric element material 23 having no defect portion, and normal polarization is performed. The location where the discharge has occurred is marked so that the location can be identified. The outer electrode 24 is formed after the above-described polarization, and then the outer skin 25 is formed. By the above process, the length of several tens of meters can be increased.

  In the piezoelectric sensor 9, a coil-shaped metal center electrode is used for the center electrode 22, and a film-like electrode (aluminum-polyethylene terephthalate-aluminum three-layer laminate film) is used for the outer electrode 24. In addition, it is possible to secure the adhesion between the electrodes 22 and 24 and to easily connect the external lead wires, thereby enabling a flexible cable-like mounting configuration.

  The center electrode 22 is a copper-silver alloy coil, the outer electrode 24 is a three-layer laminate film made of aluminum-polyethylene terephthalate-aluminum, the piezoelectric element material is polyethylene-based resin + piezoelectric ceramic powder, and the outer shell is made of thermoplastics. As a result, the relative dielectric constant is 55, the charge generation amount is 10 to 13 C (clone) / gf, and the maximum operating temperature is 120 ° C.

5A and 5B are diagrams showing the load applied to the cord-like (also referred to as linear) piezoelectric sensor 9 and the sensor output characteristics. As a result of the experiment conducted by the applicant on the relationship between the load of the piezoelectric sensor 9 and the sensor output, when a bending load such as (a) is applied to the piezoelectric sensor 9, the sensor output becomes a phenomenon as shown in (b).
(1) That is, when no load is applied to the piezoelectric sensor 9 at time t0, the sensor output indicates 2 (V).
(2) When a bending load is applied to the piezoelectric sensor 9 in a certain direction at the time t1, the sensor output increases to 4 (V) from the moment it is applied and then reverses to 0 (V), and then 2 (V) again. Return to).
(3) After that, the sensor output still shows 2 (V) even if it is kept bent.
(4) When the piezoelectric sensor 9 is returned to the original state at the time t3, the sensor output decreases to 0.8 (V) from that moment, then immediately reverses to 2.2 (V), and then 2 again. Return to (V).

  In this way, since the piezoelectric sensor 9 generates an output in response to acceleration, a signal is output only at the moment when force is applied, and after that, as long as there is no fluctuation even if force is continuously applied, that is, there is no acceleration. No more output. Similarly, when the force is removed, the output is output only at that moment.

  Therefore, even if the piezoelectric sensor sheet 1 having the piezoelectric sensor 9 is laid under the mattress 20, the piezoelectric sensor sheet 1 is turned on at the moment when the piezoelectric sensor 9 is bent, but no output is output after the laying is completed. After that, an output is output only when a force is applied to some part of the piezoelectric sensor 9.

  The piezoelectric sensor 9 outputs a signal only at the moment when a force is applied, and no longer outputs a signal as long as there is no fluctuation even if the force is continuously applied. Similarly, when the force is removed, it has the characteristic of detecting the acceleration that is output only at that moment. Therefore, even if the piezoelectric sensor 9 is bent and disposed, output is generated at the moment of bending, but the output is lost after the disposition is completed, and thereafter, a force is applied to some part of the piezoelectric sensor 9. When added, output will occur.

  Therefore, even if this cord-shaped piezoelectric sensor is bent and installed in the lower part of the bed, etc., the output is output at the moment of bending, but the output is not output after the installation. After that, an output is output only when a force is applied to some part of the cord-shaped piezoelectric sensor.

  In the above embodiment, the operation and action of the vibration detection device and the human body detection device will be described. As shown in FIGS. 1 and 6A, when a person 26 as a vibration source lies on his back on the mattress 20 of the bed apparatus, the load is applied to the piezoelectric sensor sheet 1 of the back-up floor portion 5 through the mattress 20. . The piezoelectric sensor 9 of the piezoelectric sensor sheet 1 generates a voltage as an output signal according to the acceleration of the body when lying on its back. This output signal is amplified by the signal amplifying means 10, the necessary frequency component is filtered by the filter 11, and a large output signal is input to the judging means 13 as shown in FIG. After that, it becomes a minute body movement of the body due to the activity of the heart and the respiratory activity, and an output signal with a relatively low level as in the S part is obtained.

  When an object is placed on the mattress 20, a large output signal is input to the determination means 13 at that time, but thereafter there is no low signal output as in the S section. The difference between the output signals and the presence / absence of the person and the object are determined.

  In particular, in this embodiment, the piezoelectric sensor 9 of the piezoelectric sensor sheet 1 is specified as a surface to which the acceleration of the vibration source is applied in order to improve the output sensitivity so that an output signal can be generated according to the small acceleration of the vibration source. Arranged in shape.

  In other words, the piezoelectric sensor 9 is formed in a long and flexible line shape, and is disposed so as to face the surface of the vibration source where the acceleration is applied substantially in parallel, and a large number of tensioned S-shaped curved portions 14 are continuously provided. Further, it is formed into a shape meandering from side to side with the above shape.

  With this configuration, the piezoelectric sensor 9 has a shape in which a large number of tensioned S-shaped curved portions 14 are continuous, and a shape in which the whole is meandered by the shape portion. Depending on the portion, the length of the piezoelectric sensor itself on the surface to which acceleration is applied becomes longer, and the amount of sensor (portion that functions as a sensor) increases. Therefore, the contact density between the increased portion of the piezoelectric sensor 9 and the body is increased.

  In addition, since the piezoelectric sensor 9 is continuously tensioned by a large number of S-shaped curved portions 14 arranged on the surface to which the acceleration of the body is applied, the sensitivity of the large number of continuous S-shaped curved portions 14 is increased. Furthermore, compared to the case where the piezoelectric sensor is simply arranged in a straight line, the curved portion 14 increases the vibration direction that can be sensed by the piezoelectric sensor 9, and detects more vibration regardless of the vibration direction of the human body. Output is improved.

  Further, the piezoelectric sensor 9 has a large number of S-shaped curved portions 14 that are tensioned to increase the total amount of displacement due to vibration acceleration, and the elongation at the time of displacement due to vibration is, for example, tension. There is no larger than the linear part of the piezoelectric sensor.

  Therefore, the ratio of the sensitivity improvement portion in the piezoelectric sensor 9 is increased, the overall sensitivity is improved, and the piezoelectric sensor 9 can be formed with a simple configuration without using a special vibration amplification means as in the prior art. The sensitivity of the sensor can be improved easily.

  Next, improvement of the output sensitivity of the piezoelectric sensor 9 will be described by an experimental example in which the piezoelectric sensor sheet 1 of the present embodiment and the comparison target piezoelectric sensor sheet are compared for each of the two types of mattress A and mattress B. .

  In the mattress A, FIG. 7A is a diagram of the output voltage of the piezoelectric sensor 9 in the piezoelectric sensor sheet 1, FIG. 7B is a diagram obtained by performing signal processing on the output voltage shown in FIG. 8A, and FIG. It is a figure of the output voltage of the piezoelectric sensor sheet | seat of comparison object, (b) is the figure which signal-processed the output voltage shown to (a).

  In the mattress B, FIG. 9A is a diagram of the output voltage of the piezoelectric sensor 9 in the piezoelectric sensor sheet 1, FIG. 9B is a diagram obtained by performing signal processing on the output voltage shown in FIG. 10A, and FIG. It is a figure of the output voltage of the piezoelectric sensor in the piezoelectric sensor sheet | seat of comparison object, (b) is the figure which signal-processed the output voltage shown to (a).

  FIG. 11 is a comparison diagram of the output voltage of the piezoelectric sensor in the piezoelectric sensor sheet to be compared with the present embodiment shown in FIGS. 7B, 8B, 9B, and 10B. .

  The test subject is a woman who is 156 cm tall and weighs 47 kg and sleeps on a mattress in a supine posture.

  Two types of mattresses, mattress A and mattress B, are used. The mattress A is composed of two layers of urethane foam, and uses a material having a low resilience on the human body side and a material having a high resilience on the opposite side to the other human body. The mattress B is composed of three layers of urethane foam, and the intermediate layer uses a material having low resilience and the other two layers having high resilience.

  The piezoelectric sensor sheet to be compared is the same as the piezoelectric sensor sheet and the piezoelectric sensor employed in the present embodiment. However, the piezoelectric sensor is schematically shown at the upper right end of FIGS. 8A and 10A. As shown in the figure, a simple meandering pattern in which a simple straight line meanders left and right is used.

  The arrangement of the piezoelectric sensors 9 of the piezoelectric sensor sheet 1 in this embodiment is as shown in FIGS. 1 and 2A, and is schematically shown as a waveform meander pattern at the upper right end of FIGS. 7A and 9A. It showed in.

  Each of FIGS. 7A to 10A is obtained by sampling and plotting signals obtained by amplifying 100,000 times and removing noise components with a filter every 20 msec. Each of FIGS. 7 to 10 (b) plots the difference between the maximum value and the minimum value of the signal output for 2 seconds by dividing each figure (a) every 2 seconds. Then, as shown in FIGS. 7A to 10A, in the signal from which the noise component has been removed by the filter, a signal that continuously changes based on minute body movement due to the heartbeat of the human body appears.

  As is apparent from FIG. 11 showing the distribution of the maximum value and the minimum value based on FIGS. 7B to 10B, the piezoelectric sensor 9 of the piezoelectric sensor sheet 1 in the present embodiment has two types. Even when laid under the mattresses A and B, it can be understood that the width of vibration is large and the signal output is large.

  Further, in the present embodiment, there is provided a piezoelectric sensor sheet 1 in a gage bed used for medical use, nursing care, etc., in which a piezoelectric sensor 9 of a vibration detecting device or a human body detecting device is arranged in a specified shape under a mattress. Therefore, the function as a medical and nursing care gadget bed can be fully respected, and the presence / absence of the bedridden can be reliably detected.

  In other words, such a special bet may be used by a person who stays in bed for a very long time, or by a relatively physically weak person such as a sick person or a caregiver. The touch should be pleasant. With the sensor sheet used in the present embodiment, the sensitivity is sufficiently improved by the above-described configuration. Therefore, the presence of the sensor sheet in the presence of a urethane foam mattress is not perceived. It can be installed and used in a state that does not impair the contact feeling. As described above, there is an effect that it is possible to provide a living article that is in close contact with the human body, such as bedding, through an elastic body such as a urethane foam mattress or a cushioning material, or to use it together.

  In the present embodiment, the piezoelectric sensor sheet 1 is provided between the upper surface of the back raising floor portion 5 and the lower surface of the mattress 20 of the bed apparatus shown in FIG. Two piezoelectric sensor sheets 1 may be separately provided between the floor portion 5, the knee-raised floor portion 6, and the mattress 20. The mattress of the back-raised floor portion 5 and the knee-raised floor portion 6 may be provided. A configuration may be adopted in which one piezoelectric sensor 9 is provided as one piezoelectric sensor sheet over the entirety of 20. In this case, the piezoelectric sensor sheet and the piezoelectric sensor 9 bend near the boundary between the back-up floor 5 and the knee-lift floor 6 due to the reclining operation of the bed apparatus, but the piezoelectric sensor 9 is flexible and bendable. It can be used without disconnection.

  In the present embodiment, the piezoelectric sensor 9 is sewn with the fixing thread 17 on the upper surface of one support body 7 of the piezoelectric sensor sheet 1 to rationalize the members, but the fixing thread 17 is formed on the lower surface of the support body 7. Alternatively, the piezoelectric sensor 9 may be sandwiched from above and below between the support body 7 and another support body, and sewn and fixed to both.

  Furthermore, in the present embodiment, the piezoelectric sensor 9 has a portion meandering to the left and right of the entire piezoelectric sensor sheet 1 that is sewn and fixed only to the support 7 and has freedom of movement, as shown in FIG. If the slit 27 is provided in the support body 7 positioned between the left and right meandering portions of the piezoelectric sensor 9 as described above, the tension by the support body 7 is relieved, and the piezoelectric sensor 9 becomes more easily deformed and improves the sensitivity. be able to.

  Even if the support 7 is made of a stretchable cloth instead of the slit 27 and the piezoelectric sensor 9 is sewn and fixed thereto, the same operation and effect as when the slit 27 is provided on the support 7 is expected. it can. Of course, when the piezoelectric sensor 9 is sewn integrally with the upper and lower supports, the slits 27 described above may be provided on the upper and lower supports, or the upper and lower supports may be made of stretchable fabric.

  Further, in the above embodiment, the piezoelectric sensor 9 that generates a signal corresponding to the acceleration is used. However, as the sensor, for example, a signal corresponding to deformation due to a load is output, such as a coaxial cable-type capacitive sensor. Even if other sensors are used, it is possible to expect the same effect as the present embodiment. That is, by adopting the same configuration as the shape specified by the piezoelectric sensor 9 of the present embodiment, the increase in length and contact density with respect to the vibration source is increased by a large number of curved portions, and the vibration direction that can be sensed is increased. The total amount of displacement due to vibration increases, and the elongation when displaced due to vibration increases.

  Furthermore, in the above embodiment, the vibration detection device or the human body detection device is provided in the bed device, and only the form used for the determination of the bedridden is described, but the presence / absence determination in a chair, toilet seat, etc., automobile, etc. It can also be carried out to detect the prevention of pinching of people, objects, etc. in the door opening and closing device.

  As described above, the vibration detection device or the human body detection device according to the present invention can improve the sensitivity of the pressure-sensitive sensor with a simple configuration without providing a special vibration amplification means, and the bed device. The present invention can be applied to seat devices, door opening / closing devices, and the like to detect the presence / absence of a bedridden person, the presence / absence of a seated person, the presence / absence of an object or a human body.

Configuration diagram of vibration detection apparatus or human body detection apparatus in Embodiment 1 of the present invention (A) Plan view of a piezoelectric sensor sheet in the vibration or human body detection device of the first embodiment, (b) Schematic layout of main parts of the piezoelectric sensor of another piezoelectric sensor sheet, (c) Other piezoelectric sensor sheet (D) Schematic layout of the main part of the piezoelectric sensor of the other piezoelectric sensor sheet, (e) Schematic layout of the piezoelectric sensor of the other piezoelectric sensor sheet, (f) Schematic layout of piezoelectric sensors on other piezoelectric sensor sheets Sectional drawing of the principal part when the piezoelectric sensor sheet | seat in the vibration or human body detection apparatus of Embodiment 1 is laid in the bed apparatus. The perspective view of the principal part of the piezoelectric sensor in the vibration or the human body detection apparatus of Embodiment 1 (A) The figure of the load added to the piezoelectric sensor in the vibration or human body detection apparatus of Embodiment 1, (b) The output characteristic figure with respect to the load added to the same piezoelectric sensor (A) Schematic perspective view of a bed apparatus on which the vibration or human body detection device of the first embodiment is mounted, (b) An exploded perspective view of a main part of the bed apparatus shown in (a). (A) The output voltage figure of the piezoelectric sensor of the piezoelectric sensor sheet | seat in the vibration or human body detection apparatus of Embodiment 1 and (b) are the figures which signal-processed the output voltage shown to (a). (A) The figure of the output voltage of the piezoelectric sensor in the piezoelectric sensor sheet | seat of this invention and a comparison object, (b) is the figure which signal-processed the output voltage shown to (a). (A) The figure of the output voltage of the piezoelectric sensor of the piezoelectric sensor sheet | seat in the vibration or human body detection apparatus when laying and changing the mattress in Embodiment 1, (b) is signal processing the output voltage shown to (a) Figure (A) The figure of the output voltage of a piezoelectric sensor when the piezoelectric sensor sheet of this invention and a comparison object are laid with changing mattresses, (b) is the figure which signal-processed the output voltage shown to (a). FIG. 7B, FIG. 8B, FIG. 9B, and FIG. 10B, a comparison diagram of output voltages of the piezoelectric sensors in the respective piezoelectric sensor sheets to be compared with the present invention. The top view of the other example of the piezoelectric sensor sheet | seat in the vibration or the human body detection apparatus of Embodiment 1 of this invention Configuration diagram of a conventional human body detection device Waveform diagram of the output signal of the smoothing means in the human body detection device Sectional drawing of the piezoelectric sensor part in the other conventional human body detection apparatus Sectional view when the piezoelectric sensor portion of the other human body detection device detects vibration

Explanation of symbols

9 Piezoelectric sensor (pressure sensor)
13 judging means 14 music part (S-shaped music part)
14a Bent part (curved part)

Claims (8)

A pressure-sensitive sensor that generates a signal in response to deformation by the vibration source, and a determination unit that determines the vibration source based on the signal of the pressure-sensitive sensor, the pressure-sensitive sensor is disposed to face the surface to be deformed; and A vibration detecting device which is a long and flexible line and has a large number of curved portions. A piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor being disposed opposite to a surface to which the acceleration of the human body is applied, and A human body detection device that is a flexible, linear scale and has a large number of curved portions. A piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor being disposed opposite to a surface to which the acceleration of the human body is applied, and A human body detection device that is formed in a flexible linear shape with a large number of curved portions. A piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor being disposed opposite to a surface to which the acceleration of the human body is applied, and A human body detection device having a flexible linear shape, in which a large number of curved portions are formed in a continuous shape, and are further meandered. A piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor being disposed opposite to a surface to which the acceleration of the human body is applied, and A human body detection device having a flexible linear shape, in which a large number of S-shaped curved portions are formed into a continuous shape and further meandered. A piezoelectric sensor that generates a signal according to the acceleration of the human body, and a determination unit that determines the location of the human body based on the signal of the piezoelectric sensor, the piezoelectric sensor facing a surface on which a human body acceleration is applied, such as a seat or a floor. A human body detecting device that is arranged in a long and flexible line shape, in which a large number of S-shaped curved portions are formed in a continuous shape and further meandered. The piezoelectric sensor has a central electrode at the center in the axial direction, a piezoelectric element material coated around the central electrode, an outer electrode provided on the outer periphery of the piezoelectric element material, and an external electrode such as vinyl chloride coated on the outer periphery of the outer electrode. The human body detection device according to claim 2, further comprising a cover. A bed apparatus on which the vibration detection apparatus according to claim 1 or the human body detection apparatus according to any one of claims 2 to 7 is mounted.

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