Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
  • G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
  • G01B7/20—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance formed by printed-circuit technique
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/28—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures
  • G01B7/281—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures for measuring contour or curvature along an axis, e.g. axial curvature of a pipeline or along a series of feeder rollers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/28—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures
  • G01B7/287—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures using a plurality of fixed, simultaneously operating transducers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/28—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures
  • G01B7/293—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring contours or curvatures for measuring radius of curvature
• • 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
  • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
  • G01L1/205—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using distributed sensing elements
• • 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
  • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
  • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
  • G01L1/2287—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges constructional details of the strain gauges
• • 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
  • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
  • A61B2562/0261—Strain gauges
• • 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
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
  • A61B5/0015—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network characterised by features of the telemetry system
  • A61B5/002—Monitoring the patient using a local or closed circuit, e.g. in a room or building
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Detecting, measuring or recording 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, mobility of a limb
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
  • A61B5/4538—Evaluating a particular part of the muscoloskeletal system or a particular medical condition
  • A61B5/4566—Evaluating the spine
• • 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

Definitions

• the present invention relates to a flexible sensor strip for measuring geometric shapes, such as in particular bending radii or the like. It is also possible to use a suitable evaluation device to measure and evaluate the associated time course of these geometric shapes and thus to determine corresponding movements, such as in particular bending, twisting (torsion) and/or expansion.
• Sensor strips of the type mentioned are known in principle and often contain a large number of electrical elements which can function as resistors and/or capacitors and are applied to a flexible substrate. If such a sensor strip undergoes suitable mechanical deformations, such as bending, twisting (torsion), stretching, compression or the like, some of these electrical elements can be stretched and others compressed. This results in changes in the resistance or capacitance values, which can be detected using an evaluation unit. Suitable algorithms can be used to determine where and how one of the mechanical loads mentioned occurs.
• German patent application DE 10 2008 052 406 A1 relates to a method for detecting functional parameters for characterizing movement sequences on human or animal bodies and a bending sensor for carrying out the method.
• strain gauges are provided, which are used to detect stretching deformations by changing their impedance, such as in particular their electrical resistance, even with small deformations.
• a tensile but elastically flexible substrate is preferably provided there, such as spring steel.
• an adhesive layer such as epoxy resin is used by the stretch marks attached thereto.
• International publication WO 2011/032575 A1 relates to a method and a system for detecting functional parameters for characterizing movement sequences on the human body, in particular in the area of the lumbar spine, and a method for analyzing such functional parameters.
• bending sensors are used in which strain gauges are attached, for example glued, to a substrate.
• An electronic printed circuit board or spring steel strip, among other things, are suggested there as substrate material.
• the realization of the electrical contacts between the strain gauges and conductor tracks on the printed circuit board takes place there, for example, by soldering a copper foil strip.
• the bending sensor comprises a plurality of strain gauges, two of which are attached to opposite sides of the substrate in such a way that both strain gauges detect the same bending of the substrate, which reproduces the bending or deflection of the examination object, for example a human back.
• interference variables can be compensated with the help of a bridge circuit, e.g. a Wheatstone measuring bridge, which forms a difference signal from the signals of the two strain gauges and the actual measuring signal can be amplified.
• a bridge circuit e.g. a Wheatstone measuring bridge, which forms a difference signal from the signals of the two strain gauges and the actual measuring signal can be amplified.
• fault influences such as tensile or compressive stresses, as well as temperature fluctuations, which can possibly cause additional changes in length of the substrate, can be compensated for.
• the international publication WO 2016/030752 A1 relates to a stretchable and flexible sensor and an associated system for measuring and processing data relating to movements, such as that of a back or limbs of a person or an animal.
• an elastic film strip (2) a plurality of strips (3) attached, such as by stitching (stitching), gluing, clamping, etc.
• Fig. 4 a particular embodiment in which two groups of parallel strips to form a herringbone pattern. These strips can be designed as capacitors or as elastic individual wires with a length-dependent resistance.
• the sensor strip according to the invention is defined by the main claim.
• Advantageous further developments are defined by the dependent claims.
• the subsequent device claims relate to an associated measurement and evaluation device.
• the sensor strip according to the invention has a flexible substrate which, in particular, can be bent and/or twisted (twisted).
• a film made of polyethylene terephthalate (PET) has proven particularly useful for this purpose, the thickness of which can be in the range from 10 to 1000 ⁇ m and preferably in the range from 100 to 400 ⁇ m and particularly preferably around 300 ⁇ m.
• PET polyethylene terephthalate
• other flexible materials such as polyurethanes (PU), thermoplastic polyurethane (TPU), polyethylene terephthalate (PET), polyamide (PA), other plastics and/or other suitable materials.
• At least a first pair of resistors is present on the substrate.
• a first electrical resistor is provided on one of the substrate sides, which is referred to below as the front side.
• a second resistor is provided on the other side of the substrate, which is referred to below as the rear side.
• These two resistors are designed and arranged in such a way that they essentially opposite.
• slight deviations are possible that affect the geometry and/or position. These are also to be expected, in particular due to manufacturing tolerances. It has been shown that position deviations up to certain values are quite possible and still deliver quite good results.
• Corresponding tolerance values are dependent, among other things, on the thickness of the substrate and/or on the size of the resistors. It has been shown that position deviations of up to approx. 1 to 2 mm and/or up to approx. 10% of the resistor size are tolerable. It is also possible to make corresponding electronic corrections as part of the subsequent signal evaluation.
• the first connection of the first resistor is electrically connected to a first supply line, via which it is connected to the first pole of a supply voltage.
• the first connection of the second resistor is electrically connected to a second supply line, via which it is connected to the second pole of the supply voltage. This second pole can be electrically connected to the ground connection of an electrical unit to which the sensor strip is connected.
• the second connections of the resistors are electrically connected to one another, so that the resistors form a voltage divider.
• This can be implemented, for example, by providing at least one via for the electrical connection between the second terminals of the two resistors.
• a via is any type of electrical connection that runs through an opening in the substrate between the front and the back and also electrically connects a first conductor track on the substrate front with a second conductor track on the substrate back.
• the first conductor track is in electrical contact with the second connection of the first resistor and the second conductor track is in electrical contact with the second connection of the second resistor.
• an electrical connection between the second terminals of the resistors can also be achieved in that the first conductor track on the front side of the substrate and/or the second conductor track on the rear side of the substrate run into an edge area of the substrate and are designed and arranged there in such a way that that they each have a contact point via which they can be electrically connected.
• Such an electrical connection is preferably implemented in that a first contact element has electrical contact with the first conductor track during normal operation--ie when the sensor strip is ready to carry out measurements--and a second contact element has electrical contact with the second conductor track during normal operation.
• Such a sensor strip according to the invention is very compact and also easy to produce.
• the supply voltage is present, so that a voltage divider is implemented, with the middle voltage being present at the second terminals of the resistors.
• Its value depends on the one hand on the supply voltage and on the other hand on the ratio of the resistance values (first resistance, second resistance) to one another.
• the two resistance values are preferably of the same magnitude when the substrate is in one plane without mechanical stress, such as the plane of the drawing. Now, if the substrate itself is moved, such as by bending and/or twisting (torsion), the resistance values change.
• Such a body can be an object such as a rod, a sphere or the like.
• the mean voltages are recorded by means of a suitable evaluation unit at predetermined time intervals and/or at predetermined times, and associated measured values are formed and evaluated.
• At least one second pair of resistors is provided.
• a first resistor is arranged on the front side of the substrate and a second one on the back side of the substrate.
• the first connection of the first resistor is electrically connected to the first pole of the supply voltage and the first connection of the second resistor is electrically connected to the second pole of the supply voltage.
• the second connections of the two resistors are electrically connected to one another, so that a voltage divider is formed. It is possible, but not mandatory, for the electrical connection between the second resistor terminals to have at least one through-contact or an electrical contact of the type mentioned above is available.
• This second pair of resistors is very similar to the first pair of resistors, so that reference is also made to the description above.
• the substrate is arranged in such a way that it extends along the x-y plane, that is to say it lies in the plane of the drawing.
• Such a state is also referred to below as an idle state.
• the following cases can then be distinguished for the present invention. a) A first pair of resistors and a second pair of resistors If only one of the first pair of resistors and only one of the second pair of resistors are present, then these are arranged next to one another. This means that the first pair of resistors is, for example, to the left of the second pair of resistors (x-direction). Both pairs of resistors can be at the same level or at different levels (y-direction). b) Several of the first pairs of resistors and/or several of the second pairs of resistors
• first resistor pairs are arranged one above the other (y-direction). It is possible that they are offset laterally (x-direction) to one another. If two or more of the first Resistor pairs are present, these are also arranged one above the other (y-direction) and can also be offset laterally (x-direction).
• the first pairs of resistors are located next to (e.g. to the left of) the second pairs of resistors, with an offset of adjacent pairs of resistors in y direction is possible.
• the number of the first pairs of resistors can differ from the number of the second pairs of resistors.
• a perpendicular can be defined which runs between the adjacent pairs of resistors and along the y-axis.
• This perpendicular can, for example, correspond to the longitudinal axis of the sensor strip, as is provided further below in connection with the description of preferred exemplary embodiments.
• At least some of the resistors mentioned preferably have an elongated base area. This means that they have a length that is significantly greater than their width.
• An associated resistance longitudinal axis can be determined from this. This is used in the following to define an angle of inclination between the pairs of resistors and the mentioned vertical. This angle can have a value between zero degrees and 90 degrees (in each case inclusive), with values between 20 and 40 degrees, and in particular a value of approximately 30 degrees, having proven particularly useful. It is possible that the values of these angles of inclination are the same for all pairs of resistors. However, it is also possible that they are different.
• the value of said angle of inclination determines in particular the type of possible measurement with the associated pair of resistors. This is discussed in more detail below in the description of the exemplary embodiments. If, for a specific number of first pairs of resistors, the same number of second pairs of resistors is arranged mirror-symmetrically with respect to the vertical, the sensor strip is particularly well suited for measuring torsions.
• a high-impedance paste is applied to the substrate, such as a carbon-based paste, CNT-containing paste, an electrically conductive polymer (eg PEDOT) or the like.
• a thickness in the range of about 5 to 20 ⁇ m is preferably used. Other thicknesses can also be used with other materials.
• a single resistance layer carbon layer
• a single line layer silver layer
• These layers are almost symmetrical about the y-axis (longitudinal axis) and can be used for printing on the front of the substrate as well as for printing on the back of the substrate.
• the sensor strip according to the invention can be divided into a sensor area, in which the resistors mentioned are arranged, and a contact area, in which electrical connections for an evaluation unit and/or for the above-mentioned electrical contact connections between first conductor tracks on the substrate front side and second ones Traces can be produced on the substrate back, such as by means of a connector, a clamp connection, a solder connection and/or by electrical adhesive.
• the contact area is deformed less than the sensor area in normal operation—that is, when an object (or body) is to be measured. This can be done in various ways, for example through the design of the substrate, through the existing electrical connection to the evaluation unit (in particular through a plug) and/or through appropriate attachment of the sensor strip to the object to be examined.
• the contact area is therefore also less mechanically stressed than the sensor area. It is therefore particularly advantageous to arrange at least some of the vias in this contact area in order to increase reliability.
• the sensor strip according to the invention is intended to be part of a measuring device that can measure and evaluate geometric shapes and/or dynamic movements of objects, human bodies, animal bodies, etc.
• the sensor strip is connected to an evaluation unit via suitable electrical connections. This emits the supply voltage and takes the middle voltages generated by the pairs of resistors functioning as voltage dividers as sensor signals, evaluates them and then generates an output signal that is a measure of resistance changes within the individual pairs of resistors and thus also of deformations and/or or movements experienced by the sensor strip.
• the evaluation unit can also generate a reference voltage whose value essentially corresponds to the voltage which the voltage dividers each output in the idle state.
• a differential voltage is formed from the reference voltage and the respectively measured voltages, which is amplified and evaluated.
• the evaluation unit contains a time-controlled switch (multiplexer) of the individual Center voltages emitted by voltage dividers are successively fed to further stages, such as amplifier stages, analog/digital converters, etc.
• the evaluation unit also includes memories in which values are stored that are a measure of the position or change in position of the individual resistor pairs within the sensor strip. An output signal is generated from the individual center voltages and the associated position data, which is a measure of the geometric shape and graphic representation of the sensor strip.
• the evaluation unit also includes one or more time stages, which activate the multiplex switch and/or the further stages at specified times and/or after specified time intervals in such a way that the center voltages emitted by the individual voltage dividers are processed. Dynamic movements or movement sequences of the object (body) to be examined can thus be created, such as in particular courses, speeds and/or accelerations of movements.
• the output signal generated by the evaluation unit can therefore also contain this information.
• the evaluation unit also includes a transmission stage. This is supplied with a signal which is a measure of the output signals generated. From this, a high-frequency signal is preferably generated, such as a Bluetooth or a WLAN signal, which can be received and further processed by a suitable device, such as a tablet computer, a smartphone, a PC or the like. It is possible for the output signal to be evaluated, stored and/or displayed on such a device using a suitable algorithm (such as an app or the like).
• a suitable device such as a tablet computer, a smartphone, a PC or the like. It is possible for the output signal to be evaluated, stored and/or displayed on such a device using a suitable algorithm (such as an app or the like).
• Fig. 2 front conductor tracks of the first sensor strip
• FIG. 6 shows a symbolic top view of through-plating between a front-side and a back-side conductor track
• FIG. 10 shows the upper section B of the second sensor strip
• FIG. 11 shows the lower section C of the second sensor strip
• FIG. 1 shows a Cartesian coordinate system (top left), a plan view of a first sensor strip 9 and on the right side a symbolic marking for distinguishing between a sensor area S and a contact area K of the sensor strip 9.
• This is located here within the xy level and thus in the drawing level.
• It contains a substrate 10, which consists of a material that is flexible, twistable and/or stretchable and, in the embodiment shown here, is transparent.
• a PET film polyethylene terephthalate
• the substrate 10 has a front side 12 (see FIGS. 1 and 7) and a back side 14 (see FIG. 7).
• the front 12 could also be referred to as the top.
• FIG. 2 shows those conductor tracks which are arranged on the front side 12 of the substrate 10 and FIG. 3 shows the sensor resistances of the front side 12.
• FIG. 3 shows the sensor resistances of the front side 12.
• two of these contact points 16 are connected via a conductor track 18 to a supply conductor track 20 on the front side, which here essentially runs along the longitudinal axis LA.
• Contact points 22r to the right of the supply conductor track 20 and contact points 22I to the left thereof are electrically connected to the supply conductor track 20 via associated connections.
• Each of the contact points 22r has an associated contact point 24r, which is electrically connected to one of the contact points 16 via an associated conductor track 26r.
• Five of the pairs of contact points 22r, 24r are shown in Figures 1 and 2, only two of which are referenced (see Figure 2). Between each of these pairs of contact points 22r, 24r runs one of five sensor resistors 28r, which here have an elongate, rectangular shape.
• the uppermost of these sensor resistors 28r runs in such a way that it and thus also its longitudinal axis form a right angle with the supply conductor track 20 and therefore also with the longitudinal axis LA.
• the lowest of these sensor resistors 28r runs essentially parallel to the supply conductor track 20 and thus also to the longitudinal axis LA.
• its longitudinal axis lar and also an angle of inclination a are shown in FIG. 1, which is defined by the two longitudinal axes LA and lar and is approximately 45 degrees.
• contact points 24I to the left of the upper supply conductor track 20, and thus of the longitudinal axis LA, which are each connected to a conductor track piece 25I.
• Each of these conductor track pieces 25I is connected via a special via to a conductor track 1261, which is located on the substrate rear side 14 and to the left of the longitudinal axis LA. Details are described below.
• Similar to the right-hand side there are also five pairs of contact points 22I, 24I between which associated sensor resistors 28I are arranged.
• the left-hand sensor resistances 28I are arranged mirror-symmetrically with respect to the right-hand sensor resistances, so that the explanations given above also apply analogously to the left-hand side.
• FIG. 4 shows the traces arranged on the back of the substrate 10 and FIG. 5 shows the associated sensor resistances.
• the viewing direction of the elements shown in FIGS. 4 and 5 is from above, ie from the front side 12 through the substrate 10, with the elements present on the substrate front side 12 not being present. It could therefore also be said that the rear sides of those elements that are applied to the substrate rear side 14 can be seen here. Most of these back panel elements are not visible in Figure 1 as they are obscured by front panel elements. Excluded from this are the conductor tracks 1261 already mentioned.
• the substrate rear side 14 has a lower supply interconnect 120 .
• This is connected to two of the contact points 16, which are all located on the front side 12 in this exemplary embodiment, via a conductor track 50 running on the front side 12 of the substrate (see FIGS. 1 and 2) and via a plated-through hole in the region 52, which is not shown here .
• the configuration and arrangement of the rear-side supply trace 120 is substantially identical to the configuration and arrangement of the front-side supply trace 20 above the region 52 . This also means in particular that there are a large number of contact points 122r, 1221 on the rear side 14, which correspond to the contact points 22r, 221—apart from the fact that they are connected to different supply interconnects.
• contact points 1241 to the left of the rear-side supply conductor track 120 which are each connected to one of the front-side contact points 16 via one of the left-hand conductor tracks 1261 and also via a plated-through hole (not shown here) between the front side 12 and the rear side 14 (see Fig. 1 ).
• contact points 124r to the right of the supply conductor track 120 which are each connected to a conductor track piece 125r.
• Each of these conductor track pieces 125r is connected via a special via to one of the conductor tracks 26r, which is located on the substrate front side 12 and to the right of the longitudinal axis LA. Details are described below.
• contact points are also provided on the back. These rear-side contact points can be the same size as the front-side contact points 16 and which are also located opposite them more or less congruently. If there are contact points on both sides 12, 14, an associated membrane connector should be used. A wide variety of contacting and circuit variants are possible.
• the sensor resistors 128l, 128r shown in FIG. 5 have the same--or at least essentially the same--design and arrangement as the sensor resistors 28I and 28r present on the front side 12 of the substrate. Therefore these are not visible in FIG. It should be pointed out once again that the illustration shown in FIG. 5 corresponds to a top view of the substrate front side 12 with a view through the substrate 10, with the elements present on the substrate front side 12 not being present.
• FIG. 6 shows a symbolic enlargement of the area A marked in FIG Conductor track 1261.
• FIG. 7 shows a symbolic cross-sectional representation of this via.
• FIG. 6 and 7 shows in particular that one of the left-hand sensor resistors 28I is arranged on the front side 12 of the substrate 10 and an associated sensor resistor 128I is arranged underneath (according to FIG. 7) on the rear side 14 of the substrate.
• the front-side sensor resistor 281 is connected to the front-side contact point 241 and this in turn is connected to the front-side conductor track piece 251 .
• the contact point 241 and the Conductor track piece 25I represent a common electrical connection element and are only referred to separately here for a simple description of the figures.
• the rear-side sensor resistor 1281 is connected to the rear-side contact point 1241, and this in turn is connected to the rear-side conductor track 1261, which leads to the associated contact point 16 via a further plated-through hole (see FIG. 1). Between the front side 12 and the back side 14, a via conductor 200 is arranged through a corresponding opening within the substrate 10, which here consists of the same material as the front-side conductor track piece 25I and the rear-side conductor track 1261 and electrically connects these two elements 251, 1261 to one another.
• the two sensor resistors 281 and 1281 are thus connected in series.
• the remaining of the front left sensor resistors 28I are also connected to their associated rear sensor resistors 128I in such a manner. The same also applies to the right sensor resistors 28r and 128r.
• the sensor resistors 28, 128 are preferably produced by a screen printing process in which a carbon-based paste is applied to the two sides 12, 14 of the substrate 10 in a structured manner with a thickness of approximately 5 to 20 ⁇ m.
• the sensor resistors 28, 128 in the exemplary embodiment described have a length of approximately 7 mm. Their width can be quite different depending on the application and is in the range from approx. 100 pm to 800 pm in order to realize resistance values in the range between 10 k ⁇ and 80 k ⁇ .
• the other elements present on the substrate sides 12, 14, such as in particular the conductor tracks and contact points, are preferred also produced by a screen printing process in which silver paste is applied with a thickness of approx. 5 to 15 ⁇ m.
• Fig. 8 shows a circuit diagram considering a pair of left sensor resistors 28I, 128I and a pair of right sensor resistors 28r, 128r.
• the circuit diagram is divided into the following three blocks:
• the sensor area S essentially corresponds to that part of the sensor strip 9 in which the sensor resistors 28I, 28r, 128I, 128r are arranged. It is designed in such a way that it is flexible and in particular can be bent, twisted and/or stretched.
• the contact area K essentially corresponds to that part of the sensor strip 9 in which the supply conductor tracks 20, 120 and the conductor tracks 26r, 1261 are connected to the contact points 16.
• the contact area K (see also Fig. 1) is significantly less flexible or deformable than the sensor area S, at least in the operating mode (normal operation). This can be achieved, for example, by connecting a foil connector to the contact points 16, through a lower connection of the area K to the object to be examined and/or by a corresponding design of the substrate 10 (such as its thickness, material, etc.).
• the evaluation unit A which is connected to the contact points 16 via contacts 300 of a membrane connector, contains a power supply and standard electronic elements such as amplifiers, A/D converters, memories, transmission devices, display elements and/or the like. This is discussed in more detail below.
• a supply voltage +u is present on the front-side supply line 20, the value of which is +U, for example 3 volts.
• the rear supply line 120 is grounded.
• the sensor resistors 28r and 128r are between the Supply voltage +u and ground are connected in series so that they form a voltage divider, the conductor track 26r enabling the center tap.
• the sensor resistors 28I and 1281 also form such a voltage divider, with the conductor track 1261 enabling the center tap. Both conductor tracks 26r, 1261 each lead to one of the contact points 16.
• the divided voltages, which are also referred to below as sensor signals sr or sl are fed to gain stages 302a and 302b, respectively. Their output signals are fed to an evaluation stage 304 which generates output signals sa on the basis of the amplified sensor signals and forwards them to a display stage 306 via a signal line 308 .
• FIG. 8 only shows the processing of a sensor signal s1 originating from a pair of left resistors 28, 1281 and the processing of a sensor signal sr originating from a pair of right resistors 28r, 128r.
• the evaluation unit A can also record and process the sensor signals of the remaining pairs of resistors 28I, 128I or 28r, 128r.
• a switching stage not shown here, inside or outside of the evaluation unit A.
• Such a switching stage could receive several or all of the sensor signals sl, sr and time-controlled according to the principle of a time multiplexer via the amplifier stages 302a, 302b forward the evaluation stage 304.
• each of the sensor signals sl, sr is routed to the evaluation stage 304 by means of an associated switching stage. It is also conceivable that each of the sensor signals sl, sr (ie 5 ⁇ sl+5 ⁇ sr in this exemplary embodiment) is fed to its own amplifier stage 302a, b and the evaluation stage 304 has a total of 10 inputs for the amplified sensor signals. Mixed forms of the alternatives mentioned are also possible.
• the individual resistor pairs 281, 1281 or 28r, 128r form series circuits and thus voltage dividers.
• SL Voltage value of the sensor signal sl compared to ground
• SR Voltage value of the sensor signal sr compared to ground +U: Value of the voltage +u compared to ground
• R128I Value of the sensor resistance 1281
• R28I Value of the sensor resistance 281
• R128r Value of resistor 128r
• R28r Value of resistor 28r.
• the sensor resistors 28I, 28r, 128I, 128r are designed in such a way that their values are the same when the sensor strip 9 is in one plane (such as the x-y plane of Fig 1) located. Such a state is also referred to here as an idle state. Then:
• the front resistors 28I, 28r are stretched and the rear resistors 128I, 128r are compressed.
• the effect on the individual resistances depends on their angle of inclination a and on the location and direction of the curvature. This is explained briefly with the aid of FIG. 1, assuming that the sensor strip 9 is curved downwards uniformly perpendicular to the longitudinal axis LA (i.e. has no kink but rather has the shape of a semicircular arc) and the angle of inclination a has a value between zero and have 90 degrees. Then the effect on the individual resistances is stronger, the smaller the angle of inclination a is. On the other hand, if one uniform curvature occurs parallel to the longitudinal axis LA, the greater the angle of inclination a, the greater the effect on the individual resistances.
• the front sensor resistors 28I, 28r When the sensor area S is warped forward (in the z-direction) from the x-y plane, the front sensor resistors 28I, 28r are compressed and the rear sensor resistors 128I, 128r are stretched. When the sensor area S is formed into a waveform, some of the front sensor resistors 28I, 28R may be compressed and others may be stretched.
• twisting of the sensor strip 9 or its sensor area S occurs, resistance changes also occur, which are dependent on the position of the individual sensor resistor 28, 128 and on its angle of inclination ⁇ .
• the lower part of the sensor strip 9 - i.e. the area in the direction of the contact points 16 - remains in the plane of the drawing and its upper part is rotated clockwise according to torsion arrow TP (Fig. 1), the left front resistors 28I are stretched and the left rear ones Resistors 1281 compressed.
• the front resistors 28r are compressed and the rear resistors 128r are stretched.
• the extent of such a stretching or compression depends on the angle of inclination ⁇ and also on the nature of the substrate. It has been shown that in the case of a relatively thin substrate, which essentially corresponds to a film, the resistance values change the most when the angle of inclination a has a value of approximately 45 degrees. Of course, such a change further depends on how strong the torsion is at the location of the respective resistance. It can thus be said in general: The ratio of the sensitivity of the pair of resistors to torsion to the sensitivity of the pair of resistors to bending transverse to the longitudinal axis LA can be set via the angle of inclination a.
• a bending direction that does not run transversely to the longitudinal axis LA, or a torsion superimposed on the bending that runs transversely to the longitudinal axis LA can thus be measured.
• resistors that are opposite each other such as resistor pairs 28I, 128I or 28r, 128r, are of the same design. This means they essentially have the same geometry and material properties. The effect of this is that a stretching of the sensor area S has the same effects on opposing resistances and therefore the corresponding values SL, SR ideally do not change. If, however, the respective opposing resistances differ, a change in values SL, SR is also possible with a stretching.
• the individual resistance values R28I, R128I, R28r, R128r are dependent on the mechanical influence on the sensor strip 9 or on its sensor area S. Conversely, this means that when these resistance values—and thus the associated sensor signal values SL, SR—change, there is a corresponding mechanical influence on the sensor strip 9 .
• the amplified sensor signals sl, sr are evaluated in the evaluation stage 304 using a suitable algorithm as a function of the position and orientation of the associated sensor resistors 28I, 128l, 28r, 128r.
• the evaluation stage 304 contains elements that are common and common to those skilled in the art, such as a microprocessor, an analog/digital (A/D) converter, memory modules, etc.
• the sensor signals sl, sr are each the result of the center tap on a voltage divider with two resistors. It is also possible that instead of the absolute voltages, a voltage difference is used in each case is measured and processed. Such a voltage difference can be generated, for example, by means of a Wheatstone bridge, in which the reference voltage required for such a voltage difference is usually generated by a suitable second voltage divider. If the value of the first voltage--generated by one of the voltage dividers 28, 128--is the same as the value of the reference voltage in the idle state, the difference is zero. If, during the subsequent measurement operation, the sensor area S undergoes a mechanical movement such that one of the two resistances 28, 128 changes, the value of the voltage tapped off also changes.
• this change in voltage can be relatively small, i.e. in relation to the absolute voltage value.
• Such a voltage change can be evaluated significantly better if the voltage difference generated by means of the reference voltage is processed by the evaluation stage 304 rather than the tapped voltage itself. Because their relative change is significantly greater than that of the tapped voltage.
• evaluation stage A is designed in such a way that a reference voltage is generated whose value corresponds exactly or at least essentially to the voltage value that results from the respective voltage divider 28, 128, as is preferred * +U (see above).
• the difference between the sensor signal sl and the reference voltage and the difference between the sensor signal sr and the reference voltage are generated within the amplifier stages 302a, 302b--but before the actual amplification.
• a voltage is added after amplification, the value of which is preferably i*+U (1.5 V). The value of this voltage is subtracted again during the subsequent digitization, so that negative digital sensor values can also arise and the bending direction can already be inferred from the sign.
• the result of the evaluation of the sensor signals sl, sr is output using the output signal sa.
• This can be designed in different ways.
• the display level 306, which is equipped with an associated display the sensor strip 9--more precisely, its sensor area S can be represented graphically.
• the evaluation stage 306 can have suitable memory components (not shown separately) in order to be able to record such a dynamic representation and be able to call it up later.
• the output signal sa and/or the display stage 306 are designed in such a way that, in addition to or instead of a graphic display, optical, acoustic and/or haptic (vibrations or the like) warning signals are output if the sensor area S moves in this way - for example curved , twisted and/or stretched - will ensure that specified limit values are exceeded.
• the criteria for such limit values can be very different. It can also be taken into account when predetermined geometric values, their course, their speed and/or their acceleration are exceeded or fallen below for a specific time.
• the display stage 306 can be designed in many different ways. It is also conceivable that it is arranged outside of the evaluation unit A and is designed, for example, like a PC, a tablet computer, a smartphone or the like. It is also possible for the algorithm for evaluating the sensor signals sl, sr to run partially or completely on such a device.
• the signal line 308 can be implemented as a cable and/or wirelessly.
• the evaluation unit A has a transmission stage if required.
• This can be designed in such a way that it can emit high-frequency signals (for example Bluetooth, WLAN, etc.), optical signals, acoustic signals and/or the like. This is particularly advantageous when the display stage 306 is implemented as a smartphone or tablet computer.
• the sensor strip according to the invention can be used in many ways, such as for • the field of orthopaedics
• a preferred application in the field of orthopedics relates to the measurement of a person's spine.
• the sensor strip 9 is attached to the back of the person in question by means of suitable means such as plasters, adhesive or the like.
• suitable means such as plasters, adhesive or the like.
• a type of clothing is used for this, such as a T-shirt, a body, a vest or the like, in and/or on which the sensor strip 9 is arranged or integrated.
• Individual measurements or, even better, continuous measurements over a certain period of time can be used to determine how the back is moving and how it is possibly being stressed.
• a special embodiment of the sensor strip according to the invention has proven itself, which is described below as sensor strip 900 with reference to FIGS. 9 to 11.
• FIGS. 10 and 11 show sections B and C thereof, which are marked in FIG.
• the sensor strip 900 also consists of a substrate (not shown here) with a front side and a back side. Due to the top view, essentially the elements that are located on the front side of the substrate are shown. Elements that are on the back of the substrate and are covered by the elements on the front of the substrate cannot be seen here.
• the sensor strip 900 shown in FIG. 9 has a sensor area S that is approximately 60 cm long.
• a front conductor track is along the longitudinal axis LA 18 is present on the substrate front side 12, to which 28 sensor resistors 28I on the left and 28 sensor resistors 28r on the right are electrically connected.
• These are also elongated here with an almost rectangular shape and all have the same angle of inclination a, the value of which is about 30 degrees.
• the left sensor resistors 28I are each connected to one of the left conductive tracks 26I and the right sensor resistors 28r are each connected to one of the right conductive tracks 26r.
• the sensor resistors 1281, 128r arranged on the substrate rear side 14 are located exactly (or essentially) below the front sensor resistors 28I, 28r and are therefore not visible here. These are analogous to the front-side sensor resistors 28I, 28r, on the one hand with the rear-side supply conductor track 120, of which only a small section can be seen here above area 52 (see Fig. 11), and on the other hand with rear-side conductor tracks 1261 and 126r, which are the substrate rear side 14 run opposite or below the left conductor tracks 26I and 26r, respectively.
• each of the sensor resistors 28, 128 has its own conductor track 26, 126. This is different from the sensor strip 9, in which for each pair of resistors 28, 128 first one of the vias 200 and then only one of the conductor tracks 26r, 1261 is provided.
• the vias 200 required for the realization of voltage dividers from two resistors 28, 128 lying one above the other are all located in the sensor strip 900 in an area 902 (see FIG. 11), which is located in the area of the contact points 16 and thus within the contact area K and is therefore outside the sensor area S (see FIG. 9).
• the sensor strip shown in Figures 9 to 11 can be shortened by cutting a desired length from the top. As a result, although The number of resistor pairs depends, however, the sensor strip length can be adjusted to the object to be examined.
• the vias 200 mentioned are arranged close to the individual resistor pairs (voltage dividers) 28, 128 (similar to sensor strips 9), so that only one of the conductor tracks 26, 126 is required per resistor pair and that continues
• a first number of these pairs of resistors 28, 128 are connected to the contact points 16 via conductor tracks 26 on the front side and the remaining pairs of resistors are connected via conductor tracks 126 on the rear side.
• FIG. 12 Another embodiment is shown in FIG. 12, which is partially similar to FIG.
• the main difference from the previously described embodiments is that here the front conductor track 25I is connected to the rear conductor track 1261 by a first contact element 252, a second contact element 254 and a connecting line 256 between the contact elements 252 and 254.
• the front-side conductor track 251 up to a first contact point 251 , which is located in the edge area of the front side 12 of the substrate 10 .
• the rear conductor track 1261 runs up to a second contact point 253 which is located in the edge area of the rear side 14 of the substrate 10 .
• the two contact points 251, 253 are preferably arranged in such a way that they face each other.
• the first contact element 252 is in electrical contact with the first contact point 251 and thus with the conductor track 25I and the second contact element 254 is in electrical contact with the second contact point 253 and thus with the conductor track 1261.
• the connecting line 256 is also connected to the evaluation unit A, to which a corresponding sensor signal s1 (see also FIG. 8) is emitted.
• the supply voltage +u can be a DC voltage and/or an AC voltage
• resistors 28, 128 can also be used as capacitors. To do this, these elements must be connected to the evaluation unit and a suitable AC voltage must be applied. reference character list

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• 2020
  • 2020-10-29 DE DE102020006662.3A patent/DE102020006662A1/de active Pending
• 2021
  • 2021-10-29 KR KR1020237018244A patent/KR20230106163A/ko unknown
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