Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
  • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb
  • A61B5/1102—Ballistocardiography
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
  • A61B5/0205—Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/16—Devices for psychotechnics; Testing reaction times ; Devices for evaluating the psychological state
  • A61B5/18—Devices for psychotechnics; Testing reaction times ; Devices for evaluating the psychological state for vehicle drivers or machine operators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
  • A61B5/6887—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient mounted on external non-worn devices, e.g. non-medical devices
  • A61B5/6893—Cars
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/70—Means for positioning the patient in relation to the detecting, measuring or recording means
  • A61B5/708—Breast positioning means
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
  • A61B5/7225—Details of analogue processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R22/00—Safety belts or body harnesses in vehicles
  • B60R22/12—Construction of belts or harnesses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/08—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to drivers or passengers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B2503/00—Evaluating a particular growth phase or type of persons or animals
  • A61B2503/20—Workers
  • A61B2503/22—Motor vehicles operators, e.g. drivers, pilots, captains
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
  • A61B2560/04—Constructional details of apparatus
  • A61B2560/0462—Apparatus with built-in sensors
  • A61B2560/0468—Built-in electrodes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
  • A61B2562/18—Shielding or protection of sensors from environmental influences, e.g. protection from mechanical damage
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
  • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb
  • A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/08—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to drivers or passengers
  • B60W2040/0872—Driver physiology
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2540/00—Input parameters relating to occupants
  • B60W2540/221—Physiology, e.g. weight, heartbeat, health or special needs

Definitions

• the present invention relates to the field of the collection of periodic vital signals emitted by the human body, in particular the heartbeat or the respiratory rate. It relates in particular to a device provided with a vibration sensor, which device is associated with safety equipment (for example, the seat belt) of a vehicle and allows the measurement of the heartbeat of the user.
• a vibration sensor which device is associated with safety equipment (for example, the seat belt) of a vehicle and allows the measurement of the heartbeat of the user.
• CN 106725395 offers a heart rate measurement module that includes two metal electrodes sandwiching the polyester webbing of the seat belt. Heartbeats force an insulating material placed between the two metallic electrodes to contract: the distance between the two metallic electrodes changes, thus modifying the capacitance value and giving information on the driver's heart rate.
• the present invention also relates to a solution associated with safety equipment of a vehicle. It relates in particular to a compact and sensitive device, provided with a vibration sensor, capable of capturing and analyzing the periodic vital signals of an individual in his vehicle.
• the invention relates to a device for measuring at least one periodic vital signal of an individual, intended to be attached to safety equipment of a vehicle so as to be placed between the individual and said equipment.
• the device comprises a vibration sensor comprising:
• a support layer flexible, configured to transmit a deformation to the active layer of the stack of layers at each pulsation of the vital signal, said support layer extending parallel to the main plane and including a printed circuit comprising two electrical terminals, the support layer being intended to be placed against the individual, - an electrical connection layer, placed between the stack of layers and the support layer, to connect each contact electrode to an electrical terminal.
• the device further comprises an acoustic attenuation member, intended to be placed between the safety equipment and the vibration sensor, said member being integral with the support layer and placed above and at a distance from the stack of layers .
• the acoustic attenuation member comprises a cover, made of a flexible material having a hardness of between 10 Shore 00 and 80 Shore 00, and secured to the support layer by its periphery;
• the cover is heterogeneous and comprises a second rigid material chosen from metals or polymers having a hardness of between 10 Shore D and 80 Shore D;
• the device comprises a mechanical attenuation member, on or integrated in whole or in part in the acoustic attenuation member, said mechanical attenuation member being intended to be in contact, direct or indirect, with the safety equipment ;
• the mechanical attenuation member comprises at least one damper and optionally a body forming a mass
• the active layer of the stack of layers has a thickness less than or equal to 20 microns and a Young's modulus greater than or equal to 60 GPa;
• the device comprises an impedance matching layer (40), having an acoustic impedance of between 5.105 Pa*s/m and 3.106 Pa*s/m, and arranged on a face of the support layer opposite to that in contact with the electrical connection layer;
• the piezoelectric material of the active layer is chosen from ceramics in monocrystalline, polycrystalline or composite form;
• the contact electrodes have a cumulative thickness less than twice the thickness of the active layer
• the support layer is self-supporting and has a thickness less than or equal to 500 microns;
• the impedance matching layer has a thickness greater than or equal to 10 microns
• the electrical connection layer is formed by an interposer or by an anisotropic conductive film
• the support layer includes a membrane arranged on a face of the printed circuit opposite to that in contact with the electrical connection layer;
• the stack of layers and the support layer respectively have a first area and a second area, in the main plane, the first area being less than or equal to 30% of the second area;
• the support layer comprises a stiffening structure, integral with a peripheral zone of said support layer, the acoustic attenuation member being itself integral with the stiffening structure;
• the printed circuit comprises a wired connection element, for connecting the vibration sensor to an electronic terminal;
• the vibration sensor comprises a peripheral seal;
• the device further comprises an electronic terminal connected to the vibration sensor, for analyzing and interpreting the raw signal and extracting the periodic vital signal or an output parameter representative of said periodic vital signal;
• the electronic terminal comprises an analog stage for conditioning the raw signal measured by the vibration sensor, an analog-to-digital conversion stage for the signal coming from the conditioning stage, a stage for processing the digital signal, for shaping the digital signal and the calculation of an output parameter representative of said vital signal;
• the electronic terminal comprises a communication stage with an external system.
• the invention also relates to a vehicle security system comprising:
• the safety equipment can be directly connected to the chassis by at least three contact points, and a mechanical energy absorber is then integrated into at least one of the contact points.
• the safety equipment can be connected to the seat, which is secured to the chassis by at least one contact point, and a mechanical energy absorber is then integrated into said contact point.
• FIG. 1 shows a security system comprising a device for measuring at least one periodic vital signal of an individual in a vehicle, in accordance with the invention
• Figures 2a and 2b show all or part of a device according to the invention, respectively in schematic section and in perspective;
• FIG. 3a and 3b show all or part of a device according to the invention, respectively in schematic section and in perspective;
• - Figure 4 shows different shapes, in top view, of the vibration sensor for a device according to the invention;
• FIG. 5 shows different configurations of devices for measuring a periodic vital signal, in accordance with the invention
• FIG. 6a shows two examples of acoustic attenuation member (i)(ii) and two examples of mechanical attenuation member (iii) (iv), for a device according to the invention
• FIG. 6b shows a device according to the invention, associated with safety equipment of a vehicle
• FIG. 7a shows a spectrogram A measured by a vibration sensor (alone) as included in the device of the invention and a spectrogram B measured by a device according to the invention; figure 7b presents the spectrogram B, a spectrogram B' extracted from the spectrogram B, a spectrogram B” after application of a frequency filter, and a vital signal B'” in wave form captured and processed by a device conforming to the invention.
• the invention relates to a device 200 for measuring at least one periodic vital signal, regular or irregular, of an individual.
• the periodic vital signal may in particular be the heart rate or the respiratory rate.
• the device 200 is intended to be attached to safety equipment 1, in a vehicle, so that said device 200 is placed between the individual and the equipment 1 (FIG. 1).
• safety equipment 1 is meant any equipment intended to secure the user on a seat of the vehicle, in particular a seat belt, one or more safety bar(s), a safety harness, etc.
• the vehicle can also be understood in the broad sense, and includes any mode of transporting people, rolling, flying, sliding or floating.
• the device 200 is preferably fixed to the safety equipment 1 by a sliding clip, that is to say a clip able to be clipped onto the equipment 1 to immobilize the device 200 in a given position, and able to slide (when it is unclipped), to allow each user to adjust the position of the device 200 on his thorax, according to his height and his diverence.
• the attachment system may allow a latitude of movement around the operating position, and this for the comfort of the user.
• the device 200 comprises a vibration sensor 100 and an acoustic attenuator 110.
• Different configurations of vibration sensors 100 in accordance with the present invention are illustrated in FIGS. 2a, 2b, 3a and 3b and will now be described.
• the vibration sensor 100 comprises a stack of layers 10 extending parallel to a main plane (x,y), that is to say that the main faces of this stack 10 are substantially parallel to the main plane (x,y ) and that the thickness of the stack 10 is measured along an axis z normal to said main plane.
• the denomination of layer implies that the thickness of the layer (or of the stack of layers) is, in general, significantly less than the lateral dimensions (in the main plane) of said layer.
• the stack of layers 10 includes an active layer 11 of piezoelectric material, preferably chosen from piezoelectric ceramics, in a monocrystalline, polycrystalline or composite form (corresponding to a dispersion of piezoelectric ceramic powder in a matrix, generally a polymer).
• active layer 11 of piezoelectric material preferably chosen from piezoelectric ceramics, in a monocrystalline, polycrystalline or composite form (corresponding to a dispersion of piezoelectric ceramic powder in a matrix, generally a polymer).
• the following ceramics can be mentioned: lithium niobate (LiNbCb), lithium tantalate (LiTaCb), potassium niobate (KNbCb), (BaTiCb), quartz (S1O2), magnesium niobate-lead titanate of lead (PMN-PT), lead zirconate titano (PZT), potassium sodium niobium lithium antimony (KNN-LS) or calcium titanate modified (KNN-LS-CT) materials, potassium based materials sodium lithium niobium tantalum antimony (KNLNTS), sodium bismuth titanate (BNKLBT), etc.
• the active layer 11 in piezoelectric material will polarize (and therefore generate a circulation of charges leading to a measurable electrical signal) if it undergoes a deformation, in particular here, deformation caused by the pulsation of the vital signal periodic.
• the active layer 11 advantageously has a thickness less than or equal to 20 microns and a Young's modulus greater than or equal to 60 GPa. These physical characteristics give the active layer 11 a high level of sensitivity (related to its thinness and to the fact that the measured voltage is all the greater, for a given deformation, than the Young's modulus is high) and to the sensor 100 a high signal-to-noise ratio, for the detection of acoustic waves in the frequencies relating to the periodic vital signals targeted. The small thickness of the active layer 11 also favors the compactness of the sensor 100.
• the thickness of the active layer 11 can be less than or equal to 10 microns, or even less than or equal to 5 microns, to further improve the detection sensitivity of the acoustic waves. Care will be taken to maintain a thickness of active layer 11 sufficient to generate bias voltages typically greater than 500 microvolts during deformation.
• the lateral dimensions (in the main plane (x,y)) of the active layer 11 can for example be chosen between 500 microns and 50 mm, small dimensions being of course preferred for reasons of compactness of the vibration sensor 100.
• the stack of layers 10 also includes two contact electrodes 12,13, arranged on one of the faces of the active layer 11 or on both faces (namely, on either side of the active layer 11), to allow the free circulation of charges, set in motion by the polarization (representative of the periodic vital signal) of said layer 11 .
• the contact electrodes 12,13 have a cumulative thickness less than twice the thickness of the active layer 11, or even less than the thickness of the active layer 11; each electrode 12,13 therefore advantageously has a thickness of less than 10 microns, or even less than 5 microns.
• the contact electrodes 12,13 may be formed from pure metallic materials (for example, Ag, Au, Pd, Pt, Cu, Ni, W or Ti), conductive alloys or 2D conductive materials (for example, graphene).
• a diffusion barrier for example, in TiN, WN or TaN
• a bonding layer for example, in Cr or Ti
• the stack of layers 10 consists of the active layer 11 and the two contact electrodes 12,13 only.
• the vibration sensor 100 also comprises a support layer 30, flexible, extending parallel to the main plane (x,y) and including a printed circuit 31 comprising two electrical terminals 32,33.
• An electrical connection layer 20 (which is also part of the vibration sensor 100) is arranged between the stack of layers 10 and the support layer 30, to connect each contact electrode 12,13 to an electrical terminal 32,33.
• the electrical connection layer 20 is advantageously formed by an interposer or by an anisotropic conductive film (ACF).
• ACF anisotropic conductive film
• connection layer 20 this face (known as the lower face) then being associated with the connection layer 20.
• the contact electrodes 12, 13 are respectively arranged on the lower face and the other face (known as the upper face) of the active layer 11 , it is advantageous to provide a conductive via 14 passing through said active layer 11 and electrically connecting electrode 12, disposed on the upper face, to a pad 12a disposed on the lower face and electrically isolated from the other electrode 13 also disposed on the underside.
• An interposer can be composed of thermoplastic resin (insulator) and an electrically conductive material (for example, nickel) allowing the connection between each contact electrode 12,13 and an electrical terminal 32,33.
• An anisotropic conductive film is conventionally composed of conductive balls dispersed in an insulating polymer matrix; when pressure or thermocompression is applied to the stack of layers 10/ACF 20/support layer 30 assembly, vertical electrical conduction is established between electrodes 12a, 13 and terminals 32,33 (usually extra thick) via the balls conductive, while the intermediate zones remain insulating.
• anisotropic conductive adhesives which could be used to form the electrical connection layer 20.
• These adhesives are based on the same principle as the aforementioned anisotropic conductive film (ACF), except that the matrix polymer is replaced by a liquid precursor capable of being thermally activated to form the final polymer (by polymerization); the final result remains similar to the ACF (conductive balls dispersed in an insulating matrix), but taking into account the fact that the application is done in the liquid phase, it is possible to drastically reduce the thickness of the electrical connection layer 20 .
• a more basic solution can also be considered: namely the implementation of a conductive paste to connect each electrode and pad of the lower face, to an associated terminal 32,33, and an insulating filling material to electrically isolate the electrodes 12a, 13 between them and the terminals 32,33 between them.
• the electrical connection layer 20 is only in contact with one of the main faces of the stack of layers 10; the edges and the other main face of the stack of layers 10 are completely free, without mechanical contact with the connection layer 20.
• the electrical connection layer 20 is therefore at least partly composed of an electrically conductive material and provides a direct vertical connection between electrodes and terminals, unlike a connection for example by cables or wires possibly coated in an insulator.
• the absence of cables improves the sensitivity of the 100 vibration sensor, avoiding the introduction of additional stiffness in the structure, linked to the cables and associated welds.
• the electrical connection layer 20 is therefore in direct and homogeneous contact against the entirety of a main face of the stack of layers 10.
• the layer 20 is advantageously in direct and homogeneous contact against one face of the support layer 30.
• the electrical connection layer 20 typically has a thickness of less than 50 microns, in particular a thickness of between 1 micron and 10 microns.
• the support layer 30 is a self-supporting layer, which advantageously has a thickness less than or equal to 500 microns. This gives it the required flexibility.
• the support layer 30 is essentially composed of the material forming the printed circuit 31: for example, a composite of epoxy resin reinforced with glass fibres.
• the support layer 30 also comprises a membrane 35, the printed circuit 31 then being located between the membrane 35 and the electrical connection layer 20 (FIGS. 2a and 3a).
• the material of the membrane 35, and its thickness, can thus be chosen and adjusted so as to confer the intended flexibility on the support layer 30.
• the membrane 35 can for example be formed of metal, polyvinyl chloride (PVC), or epoxy and fiberglass.
• PVC polyvinyl chloride
• the membrane 35 when present can have a thickness of between 50 and 300 microns
• the printed circuit 31 can have a thickness of between 30 and 200 microns.
• the support layer 30 has a stiffness of between 1150000 N/m and 6900000 N/m.
• the flexible character of the support layer 30, linked to its thickness and its stiffness, makes it possible to effectively transmit a deformation to the active layer 11, with each pulsation of the vital signal.
• the stack of layers 10 and the support layer 30 respectively have a first area and a second area, in the main plane (x,y), the first area being less than or equal to 30% of the second area.
• the stack of layers 10 can be arranged in the central part of the support layer 30, in particular for ease of assembly, or on the periphery to interfere as little as possible with the deformation of said support layer 30, which deformation is generated by the periodic pulsation of the vital signal that it is sought to measure; the overall objective is to optimize the deformation undergone by the stack of layers 10, this depending on the geometry of the vibration sensor 100. Note that, although illustrated in a square shape, the stack of layers 10 of the vibration sensor 100, can, of course, have any shape.
• the support layer 30 is intended to be in contact with the individual: the support layer 30 will then deform due to the periodic pulsation of the vital signal, and transmit this deformation to the active layer 11 of the stack 10.
• the vibration sensor 100 further comprises an impedance matching layer 40, which has an acoustic impedance ideally between 5.10 5 Pa*s/m and 3.10 6 Pa*s/m .
• This acoustic impedance is deliberately chosen close to the acoustic impedance of muscles and fat (impedance between 1.3.10 6 and 1.5.10 6 Pa*s/m), so as to favor the transmission of vital signal pulses to the support layer 30.
• the impedance matching layer 40 can be formed of silicone (acoustic impedance 1.6.10 6 Pa*s/m) or of bioplastic, for example of the Ecoflex® brand (acoustic impedance 1.6. 053.10 6 Pa*s/m).
• the impedance matching layer 40 is placed against the support layer 30, on a face of said support layer 30 opposite to that in contact with the electrical connection layer 20.
• the impedance matching layer 40 typically has a thickness greater than or equal to 10 microns, for example between 50 microns and 5 mm.
• the support layer 30 comprises a membrane 35, the latter is in contact with the impedance matching layer 40.
• the impedance matching layer 40 is intended to be in contact with the individual. In addition to efficiently transmitting pulsations due to its impedance matching with the body tissues, this layer 40 also promotes the maintenance of the sensor 100 against the individual because its flexible and deformable material tends to "adhere" to the surface of contact, by adhesion friction on clothing.
• the presence of the impedance matching layer 40, in the second embodiment of the sensor 100, is therefore particularly favorable when the measurement environment is noisy around the individual whose vital signal must be captured.
• the vibration sensor 100 may include a peripheral seal 60 surrounding at least the impedance matching layer 40 (when present) , as shown in Figures 3a and 3b, or surrounding all or part of the support layer 30 (in the absence of impedance matching layer 40).
• This joint 60 makes it possible to accommodate the local topology when the sensor 100 is placed in contact with the individual.
• the support layer 30 of the vibration sensor 100 can also comprise a stiffening structure 50, integral with a peripheral zone of the support layer 30.
• the function of the stiffening structure 50 is to immobilize the periphery of the support layer 30 and to the impedance matching layer 40 (if present), and thus to accentuate their deformation generated by the periodic pulsation of the vital signal that one seeks to measure.
• the stiffening structure 50 can take various forms such as for example:
• FIG. 4(b) a discontinuous frame, composed of two rigid zones (FIG. 4(b)), of three rigid zones (FIG. 4(c)), or even more.
• the stiffening structure is advantageously formed in a material having a hardness greater than 30 Shore D, such as PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), PU (polyurethane), PVC (polyvinyl chloride), PP (polypropylene), etc.
• PET polyethylene terephthalate
• PMMA polymethyl methacrylate
• PU polyurethane
• PVC polyvinyl chloride
• PP polypropylene
• the stiffening structure 50 participates in such a system.
• the device 200 comprises, in addition to the vibration sensor 100 which has just been described, an acoustic attenuation device 110, intended to be placed between the safety equipment 1 and the vibration sensor 100.
• This member 110 is arranged above and at a distance from the stack of layers 10 of the vibration sensor 100, and it is integral with the support layer 30. Because it is located at a distance (along the z axis on the figures) of the stack of layers 10 (without contact with the stack 10, therefore), typically at a distance of the order of 0.1 mm to 10 mm, it does not disturb the deformation of the latter in connection with the supporting layer 30.
• the acoustic attenuation member 110 advantageously takes the form of a cover (FIG. 6a (i), (ii)), the periphery of which is fixed to the support layer 30, or when it is present, to the structure of stiffening 50.
• the thickness of the cover, above the layer stack 10 can vary between 0.1 mm and 20 mm.
• the purpose of the acoustic attenuation device 110 is to isolate the acoustic sensor 100 (and more particularly the support layer 30 which deforms with the vibrations and the active layer 11 sensitive to said deformations) from the surrounding acoustic disturbances, which propagate in the air: namely, the sound of the engine, the sound of the road, the friction of the air on the bodywork, the voices of the passengers in the vehicle, the radio, etc. It is preferably composed of a flexible material of the elastomer type such as silicone, sorbothane or rubber. More generally, the flexible material of the acoustic attenuation member 110 can be qualified by its Shore hardness: it has a hardness of between 10 Shore 00 and 80 Shore 00. In addition to its acoustic attenuation function, the member 110 contributes to the robustness of the device 200 by protecting in particular the active layer 11 of the vibration sensor 100.
• the acoustic attenuation member 110 can comprise several types of materials. If it is in the form of a hood, then it is called a heterogeneous hood.
• the second material is chosen rigid, metallic or polymeric in nature (for example, aluminum, PVC). If the second material is a polymer, its hardness will preferably be chosen between 10 Shore D and 80 Shore D.
• the heterogeneous cover 110 is formed by alternating at least a first layer 110a of flexible material and at least a second layer 110b of rigid material as illustrated in FIG. 6a (ii).
• the heterogeneous cover can also be made of one or more porous material(s), such as polyurethane foam, for example.
• the device 200 further comprises a mechanical attenuation member 120 whose role is to isolate the vibration sensor 100 from the mechanical vibrations generated by the engine of the vehicle, by the road conditions and/or by the movements of the user, and transmitted to the security equipment 1 via the chassis.
• the mechanical attenuation member 120 is therefore intended to be in contact (direct or indirect) with the safety equipment 1 .
• This mechanical attenuation member 120 can be arranged on the acoustic attenuation member 110 or integrated in whole or in part into the latter.
• the mechanical attenuation member 120 is composed of a body 120a forming a mass and of at least one damper 120b (FIG. 6a (iii)).
• the body 120a is placed against the acoustic attenuation member 110 and the damper(s) is (are) placed on the side of the safety equipment 1 .
• the damper 120b is defined by a stiffness k comprised between 0 (friction alone) and 7 N/mm, and by a coefficient of friction f comprised between 0 (stiffness alone) and 0.6.
• Each damper 120b can for example be formed by a metal spring, a resin, rubber or silicone pillar, or even a simple, mixed (rubber/metal) or hydraulic damper element.
• the body 120a has a mass m of between 1 g and 1 kg.
• the mechanical attenuation member 120 forms a “mass-spring-piston” system acting as a high-pass mechanical filter.
• mass m By adjusting the mass m, the stiffness k and the coefficient of friction f, one can change the properties of the mechanical filter and specifically attenuate the mechanical vibrations transmitted to the safety equipment 1
• the mass of the acoustic attenuation device 110 and that of the vibration sensor 100 must be taken into consideration, and added to the mass of the body 120a to arrive at the properties of the mechanical filter desired.
• the mechanical attenuation member 120 is partially integrated into the acoustic attenuation member 110, that is to say that the body 120a consists of a layer of rigid material 110b which makes up said acoustic attenuation member 110 (for example, in the form of a heterogeneous cover, as illustrated in figure 6a (iv) ).
• the damping part 120b of the mechanical attenuation member 120 is then fixed to the acoustic attenuation member 110 and can be formed by the various elements stated in the first option.
• the mechanical attenuation member 120 is fully integrated into the acoustic attenuation member 110.
• the mechanical attenuation member 120 (included in the acoustic attenuation member 110) can be formed from composite materials with viscoelastic properties.
• the device 200 according to the invention can have a generally circular, square, rectangular or polygonal shape, in the main plane (x,y). As illustrated in Figure 6b, it is intended to be placed between the safety equipment 1 and the individual seated in the vehicle.
• the face of the device 200 located on the side of the support layer 30 of the vibration sensor 100 (and on the side of the impedance matching layer 40 when the latter is present), is placed against the thorax of the individual, preferentially in an area where the heartbeat or respiratory rhythm is palpable.
• the other face of the device 200 located on the side of the acoustic attenuation member 110 (and of the mechanical attenuation member 120, if present), is held against the safety equipment 1.
• the contact between the device 200 and the equipment 1 is preferably made by means of a sliding fastener 201 (FIG. 6b): in particular, the face of the device 200 is integral (glued or mechanically fixed) to a support element 201 a of the clip 201, which element is fixed to the safety equipment 1 by a sliding clip 201b.
• the device 200 has the advantage of strongly attenuating the frequencies situated outside the range of frequencies to be measured (range of frequencies typically between 0.2 Hz and 500 Hz for the heart and respiratory rhythms, or even frequencies less than or equal to 70 Hz) and also to attenuate parasitic frequencies located in the range of frequencies of interest.
• frequencies situated outside the range of frequencies to be measured range of frequencies typically between 0.2 Hz and 500 Hz for the heart and respiratory rhythms, or even frequencies less than or equal to 70 Hz
• parasitic frequencies located in the range of frequencies of interest.
• the sound environment of the individual at the time of taking the measurement therefore does not need to be calm and silent. This is possible thanks to the particular structure of the vibration sensor 100 as well as due to the presence of the acoustic attenuation member 110.
• the presence of the mechanical attenuation member 120 (or as will be described later with reference to the security system, object of the present invention, the presence of at least one mechanical energy absorber 210) attenuates significantly the mechanical vibrations produced by the engine in operation and possibly the irregularities of the road, vibrations which are transmitted to the safety equipment 1 via the chassis of the vehicle.
• the neutralization of these parasitic mechanical vibrations allows a reliable and reproducible capture of the vital signals of the individual by the vibration sensor 100.
• the device 200 is associated with a fabric 130 and a foam 140 to improve the comfort of the user (FIG. 6b).
• the fabric 130 can for example border the support layer 30 and the impedance matching layer 40 if it is present; it can, in general, border all or part of the vibration sensor 100 and thus provide a smooth and uniform surface of contact with the individual, which will make it possible to accommodate the morphologies of the user, the types of clothing and/or variations adjustment of safety equipment 1 .
• the foam 140 typically forms the link between the fabric 130 and the fastener 201; it is flexible and deformable and does not or very little modify the mechanical filter defined by the mechanical attenuation member 120.
• the fabric 130 may be formed of cotton, nylon, or even polyethylene; the foam 140 may be formed of polyurethane, polyethylene or polystyrene.
• the device 200 associated with safety equipment 1 in a vehicle, allows the measurement of at least one raw signal representative of a periodic vital signal of the individual installed in said vehicle.
• the device 200 further comprises an electronic terminal 150 electrically connected to the vibration sensor 100.
• the device 200 may comprise a sensor of vibration 100 (FIG. 5 (a), (b)) or a plurality (two or even more) of sensors 100 connected to the electronic terminal 150 (FIG. 5 (c)).
• a sensor of vibration 100 FIG. 5 (a), (b)
• a plurality (two or even more) of sensors 100 connected to the electronic terminal 150 FIG. 5 (c)
• the printed circuit 31 of the vibration sensor 100 may comprise a wired connection element 31b, for example a cord in the form of a sheet, as illustrated in FIGS. 2a, 2b, 3a, 3b and 5(a).
• the tip of the wired connection element 31b comprises electrical contact sockets, connected to the electrical terminals 32,33 of the printed circuit 31, and which can be connected to the electronic terminal 150.
• the electronic terminal 150 can be attached to the sensor 100 or located at a distance from the sensor 100, in particular on a module for fixing to the safety equipment 1 or to another part of the vehicle.
• the electronic terminal 150 can be connected or integrated into a more complex external system, such as a monitor, fixed or possibly transportable.
• the electronic terminal 150 can be arranged on the acoustic attenuation member 110 and form all or part of the body 120a of the mechanical attenuation member 120. This configuration ensures great compactness of the device 200. In this case, it is no longer possible to envisage a wired connection element 31b to electrically connect the vibration sensor 100 and the terminal 150, but contact points 82,83 rising vertically from the printed circuit 31 of the sensor 100 to the surface of the acoustic attenuation member 110, via the stiffening structure 50 for example (FIG. 5(b)).
• the terminal 150 may include various electronic stages allowing it to analyze and interpret the raw signal measured by the vibration sensor 100.
• An analog stage for conditioning the raw signal measured by the vibration sensor 100 will first of all amplify and filter the electrical signal received from the sensor 100.
• This stage is typically composed of a first block of the charge amplification type whose resistance ratio sets the amplification gain of the electrical signal received from the sensor 100, and a second block of Sallen & Key type filter allowing frequencies beyond the acoustic spectrum of the vital signals targeted to be filtered.
• the electronic terminal 150 then comprises an analog-to-digital conversion stage of the signal coming from the conditioning stage.
• a digital signal processing stage made up of a microcontroller, shapes the signal by calculating an envelope function of the Shanon energy type. Finally, from the shaped signal, the output parameter of interest, representative of said vital signal, can be calculated.
• the data collected, relating to the vital signal or the output parameter of interest, can be interpreted in real time and trigger the response of a secondary system included in the device 200 or external.
• the response can be feedback (visual, acoustic, mechanical, vibratory, etc.) and/or the triggering of one or more actions, for example:
• the response of the secondary system aims to inform the individual (typically the driver of the vehicle), or even to alert him, if the vital signal detected reveals that there is a risk of falling asleep or another abnormal situation.
• the electronic terminal 150 can include a communication stage.
• Known connection protocols CAN, UART, USB
• wireless data transmission Wi-Fi, bluetooth, etc.
• the device 200 it is also possible to provide a battery, preferably rechargeable, making it possible to supply energy to the vibration sensor 100 and/or the various aforementioned stages of the electronic terminal 150. If the terminal 150 is remote to an area of the vehicle's dashboard, it can be powered by the vehicle's battery.
• the device 200 can be declined in different configurations: - A portable and autonomous device, capable of being positioned on any vehicle safety equipment 1;
• the terminal 150 is wired to the sensor 100 or integrated into a fixed and more complex external system (system fixed to the dashboard of the vehicle or integrated into said dashboard).
• the present invention also relates to a security system of a vehicle comprising security equipment 1 attached (directly or indirectly) to the chassis of the vehicle, at at least one contact point 2 (FIG. 1).
• the safety equipment 1 can be directly connected to the chassis, usually via at least three contact points 2 for example for a seat belt.
• the safety equipment 1 may alternatively be indirectly connected to the chassis, when said equipment 1 is fixed to the seat of the vehicle, which seat is fixed to the chassis, at one or more contact points 2.
• the safety system comprises the aforementioned device 200 , for measuring at least one periodic vital signal of an individual (for example the driver of the vehicle), attached to the safety equipment 1 by a sliding clip 201 .
• the device 200 allows the effective collection and analysis of a vital signal from the individual in the vehicle in operation because it isolates the vibration sensor 100 from the vibrations mechanics of the engine transmitted to the safety device 1 by the frame, as will be illustrated later in the application example.
• a device 200 according to the invention devoid of the mechanical attenuation member 120, can also be implemented in the security system.
• the security system comprises at least one mechanical energy absorber 210 placed at at least one contact point 2, so as to isolate the security equipment 1 from the vibrations of the chassis, upstream of the vibration sensor 100 .
• a mechanical energy absorber 210 is preferably positioned at the contact point(s) 2 between the seat and the vehicle chassis .
• a mechanical energy absorber 2 it is also possible to position a mechanical energy absorber 2 at the point(s) of contact 2 between the seat and the chassis, in the case where the safety equipment 1 is connected directly to the chassis.
• the mechanical energy absorber 210 will form a mechanical filter and therefore comprises a body (mass) and a damper (stiffness, coefficient of friction), as has been described with reference to the mechanical attenuation member 120.
• a PZT precursor solution is deposited by centrifugation (“spin-coating”) on a sacrificial substrate (for example, aluminum), to form a viscous layer. An opening is made through said layer to allow the passage of an electrical path. Then, a heat treatment at 650°C is applied to crystallize the PZT and form an active layer 11 of piezoelectric material with a thickness of 5 microns.
• a temporary polymer layer e.g. PET, 200 microns thick, is attached to the layer polyurethane adhesive by thermocompression, to facilitate handling of the active layer 11 . The temporary layer is opened to allow passage of the electrical pathway, and filled with conductive glue, which will form the conductive via 14, in electrical contact with the contact electrode 12.
• the sacrificial substrate is then chemically etched until expose the lower face of the active layer 11 in PZT.
• the other contact electrode 13 and the pad 12a, in electrical contact with the via 14, are formed by depositing aluminum (approximately 400 nm) on said lower face of the PZT.
• the active layer 11 has lateral dimensions (along the main plane (x,y)) of 5 mm by 15 mm.
• a printed circuit (PCB) 31 is then chosen having a thickness of 100 microns, lateral dimensions substantially identical to those of the active layer 11 and comprising two electrical terminals 32,33.
• An anisotropic conductive film (ACF) 20 is laminated on the printed circuit 31 .
• the active layer 11 is positioned opposite the connection layer 20, so that each electrode 12a, 13 (on the lower face of the active layer 11) is located directly above an electrical terminal 32,33 of the printed circuit 31; then an assembly by thermocompression is operated.
• the temporary polymer layer can then be removed.
• the printed circuit 31 is then bonded to a PVC membrane 35, 300 microns thick and with lateral dimensions (or diameter) of 50 mm, to finalize the formation of the support layer 30.
• An impedance matching layer 40 made of silicone, with a thickness of 3 mm, can be assembled by lamination, screen printing or molding against the membrane 35.
• a stiffening structure 50 made of polypropylene and a peripheral seal 60 made of silicone are fixed to the periphery of the membrane 35 by interlocking.
• a silicone cover forming the acoustic attenuation member 110 above and at a distance from the active layer 11, is molded then glued to the stiffening structure 50. It has a thickness of 2 mm.
• a mechanical attenuation member 120 can also be formed: it is made up of rubber pillars 120b, glued to a steel body 120a 5 mm thick. The body 120a is glued against the acoustic attenuation member 110. On the side of their free end, the pillars 120b are glued to the support element 201a of a clip 201, which can be associated with the safety equipment 1 of one vehicle (a seat belt 1 in this example).
• the clip 201 can for example be formed from polyoxymethylene.
• the assembly can be covered with 130 fabric and/or 140 foam, around the measurement area.
• the printed circuit 31 comprises a wired element 31b (tablecloth) which makes it possible to connect the electrical terminals 32,33 of the printed circuit 31 to the electronic terminal 150, via electrical contact sockets.
• Terminal 150 includes the electronic stages set forth in the general description. For example, it is placed under the user's seat.
• FIGS. 7a and 7b an example of application to the measurement of the heart rate of a driver is illustrated in FIGS. 7a and 7b.
• the device 200 is adjusted in height along the safety belt 1, so as to be placed on the thorax of the individual, substantially on the left, the impedance matching layer 40 of the vibration sensor 100 being placed in contact with his clothes, and the mechanical attenuation member 120 being in contact with the seat belt 1, via the sliding fastener 201 .
• Figure 7a presents two raw A, B spectrograms, acquired on a frequency scale ranging from 0 to 150 Hz, by a vibration sensor 100 as previously described (acquisition frequency 128 kHz).
• the measuring device comprises neither the acoustic attenuation member 110 nor the mechanical attenuation member 120; the security system does not include a mechanical energy absorber 210 either. mechanical 120.
• the two spectrograms A, B show regular peaks which, after processing, provide reliable information on the driver's heart rate; this information is reliable regardless of the surrounding noise level in the vehicle.
• the vibrations of the engine generate a lot of parasitic noises and vibrations, which make the spectrogram A unusable.
• the device 200 according to the invention makes it possible to obtain a much less noisy B spectrogram, thanks to the presence of the acoustic 110 and mechanical 120 attenuation members.
• the vehicle security system comprises at least one mechanical energy absorber 210, at (x) point (s) of contact 2, direct or indirect, between the seat belt 1 and the chassis.
• the B” spectrogram is obtained by applying a filter between 40Hz and 70Hz and normalizing the signal.
• the peaks shown on the spectrogram B” can be visualized in the form of a wave: this is the signal B’”, which reveals the peaks representative of the driver’s heart rate.
• the signal B’ it is possible to extract the periodic signal and/or an output parameter, representative of the heart rate of the individual, with an excellent level of precision.
• the device 200 is capable of triggering an action (sound or light signal for example) as mentioned previously.
• the non-intrusive device 200 for measuring a periodic vital signal provides reliable information as to the vital signal of the driver, whatever the sound environment in the vehicle. , engine stopped or running.

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• 2022
  • 2022-05-11 US US18/561,471 patent/US20240225551A9/en active Pending
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