Insole for monitoring a person's foot temperature

Abstract

The present invention relates to an insole (100) comprising: a) a technical layer (10) integrating an electronic board (11) made on a flexible substrate (12) the upper face (11a) of which is instrumented by a plurality of temperature sensors (13); and b) an intermediate layer (20) comprising a convoluted foam (21) assembled with the upper face (11a), said convoluted foam (21) having a plurality of cells (22), each formed by a hole (23) passing through the intermediate layer (20), said cells (21) each being positioned opposite one of the temperature sensors (13) so that each cell (22) receives a temperature sensor (13) in such a way that each temperature sensor (13) opens onto an upper face (20a) of the intermediate layer (20) while being isolated from the other temperature sensors (13) in order to avoid any electromagnetic interference between the sensors (13). Abbreviated figure: Figure 3

Description

Title of the invention: Insole for monitoring the temperature of a person's foot technical field

[0001] The present invention relates to the field of monitoring the temperature of a person's foot.

[0002] The present invention relates more particularly to an insole for footwear, said insole comprising an electronic board equipped with temperature sensors, which consumes little energy and whose innovative design allows monitoring of the temperature of a person's foot without hindering foot movements, including during physical activity such as walking or running.

[0003] By insole for footwear article, we mean here an insole, removable or not, intended to be placed inside a footwear article and comprising a plantar surface intended to be in direct or indirect contact with the sole of the foot.

[0004] Such an insole is distinguished from an outsole whose lower face is intended to be in direct contact with the ground.

[0005] For the purposes of this invention, the term "footwear" refers to any item that can be worn; this may include footwear such as dress shoes or athletic shoes. It may also include boots, slippers, or any other item into which a person can place their foot.

[0006] The present invention will find many advantageous applications, particularly in the field of health by offering people such as, for example, patients suffering from diabetes, arteriopathy or acute Charcot, a connected insole capable of taking measurements of foot temperature to determine early or even predictively the presence or absence of plantar lesions.

[0007] The present invention will find other advantageous applications, for example in the field of sport, by enabling the detection of abnormal heating of certain areas of the foot, in order to improve performance, recovery or even avoid injuries.

[0008] The present invention will find other advantageous applications in other fields by enabling the detection of poor load distribution, in order to reduce the occurrence of musculoskeletal disorders (MSDs). Previous art

[0009] One of the major problems encountered by patients suffering from diabetes is the appearance of plantar lesions, more commonly known as diabetic foot ulcers.

[0010] Nearly 25% of diabetic people are affected at some point by these foot conditions.

[0011] These diabetic foot ulcers manifest as open sores resulting from the combination of pressure, friction and poor healing.

[0012] These open wounds appear in the form of a deep excavation in the skin exposing the dermis or even the hypodermis without a tendency to heal.

[0013] Such open wounds can quickly become infected in the absence of proper care, too often leading to severe complications, such as osteomyelitis (bone infection) and / or gangrene, which may require amputation.

[0014] The detection of these ulcers in patients suffering from diabetes therefore represents a major challenge for healthcare professionals; the consequences of this ulceration can be extremely serious since diabetes remains the leading cause of amputation:

[0015] - 1 amputation every 30 seconds worldwide,

[0016] - 85% of amputations are secondary to a diabetic foot ulcer,

[0017] - The overall cost of an amputation is estimated to be between €15,000 and €50,000.

[0018] Diabetic foot is classified according to several risk categories ranging from risk very low risk grade 0 to high risk grade 3.

[0019] In Europe, there are nearly 6 million patients with grade 2 and grade 3 diabetes. Each year, 1.2 million patients develop a diabetic foot ulcer and 250,000 undergo a lower limb amputation following the onset of the ulcer.

[0020] It should also be noted that, even with adequate care, complete healing of an ulcer requires 1 year in 77% of cases;

[0021] The management of complications related to diabetic foot represents a significant cost amounting to nearly €28 billion per year in Europe and €700 million in France.

[0022] It seems important here to understand the origin of these plantar ulcers in diabetics.

[0023] These lesions occur due to several disease-related factors, including peripheral neuropathy and obliterative arteriopathy of the lower limbs.

[0024] Peripheral neuropathy is a common condition in diabetics that results in a loss of sensation in the feet, making patients less able to perceive minor trauma or areas of excessive pressure. It is understood here that the loss of sensation in the feet due to neuropathy reduces the patient's ability to detect injuries, thereby increasing the risk of infections and ulcerations.

[0025] Circulatory insufficiency, a consequence of arteriopathy, slows down the healing process, thus increasing the risk of ulceration.

[0026] For these reasons, diabetic patients are at-risk subjects who are particularly susceptible to developing ulcer-type lesions on the feet.

[0027] Prevention and early detection of these lesions are therefore crucial to reducing the risks of morbidity and improving the quality of life of these patients.

[0028] In the prior art, medical devices and innovative technologies are known that aim to improve the quality of life of diabetic patients by detecting, if possible at an early stage, the presence of these ulcers.

[0029] Unfortunately, to date, it has been observed that the prevention systems put in place are not optimal; the associated medical follow-up is also irregular and discontinuous.

[0030] Several solutions have been developed so far to enable the detection of plantar lesions in diabetic patients:

[0031] Regular visual and manual inspections: Healthcare professionals recommend that patients perform daily self-examinations of their feet to detect any abnormalities. These inspections are often supplemented by regular consultations with podiatrists. However, this method relies on the patient's constant vigilance and may be ineffective in cases of advanced neuropathy.

[0032] Traditional orthotic insoles: Designed to redistribute pressure on the sole of the foot, these insoles aim to prevent the formation of ulcers. Although they offer a certain degree of protection, they do not provide real-time data on the condition of the patient's feet.

[0033] Plantar pressure sensing technologies: These devices are equipped with pressure sensors integrated into the soles or shoes, capable of measuring and analyzing areas of excessive pressure that could lead to ulcerations.

[0034] Connected insoles with multiple sensors: More recently, smart insoles equipped with several types of sensors (pressure, temperature, humidity) have been developed. These multi-sensors are capable of collecting several types of physiological data to detect abnormal changes which, combined, could indicate the development of an injury.

[0035] The company ORPYX® has thus developed a solution aimed at designing a connected insole comprising both pressure sensors and temperature sensors.

[0036] From a scientific point of view, the coupled measurement of these two types of measurement is relevant and allows for a good prediction of ulcers.

[0037] The Applicant observes, however, that measuring several data such as pressure and temperature is energy-intensive and does not allow for a System autonomy exceeding two weeks thus rendering such a device ineligible for long-term remote monitoring.

[0038] In addition, the integration of temperature and pressure sensors makes the sole too complex to make and too thick, which makes it difficult to manufacture on the one hand and not very attractive from a practical point of view because it cannot be integrated into just any footwear.

[0039] In conclusion, although significant progress has been made in the prevention and detection of diabetic foot ulcers, there is a constant need to improve these technologies to provide more accurate monitoring, better adherence and faster intervention. Summary of the invention

[0040] The present invention aims to improve the situation described above.

[0041] The present invention thus aims to solve the various problems mentioned above by offering a simple insole to design offering good autonomy and equipped with sophisticated sensors intended to accurately monitor the temperature of a person's foot while taking into account the anatomy of the foot without hindering the movements of the foot in a walking cycle.

[0042] To this end, the object of the present invention relates, in a first aspect, to an insole for monitoring the temperature of a person's foot, such an insole being intended, for example, to: - monitoring temperature variations between a patient's two feet to allow, for example, the (predictive or early) detection of a plantar lesion in a person such as a diabetic patient; or - Monitor temperature variations between different areas of the foot: toes, metatarsals, midfoot or heel

[0043] By early or predictive, we mean here the detection of the lesion as early as possible in its formation process.

[0044] According to the present invention, the insole advantageously has a multilayer structure comprising at least one technical layer and one intermediate layer.

[0045] Advantageously, the technical layer includes the embedded electronics which will be used to measure the physiological data relevant for this monitoring.

[0046] In the example described here, this technical layer therefore integrates an electronic board made on a flexible substrate.

[0047] Advantageously, the upper face of the electronic board is instrumented by a plurality of temperature sensors oriented towards the sole of the foot.

[0048] It is therefore understood here that the upper surface of the electronic board is the functional surface of the electronic board on which the temperature sensors are arranged. The objective here is for the temperature sensors to be as close as possible to the plantar surface of the foot in order to acquire the best possible temperature measurement.

[0049] This upper face of the electronic card is therefore intended to be oriented towards the plantar face of the user's foot when the latter is wearing the sole.

[0050] It should be noted here that the present electronic board does not include pressure sensors, the measurements carried out only relate to temperature measurement.

[0051] In the example described here, the intermediate layer comprises a honeycomb foam assembled with the upper face of the technical layer.

[0052] It is understood here that the lower face of the inner layer is assembled to the upper face of the technical layer.

[0053] This foam is used in particular to provide the necessary comfort to users during walking or during other pedestrian activity associated with foot movement.

[0054] Advantageously, this open-cell foam comprises a plurality of cells, each formed by a hole passing through the intermediate layer. By a hole passing through, we mean a hole connecting the lower and upper faces of the foam.

[0055] Preferably, the through hole is straight. The latter may have an elliptical, oblong or other shape.

[0056] Advantageously, the cells are each positioned opposite one of the temperature sensors when the technical layer and the intermediate layer are assembled together.

[0057] It is therefore understood here that a honeycomb foam is planned, designed so that each honeycomb receives a temperature sensor.

[0058] This honeycomb foam is intended in particular to protect the temperature sensors from various mechanical stresses and from any adjacent electronic circuit.

[0059] Thus, the alveoli serve as housing for each of the sensors when the two layers are superimposed on each other.

[0060] When the two layers are therefore joined together by gluing, each temperature sensor is housed in a cavity and opens onto an upper face of the intermediate layer while being isolated from the other temperature sensors.

[0061] Thus, the presence of these alveoli suitable for receiving temperature sensors makes it possible to isolate the sensors from each other and to avoid any electromagnetic interference between the sensors or with other electronic devices.

[0062] Thus, thanks to the design of this multilayer sole formed by an electronic board on a flexible substrate comprising temperature sensors and a honeycomb foam comprising cells suitable for receiving the sensors, we have The shoe features a robust sole capable of deforming under the stresses exerted by the user during physical activity, while incorporating a network of sensors protected within alveoli and positioned close to the underside of the foot to collect temperature data. This design allows for precise monitoring of foot temperature, enabling, for example, the early detection of lesions in diabetic foot. It also allows for monitoring the temperature of different areas of the foot to detect abnormal overheating or uneven weight distribution, thereby reducing the risk of musculoskeletal disorders (MSDs).

[0063] Advantageously, the flexible substrate on which the electronic board is made is of the PCB type (for "Printed Circuit Board"). It is also referred to as a "flex PCB" (flexible printed circuit board).

[0064] This flexible PCB card is therefore capable of being bent and / or twisted without being damaged and thus aligns with the classic properties of a sole which must be flexible to offer comfort and adaptability to foot movements and also allow easy introduction into all types of shoes.

[0065] The use of flexible PCBs is also advantageous because flexible PCBs are lighter and thinner than rigid PCBs. This design helps to further reduce the overall weight of the electronics integrated into the sole, which is essential for comfort and practicality.

[0066] The Applicant observes that, due to their flexibility, the flexible PCB can be integrated more naturally into the sole structure. This technical layer can therefore conform to curved shapes and follow specific contours without compromising its functionality as an electronic component.

[0067] The Applicant further observes that PCB flex is a material which is highly resistant to shocks and vibrations, which is an important advantage for soles which are subjected to significant mechanical stresses during walking or other activities.

[0068] Finally, the Applicant notes that the chosen Flex PCB is resistant to water and other environmental elements. This represents a significant advantage for shoes, which may be exposed to various weather conditions and moisture inside the shoe.

[0069] Advantageously, the temperature sensors are each positioned on the substrate at predetermined locations to measure temperatures in specific predetermined areas of the foot corresponding to areas of friction and / or contact. Such areas are often at risk for foot injuries.

[0070] Preferably, the temperature sensors are positioned according to a zone of the heel, a midfoot zone, a zone of the metatarsal heads, a zone of the toes.

[0071] Advantageously, each cell is sized to receive a temperature sensor without the sensor being in contact with the side walls of the cell.

[0072] It is understood here that it is preferable for the foam not to come into contact with the sensors so as not to influence the measurements. Each cell therefore has dimensions larger than the dimensions of the temperature sensor. For example, the cell has a tubular shape with a diameter at the base of the cylinder greater than the width of the temperature sensor and a height slightly greater than or equal to the height of the temperature sensor.

[0073] Preferably, the honeycomb foam has a thickness slightly greater than the height of the temperature sensor so that the sensor is flush with the surface of the hole opening from the honeycomb without protruding from it.

[0074] By measuring the temperature on the top, the measurement is taken as far away as possible from the pins of the integrated circuit to avoid parasitic heating and to obtain a reliable and accurate measurement.

[0075] Advantageously, each temperature sensor is centered in its associated cavity.

[0076] In an advantageous embodiment, the sole further comprises a protective layer formed by a silicone coating filling the cells and covering the alveolar foam.

[0077] A silicone is therefore applied to the foam. This is also referred to as a silicone coating of the foam surface. This coating homogenizes the surface of the foam and, in particular, its hardness (called Shore), thus improving user comfort.

[0078] Advantageously, the silicone coating incorporates metallic particles that promote thermal conductivity.

[0079] Advantageously, the sole further comprises a textile cover layer configured to cover the protective layer, said textile cover layer comprising a thermally conductive fabric configured to allow heat to pass through but not moisture, in order to ensure comfortable wear of the sole while allowing accurate temperature measurement. This layer serves to ensure comfortable wear of the sole with which the foot will be in contact

[0080] Preferably, the silicone coating is made by an adhesive silicone ensuring an assembly by bonding of the covering textile layer with the intermediate layer.

[0081] Advantageously, the technical layer comprises, on the inner face of the flexible substrate, stiffening elements, also called stiffeners, positioned under each of the temperature sensors and possibly other electronic components in order to reduce the various mechanical stresses applied to the sensors and any other components during the user's walk, for example.

[0082] The presence of these elements, which are placed under the electronic board (PCB flex) at the level of the sensors and other electronic components, makes it possible to stiffen these elements in order to protect them against the various mechanical stresses applied.

[0083] Advantageously, the sole according to the present invention comprises a mechanical layer placed beneath the technical layer, said mechanical layer being configured to provide an orthopedic function to the sole. Such a mechanical layer preferably has a shape configured to optimize the function and performance of the foot in a gait cycle.

[0084] Advantageously, the mechanical layer includes on its upper face a plurality of indentations serving as housings for the stiffening elements.

[0085] Advantageously, the electronic board is powered by a harvesting type energy system comprising MFC sensors (for "Macro Fiber Composite" or micro-fiber composite) implementing piezoelectric elements which, by deforming, are able to generate electricity for example when subjected to mechanical stress, such as compression or bending during walking.

[0086] The presence of this power supply system gives the system good autonomy.

[0087] It should be noted here that simulations have shown that with 3800 steps, it is possible to obtain an autonomy of 2 to 3 days.

[0088] Preferably, the electrical energy generated by the deformation of the piezoelectric elements is stored in a rechargeable solid-state Lithium-ion micro-battery.

[0089] This type of battery has several advantages:

[0090] - Small footprint: Dimensions of 4.5x3x2 mm,

[0091] - Good compromise between energy density and available peak current,

[0092] - Constant voltage charging (simplicity of the charging circuit),

[0093] - 100 pAh to 500 pAh battery allowing current peaks of several tens of mA for 100 ms,

[0094] - Possibility of connecting the micro-batteries in parallel

[0095] - No explosion possible (because it is in a solid state), no toxic material or material rare.

[0096] Advantageously, it is also possible to provide a non-rechargeable lithium-manganese dioxide button cell having a capacity approximately 230 mAh @3.0 V to power the entire system and achieve a minimum autonomy of 12 months.

[0097] Advantageously, the electronic card includes wireless communication means capable of communicating with a communication terminal to transmit periodically or continuously the measurement data obtained by each of the temperature sensors.

[0098] Preferably, a BLE (for "Bluetooth Low Energy") antenna can be provided, printed on the flexible PCB; such an antenna allows the user's communication terminal to:

[0099] - detect the presence of the sole and be able to associate with it (ADVERTISING WHEAT) ;

[0100] - connect to the sole so that the measured information is transmitted to the communication terminal which then acts as a gateway in order to transmit this information to the remote monitoring platform;

[0101] - Update the device firmware via OTA (Over The Air) BT using the application installed on the communication terminal;

[0102] - to retrieve battery information from the sole; and

[0103] - configure certain sole settings

[0104] In an advantageous embodiment, the temperature sensors are electrically connected to the electronic board by conductive tracks made of a flexible material and extending lengthwise to form a succession of open Q-shaped loops with cutouts in the PCB Flex

[0105] The configuration of these tracks gives the card additional flexibility which allows it to withstand all the mechanical stresses related to walking: torsion, bending, tension, compression and shear.

[0106] Advantageously, the temperature sensors are clinical grade temperature sensors according to ASTM El 12 and ISO 80601-2-56 which are configured to perform temperature measurement with an accuracy of 0.1 °C.

[0107] It should be noted that the selected temperature sensors offer, but are not limited to, the following advantages: - low power consumption during measurement (3.5-pA), and extremely low power consumption when in standby mode (150-nA); - an accuracy of 0.1 °C over a temperature range of 5° to 50°

[0108] Advantageously, the electronic board includes an accelerometer associated with an odometer configured to detect the user's movements and walking.

[0109] The accelerometer must allow the detection of the user's foot movements.

[0110] The odometer must allow the detection of the position and orientation of the foot.

[0111] The person skilled in the art will understand here that the parameterization of these components and the tolerance of motion detection depend here on the chosen detection use case in order that the temperature information is brought back in a relevant and optimized manner.

[0112] For example, it is unnecessary for the device to be in normal operation during the night. It can, in fact, enter deep sleep mode and wake up only when, for example, the accelerometer / odometer sends an interrupt following a confirmed motion detection.

[0113] Advantageously, the electronic board includes a resin coating on all or part of the electronic components of which it is made.

[0114] Thus, the electronic components of the electronic board are resin-coated, which ensures their protection and integrity, but also prevents injuries to the user's foot in the event of tearing of the textile covering and the honeycomb foam.

[0115] Correspondingly, the object of the present invention relates, according to a second aspect, to a footwear article incorporating a sole as described above.

[0116] Thus, through its various structural and functional technical characteristics, the present invention proposes an innovative design integrating embedded electronics capable of reliably and accurately monitoring foot temperature (for example to detect the presence of lesions such as ulcers) while taking into consideration the anatomy of the foot and the kinematics of its natural biomechanical deformations to improve the wearer's comfort.

[0117] Description of the attached figures

[0118] Other features and advantages of the present invention will become apparent from the description below, with reference to the attached Figures 1 to 7, which illustrate an example of an embodiment without being limiting in any way and on which:

[0119] [Fig.1]

[0120] Fig. 1 represents an exploded perspective view of a sole according to an embodiment of the present invention.

[0121] [Fig.2]

[0122] Fig. 2 represents a top view of the upper face of the open-cell foam assembled to the technical layer and covered with the silicone coating.

[0123] [Fig.3]

[0124] Fig. 3 represents a cross-section of a section of a sole conforming to Fig. 1.

[0125] [Fig.4]

[0126] Fig. 4 represents a flat view of the top face of the technical layer comprising the electronic board with temperature sensors and made on a flexible PCB substrate.

[0127] [Fig.5]

[0128] Fig. 5 represents a flat view of the lower face of the technical layer comprising stiffener-type stiffening elements.

[0129] [Fig.6]

[0130] Fig. 6 represents a flat view of the upper face of the mechanical layer including indentations for receiving the stiffening elements.

[0131] [Fig.7]

[0132] Fig. 7 represents a flat view of another example of the electronic board being mounted on a flexible PCB substrate. Detailed description

[0133] An insole according to an advantageous embodiment of the present invention will now be described in what follows with joint reference to figures 1 to 7.

[0134] In the embodiment described here, we take the example of an application aimed at monitoring the temperature between the two feet of a diabetic patient in order to detect the early appearance of lesions.

[0135] It is understood here that this is one example of application among others and that it is possible to consider using the sole according to the invention for other applications such as, for example, detecting the distribution of loads on the foot to reduce musculoskeletal disorders or detecting abnormal heating under the foot to, for example, reduce the risk of injury in an athlete.

[0136] As a reminder, as stated previously in the preamble, people with diabetes have an increased risk of foot lesions that can develop into ulcers. These complications can be due to poor blood circulation in the arteries of the lower limbs and are also exacerbated by decreased sensation in the feet.

[0137] In the most serious cases, these complications may require prolonged hospitalization and sometimes lead to amputation.

[0138] It is therefore important to be able to detect the appearance of a lesion that is a precursor to an ulcer as early as possible in order to improve medical care and avoid amputation.

[0139] Prior art solutions are not satisfactory: they are complex to manufacture, are not suitable for promoting walking, do not allow for continuous measurement, and offer little autonomy.

[0140] Designing an insole comprising embedded electronics specifically designed to promote temperature monitoring between the two feet of a patient while respecting the anatomy of the foot and reducing energy consumption is one of the objectives of the present invention.

[0141] This is made possible in the following example.

[0142] In the example described here, and as illustrated in particular in figures 1 and 3, an insole 100 is provided comprising a multilayer structure.

[0143] Such a multilayer structure takes the form of a complex with several functional layers superimposed on one another.

[0144] The combination of these layers is characteristic of the present invention.

[0145] The first layer 10, called the technical layer, integrates the embedded electronics of the sole.

[0146] This layer 10, illustrated in particular in figures 4 and 5, constitutes the main layer in which the inventive concept of the invention resides.

[0147] Indeed, one of the technical challenges solved by the present invention was to design a connected insole incorporating miniaturized electronics that does not compromise user comfort and offers good battery life. This differs from existing solutions that use energy-intensive, bulky, and complex electronics, making the insole heavy, thick, and uncomfortable for the patient.

[0148] In the example described here, this electronic board 11 is made on a flexible substrate, preferably here a flexible PCB (PCB for "Printed Circuit Board").

[0149] This flexible PCB serves as a mechanical and electronic support structure and improves the electrical and physical connections of the components while allowing efficient signal transmission and good power distribution.

[0150] This flexible PCB also offers an optimal solution for giving the sole the suppleness and flexibility necessary for its deformation during the user's movements. Finally, it should be noted that this flexible PCB provides good mechanical resistance.

[0151] The underlying concept of the present invention is the implementation of a solution that uses only temperature data. Indeed, connected insoles known in the prior art have thus far used data relating primarily to the pressure exerted under the foot. This pressure data was sometimes combined with temperature data.

[0152] The Applicant observes that under no circumstances has a sole solution exploiting only the temperature of the foot been considered so far.

[0153] However, after numerous tests, it turned out that such an approach with temperature data only made it possible to accurately detect the appearance of lesions under the foot.

[0154] Thus, the electronic card 11 provided for in the context of the present invention integrates temperature sensors 13. These sensors 13 are provided on the upper face 10a of the technical layer so as to be oriented with regard to the lower face of the foot and thus measure the temperature under the foot.

[0155] As illustrated in [Fig.4], the temperature sensors 13 are positioned according to determined locations to measure temperatures in specific predetermined areas of the foot corresponding to areas at risk for foot lesions, namely here for example the heel area 14a, the metatarsal heads area 14b, the toe area 14c and the midfoot area 14d.

[0156] These zones 14a, 14b, 14c and 14d constitute the most frequent friction and pressure points. Therefore, these are the zones where the risks of injury and ulceration are highest.

[0157] In the example described here, there are nineteen of these sensors. Obviously, it will be understood that this number can vary (increase or decrease) depending on the required precision.

[0158] In the example described here, clinical grade temperature sensors 13 according to ASTM El 12 and / or ISO 80601-2-56 were selected to perform a temperature measurement with an accuracy of 0.1 °C; preferably the sensors are configured so that such accuracy is achieved over a range of 5 to 50°C.

[0159] This technical layer 10 is coupled to an intermediate layer 20 which includes an open-cell foam 21.

[0160] This alveolar foam 21 is superimposed on the upper face lia.

[0161] The honeycomb foam 21a has the function of isolating the sensors 13 from each other to avoid any electrical and electromagnetic interference between the sensors 13.

[0162] It also serves to improve patient comfort.

[0163] In the example described here and as illustrated in figures 1, 2 and 3, the foam 21 has cells 22. It is understood here that each cell 22 is in the form of a hole 23 passing through the intermediate layer 20 on either side of the lower and upper face of the foam.

[0164] The location of the cells 22 follows the distribution of the location of the sensors 13. The cells 22 are therefore each positioned opposite one of the temperature sensors 13 when the technical layer 10 and the intermediate layer 20 are assembled together.

[0165] Thus, during the assembly of layers 10 and 20, the temperature sensors 13 each fit into their dedicated cavity 22 so that Each temperature sensor 13 opens onto the upper face 20a of the intermediate layer 20 while being isolated from the other temperature sensors 13 in order to avoid any electromagnetic interference between the sensors 13.

[0166] The association of this electronic board 11 on a flexible PCB with the temperature sensors 13 combined with the honeycomb foam 21 is characteristic of the present invention.

[0167] It is preferable that the sensors 13 not be in contact with the foam 21.

[0168] It is therefore expected in the example described here that each temperature sensor 13 is centered in the cavity 22 and that each cavity 22 is sized to receive a temperature sensor 13 without said sensor 13 being in contact with the lateral walls 22a of the cavity 22.

[0169] This electronic card 11 is instrumented by other electronic components.

[0170] For power supply, a non-rechargeable button cell battery with a capacity of approximately 230 mAh @3.0 V is provided.

[0171] To improve autonomy, it is also planned to provide power from a harvesting type energy system 16 comprising MFC sensors implementing piezoelectric elements which, by deforming, are able to generate electricity for example when they are subjected to mechanical stress, such as compression or bending during walking.

[0172] In the example described here, wireless communication means 17, of the BLE antenna type (or equivalent), are also provided for communicating with a communication terminal in order to transmit the measurement data made by each of the temperature sensors 13.

[0173] In the example described here, this transmission occurs periodically (for example, every 15 or 30 minutes). Of course, this frequency can be adjusted according to the practitioner's preference.

[0174] In the example described here, the implementation on the electronic board 11 of an accelerometer / odometer is planned to detect the movements and orientation of the patient's foot; this makes it possible to determine the patient's activity (stationary or in motion).

[0175] The detection model used to exploit this data to weight the temperature, for example in the case of sustained activity.

[0176] Resin coating is also provided here on the electronic board and all of its electronic components; such resin coating ensures the protection and integrity of these components and also prevents injury to the patient's foot in the event, for example, of tearing of the alveolar foam 21 (or of the textile coating layer 30 described below).

[0177] On the electronic card 11, it is also characteristic to have provided conductive tracks 18 which are made of a flexible material and which stretch lengthwise, forming a succession of open Q-shaped loops.

[0178] Such tracks 18 are illustrated in figures 4, 5 and 7.

[0179] This Q-shaped form, as can be understood, allows for a deformation of the tracks without risk of breakage, which improves the flexibility of card 11 and its robustness.

[0180] The Applicant observes here that such Q-tracks had never been used until now in a sole for its on-board electronics.

[0181] It should be noted here that, thanks to the use of "Ultra Low Power" components (temperature sensors, BLE module, accelerometer, processor), it is possible to achieve a battery life of twelve months; such battery life is greatly appreciated by patients who do not have to worry about frequently recharging their device as is currently the case with prior art solutions which offer a battery life of two weeks (only).

[0182] The sole proposed according to the present invention therefore significantly improves the user experience with an additional gain in terms of comfort.

[0183] This comfort is further enhanced by an additional protective layer 30 which is formed by a silicone coating 31.

[0184] This silicone coating layer 30 31 illustrated in [Fig.3] fills the alveoli (22) and covers the upper face 21a of the alveolar foam 21.

[0185] This coating thus makes it possible to homogenize the surface of the foam and in particular its hardness, which improves comfort for the patient.

[0186] The sensors 13 are therefore embedded in this silicone coating 31, which protects them from deterioration.

[0187] It should also be noted that this silicone coating 31 incorporates metallic particles that enhance thermal conductivity. The presence of these particles therefore makes it possible to obtain a precise temperature measurement despite the encapsulation of the sensor 13 in the silicone 31.

[0188] In the example described here, the use of an adhesive silicone is planned to allow the assembly by gluing of the honeycomb foam 21 with a layer of covering textile 40.

[0189] This layer 40 which covers the protective layer 30 is made of a thermally conductive fabric 41 in order to allow the passage of heat but not moisture.

[0190] The presence of this additional layer 40 guarantees comfort when wearing the sole 100 while allowing good temperature measurement.

[0191] The use of Dermodry® fabric is envisaged here. Of course, a person skilled in the art may consider the use of another technical fabric having these properties (thermal conductivity and moisture barrier).

[0192] Finally, under the technical layer 10, a final layer called mechanical layer 50 is planned.

[0193] In the example described here, this mechanical layer 50 provides an orthopedic function to the sole 100.

[0194] It is therefore understood here that this mechanical layer 50 has a shape that respects the anatomy of the foot in order to improve its function during an activity.

[0195] To reinforce the strength of the electronic components, stiffening elements 15, also called stiffeners, are provided on the lower face 10b on the flexible substrate 12.

[0196] These elements 12 are positioned under each of the temperature sensors 13 in order to reduce the various mechanical stresses applied to the sensors 13 during the patient's walking, for example.

[0197] Here, the mechanical layer 50 includes on its upper face 50a a plurality of indentations 51, or notches, serving as housings for the stiffening elements 15.

[0198] By superimposing layers 10 and 50, the stiffeners 15 will therefore fit into these notches.

[0199] Thus, the present invention provides for the design of a sole which significantly improves existing solutions and whose main advantages are comfort, efficiency, robustness and autonomy:

[0200] - Comfort is primarily achieved through optimization of the size and the component placement. The sole components were chosen so that the sole would be as thin, flexible and lightweight as possible.

[0201] - Efficiency is achieved through precise placement of temperature sensors, at to know which areas are most prone to developing an ulcer.

[0202] - Battery life has also been significantly improved by moving from battery life from approximately two weeks to a minimum of twelve months of autonomy. The Applicant observes here that by increasing this autonomy, patient compliance is greatly improved, thus preventing complications related to diabetic foot.

[0203] This improved autonomy is achieved through:

[0204] - components such as the electronic board and sensors which consume a lot low energy consumption and perfectly optimized consumption patterns.

[0205] - The elimination of pressure sensors compared to competing solutions

[0206] - An energy harvesting system that allows the conversion of mechanical motion from the patient's foot in energy.

[0207] It should be noted that this detailed description relates to a particular embodiment of the present invention, but that in no way does this description limit the scope of the invention; on the contrary, Its objective is to remove any possible inaccuracies or misinterpretations of the claims that follow.

[0208] It will be understood here that the present invention has been described in the example below for the monitoring and surveillance of the feet of a diabetic patient.

[0209] It will be understood, however, that the insole according to the invention is suitable for monitoring other people such as, for example, people suffering from neuropathies, arteriopathy or even acute Charcot.

[0210] Other applications could also be considered, such as: - enabling the detection of abnormal heating in certain areas of the foot to improve performance, recovery, or even prevent injuries; or - by enabling the detection of poor load distribution, thereby reducing the occurrence of musculoskeletal disorders (MSDs).

[0211] It should also be noted that the reference signs in parentheses in the following claims are in no way intended to be limiting; these signs are solely intended to improve the intelligibility and understanding of the following claims and the scope of protection sought.

Claims

Demands

1. Insole (100) for monitoring the temperature of a user's foot, said insole (100) having a multilayer structure comprising: - a technical layer (10) integrating an electronic board (11) made on a flexible substrate (12) the upper face (lia) of which is instrumented by a plurality of temperature sensors (13) oriented towards the lower face of the foot;- an intermediate layer (20) comprising a convoluted foam (21) assembled with the upper face (1a), said convoluted foam (21) having a plurality of cells (22) each formed by a hole (23) passing through the intermediate layer (20), said cells (21) each being positioned opposite one of the temperature sensors (13) when the technical layer (10) and the intermediate layer (20) are assembled together so that each cell (22) receives a temperature sensor (13) in such a way that each temperature sensor (13) opens onto an upper face (20a) of the intermediate layer (20) while being isolated from the other temperature sensors (13) in order to avoid any electromagnetic interference between the sensors (13).;

2. Sole (100) according to claim 1, wherein the flexible substrate (12) on which the electronic board (11) is made is a flexible PCB board.

3. Sole (100) according to claim 1 or 2, wherein the temperature sensors (13) are each positioned on the substrate (12) according to determined locations (14a, 14b, 14c) to measure temperatures in specific predetermined areas of the foot corresponding to areas of friction and / or contact.

4. Insole (100) according to claim 3, in which the temperature sensors (13) are positioned according to a zone of the heel (14a), a zone of the metatarsal heads (14b), a zone of the toes (14c), a midfoot zone (14d).

5. A sole (100) according to any one of the preceding claims, wherein each cavity (22) is dimensioned for receive a temperature sensor (13) without said sensor (13) being in contact with the side walls (22a) of the cavity (22).

6. Sole (100) according to claim 5, wherein each temperature sensor (13) is centered in the associated cavity (22).

7. Insole (100) according to any one of the preceding claims, which includes a protective layer (30) formed by a silicone coating (31) filling the cells (22) and covering said upper face (21a) of the convoluted foam (21).

8. Sole (100) according to claim 7, wherein the silicone coating (31) incorporates metallic particles promoting thermal conductivity.

9. Insole (100) according to claim 7 or 8, which includes a textile cover layer (40) configured to cover the protective layer (30), said textile cover layer (40) comprising a thermally conductive fabric (41) configured to allow the passage of temperature but not moisture in order to ensure comfortable wearing of the insole (100) while allowing good temperature measurement.

10. Sole (100) according to claim 9, wherein the silicone coating (31) is made by an adhesive silicone ensuring a bonding of the covering textile layer (40) with the intermediate layer (20).

11. A sole (100) according to any one of the preceding claims, wherein the technical layer (10) comprises on the inner face (10b) on the flexible substrate (12) stiffening elements (15) positioned under each of the temperature sensors (13) in order to reduce the various mechanical stresses applied to said sensors (13) during the user's walking, for example.

12. Insole (100) according to any one of the preceding claims, which includes a mechanical layer (50) placed under the technical layer (10) to provide an orthopedic function to said insole (100).

13. Sole (100) according to claim 12 related to claim 11, wherein the mechanical layer (50) comprises on its upper face (50a) a plurality of indentations (51) serving as housings for the stiffening elements (15).

14. Sole (100) according to any one of the preceding claims, wherein the electronic board (11) is powered by a harvesting-type energy system (16) comprising MFC sensors implementing piezoelectric elements which, by deforming, are capable of generating electricity, for example, when subjected to mechanical stress, such as, for example, compression or bending during walking.

15. Sole (100) according to any one of the preceding claims, wherein said electronic card (11) includes wireless communication means (17) capable of communicating with a communication terminal to transmit periodically or continuously the measurement data obtained by each of the temperature sensors (13).

16. A sole (100) according to any one of the preceding claims, wherein the temperature sensors (13) are electrically connected to the electronic board (11) by conductive tracks (18) made of a flexible material and stretching lengthwise to form a succession of open Q-shaped loops.

17. Insole (100) according to any one of the preceding claims, wherein the temperature sensors (13) are clinical grade temperature sensors according to ASTM El 12 and / or ISO 80601-2-56 that are configured to perform temperature measurement with an accuracy of 0.1 °C.

18. Sole (100) according to any one of the preceding claims, wherein the electronic card (11) includes an accelerometer associated with an odometer.

19. Base (100) according to any one of the preceding claims, wherein the electronic board (11) includes a resin coating on all or part of the electronic components of which it is made.

20. Footwear article incorporating a sole (100) according to any one of the preceding claims.

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