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WO2006030405A1 - Dispositif a transducteur pour mesurer des pressions biomedicales - Google Patents

Dispositif a transducteur pour mesurer des pressions biomedicales Download PDF

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Publication number
WO2006030405A1
WO2006030405A1 PCT/IE2005/000100 IE2005000100W WO2006030405A1 WO 2006030405 A1 WO2006030405 A1 WO 2006030405A1 IE 2005000100 W IE2005000100 W IE 2005000100W WO 2006030405 A1 WO2006030405 A1 WO 2006030405A1
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WO
WIPO (PCT)
Prior art keywords
transducer apparatus
sub
elements
sensor element
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IE2005/000100
Other languages
English (en)
Inventor
Vincent Casey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Limerick
Original Assignee
University of Limerick
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Limerick filed Critical University of Limerick
Publication of WO2006030405A1 publication Critical patent/WO2006030405A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6802—Sensor mounted on worn items
    • A61B5/6804—Garments; Clothes
    • 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
    • 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
    • A61B5/6892—Mats
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • G01L1/146—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors for measuring force distributions, e.g. using force arrays
    • 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
    • A61B2560/0406—Constructional details of apparatus specially shaped apparatus housings
    • A61B2560/0412—Low-profile patch shaped housings
    • 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
    • A61B2562/16—Details of sensor housings or probes; Details of structural supports for sensors
    • A61B2562/164—Details of sensor housings or probes; Details of structural supports for sensors the sensor is mounted in or on a conformable substrate or carrier

Definitions

  • This invention pertains to transducers for estimating the pressure applied to body-tissue by an object such as a medical device, bandage or dressing.
  • bandages have visual aids to help the clinician establish a constant extension in the bandage as it is applied, typically 50% extension.
  • bandage extension only provides a crude estimate of the actual tension in the bandage and so pressures calculated using the law of Laplace cannot be expected to reflect the actual sub-bandage pressure at a given location on a limb or support tissue with a great degree of accuracy.
  • a transducer which establishes the actual pressure applied by a device such as a bandage to the underlying tissue, in a continuous way, during the time while the bandage is being applied but also over prolonged periods of time while the patient is undergoing treatment.
  • a device such as a bandage to the underlying tissue
  • US6526043 (Boie et al) describes a tactile transducer having a planar deformable layer and multiple conductive elements on each side. This arrangement appears to be complex.
  • GB2199953 (Medimatch) describes a biomedical pressure transducer having fluid-filled cells.
  • US4869265 describes a biomedical pressure transducer having a pressurisable chamber containing integral membrane switch type electrical contacts interposed between the tissue and an apparatus such as a tourniquet cuff.
  • the normally closed contacts are opened when the pressure within the chamber is equal to the pressure applied by the cuff.
  • This approach does not appear to provide a continuous dynamic estimate of the pressure applied and suffers from signal damping introduced by the fluid line.
  • this device appears to be complex.
  • the invention is directed towards providing an improved transducer for measuring biomedical pressures.
  • a pressure transducer apparatus for measuring biomedical pressures, the transducer comprising:
  • a primary transduction part having a deformable sensor element
  • a secondary transduction part for measuring deformation of the sensor element, to generate an indication of pressure on the element, wherein:
  • the sensor element comprises a plurality of co-planar deformable sub- elements, and - A -
  • the secondary transduction part comprises an electrode on each side of the sensor element so that the sensor element is a dielectric, and a circuit for monitoring change in capacitance between the electrodes.
  • the sub-elements are arranged in an array.
  • the sub-elements have a trapezoidal shape in cross-section in at least one dimension.
  • the span to base ratio of the sub-elements is in the range of 0.1 to 1.
  • the ratio of the sub-element base width to height is in the range of 1 to 5.
  • the sensor element material is silicone.
  • the apparatus further comprises an encapsulant comprises opposed encapsulant layers, and preferably the encapsulant is flexible.
  • the apparatus further comprises a substrate for each electrode, each substrate having a thickness of less than 150 microns, wherein the sensor element has a thickness of less than 30 microns, and wherein the thickness of each encapsulant layer is less than 150 microns.
  • the overall thickness of the apparatus in a normal plane through the sensor element is less than 750 microns.
  • the sub-elements each have a trapezoidal cross section in at least one dimension and comprise a pair of parallel opposing surfaces in contact with the electrodes, and each sub-element has two or four free surfaces inclined at an angle of between 0 and 60 degrees to the normal to the plane of the electrodes.
  • the apparatus further comprises a screening electrode adhesively joined to the encapsulant at an external surface, and which is itself enclosed in an encapsulation layer.
  • the apparatus further comprises an adhesive member for attaching to medical dressings, devices or to living tissue.
  • the apparatus further comprises means for calibrating in terms of known ' values of pressure, wherein the calibrating means comprises inflatable bladders which contact the apparatus above and below the plane of the sensor element in order to impose predetermined pressure to the sensor element.
  • the invention provides a method of producing any pressure transducer apparatus as defined above, the method comprising the steps of:
  • the sub-elements are moulded onto the first electrode.
  • the sub-elements are moulded in a mould which is formed using a lithography stamp, in turn moulded from a micro-machined silicon master.
  • an adhesion promotion agent is applied to the first electrode before depositing the sub-elements.
  • the electrodes and electrical leads are on substrates.
  • the method comprises the further step of enveloping the sensor sub- elements and the electrodes in opposed encapsulant layers.
  • the encapsulant layers comprise polymer film.
  • the encapsulant layers are coated with adhesive on their inner surfaces.
  • part of an electrode protrudes from the encapsulation, and an edge connector is connected to the protruding part of the electrode.
  • the encapsulant layers are applied under controlled tension.
  • the tension is controlled to produce a pressure acting normal to the plane of the sensor element.
  • the tension is controlled to adjust the zero offset capacitance of the transducer apparatus
  • Fig. 1 is a schematic diagram depicting a flexible pressure transducer disposed between a bandage and a human limb as well as electronic processing circuitry;
  • Fig. 2 is a cross-sectional view in the direction of the arrows II - II of Fig. 1 showing details of the sensor construction of the invention;
  • Figs. 3 and 4 respectively illustrate a plan view and an exploded perspective view of the flexible pressure transducer;
  • Fig. 5 is a plan view and Fig. 6 a cross-sectional view in the direction of the arrows VI - VI, of a deformable layer of the transducer;
  • Fig. 7 is a plan view of an alternative deformable layer
  • Fig. 8 is a block diagram showing the electronic processing circuitry in more detail
  • Fig. 9 is a detailed circuit diagram illustrating an arrangement for connecting the transducer to the circuitry
  • Fig. 10 is a transducer calibration curve
  • Fig. 11 is an output display illustrating the course of the sub-bandage pressure variation as a bandage is applied to a human limb;
  • Fig. 12 is an output display illustrating the course of the sub-bandage pressure variation due to limb movement
  • Figs. 13 and 14 respectively illustrate a plan view and an exploded perspective view of an alternative embodiment of flexible pressure transducer
  • Figs. 15 and 16 respectively illustrate a plan view and an exploded perspective view of a further embodiment of flexible pressure transducer of the invention.
  • Fig. 17 is a schematic diagram depicting a flexible pressure transducer array disposed between a bandage and a human limb as well as electronic processing circuitry. Description of the Embodiments
  • a transducer 1 having an active part 2 is disposed between a limb 9 and a compression bandage 8.
  • the transducer 1 has a plurality of layers of materials including a deformable polymer sensor element 15, and the layers are stacked in a thickness direction.
  • the transducer 1 is positioned at a desired location on the limb 9 using an adhesive retainer 7 such as a medical adhesive tape or adhesive pads.
  • the primary transduction is compression of the sensor element 15, and the secondary transduction is monitoring change in capacitance between electrodes (16, 18) on either side of the sensor element 15, which is a dielectric.
  • Each of the layers of the transducer 1 is flexible and bendable out of a regular plane of the flexible transducer about both a lengthwise axis and a width- wise axis. This is achieved because of the configuration of the sensor element and the thin layers surrounding the sensor element.
  • electrode layers are of Cu but are nevertheless flexible because of the very small thickness. This flexibility allows excellent accuracy and non-intrusiveness for a patient.
  • a transducer apparatus comprises the transducer 1 and processing electronics including a Universal Transducer Interface (UTI) module 11 connected to the transducer 1 via a screened cable 10, for monitoring changes in capacitance between the electrodes to determine pressure.
  • the screened cable 10 is terminated with standard electronic connectors 3 and 41.
  • the UTI module 11 in turn is connected via a serial port cable 12 to a personal computer 13.
  • the active part 2 is electrically connected to the terminal end 43 using planar conductor tracks 4.
  • the transducer 1 and these electronic items together form a complete transducer apparatus.
  • polyimide such as Kapton, TM DuPont
  • a base substrate 6 and a top substrate 17 polyimide (such as Kapton, TM DuPont) tape 125 ⁇ m thick is used as a base substrate 6 and a top substrate 17.
  • a top electrode 18, and a base electrode 16 as well as the conductor tracks 4 comprising a top electrode interconnect track 38, a base electrode interconnect track 39, a top electrode flying track 19 and a screen track 37 are formed from 35 ⁇ m thick copper foil which is adhesively joined to the polyimide substrates 6 and 17.
  • An insulating polyester film is used as an encapsulation 5 (a) and 5(b) to enclose the entire assembly and seal it from the environment.
  • the base electrode 16 and the top electrode 18 have a circular geometry. The diameter of the base electrode 16 is 8mm.
  • the top electrode 18 has a diameter lmm smaller than that of the base electrode 16. This mismatch in the diameter of the electrodes reduces the criticality of alignment of the electrodes in order to obtain sensors with closely matched characteristics.
  • the diameter of the electrodes is not restricted to the value used here but may be chosen to suit the particular sensor application.
  • the deforniable polymer sensor element 15 comprises silicone rubber (polydimethylsiloxone, PDMS).
  • the sensor element 15 may be formed directly onto the copper base electrode 16 using a variety of techniques such as photolithographic printing, moulding and soft lithography.
  • a rigid polymer mould formed using a soft lithography stamp that in turn was moulded from a micro-machined silicon master is used to pattern the sensor element 15 onto either the top 18 or base copper electrode 16. Strong adhesion between the sensor element 15 and the copper electrode is achieved by treating the copper surface with an adhesion promotion agent such as DC1200 (TM Dow Corning).
  • an adhesion promotion agent such as DC1200 (TM Dow Corning).
  • the total thickness can be from less than 500 microns up to a maximum of lmm but is typically 700-800 microns (0.7-0.8mm), and the overall sensor width can be 10-20mm.
  • the reproducibility of the sensor element 15 thickness allows effective use of a capacitive transduction measurement technique.
  • the sensor element 15 comprises multiple sub- elements 46.
  • the pattern of the sub-elements 46 is chosen so as to achieve the optimum deformation characteristics for the application.
  • the shape in plan for the sub-elements 46 can be chosen from a range including square, (this embodiment), striped (cfr. strips
  • Important sensor element parameters to control relate to the cross-sections of the sub-elements, the spacing between neighbouring sub-elements, and the height of the sub-elements.
  • the shape of the sub-elements 46 is determined by the shape of the master mould used.
  • Micro-machined silicon moulds which have been formed through anisotropic etching of silicon produce pits and trenches with side walls tapered at an angle of 54.7° to the normal to the plane of the wafer.
  • Etching of square planar patterns will produce pits of trapezoidal cross section in silicon.
  • Etching of lines will produce trenches of trapezoidal cross section.
  • the etch depth will control the eventual height of the moulded sub-elements 46. However, the etch depth also determines the ratio of the contact surface area to that of the non-contact surface area for each sub-element.
  • the optimum span to base width ratio, (G/F), for sub- element 46 cross-sections is within a range from 0.1 to a maximum 1. At ratios greater than 1, excessive deformations will be encountered in the structure which will cause increased non-linearity in the relationship between the compressive stress in the body and the deformation of the body, and, a reduced working range for the device. A G/F ratio of less than 0.1 on the other hand, may cause contact between adjacent sub- elements 46 under load conditions.
  • the ratio of the base width, F, to the height, D, of the individual sub-elements 46, F/D can vary from a value of 1 to 5. A value of less than 1 would lead to a structure that would have relatively low resistance to shear loading.
  • S shape factor
  • S W/2R
  • R D/cos(A)
  • W the side width of the stripe.
  • S W 2 /(4R(W + ⁇ (F - W))
  • the deformable sensor element of the embodiment of Fig. 7 has sub-elements in the form of strips 47 with a similar cross-section along the lines VI - VI as the sensor element 15 of Figs. 5 and 6
  • the invention may be implemented using other suitable regular geometric shapes for the electrodes such as square or rectangle.
  • the dimensional extent of the sensor element 15 is chosen such that it extends at least 0.5mm beyond the perimeter of the base electrode 16 in order to electrically isolate the base electrode 16 from the top electrode 18 and also to ensure electrical isolation between a given electrode and the conductor track of the opposing electrode .
  • the base substrate 6 In addition to the base electrode 16 the base substrate 6 also supports a series of conductor tracks, 4.
  • the screen track 37 is used to isolate the electrode conductor tracks 38, 39 from each other and is positioned centrally on the base substrate 6.
  • the base electrode conductor track 39 electrically connects the base electrode 16 to the terminal end 43 of the transducer. It is positioned to one side of the screen track 37.
  • a top electrode conductor track 38 is positioned on the other side of the screen track 37 and is of similar dimensional extent to it.
  • the sensor element 15 is affixed to the base electrode 16 and extends over the edge of the base electrode 16.
  • the top substrate 17 supports the top electrode 18 and the top electrode flying track 19.
  • the top electrode flying track 19 is connected to the top electrode 18 at one end and extends over the end of the top substrate 17 at the other end by about 5mm.
  • the top substrate 17 has a minimum width equal to the diameter of the top electrode 18 plus lmm and may have a maximum width equal to the width of the base substrate 6. Its length is chosen such that it accommodates the top electrode 18 and provides for an overlap of the top electrode flying track 19 with the top electrode interconnect track 38 of at least 2mm.
  • the top electrode 18 and the top electrode flying track 19 are positioned on the top substrate 17 such that when the top substrate 17 is fixed in place the top electrode 18 faces the sensor element 15 with its centre directly over the centre of the base electrode 16 and the top electrode flying track 19 is directly above the top electrode interconnect track 38 of the base substrate 6. Electrical connectivity between the top electrode interconnect track 38 and the top electrode 18 is completed by soldering the top electrode flying track 19 to the top electrode interconnect track 38.
  • the widths and spacing of the conductor tracks is chosen to correspond with one of the standard PCB values so as to facilitate the use of standard cable interconnectors and PCB connectors. In the embodiment described here, the track width and spacing is lmm.
  • the encapsulation polymer film 5 is used to package the transducer assembly.
  • the encapsulation polymer film is coated on one side with thermally activated adhesive. Two layers of the film are used to achieve optimum encapsulation, a base encapsulation layer 5(a) and a top encapsulation layer 5(b).
  • the base substrate 6 is placed onto the adhesive coated side of the base encapsulation 5(a) and is positioned so that the terminal end 43 extends a distance of at least lcm beyond the end of the base encapsulation layer 5(a). This is sufficient to allow the use of pcb type edge connectors or other standard electrical connectors to be used to connect the transducer via standard cable assemblies to the UTI module 11.
  • the base encapsulation layer 5 (a) extends a distance of at least 2mm beyond the remaining sides and end of the transducer.
  • the top encapsulation layer 5(b) is then placed onto the base encapsulation layer 5 (a), adhesive coated side facing the adhesive coated side of the base encapsulation layer with all edges corresponding to the edges of the base encapsulation layer.
  • Encapsulation of the transducer and zero adjustment of the sensor zero pressure capacitance are achieved in the one process as follows.
  • the lateral edges of the encapsulation layers are clamped between metal straight edge clamps of a tensioning device.
  • the tension of the device is adjusted so as to produce a pressure acting normal to the plane of the transducer which presses the two substrates into intimate contact.
  • the zero offset capacitance of the sensor may be adjusted to a value corresponding to the lower limit of the sensor working range.
  • the encapsulation film is then heated to 110°C to activate the adhesive.
  • a very thin insulating polymer film such as Teflon tape 42 (Fig. 14) may be wrapped under tension around the sensor end of the transducer in order to bring the sensor electrodes into intimate contact with the sensor element and adjust the zero offset capacitance of the sensor to the lower limit of its working range.
  • encapsulation may be achieved by simple lamination with polyester laminate film or by moulding encapsulant around the transducer.
  • the transducer 1 may be placed between a compression bandage 8 and a limb 9 or tissue (Fig. 1).
  • the transducer 1 is sufficiently thin that it does not displace substantially the tissue from its normal location in relation to the compression bandage 8.
  • the pressure applied by the bandage 8 to the tissue may be determined using the transducer 1 in conjunction with the electronics circuitry.
  • the deformation of the sensor element 15 will result in a change in the degree of separation of the sensor top electrode 18 and the sensor base electrode 16. This will change the capacitance of the sensor 2 which is measurable using the electronic measurement system, illustrated schematically in Fig. 6 and Fig. 7.
  • the transducer 1 may be connected directly to the universal transducer interface module 11 or the cable assembly 10 may be used for this purpose.
  • the cable assembly 10 comprises at least one coaxially screened cable 48 and a second cable which may or may not be screened 49.
  • One electrode is connected via the screened cable 48 to the A pin 26 of the UTI chip 21.
  • the other electrode is connected to pin D 27 of the UTI chip 21 using the second cable 49.
  • a reference capacitor 24 is also connected via coaxially screened cable 50 to the A pin 26 of the UTI chip 21.
  • the other lead of reference capacitor 24 is connected to the C pin 28 of the UTI chip 21.
  • Pin F 30 of the UTI chip 21 is connected to ground.
  • the supply voltage is connected to the UTI chip 21 via pins Sel2 34 and PD 35 directly and via the potential divider resistors 32 (25k ⁇ ) and 33 (lk ⁇ ) to pin E 31.
  • the UTI chip 21 is designed for use in smart microcontroller-based systems. One output-data wire reduces the number of interconnect lines and reduces the number of opto-couplers required in isolated systems. Continuous auto-calibration of offset and gain of the complete system is performed by using a three-signal technique. Low frequency interference is removed by using an advanced chopping technique. The function selection can be configured in both software and hardware.
  • the mode of the UTI chip 21 can be used to measure a relatively large value of capacitance up to 30OpF.
  • the output signal of the UTI 21 is period modulated.
  • a microcontroller 23 is used to measure the period modulated signals from the UTI chip 21, to process the measured data and to output digital data to a personal computer 13 via a serial RS232 communication interface 22.
  • the RS232 interfacing chip 22 offers serial communication between the microcontroller 23 and, for instance a personal computer 13.
  • a 12 MHz crystal is used for the on-chip oscillator of the microcontroller 23.
  • the power supply 25 of 5 V is used for the UTI 21, microcontroller chip 21 and the RS232 interface 22.
  • the counting function of the microcontroller 23 is used to measure the periods of the output signal from the UTI chip 21.
  • the periods T AB , T AC and T AD are quantized in numbers, NA B , N AC and NAD, respectively by the microcontroller 23 and these numbers in turn relate to the offset capacitance C 0 the reference capacitor C ref 28 and the sensor 2 capacitor Cs .
  • C x may be accurately measured.
  • the quantized number NAD is proportional to this
  • Known pressures may be used to calibrate the sensor output, Xs, in any desired pressure units.
  • the method of transducer encapsulation used here facilitates absolute pressure calibration using a simple air compression chamber since the encapsulation provides an air-tight seal for the transducer.
  • the transducer is placed in the compression chamber and connected to an air-tight lead-through which facilitates connection of the sensor to the control electronics.
  • the air pressure within the chamber is adjusted in a controlled way to provide known pressures thereby allowing transducer calibration.
  • a particularly simple calibration is possible by applying two reference weights to the sensor corresponding to two datum points within the desired pressure measurement range, e.g. 20mmHg and 60mmHg for sub-bandage pressure measurement.
  • the weights are shaped such that they have a bottom smooth surface which has a geometry which corresponds exactly to the planar geometry of the sensor. Reliable and reproducible applied pressures are obtained once a soft elastomer layer 2mm thick is affixed to the base of the weights.
  • the transducer output is correlated with pressure by applying known pressures to the sensor and recording a calibration curve such as that shown in Fig. 10.
  • the linear response of the sensor makes this invention particularly easy to calibrate over the range of interest for sub-bandage pressure measurement.
  • a GUI displays the value of P as a function of time as depicted in Fig. 11.
  • the update rate is programmable but is typically in the range 10 to 50 readings per second.
  • a pre-tensioning film 42 which is selected from a range of insulating polymers including Teflon (TMDu Pont) and Cling Film (Saran, TMDow Chemical Company) is wrapped under tension around the electroded end of substrates 6 and 17 in order to adjust the sensor zero pressure capacitance to a desired value within the sensor working range.
  • This embodiment is particularly advantageous where it is desirable to use a moulded encapsulation layer such as silicone rubber rather than a polyester or other such preformed film as the transducer packaging.
  • a third embodiment is shown in Figs. 15 and 16 where the base electrode 16 and top electrode 18 oppose one another and are separated by the sensor element 15. There are no substrate layers 6, 17, and necessity for these is avoided because the base electrode 16 and top electrode 18 are formed directly onto the encapsulation layers 5. This embodiment is particularly advantageous where highly compliant flexible pressure transducers are required.
  • the compliance of the flexible pressure transducer may be adjusted by the choice of the encapsulation polymer layer 5 which may be selected from a wide range of polymers including polyester, rubber and other biomedically approved polymers.
  • further control over transducer compliance is afforded through the choice of encapsulation polymer layer 5 thickness.
  • a practical range of thicknesses for polyester encapsulation polymer layers 5 is from 12 to 150 microns.
  • the lower limit is determined largely as a compromise between the degree of compliance desired and the level of durability desired for the flexible pressure transducer 1. Generally, compliance will increase with reduced thickness. However, durability and ease of handling will decrease with reduced thickness. The upper limit is largely determined by the durability and ease of handling desired. Thicker encapsulation will generally confer increased durability and increased ease of handling possibly at the expense of an increase in intrusiveness and/or reduced the accuracy.
  • EMI screening consistent with best practice in sensors technology may be provided by adhesively joining a continuous layer of copper foil, or by spray coating a proprietary screening film, onto the base encapsulation layer and connecting this electrically to the screen track 37 which in turn is connected to the UTI ground.
  • This screening film may be extended over the encapsulated interconnect track region of the transducer but should not cover the top electrode sensor region nor should it contact electrically the terminal area 43 of the transducer.
  • the entire screening layer may be conveniently electrically isolated by encapsulating it in 12 ⁇ m thick insulating adhesive tape.
  • the invention may also be used to form one-dimensional and two-dimensional flexible pressure transducer arrays.
  • Fig. 17 demonstrates a one-dimensional transducer array comprising a linear series of three sensors which is particularly advantageous for measuring pressure gradients along a limb during compression therapy (such as used in the treatment of venous leg ulcers).
  • the transducer may be sterilized by heating in an autoclave or by exposure to UV radiation.
  • the transducer combines a pressure sensor, sensor package (encapsulant) (which in addition to normal packaging functions provides a means of zero offsetting the sensor) and interconnects in a single integrated solution which has an ultra low profile, is flexible, so that it can be incorporated into arrays which conform to body parts/tissue. Because of the extremely low profile of the sensor (minimally intrusive) and its structure it is relatively immune to 'hammocking" errors.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Surgery (AREA)
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  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un dispositif à transducteur comportant un transducteur (1) et qui se place par exemple entre un bandage (8) et la jambe (9) d'un patient. Une partie active (2) comporte un élément sensible (15) comprenant un réseau de sous-éléments (46) de forme trapézoïdale en section. L'élément sensible (15) est un diélectrique se situant entre des électrodes (16, 18) prévues sur des substrats (6, 17). L'ensemble est enveloppé dans des films (5a et 5b) polymères d'encapsulation. L'élément sensible (15) est conçu de manière à produire une réponse linéaire, et sa forme très mince peu encombrante garantit un étalonnage fiable.
PCT/IE2005/000100 2004-09-14 2005-09-14 Dispositif a transducteur pour mesurer des pressions biomedicales Ceased WO2006030405A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60924504P 2004-09-14 2004-09-14
US60/609,245 2004-09-14

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WO2006030405A1 true WO2006030405A1 (fr) 2006-03-23

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2439750A (en) * 2006-07-06 2008-01-09 Wound Solutions Ltd Monitoring a limb wound
WO2008102308A3 (fr) * 2007-02-23 2008-10-23 Philips Intellectual Property Mesure de pression et de force de cisaillement dans des textiles portables
WO2009023937A1 (fr) * 2007-08-22 2009-02-26 Commonwealth Scientific And Industrial Research Organisation Système, vêtement et procédé
JP2009192256A (ja) * 2008-02-12 2009-08-27 Toshiba Corp 圧力センサおよびロボットハンドシステム
FR2940904A1 (fr) * 2009-01-13 2010-07-16 Urgo Laboratoires Systeme de mesure de pression d'interface
DE102010005792B3 (de) * 2010-01-25 2011-06-16 Innovations-Transfer Uphoff Gmbh &.Co.Kg Druckkraftmesseinrichtung
WO2013073677A1 (fr) * 2011-11-18 2013-05-23 国立大学法人長崎大学 Capteur capacitif
WO2014086673A1 (fr) * 2012-12-04 2014-06-12 University Of Limerick Système de mesure de pression d'interface intrabuccale
US8764685B2 (en) 2011-06-14 2014-07-01 Abatis Medical Technologies Limited Biomedical interface pressure transducer for medical tourniquets
US8925392B2 (en) 2012-01-30 2015-01-06 Sensoria Inc. Sensors, interfaces and sensor systems for data collection and integrated remote monitoring of conditions at or near body surfaces
US9281415B2 (en) 2010-09-10 2016-03-08 The Board Of Trustees Of The Leland Stanford Junior University Pressure sensing apparatuses and methods
WO2020081769A1 (fr) * 2018-10-18 2020-04-23 Boston Scientific Scimed Inc Dispositif multicouche pouvant être porté
JP2021001839A (ja) * 2019-06-24 2021-01-07 国立大学法人弘前大学 接着力センサ、多点接着力センサおよび多点接着力センサの製造方法
JP2021148694A (ja) * 2020-03-23 2021-09-27 豊田合成株式会社 センサユニット
WO2022008927A1 (fr) * 2020-07-09 2022-01-13 Veinsense Ltd Bande de capteurs de pression

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3875481A (en) 1973-10-10 1975-04-01 Uniroyal Inc Capacitive weighing mat
US4266263A (en) 1977-01-21 1981-05-05 Semperit Aktiengesellschaft Force measuring capacitor
US4584625A (en) 1984-09-11 1986-04-22 Kellogg Nelson R Capacitive tactile sensor
GB2199953A (en) 1986-11-27 1988-07-20 Medimatch Limited Measurement of pressure at an interface
US4869265A (en) 1987-04-03 1989-09-26 Western Clinical Engineering Ltd. Biomedical pressure transducer
US5447076A (en) * 1990-09-01 1995-09-05 Ziegler; Karlheinz Capacitive force sensor
US5693886A (en) 1995-07-28 1997-12-02 Nippon Dyne-A-Mat Corp. Pressure sensor
US6526043B1 (en) 1996-10-28 2003-02-25 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for charging for an outgoing voice call performed during an internet session
US6636760B1 (en) 1998-07-03 2003-10-21 Vincent Casey Planar transducer for measuring biomedical pressures

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3875481A (en) 1973-10-10 1975-04-01 Uniroyal Inc Capacitive weighing mat
US4266263A (en) 1977-01-21 1981-05-05 Semperit Aktiengesellschaft Force measuring capacitor
US4584625A (en) 1984-09-11 1986-04-22 Kellogg Nelson R Capacitive tactile sensor
GB2199953A (en) 1986-11-27 1988-07-20 Medimatch Limited Measurement of pressure at an interface
US4869265A (en) 1987-04-03 1989-09-26 Western Clinical Engineering Ltd. Biomedical pressure transducer
US5447076A (en) * 1990-09-01 1995-09-05 Ziegler; Karlheinz Capacitive force sensor
US5693886A (en) 1995-07-28 1997-12-02 Nippon Dyne-A-Mat Corp. Pressure sensor
US6526043B1 (en) 1996-10-28 2003-02-25 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for charging for an outgoing voice call performed during an internet session
US6636760B1 (en) 1998-07-03 2003-10-21 Vincent Casey Planar transducer for measuring biomedical pressures

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2439750A (en) * 2006-07-06 2008-01-09 Wound Solutions Ltd Monitoring a limb wound
WO2008102308A3 (fr) * 2007-02-23 2008-10-23 Philips Intellectual Property Mesure de pression et de force de cisaillement dans des textiles portables
WO2009023937A1 (fr) * 2007-08-22 2009-02-26 Commonwealth Scientific And Industrial Research Organisation Système, vêtement et procédé
US9427179B2 (en) 2007-08-22 2016-08-30 Sensoria Inc. System, garment and method
US9186092B2 (en) 2007-08-22 2015-11-17 Sensoria, Inc. System, garment and method
JP2009192256A (ja) * 2008-02-12 2009-08-27 Toshiba Corp 圧力センサおよびロボットハンドシステム
US8894590B2 (en) 2009-01-13 2014-11-25 Laboratoires Urgo Interface pressure measurement system
FR2940904A1 (fr) * 2009-01-13 2010-07-16 Urgo Laboratoires Systeme de mesure de pression d'interface
WO2010081989A1 (fr) * 2009-01-13 2010-07-22 Laboratoires Urgo Systeme de mesure de pression d'interface
DE102010005792B3 (de) * 2010-01-25 2011-06-16 Innovations-Transfer Uphoff Gmbh &.Co.Kg Druckkraftmesseinrichtung
US9281415B2 (en) 2010-09-10 2016-03-08 The Board Of Trustees Of The Leland Stanford Junior University Pressure sensing apparatuses and methods
EP2614511B1 (fr) * 2010-09-10 2018-02-28 The Board of Trustees of the Leland Stanford Junior University Appareils et procédés de détection de pression
US10545058B2 (en) 2010-09-10 2020-01-28 The Board Of Trustees Of The Leland Stanford Junior University Pressure sensing apparatuses and methods
US8764685B2 (en) 2011-06-14 2014-07-01 Abatis Medical Technologies Limited Biomedical interface pressure transducer for medical tourniquets
WO2013073677A1 (fr) * 2011-11-18 2013-05-23 国立大学法人長崎大学 Capteur capacitif
US8925392B2 (en) 2012-01-30 2015-01-06 Sensoria Inc. Sensors, interfaces and sensor systems for data collection and integrated remote monitoring of conditions at or near body surfaces
WO2014086673A1 (fr) * 2012-12-04 2014-06-12 University Of Limerick Système de mesure de pression d'interface intrabuccale
WO2020081769A1 (fr) * 2018-10-18 2020-04-23 Boston Scientific Scimed Inc Dispositif multicouche pouvant être porté
JP2021001839A (ja) * 2019-06-24 2021-01-07 国立大学法人弘前大学 接着力センサ、多点接着力センサおよび多点接着力センサの製造方法
JP2021148694A (ja) * 2020-03-23 2021-09-27 豊田合成株式会社 センサユニット
WO2022008927A1 (fr) * 2020-07-09 2022-01-13 Veinsense Ltd Bande de capteurs de pression
US20230255837A1 (en) * 2020-07-09 2023-08-17 Veinsense Ltd. Pressure sensor strip

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