Sensorized insole for shoe

Abstract

The present invention relates to a sensorized insole (1) adapted to be placed on an insole. A sensorized insole (1) comprises a sensor plane (20), a dielectric layer (30) and a ground plane (10). The dielectric layer (30) separates the ground layer (10) from the sensor plane (20). In use, compression of the dielectric layer (30) results in a change in capacitance between the ground layer (10) and at least one of the plurality of sensor pads (211) formed in the sensor layer (21) of the sensor plane (20). Each sensor pad (211) is electrically connected to a respective electrical terminal (41) by means of a trace (212) of electrically conductive material. The sensor layer (20) further comprises a shielding layer (22) separated from the sensor layer (21) by a support layer (23) of flexible material. The sensor plane (20) is arranged such that the shielding layer (22) is interposed between the sensor layer (21) and the dielectric layer (30). The shielding layer (22) includes a plurality of vias (226), a plurality of first shielding elements (224d), and a plurality of second shielding elements (224b). Each through-hole has a shape and size substantially corresponding to a respective sensor pad (211) and overlaps over the respective sensor pad (211) in plan view. Each first shielding element (224d) surrounds a respective through hole (226). Each second shielding element (224b) connects a respective first shielding element (224d) to an electrical terminal (227) and overlaps a corresponding conductive material trace in plan view. Finally, the trace (212) and the second shielding element (224b) have corresponding tortuous shapes.

Description

Technical Field

[0001] The present invention relates to a sensorized insole for shoes. Background Art

[0002] Gait and posture analysis are very important in the health sector because of the close relationship between gait and posture and certain diseases and their progression. For example, real-time control of the gait of Parkinson's patients allows monitoring of the progression of the disease.

[0003] Furthermore, gait analysis has become an important aspect in the sports sector (especially in competitive sports). In fact, gait analysis makes it possible to correct any defects in the gait of athletes, thus improving their performance.

[0004] In order to provide information about the gait of a subject, several solutions involving sensorized insoles have been proposed in the literature.

[0005] A first example of a sensorized insole is known from the writing [1] by Gonzàlez et al. In this solution, four force-sensitive resistors (FSRs) are applied to the lower surface of a conventional insole. Each of the four FSR sensors has an elongated structure, and wires of a flat cable are welded to the ends of the elongated structure. The flat cable is in turn connected to an inertial measurement unit (IMU), which analyzes the data and transmits the data to a mobile device via a Bluetooth connection.

[0006] Another example of a sensorized insole is known from the article [2] by Oerbekke et al. The article describes the OpenGo sensorized insole sold by the German company Moticon. The insole consists of several stacked layers. In order from top to bottom, there are an upper layer, a ground layer, a dielectric layer, a sensor support layer, and a lower layer with slots into which an electronic module is inserted, which can read the data of the sensors and transmit them to a mobile device application, such as for example a smartphone. The article does not address the electrical connection between the electronic device and the sensors.

[0007] From this article [3], a sensorized flexible insole is known. The insole has a piezoelectric polyvinylidene fluoride (PVDF) layer on which 24 square copper electrodes are positioned, the copper electrodes being etched on two polyimide substrates sandwiching the PVDF layer. To protect the electrodes, two outer layers of polyethylene terephthalate (PET) are provided.

[0008] The polyimide layer that houses the sensors and the electrical traces of the insole is flexible but not stretchable, which is a limitation when this material is used for an insole and is subjected to significant stress due to walking.

[0009] In addition, this solution has limitations in that the piezoelectric sensors used do not have the ability to accurately measure pressure under static conditions. Specifically, piezoelectric sensors use materials that may generate electric charges on the surface when subjected to pressure. However, such charges dissipate over time, meaning that over time, the sensor loses its ability to measure static pressure. While during dynamic activities such as walking, the pressure on the insole is a continuously varying quantity, in some cases (such as checking the subject's ability to stand still), measuring static pressure that changes over time may be useful - something that piezoelectric technology cannot do.

[0010] From article [4], a flexible capacitive sensor suitable for insertion into an insole for continuous analysis of walking signals is known. However, this article does not explain how to integrate the signal acquisition electronics into the insole. The sensor is made of a flexible but non-stretchable material, which may lead to robustness issues under high stress. The sensor also has a very low signal acquisition frequency (about 0.1 - 0.5 Hz). Given this, the device proposed in this article can be used for calorie estimation as proposed by the author, but it is not made suitable for monitoring the pressure distribution during walking activities.

[0011] In addition to what has been reported above, the signals generated by the sensors of the proposed sensorized insole are interfered with by electronic noise, especially due to the operation of other sensors and / or electrical tracks of the sensorized insole, and any electromagnetic radiation sources external to the sensorized insole - for example, personal portable devices capable of generating electromagnetic waves, such as smartphones and / or wearable devices carried or worn by the user.

[0012] The electronic noise overlaps with the useful signals generated by the sensors, reducing the overall sensitivity of the sensorized insole, limiting the useful information that can be extracted from the signals generated by the sensorized insole, and thus limiting the analysis of the user's gait based on the signals generated by the sensorized insole.

[0013] References

[0014] [1] I.Gonzalez and et al., “An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles,” Sensors, vol.15, pp.16589 - 16613, 2015.

[0015] [2]M.S. Oerbekke and et al., "Concurrent validity and reliability of wireless instrumented insoles measuring postural balance and temporal gait parameters," Gait & Posture, vol. 51, pp. 116 - 124, January 2017.

[0016] [3]J. Chen and et al., "A Piezoelectric Flexible Insole System for Gait Monitoring of Internet of Heath Things," IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS), 2020.

[0017] [4]Seong Won Park and et al., "Development of wearable and flexible insole type capacitive pressure sensor," Organic Electronics, no. 53, pp. 213 - 220, 2018. Summary of the Invention

[0018] The object of the present invention is to overcome the drawbacks of the prior art

[0019] In particular, the object of the present invention is to provide an electronically noise - resistant sensorized insole.

[0020] In addition, the object of the present invention is to provide an insole that can withstand mechanical stresses associated with actions such as walking, running, standing, etc. performed by the user of the insole.

[0021] Moreover, the object of the present invention is to provide a system including a sensorized insole that allows for precise analysis of gait, joint stresses performed by the user, and estimation of the physical exertion performed by the user.

[0022] These and other objects of the present invention are achieved by a sensorized insole that incorporates the features of the appended claims, which form a part of this specification.

[0023] A first aspect of the present invention relates to a sensorized insole adapted to be placed on an insole. The sensorized insole includes a sensor plane, a dielectric layer, and a ground layer. The dielectric layer separates the ground layer from the sensor plane. In use, compression of the dielectric layer causes a change in capacitance between the ground layer and at least one of a plurality of sensor pads formed in the sensor layer of the sensor plane. Each sensor pad is electrically connected to a corresponding electrical terminal by means of a track, a trace of a conductive material.

[0024] The sensor plane further includes a shielding layer separated from the sensor layer by a support layer made of a flexible material. The sensor plane is arranged such that the shielding layer is inserted between the sensor layer and the dielectric layer.

[0025] The shielding layer includes a plurality of through-holes, a plurality of first shielding elements, and a plurality of second shielding elements. Each through-hole has a shape and size substantially corresponding to a respective sensor pad and is superimposed above the corresponding sensor pad in a plan view. Each first shielding element surrounds the respective through-hole. Finally, each second shielding element connects the respective first shielding element to the electrical terminal and is superimposed above the corresponding track in a plan view.

[0026] Preferably, the second shielding element and the track have a meander shape. For example, the second shielding element and the track are metal material strips including a plurality of meanders, such as copper.

[0027] Due to the above structure of the sensor plane, the sensorized insole can generate reliable signals without affecting the posture and gait of the user using the insole in a shoe.

[0028] In particular, the shielding layer of the sensorized insole effectively shields electromagnetic radiation hitting the sensorized insole or electromagnetic interference generated by capacitance changes associated with adjacent pads, thereby preventing the signals generated by the insole from being masked by electronic noise.

[0029] Furthermore, the structure of the shielding layer of the insole according to the present invention allows such anti-electronic noise to be achieved without restricting the mobility of the foot or reducing the comfort of the user. In fact, the shielding layer includes a limited number of metal traces that do not hinder the deformation of the insole and thus do not hinder the movement of the user's foot.

[0030] In one embodiment, the sensor layer further includes a plurality of third shielding elements. Each of these third shielding elements surrounds the respective sensor pad. Preferably, each third shielding element is superimposed above the corresponding first shielding element of the shielding layer in a plan view, and even more preferably, has the same shape and size as its corresponding one.

[0031] In addition, a fourth shielding element connects the respective third shielding element to an electrical shielding terminal. Advantageously, pairs of fourth shielding elements are placed on opposite sides of at least one conductive material track.

[0032] Due to these features, the signals generated by the insole can be shielded from external and internal electromagnetic interference more effectively.

[0033] In one embodiment, the sensor layer includes a plurality of wires electrically connected to a plurality of second and fourth shielding elements. Advantageously, the plurality of wires - optionally together with a plurality of third and fourth shielding elements - form a plurality of meshes on at least a part of the surface of the sensor layer.

[0034] Additionally or alternatively, the shielding layer includes a plurality of wires electrically connected to a plurality of first and second shielding elements. Advantageously, the plurality of wires form a plurality of meshes on at least a part of the surface of the shielding layer - optionally, the meshes are formed by one or more of the wires and one or more of the plurality of first and / or second shielding elements.

[0035] The formation of a mesh of conductive tracks makes it possible to significantly increase the resistance to electromagnetic interference without compromising the deformability of the insole.

[0036] In one embodiment, the sensor layer further includes a first peripheral wire, a second peripheral wire, a third peripheral wire, and a plurality of additional wires. The first conductive perimeter line at least surrounds a part of the sensor pad and is electrically connected to the plurality of conductive wires and the electrical shielding terminal. The second and third peripheral wires are substantially parallel to the first peripheral wire, and the third peripheral wire surrounds the second peripheral wire, which in turn surrounds the first peripheral wire. Both the second and third peripheral wires are electrically connected to the reference terminal. In addition, the additional wires of the sensor layer are electrically connected to the second and third peripheral wires and - optionally together with the second and third peripheral wires - form a plurality of meshes therebetween.

[0037] Additionally or alternatively, the shielding layer includes a fourth peripheral wire, a fifth peripheral wire, a sixth peripheral wire, and a plurality of additional wires. The fourth conductive perimeter line at least surrounds a part of the through hole and is electrically connected to the plurality of conductive wires and the corresponding electrical shielding terminal. The fifth and sixth peripheral wires are substantially parallel to the fourth peripheral wire. Similar to the above-described content, the sixth peripheral wire surrounds the fifth peripheral wire, which in turn surrounds the fourth peripheral wire. Both the fifth and sixth peripheral wires are electrically connected to the reference terminal. In addition, the additional wires of the shielding layer are electrically connected to the fifth and sixth peripheral wires and - optionally together with the fifth and sixth peripheral wires - form a plurality of meshes therebetween.

[0038] Preferably, the peripheral wires and / or wires of the sensor layer and the shielding layer are formed such that they overlap in a plan view.

[0039] Adding one or both of these structures connected to the reference terminal makes it possible to further increase the robustness against electronic noise inside or outside the sensorized insole without limiting the deformability of the sensorized insole.

[0040] In one embodiment, the sensorized insole includes more than one sensor layer and corresponding shielding layers. Advantageously, the sensor pads of each sensor layer - and thus the through-holes of the corresponding shielding layers - are arranged in different positions of the insole - in a plan view.

[0041] This multi-layer structure makes it possible to significantly increase the number of measurements performed by the insole without compromising its deformability or resistance to electronic noise.

[0042] Different aspects of the present invention relate to an analysis system. The analysis system includes at least one sensorized insole according to any of the above embodiments and a processing system. Specifically, the processing system includes an acquisition module and a data processing module. The acquisition module is connected to each electrical terminal of the sensorized insole and is adapted to receive the signals generated by the sensorized insole during its compression and convert the signals into corresponding digital signals. In addition, the data processing module is adapted to receive the digital signals and process them to provide information about the posture and / or gait of the corresponding user.

[0043] The analysis system allows for an accurate analysis of the user's posture and / or gait in an efficient manner. In particular, the signal quality provided by the sensorized insole - in terms of signal-to-noise ratio - allows for a reduction in the specifications of the acquisition module and the accuracy of the analysis performed. Advantageously, the deformability of the sensorized insole does not compromise the user's posture and / or gait, which results in the acquisition of unchanged data and thus a more reliable analysis of the posture and / or gait.

[0044] Additional features and advantages of the present invention will become more apparent from the description of the drawings. Description of the Drawings

[0045] The present invention will be described below with reference to some examples, which are given by way of non-limiting examples and are shown in the drawings.

[0046] In such drawings:

[0047] - Figure 1 is a schematic top view of a sensorized insole according to an embodiment of the present invention connected to a processing system;

[0048] - Figure 2 is Figure 1 a schematic side view of the sensorized insole;

[0049] - Figure 3Ais a top view of a sensor plane of a circuit in a sensorized insole included in Figure 1 ;

[0050] - Figure 3B is an enlarged view of a portion of the sensor plane in Figure 3A in the indicated box B included in Figure 3A ;

[0051] - Figure 3C is an enlarged view of a portion of the sensor plane in Figure 3A in the indicated box C included in Figure 3A ;

[0052] - Figure 4A is a top view of a shielding plane of a circuit in a sensorized insole included in Figure 1 ;

[0053] - Figure 4B is an enlarged view of a portion of the shielding plane in Figure 4A in the indicated box B included in Figure 4A ;

[0054] - Figure 5 is a top view of a portion of a meandering conductive trace for a sensorized insole according to an embodiment of the present invention;

[0055] - Figure 6A is a top view of a portion of a sensorized insole according to an alternative embodiment including two sensor layers, and

[0056] - Figure 6B is Figure 6A a qualitative decomposition diagram of sensor and shielding planes of a multi-layer circuit of a sensorized insole in DETAILED DESCRIPTION

[0057] While the present invention is susceptible to various alternative modifications, some preferred embodiments will be described in detail below. In any case, it must be understood that there is no intention to limit the present invention to the specific embodiments shown, but rather, the present invention is intended to cover all modifications and equivalents falling within the scope of the present invention as defined in the claims.

[0058] Unless otherwise defined, all technical terms, symbols, and other scientific terms used herein are intended to have the meaning commonly understood by one of ordinary skill in the art to which this specification pertains. In some cases, terms having a commonly understood meaning are defined herein for clarity and / or ease of reference; thus, the insertion of such definitions in this specification should not be construed as representing a significant difference from what is commonly understood in the art.

[0059] The terms “comprise”, “have”, “include” and “contain” are to be understood as open-ended terms (i.e., meaning “including, but not limited to”), and are to be considered as also supporting terms such as “essentially consist of”, “consisting essentially of”, “to consist of” or “consisting of”.

[0060] Unless otherwise stated, the use of “for example”, “etc.”, “or” indicates non-exclusive alternatives without limitation. Unless otherwise stated, the use of “include” means “including, but not limited to”.

[0061] Reference Figure 1 , schematically shows a sensorized insole 1 according to an embodiment of the present invention.

[0062] The sensorized insole 1 is implemented as a multi-layer element including a plurality of pressure sensors 2. The sensorized insole 1 has a shape adapted to fit exactly into a shoe, and thus it includes an enlarged front region intended to accommodate the front foot relative to a rear region intended to accommodate the heel. The pressure sensors 2 are electrically connected to a connector 4 formed in a side tab 3 of the sensorized insole 1. In Figure 1 the example of, two connectors 4 are formed in the side tab 3 of the insole 1. A subset of twelve pressure sensors 2 is connected to each connector via appropriate wiring, as described below, and is omitted in Figure 1 for simplicity. Thus, each connector includes a total of 14 pins ( Figure 1 not shown in, but substantially corresponding to the terminals visible in Figure 3A ): one pin for connection to each of the twelve pressure sensors 2 of the connector 4, one pin connected to a reference or ground voltage (ground pin), and one pin connected to a shielding voltage (shield or shielding pin).

[0063] As shown in the schematic side cross-sectional view of Figure 2 , the sensorized insole 1 includes a ground layer 10 separated from a sensor plane 20 by an intermediate dielectric layer 30 made of a dielectric material - for example TPU in the case considered. In the embodiment considered, the ground layer 10 includes a conductive fabric sheet coupled to the dielectric layer 30. The dielectric layer 30 is a layer made of a non-conductive material adapted to comfortably support the user's sole (not shown). Finally, the sensor plane 20 includes a sensor layer 21 (lower) and a shielding layer 22 (upper) coupled to a support layer 23.

[0064] Preferably, the sensor plane 20 of the sensorized insole 1 is an extensible printed circuit board (PCT). Advantageously, the support layer 23 is made of a flexible and extensible material, i.e., when subjected to a force transverse to the plane (such as a person's weight), the support layer 23 has the ability not only to bend but also to expand in the plane.

[0065] For example, in a preferred embodiment, the support layer 23 is a polyether-based thermoplastic polyurethane (TPU) film, such as, for example, TFL-2EA, preferably with a thickness of less than 0.5 mm. TFL-2EA has a soft touch and excellent deformation capabilities - especially elongation capabilities - and tensile strength. It also has good antimicrobial, hydrolysis resistance, and wear resistance, making it a suitable material for this application.

[0066] The PCT of the sensor plane 20 is made in a known manner, i.e., each conductive layer - namely the sensor layer 21 and the shielding layer 22 - is made starting from a corresponding copper sheet laminated to the support layer 23. The circuits of the layers are made by successive etching and removal of copper portions. Preferably, the sensors and copper tracks of the sensor layer 21 are embedded in the support layer 23, thus ensuring a high level of comfort for the user (not shown) during the use of the sensorized insole.

[0067] In the example considered, the sensor plane 20 is shaped to be deformable in all directions, reaching at least 30% of its size along the considered direction. Preferably, the sensor plane is made capable of withstanding a deformation of up to 50% of its size along the considered direction.

[0068] As Figure 1 shown, the processing system 5 connected to the connector 4 is able to receive, during its use, the signals generated by the pressure sensors 2 of the sensorized insole 1 in order to process the information generated by the sensorized insole 1.

[0069] The processing system 5 includes an acquisition module 51 and a data processing module. The acquisition module 51 receives the signals generated by the pressure sensors 2 and converts them into digital signals, and then the data processing module 52 processes the digital signals in a predetermined manner in order to provide useful information for the analysis of the posture and / or gait of the corresponding user (not shown).

[0070] For example, the acquisition module 51 includes - in a non-limiting manner - one or more analog-to-digital conversion (ADC) devices, filters, amplifiers, etc. However, the processing module 52 includes - in a non-limiting manner - one or more processors, DSPs, FPGAs, ASICs, etc., which are configured to perform the desired signal processing.

[0071] In the example considered, the acquisition module 51 includes a pair of analog / digital conversion devices (not shown), each connected to a respective connector 4 of the instrumented insole 1. The analog / digital conversion devices are configured to convert the signals generated by the pressure sensors 2 into digital signals and supply a reference voltage and a supply voltage to the instrumented insole 1.

[0072] Returning to the instrumented insole 1, in an embodiment of the present invention, the sensor plane 20 includes two superimposed layers: a sensor layer 21 (lower), schematically shown in Figure 3A , 3B and 3C, and a shielding layer 22 (upper), schematically shown in Figure 4A and 4B . The two layers are superimposed on each other, with the shielding layer 22 being located above the sensor layer 21 - that is, the shielding layer 22 is closer to the dielectric layer 30 than the sensor layer 21.

[0073] In Figure 3A and in the Figure 3B and 3C magnified detail, the sensor layer 21 includes a plurality of sensing elements or sensor pads 211 of the pressure sensors 2.

[0074] In the example considered, the sensor layer 21 includes a plurality of circular sensor pads 211, 24 in the example considered, each sensor pad being connected via a meandering conductive trace 212 to a corresponding signal terminal or pin 41 of one of the two connectors 4.

[0075] Preferably, the sensor layer 21 includes an annular shield 213 surrounding the respective sensor pads 211. The annular shield 213 is intended to provide enhanced protection against electromagnetic interference where it is most needed, namely at the sensor pads 211. In particular, the annular shield 213 avoids or at least significantly attenuates sensor-sensor cross-interference.

[0076] Furthermore, in an embodiment of the present invention, the sensor layer 21 includes at least two voltage shielding elements or AC shields 214, and two ground shielding elements or GND shields 215.

[0077] In the Figure 3A - Figure 3C exemplary embodiment, the GND shields 215 divide the sensor layer 21 into two parts. These two parts can be identified as: a first part or front part, which extends from the toes of the instrumented insole 1 to approximately half of the instrumented insole; and a second part or rear part, which extends from the heel of the instrumented insole 1 to approximately half of the instrumented insole. Each GND shield 215 surrounds a respective AC shield 214, which in turn surrounds a respective subset of the sensor pads 21l which, in the example considered, is 12.

[0078] from Figure 3A and Figure 3B As can be better seen from the details in and, each AC shield 214 includes a peripheral (conductive) line 214a, a plurality of isolation lines 214b, and a plurality of grid lines 214c.

[0079] Specifically, the perimeter line 214a defines the area of the AC shield 214 and is connected to the shield terminal or pin 42 of the connector 4. Preferably, the shield pin 42 is held at a shield voltage by the processing system 5 such that the AC shield 214 is biased to the shield voltage. Pairs of isolation lines 214b isolate the respective conductive traces 212 from the AC shield 214 - in other words, two isolation lines 214b surround the entire corresponding conductive trace 212 while remaining spaced apart therefrom. A pair of isolation lines 214b includes the respective conductive traces 212 from its connection to the respective sensor pad 211 to its connection to the shield pin 42 of the connector 4.

[0080] Finally, the grid lines 214c extend in two different directions transverse to each other in the space defined by the perimeter line 214a and are electrically connected to the perimeter line 214a, the isolation lines 214c, and the shield ring 213 that surrounds the sensor pads 211 included in the space defined by the perimeter line 214a. In other words, the grid lines 214c form a grid of conductors defined by the perimeter line 214a.

[0081] Each GND shield 215 surrounds the corresponding AC shield 214. The GND shield 215 includes a first (conductive) perimeter line 215a (inner), a second perimeter line 215b (outer), and a plurality of grid lines 215c.

[0082] The first perimeter line 215a is substantially parallel to and spaced apart from the perimeter line 214a of the AC shield 214; in addition, the first perimeter line 215a is connected to the reference terminal or pin 43 (e.g., ground terminal) of the connector 4.

[0083] The second perimeter line 215b is a closed line formed by a first part and a second part, the first part substantially along a part of the perimeter of the sensorized insole 1, the second part connecting the two ends of the first part at its two ends; in addition, the second perimeter line 215b is connected to the ground pin of the connector 4.

[0084] in Figure 3A - Figure 3CIn an exemplary embodiment, a second portion of a second peripheral line 215b of two GND shields 215 are parallel to each other and include a conductive strip 215d having a much larger area than the remaining lines of the GND shield 215 and the AC shield 214. The conductive strip 215d serves as a protection element against discharge and electrically separates circuits formed by two different AC shields 214 and thus electrically separates two supply voltage signals provided by an analog / digital converter of the acquisition module 51.

[0085] Finally, the grid lines 215c extend in two different directions transverse to each other in a space between the first peripheral line 215a and the second peripheral line 215b and are electrically connected to the two peripheral lines 215a and 215b. In other words, the grid lines 215c form a grid of conductors defined by the first peripheral line 215a and the second peripheral line 215b.

[0086] The shielding layer 22 also includes at least two charged shielding elements or AC shields 224, and two ground shielding elements or GND shields 225.

[0087] Reference Figure 4A - Figure 4B , the GND shields 225 divide the shielding layer 22 into two parts. These two parts substantially correspond to the parts into which the sensor layer 21 is divided, i.e., a first part or front part extending from the front end of the sensorized insole 1 to about half of the sensorized insole, and a second part or rear part extending from the rear end of the sensorized insole 1 to about half of the sensorized insole. Each GND shield 225 surrounds a corresponding AC shield 224, which in turn surrounds a corresponding subset of the through-holes 226, which is 12 in the example considered. The through-holes 226 are formed in the shielding layer 22 so as to correspond to the sensor pads 211 on the sensor layer 21.

[0088] Each AC shield 224 includes a peripheral (conductive) line 224a, a plurality of meandering shielding lines 224b, a plurality of grid lines 224c, and a plurality of annular shields 224d.

[0089] The peripheral line 224a defines the area of the AC shield 224. Each shield line 224b is shaped and arranged to overlay over a respective conductive trace 212 formed on the sensor layer 21 and is connected to a respective annular shield 224d. Each annular shield 224d surrounds a respective via 226. The peripheral line 224a and the shield lines 224b are connected to pads 227, which are connected via a path (not shown) to the shield pins 42 of the connector 4 formed on the sensor layer 21. Finally, the grid lines 224c extend in two different directions transverse to each other in the space defined by the peripheral line 224a and are electrically connected to the peripheral line 224a, the shield lines 224b, and the annular shields 226 included in the space defined by the peripheral line 224a. In other words, the grid lines 224c form a grid of conductors defined by the peripheral line 224a.

[0090] Each GND shield 225 surrounds a corresponding AC shield 224. The GND shield 215 includes a first (conductive) peripheral line 225a (inner), a second peripheral line 225b (outer), and a plurality of grid lines 225c.

[0091] The first peripheral line 225a is substantially parallel to and spaced apart from the peripheral line 224a of the AC shield 224; additionally, the first peripheral line 225a is connected via a path to a pad 228, which is connected to the ground pin 43 of the connector 4 formed on the sensor layer 21.

[0092] The second peripheral line 225b is a closed line formed by a first portion and a second portion, the first portion substantially along a part of the perimeter of the sensorized insole 1, and the second portion connecting the two ends of the first portion. The second peripheral line 225b is also connected via a path 228 to the ground pin of the connector 4.

[0093] In Figure 4A - Figure 4B the exemplary embodiment, the second portions of the second peripheral lines 225b of the two GND shields 225 are parallel to each other and include conductive bands 225d that are much larger in area than the remaining lines of the GND shields 225 and the AC shields 224. Preferably, each of the conductive bands is formed to correspond in size and arrangement to the respective conductive bands 215d of the GND shield 215 and the AC shield 214 of the sensor layer.

[0094] Finally, the grid lines 225c extend in two different directions transverse to each other in the space between the first peripheral line 225a and the second peripheral line 225b and are electrically connected to the two peripheral lines 225a and 225b. In other words, the grid lines 225c form a grid of conductors defined by the peripheral line 225a and the second peripheral line 225b.

[0095] The applicant has determined that when the grids defined by the grid lines 214c, 215c, 224c, and 225c have a size (e.g., area or diameter) of the same order of magnitude as or less than the size (e.g., area or side length) of the sensor 2, they ensure optimal electromagnetic shielding. Otherwise, there will be a negligible shielding effect, and in particular, the grid defined by the grid lines 214c and 224c will become too dense to have a sufficient number of electrical contacts with the rings 213 and 224d.

[0096] For example, in one embodiment, the size of the grid defined by the grid lines 214c, 215c, 224c, and 225c is about 2 cm on the side (i.e., a square grid), while the diameter of the sensor 2 is about 1.5 cm, and the total copper percentage on the total area of the sensor plane 20 is about 1 - 2%.

[0097] For example, the wires of the layers 21 and 22 are made of copper or aluminum. In one embodiment, the wires of the layers 21 and 22 are made starting from copper foils with a thickness between 5 microns and 70 microns.

[0098] The structure of the layers 21 and 22 (in particular, the grid of conductive materials formed by the grid lines 214c and 215c and the annular shield 213 in the sensor layer 21, and the wires 224c and 224d and the annular shield 224d in the shield layer 22) ensures robust protection against electromagnetic interference (e.g., interference between the pressure sensors 2) from sources outside the sensorized insole 1 and from sources inside the sensorized insole 1, without compromising the flexibility and stretchability of the sensorized insole 1.

[0099] Preferably, the annular shield 213 in the sensor layer 21 and the grid lines 214c and 215c, and the wires 224c and 225c and the annular shield 224d in the shield layer 22 are arranged so as to be substantially superimposed on each other.

[0100] In the considered embodiment, in order to operate correctly during the extension and length changes to which the sensorized insole 1 is subjected, the conductive traces 212 and the shield wires 224b have corresponding meandering shapes.

[0101] Preferably, the meandering of the conductive traces 212 and the shield wires has a substantially "U-shaped" or substantially semi-circular shape - as Figure 5 shown. The applicant has determined that the geometric parameters of the meandering that allow optimal performance of the conductive traces 212 are as follows:

[0102] - The radius R, which must be greater than 0.125 mm and must not exceed a value of 0.5 cm

[0103] - To ensure that the channels between the sensor pads 211, i.e., the traces 212 and the lines 224b, do not come into contact with other conductive elements,

[0104] - The opening angle W is between -45° and +45°, and

[0105] - The width L of the trace is between 0.1 mm and 0.3 mm

[0106] The maximum possible repeated elongation for this geometry is approximately 30% of the initial length. In addition, this shape of the conductive trace 212 has been shown to withstand deformations up to 50% of the initial length of the trace by chance.

[0107] During operation, during use by the user, the compression of the dielectric layer 30 of the sensorized insole 1 causes a change in the distance between the ground layer 10 and the sensor plane 20, and thus causes a change in the capacitance of one or more sensors 2. The capacitance values associated with the sensors 2 - in the example considered, the capacitance measurements associated with each sensor or their variations - are acquired and digitized by the acquisition module 51. For example, the connection between the analog / digital converter of the acquisition module 51 and the corresponding pin 4 is made via a serial bus communication link. Then, each capacitance measurement is converted into a pressure value by the processing module 52 by means of non-linear calibration. The calculated information together with the positions of the sensors 2 makes it possible to estimate the pressure distribution over the entire surface area of the sensorized insole 1, and thus to estimate the pressure distribution on the insole of the user.

[0108] However, it is clear that the above examples must not be construed as restrictive, and the invention so conceived is susceptible to various modifications and variations.

[0109] For example, in other embodiments (not shown), the sensorized insole includes a multi-layer having more than two layers.

[0110] In particular, the low-density conductive material of the shielding layer according to the invention can provide one or more additional stacked sensor planes. Advantageously, each sensor plane provides sensors arranged at positions different from the sensor positions in other sensor planes.

[0111] As Figure 6A and Figure 6B schematically shown in, the alternative sensorized insole 1 includes two superimposed sensor planes 20a and 20b, and the sensors 2a of the first sensor plane 20a have a different arrangement from the sensors 2b of the second sensor plane 20b.

[0112] Thus, according to the specific requirements of each application - such as medical, sports, etc., it is possible to implement a sensorized insole with optimized sensor resolution and / or arrangement.

[0113] Advantageously, the two sensor planes are independent of each other, and each sensor plane includes sensor layers 21a and 21b and shielding layers 22a and 22b. In this way, the shielding layers can also protect their sensors and traces from electromagnetic radiation generated by other sensor layers.

[0114] In a simplified embodiment (not shown), the sensor layer and / or the shielding layer do not have grid lines. In this case, the electromagnetic shielding is limited to the shielding generated by the above-mentioned annular shielding and meandering shielding.

[0115] Naturally, all details can be replaced by other technically equivalent elements.

[0116] For example, the connecting traces may include meanders of a shape different from the above-mentioned horseshoe shape. For example, in other embodiments (not shown), the meander is in the shape of a semicircle, a wave, a rectangle, a square, etc.

[0117] In summary, without departing from the scope of protection of the appended claims, the materials, shapes, and possible dimensions used in the above-mentioned devices, equipment, and terminals may be determined according to specific implementation requirements.

Claims

1. A sensorized insole (1) adapted to be placed on an insole, comprising a sensor plane (20), a dielectric layer (30) and a ground layer (10), wherein: the dielectric layer (30) separates the ground layer (10) from the sensor plane (20), in use, compression of the dielectric layer (30) causes a change in capacitance between the ground layer (10) and at least one of a plurality of sensor pads (211) formed in a sensor layer (21) of the sensor plane (20), and each sensor pad (211) is electrically connected to a corresponding electrical terminal (41) by means of a trace (212) of conductive material, characterized in that the sensor plane (20) further comprises a shielding layer (22) separated from the sensor layer (21) by a support layer (23) made of a flexible material, the sensor plane (20) being arranged such that the shielding layer (22) is inserted between the sensor layer (21) and the dielectric layer (30), the shielding layer (22) comprising: a plurality of through-holes (226), each through-hole having a shape and size substantially corresponding to a respective sensor pad (211) and being superimposed above the corresponding sensor pad (211) in a plan view, a plurality of first shielding elements (224d), each first shielding element (224d) surrounding a respective through-hole (226), and a plurality of second shielding elements (224b), each second shielding element (224b) connecting a respective first shielding element (224d) to an electrical shielding terminal (227) and being superimposed above a corresponding trace (212) in a plan view, wherein the trace (212) and the second shielding element (224b) have corresponding meandering shapes.

2. The sensorized insole (1) according to claim 1, wherein, The sensor layer (21) further comprises a plurality of third shielding elements (213), each third shielding element (213) surrounding a respective sensor pad (211) and being superimposed above a corresponding first shielding element (224d) of the shielding layer (22) in a plan view.

3. The sensorized insole (1) according to claim 2, wherein, The sensor layer (21) further comprises a fourth shielding element (214b), each fourth shielding element (214b) connecting a respective third shielding element (213) to an electrical shielding terminal (42), and wherein pairs of fourth shielding elements (214b) are placed on opposite sides of at least one conductive material trace (212).

4. The sensorized insole (1) according to claim 2 or 3, wherein, The sensor layer (21) further comprises a plurality of wires (214c) electrically connected to the plurality of third shielding elements (213) and the plurality of fourth shielding elements (214b), the plurality of wires (214c) forming a plurality of meshes (214e) at least on a part of the surface of the sensor layer (21).

5. The sensorized insole (1) according to any one of the preceding claims, wherein, The shielding layer (22) further comprises a plurality of wires (224c) electrically connected to the plurality of first shielding elements (224d) and the plurality of second shielding elements (224b), the plurality of wires (224c) forming a plurality of meshes (224e) at least on a part of the surface of the shielding layer (22).

6. The sensorized insole (1) according to claim 4 or 5, wherein, The sensor layer (21) further comprises: A first peripheral wire (214a) that at least surrounds a part of the sensor pad (211) and is electrically connected to the plurality of wires (214c) and the electrical shielding terminal (42), A second peripheral wire (215a) and a third peripheral wire (215b) that are substantially parallel to the first peripheral wire (214a), wherein the second peripheral wire (215a) surrounds the first peripheral wire (214a), and the third peripheral wire (215c) surrounds the second peripheral wire (215b), and both the second peripheral wire (215a) and the third peripheral wire (215b) are electrically connected to the reference terminal (43), and A plurality of additional wires (215c) that are electrically connected to the second peripheral wire (215a) and the third peripheral wire (215b), and the plurality of additional wires (215c) form a plurality of meshes (215e) between the second peripheral wire (215a) and the third peripheral wire (215b).

7. The sensorized insole (1) according to claim 5 or claim 6, wherein, The shielding layer (22) further includes: A fourth peripheral wire (224a) that at least surrounds a part of the through hole (226) and is electrically connected to the plurality of wires (224c) and the corresponding shielding electrical terminal (227), A fifth peripheral wire (225a) and a sixth peripheral wire (225b) that are substantially parallel to the fourth peripheral wire (224a), wherein the fifth peripheral wire (225a) surrounds the fourth peripheral wire (224a), and the sixth peripheral wire (225b) surrounds the fifth peripheral wire (225a), and both the fifth peripheral wire (225a) and the sixth peripheral wire (225b) are electrically connected to the reference terminal (228), and A plurality of additional wires (225c) that are electrically connected to the fifth peripheral wire (225a) and the sixth peripheral wire (225b), and the plurality of additional wires (225c) form a plurality of meshes (225e) between the fifth peripheral wire (225a) and the sixth peripheral wire (225b).

8. The sensorized insole (1) according to claims 5, 6, and 7, wherein, The fourth peripheral wire (224a) of the shielding layer (22) is superimposed on the first peripheral wire (214a) of the sensor layer (21) in a plan view, wherein the fifth peripheral wire (225a) of the shielding layer (22) is superimposed on the second peripheral wire (215a) of the sensor layer (21) in a plan view, and wherein the sixth peripheral wire (225b) of the shielding layer (22) is superimposed on the third peripheral wire (215b) of the sensor layer (21) in a plan view.

9. The sensorized insole (1) according to any one of the preceding claims further comprises at least one additional sensor layer (21b) and a corresponding at least one additional shielding layer (22b), wherein, The additional sensor layer (21b) and the additional shielding layer (22b) are shaped corresponding to the sensor layer (21) and the shielding layer (22) according to any one of the preceding claims, and wherein the additional sensor pads (211) of the additional sensor layer (21b) have an arrangement different from that of the sensor pads (211) of the sensor layer (21), and the additional through-holes (226) of the additional shielding layer (22b) are arranged to be superimposed on the additional sensor pads (211) in a plan view.

10. An analysis system (1, 5), comprising at least a sensorized insole (1) according to any one of the preceding claims, and a processing system (5), wherein the processing system (5) comprises: an acquisition module (51) connected to each electrical terminal (41, 42, 43) of the sensorized insole (1) and adapted to receive the signals generated by the sensorized insole (1) during its compression and to convert the signals into corresponding digital signals, and a data processing module (52) adapted to receive the digital signals and process them to provide information about the posture and / or gait of the corresponding user.

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