Device for capturing perspiration from a body, and method for manufacturing such a device

Abstract

The invention relates to a device (100) configured to capture the perspiration from a perspiring body and to be attached to an electronic component, comprising a multi-layer structure (9) having a contact surface (1) configured to be placed in contact with the body, the structure (9) comprising a microfluidic channel (5) connecting a fluid inlet (3) to a fluid outlet (19), and at least one pair of electrical conductors (27a, 27b), each conductor (27a, 27b) of the pair of conductors (27a, 27b) comprising, at a first end, an electrode (23a, 23b) having a surface area extending along a wall of the microfluidic channel (5), and, at a second end, a connection portion (25a, 25b), the connection portion (25a, 25b) being accessible via a surface (22a, 22b) adjacent to or a surface (17) opposite from the contact surface (1) and being configured to be coupled electrically to the electronic device.

Description

DESCRIPTION Title: Device for capturing perspiration from a body and method of manufacturing such a device Field of invention

[0001] The present invention relates to a device configured to capture perspiration from a perspiring body and to be attached to an electronic device, as well as a method for manufacturing said device. Technological background

[0002] Devices are known in the art for providing measurements of the perspiration of a sweating body. Perspiration is a biological thermoregulatory mechanism prevalent in mammals, in which fluid is secreted by glands and expelled through pores in the skin. Parameters of this biological phenomenon can provide useful medical insights into the condition, health, and environment of the sweating body in question.

[0003] Thus, it may be desirable to obtain information about the volumetric flow rate of perspiration of a body, the temperature of the perspiration fluid, or the composition of the perspiration fluid, for example the concentration of ureas, lactate or minerals, such as sodium chloride (NaCl). This information may be useful for medical purposes, for example by evaluating data during long-term monitoring, as well as in real time, for example during physical exercise and / or when the body is subjected to high temperatures.

[0004] In particular, during a physical exercise session, real-time monitoring of the perspiration parameters of the sweating body can provide more accurate information about the body's state and allow for adaptation of the effort or environment. For example, monitoring of perspiration parameters can be used to obtain optimized hydration instructions to achieve a desired physical performance.

[0005] Thus, to capture the perspiration of a sweating body, various devices have been proposed aimed at obtaining one of the measurements indicated above. These devices generally comprise at least one capture device and at least one capture measurement and analysis device. The capture device comprises a surface contact device configured to be placed in contact with the body, so as to be able to carry out a capture operation on a parameter of the liquid secreted by one or more pores of the skin of the perspiring body. The measurement and analysis device is interfaced with the capture device so as to measure the capture and to process and analyze the measurement, in order to communicate it subsequently, for example to a user. Technical problem

[0006] In the context of physical exercise, the sweat-capturing device is subject to a high risk of physical degradation. For example, the device may be subjected to a significant amount of sudden movements and jolts, and may also suffer from vibrations, shocks, or exposure to precipitation or be contaminated by the natural environment (dust, mud, etc.). Thus, the device must have a good level of resistance to external effects, have a sufficient level of accuracy, and be comfortable to use. Subject of the invention

[0007] In view of the above, an aim of the invention is to provide a device for capturing perspiration, which is reliable, compact and economical to manufacture. In particular, the aim of the invention is to obtain a device for capturing perspiration which is consumable, i.e. replaceable at low cost at the end of a physical exercise session.

[0008] This object is achieved with a device configured to capture perspiration from a sweating body and to be attached to an electronic device. The device comprises a multi-layer structure having a contact surface configured to be placed in contact with the body, the structure comprising an interior microfluidic channel extending through the structure and fluidically connecting at least one fluid inlet to at least one fluid outlet. The inlet is located at said contact surface and is configured to be interfaced with a surface of the body comprising at least one pore, and the outlet is located at another surface different from said contact surface.

[0009] The structure further comprises at least one pair of electrical conductors, in particular copper conductors, each conductor of the pair of conductors comprising at a first end an electrode having a surface area (S) extending along a wall of the microfluidic channel, and at a second end a connecting portion, the connecting portion being accessible through a surface adjacent or opposite the contact surface and being configured to be electrically coupled to the electronic device. For example, one or more openings may be configured in the surface adjacent or opposite the contact surface to receive connecting elements from the electronic device.

[0010] Implementing such a device with a microfluidic channel inlet allows the introduction of sweat in liquid form into the microfluidic channel, which guides by capillary force a laminar flow of the liquid to the outlet, along the electrodes. The inclusion of such a microfluidic channel as well as electrical conductors in a multilayer structure allows the device to be manufactured using microfabrication techniques that benefit from significant economies of scale, for example reel-to-reel processes. Thus, the device can be manufactured economically enough to be used in a consumable manner during a physical exercise session.

[0011] In addition, an arrangement of connection portions of the conductors so as to be accessible by a surface adjacent or opposite the contact surface of the multilayer structure allows attachment to an electronic device configured to measure resistance and / or conductance between the electrodes, without cluttering the contact surface. Thus, the simple operation and comfort of the device are preserved.

[0012] In one embodiment, the microfluidic channel may extend in a straight line from the fluidic inlet to the fluidic outlet of the structure.

[0013] Thus, the amount of sweat entering the microfluidic channel accesses the outlet through a direct path, and the liquid can more quickly come into contact with the electrode pair(s), and be ejected more quickly through the outlet. The risk of clogging can then be reduced, and the device, in particular the guidance of the liquid through the microfluidic channel, can be made more reliable.

[0014] In one embodiment, the contact surface may include at least one groove for conducting perspiration toward the fluid inlet.

[0015] The groove can guide sweat discharged through additional pores to the fluid inlet of the device. Thus, the amount of liquid received by the device can be greater and the information obtained more complete.

[0016] In one embodiment, the respective electrodes of the pair of conductors may extend along a common wall of the microfluidic channel.

[0017] This configuration is simple to produce using microfabrication, such as a reel-to-reel process, because the electrical conductors can be arranged in the same plane. Thus, this configuration may only require the use of a single layer of conductive material, such as copper.

[0018] In an alternative embodiment, the respective electrodes of the pair of conductors may extend along opposite walls of the microfluidic channel.

[0019] In this configuration, two walls of the channel can be provided with electrodes. The electrodes can be opposite each other and thus involve a smaller amount of sweat, especially in comparison with a configuration of electrodes juxtaposed in the same plane. This can allow a more precise measurement.

[0020] In one embodiment, the multilayer structure may have the shape of a parallelepiped, in particular a flat rectangular parallelepiped.

[0021] A parallelepiped shape can allow for simple and robust attachment at four corners. A flat shape can also ensure user comfort when the device is in contact with the skin.

[0022] In one embodiment, the ratio between the distance (L) separating the electrodes and the surface area (S) of the electrodes may be between 0.01 and 0.1 m A -1, especially between 0.03 and 0.05 m A-1 .

[0023] According to the inventors' discovery, within this range, the relationship between the conductivity of sweat and its molar sodium chloride concentration is linear. Thus, a particularly simple and accurate measurement of the sodium chloride content in sweat can be obtained.

[0024] In one embodiment, the multi-layer structure of the device may include a base layer, an intermediate layer, and a cover layer. The base layer may include the contact surface configured to be placed in contact with the body. The intermediate layer may be disposed between the base layer and the cover layer.

[0025] In one embodiment, the microfluidic channel may be provided in the intermediate layer. The intermediate layer may be deposited directly on the surface of the base layer that is opposite said contact surface of the base layer.

[0026] In one embodiment, at least one electrode, in particular the respective electrodes of the pair of conductors, can be directly deposited on the surface of the base layer which is opposite to said contact surface of the base layer. This arrangement of the electrodes, which are deposited on the base layer in the microfluidic channel, makes it possible to provide a more compact device because it makes it possible to reduce the number of layers required to form the device. Furthermore, this arrangement makes it possible to reduce manufacturing costs because the deposition of the electrodes and conductors on the base layer can be achieved with microfabrication techniques of the reel-to-reel processing type. The reduction in manufacturing costs of the multilayer structure is particularly advantageous for the manufacture of a consumable device, which the user can replace after each use, in particular for hygienic reasons.

[0027] In one embodiment, in a cross-section of the device along the thickness of the multi-layer structure, the microfluidic channel may extend in the intermediate layer from the base layer to the cover layer. The microfluidic channel may thus have a height equal to the thickness of the intermediate layer.

[0028] In one embodiment, the device may be characterized in that the multilayer structure comprises only three layers. The device is thus simple to manufacture, which reduces its cost. In addition, comprising only three layers, a compact device is obtained, which is particularly advantageous for a portable device. A less bulky device can thus be made available to the user.

[0029] In one embodiment, the device may be characterized by the absence of electronic components. The device may thus be manufactured at a lower cost, which is all the more advantageous for the production of a single-use or consumable device.

[0030] The object of the invention is further achieved by means of a perspiration measuring apparatus, comprising a microfluidic device according to one of the embodiments described above and an electronic device, the microfluidic device being attached to the electronic device, the connection portions of at least one pair of conductors of the microfluidic device being electrically coupled to the electronic device, and the electronic device being configured to measure an electrical conductance and / or an electrical resistance between the electrodes of the device.

[0031] This perspiration measuring device has the advantage of having separated the electronic elements of electrical measurement and signal transformation from the capture device in direct contact with the user's skin.

[0032] In one embodiment of the apparatus, the apparatus may include a wristband attached to the electronic device and configured to be worn around a wrist of a user. In particular, the wristband may be configured such that a contact surface of the device configured to capture perspiration is arranged along a surface of the user's skin.

[0033] Such installation of the measuring device can avoid discomfort of movements during a physical exercise session, as well as allow immediate visual access to the device and comfortable use in the manner of a watch.

[0034] In one embodiment, the electronic device may include a transmitting device configured to transmit the measurements and / or receive instructions.

[0035] Thus, the measurements of the electronic device can be received, processed, analyzed and recorded by a third-party device not exposed to external effects in the immediate environment of the user during a physical exercise session.

[0036] The object of the invention is further achieved by means of a method for manufacturing a device configured to capture the perspiration of a perspiring body according to one of the embodiments described above.

[0037] The method comprises the steps of: providing a base layer and fabricating at least one pair of electrical conductors on a base layer, each conductor comprising at a first end an electrode, and at a second end a connection portion; providing an additional layer comprising at least one cut-out region forming a microfluidic channel; and assembly, in particular by colamination, of the base layer and of said at least one additional layer such that the electrodes are arranged in the cut-out region.

[0038] This process makes it possible to obtain, economically and quickly, a device having the characteristics and advantages described above.

[0039] In one embodiment, the method may comprise an additional step of closing the microfluidic channel with another additional layer, in particular by colamination.

[0040] In one embodiment, the method may comprise an additional step of providing a through hole in the base layer forming an entrance to the microfluidic channel.

[0041] In one embodiment of the method, the cut-out region forming a microfluidic channel may include an access point to the inlet-forming through-hole.

[0042] In one embodiment, step a) of the method according to the invention may further comprise the steps of i) Providing a base layer ii) Covering the base layer with a copper layer iii) Applying a layer of photosensitive resin at least on the copper layer iv) Selectively exposing the photosensitive resin to a light beam, in particular an ultraviolet beam, so as to delimit a path of the conductors v) Dissolving the unexposed photosensitive resin, and vi) Chemically etching the copper layer so as to obtain a base-conductor complex.

[0043] This process can be implemented on a large scale and thus lead to sufficient cost efficiency to offer a device for capturing consumable perspiration.

[0044] In another embodiment, step a) of the method according to the invention may comprise the steps of i) providing a base layer, and ii) printing the conductors on the base layer.

[0045] In one embodiment, the method may further comprise an additional step of

[0046] x) Plating the conductors, in particular the electrodes, with at least one metal, preferably a metal selected from nickel, gold, silver, and palladium, or with a metal alloy, preferably a metal alloy comprising at least one metal selected from nickel, gold, silver, and palladium.

[0047] Such plating, also called metallization, makes it possible to obtain electrodes and / or connection portions with lower contact resistance and greater corrosion resistance. Thus, a process implementing this step makes it possible to produce a device for capturing perspiration offering a more reliable and more precise measurement.

[0048] In one embodiment, the plating of step x) may be a plating with a layer of nickel covered with a layer of gold. The properties of such plating are particularly advantageous.

[0049] In one embodiment, step x) may take place after step vi). Brief description of the drawings

[0050] The objects, features and advantages of the invention as set forth above will be more fully understood and appreciated by studying the following more detailed description of the invention, and the accompanying drawings.

[0051] Figure 1 illustrates a perspiration measuring apparatus according to one embodiment of the invention, comprising a device for capturing perspiration

[0052] Figure 2A is a perspective view of the device of Figure 1, partially open at the microfluidic channel.

[0053] Figure 2B is a perspective view of the device of Figure 1 highlighting the electrical conductors.

[0054] Figure 3A shows cross-sections of the device of Figure 1 along the section axis AA of Figure 2A of Figure 2A.

[0055] Figure 3B shows cross-sections of the device of Figure 1 along the section axis BB of Figure 2A.

[0056] Figure 3C shows cross-sections of the device of Figure 1 along the section axis CC of Figure 2A.

[0057] Figure 4A shows cross-sections of a device for capturing perspiration according to a second embodiment of the invention.

[0058] Figure 4B shows cross-sections of a device for capturing perspiration according to a second embodiment of the invention.

[0059] Figure 5 schematically represents the successive steps of a method for manufacturing a device according to an embodiment of the invention.

[0060] For reasons of readability of the figures, the elements illustrated are not necessarily represented to scale, nor relative to each other, nor in their relative Cartesian dimensions. Detailed description of the drawings

[0061] Figure 1 illustrates a perspiration measuring apparatus according to one embodiment of the invention. The apparatus 1000 comprises a device for capturing perspiration 100 and an electronic device 200. The device 100 has in this embodiment a flat rectangular parallelepiped shape, having length and width dimensions in two Cartesian directions x,y which are of the same order of magnitude, and a height dimension in a third Cartesian direction z which is much smaller, for example, at least 5 times smaller than the length and / or width dimensions.

[0062] In other embodiments, it is also conceivable to provide a device for capturing perspiration 100 with a section in the xy plane which is triangular, hexagonal, octagonal, and / or with rounded or chamfered corners.

[0063] In the embodiment of Figure 1, the electronic device 200 also has substantially the shape of a flat rectangular parallelepiped, having length and width dimensions in two Cartesian directions x,y which are of the same order of magnitude and a height dimension in a third Cartesian direction z which is much smaller, for example, at least 5 times smaller than the length and / or width dimensions.

[0064] The dimensions of the electronic device 200 are, one by one, larger than those of the device, in particular larger by 10 to 30%, so that the device 100 can be received in an opening of a space excavated in the electronic device 200, as illustrated in FIG. 1.

[0065] In the view of Figure 1, the device 100 is received in a space excavated in the electronic device 200 and is attached thereto by a form-fitting attachment means not shown in Figure 1, for example a snap-fit ​​means or adhesive bonding. In this position, the device 100 is electrically coupled to the electronic device 200.

[0066] The apparatus 1000 further comprises two parts 300a, 300b of a watch strap, attached respectively at two opposite thin portions of the electronic device 200. Thus, the apparatus 1000 can be worn comfortably at a limb of a user, for example at a wrist or an ankle. The two parts 300a, 300b of the watch strap are arranged so that the contact surface 1 of the device 100, received in an excavated space, is arranged along a surface of the skin of the user. That is to say, the device 100 is face-hidden with respect to the field of vision of the user.

[0067] The electronic device 200 comprises a transmission device (not shown) for transmitting measurements relating to the electrical coupling and / or receiving instructions. The casing of the electronic device 200 is made of a rigid and lightweight material.

[0068] The device 100 has a contact surface 1 configured to be placed in contact with a sweating body. The surface 1 is planar and, when the device 100 is attached to the electronic device 200, protrudes slightly in a z-direction of the electronic device 200. That is, the device 100 protrudes slightly, in particular by 1% to 10% of the height of the device 200, from the excavated space of the device 200. Thus, the device 100 is brought into contact with the skin of a user's sweating body when device 1000 is worn by the user.

[0069] The surface 1 further has a fluid inlet 3 to a microfluidic channel 5 (visible in FIG. 2A), the inlet 3 being located in the center of the surface 1. The contact surface 1 also has a pattern of a plurality of grooves 7. The pattern is centered on the inlet 3, each groove 7 of the pattern being connected to the inlet 3. The pattern of grooves 7 makes it possible to conduct a high quantity of sweat more efficiently towards the fluid inlet 3.

[0070] The structure and operation of the device 100 of FIG. 1 are described in more detail below, with reference to FIGS. 2A, 2B and 3A-3C. In particular, it will be described that the device 100 does not comprise electronic components, for example chips. Thus, in the measuring apparatus 1000, the electronic elements for electrical measurement and signal transformation are moved from the capture device 100, in direct contact with the user's skin, to the electronic device 200. Thanks to the transmission device included in the electronic device 200, the processing, analysis and storage of the measured data can be carried out by a third-party device not exposed to the external effects of the user's immediate environment during a physical exercise session. At the same time, the apparatus 1000 comprising the electronic device 200 is flexible and comfortable to wear, as well as simple to manufacture.

[0071] Figure 2A is a perspective view of the device 100 for capturing perspiration. For the purposes of illustration and understanding, the view of Figure 2A is partially sectioned along the microfluidic channel 5, in order to identify the path of the microfluidic channel 5 inside the device 100.

[0072] The device 100 has a multi-layer structure 9, comprising a base layer 11, an intermediate layer 13, and a cover layer 15. Preferably, the layers 11, 13, 15 are layers of a thin material, for example selected from polyethylene terephthalate (PET), a glass-epoxy composite film, polyimide (PI), polyethylene (PE), polyethylene naphthalate (PEN), an adhesive or paper. The layers 11, 13, 15 may be layers of materials that are the same or different from each other. In particular, in one embodiment, the layer 13 may be a layer of an adhesive material, for example a pressure-sensitive adhesive, PSA according to the English acronym, to hold the layers 11 and 15 together. The base layer 11 has, on the hidden face not visible in Figure 2A, the contact surface 1 and includes the inlet 3 to the microfluidic channel 5. The cover layer 15 has a outer connection surface 17. Each of the layers has a thickness of between 20 μm and 200 μm thick, and preferably, the base layer 11 is thicker than the intermediate layer 13, and the layer 13 is thicker than the cover layer 15. For example, the base layer 11 may have a thickness of 120 μm, the intermediate layer 13 a thickness of 50 μm and the cover layer 15 a thickness of 20 μm.

[0073] The multilayer structure 9 comprises the microfluidic channel 5 extending inside the structure 9 in an xy plane. In particular, the channel 5 is located at the intermediate layer 13, between the base layer 11 and the cover layer 15, and extends linearly, i.e. in a straight line, from the inlet 3 at the center of the parallelepiped of the device 100 to the fluid outlet 19 of the channel. The channel 5 may have a thickness of 20 pm to 200 pm and a width in the xy plane of 200 pm to 5 mm. The outlet 19 is arranged at a corner 21 a of the parallelepiped of the device 100, at the intersection of two surfaces 22 a, 22 b adjacent to the contact surface 1 .The channel 5 has a lower wall corresponding to a portion of the surface 29 (visible in FIGS. 3B and 3C) of the base layer 11 opposite the contact surface 1, an upper wall corresponding to a portion of the surface 31 (visible in FIGS. 3B and 3C) of the cover layer 15 opposite the external connection surface 17, and two opposite lateral walls internal to the intermediate layer 13.

[0074] Figure 2A also shows two electrodes 23a, 23b, arranged in the microfluidic channel 5 so as to extend along the side walls of said channel 5. Furthermore, two connection portions 25a, 25b are arranged in the structure 9 so as to be accessible by the external connection surface 17. For example, one or more openings may be configured in the external connection surface 17 to receive connection elements from the electronic device 200. The electrodes 23a, 23b correspond to the respective first ends and the portions 25a, 25b correspond to the respective second ends of two electrical conductors 27a, 27b, which will be described in more detail with reference to Figure 2B.

[0075] The external connection surface 17 and the contact surface 1 correspond to opposite functional surfaces of the parallelepiped of the device 100. While the contact surface 1 is configured to be brought into contact with the skin of a perspiring body, the external connection surface 17 is brought into engagement with the device electronics 200 (see figure 1) so as to contact the connection portions 25a, 25b with the electronics of the electronic device 200 and establish an electrical coupling.

[0076] The device 100 according to this embodiment comprises a microfluidic channel 5 connecting an inlet 3 to an outlet 19. Alternative embodiments with several inlets leading to the channel 5, and / or several outlets for the escape of the liquid from the channel 5, are conceivable without departing from the spirit of the invention. Similarly, it is conceivable to arrange several microfluidic channels in the device 100, for example four channels respectively connecting four inlets and extending respectively towards the four corners of the parallelepiped of the device 100, each channel being provided with a pair of electrodes as well as connection portions.

[0077] Figure 2B shows a view of a base-conductor complex of the device 100, i.e. without the intermediate layer 13 and without the cover layer 15, thus highlighting the path of the conductors 27a, 27b. The electrical conductors 27a, 27b are arranged on the surface 29 (visible in Figures 3B and 3C) opposite the contact surface 1 of the base layer 11 of the multilayer structure 9. The conductors 27a, 27b are made of an electrically conductive material, preferably copper (Cu) and comprise at their respective first ends the electrodes 23a, 23b and at their respective second ends connection portions 25a, 25b. In particular, the conductors 27a, 27b are made from the same layer of copper formed on the base layer 11, the copper having been chemically etched to obtain the desired shape.

[0078] The connection portions 25a, 25b are exposed parts of the conductors 27a, 27b. For example, the layers 13 and 15 are open at the connection portions 25a, 25b in order to allow a physical connection with the electronic device 200 (see FIG. 1) via the external surface 17. Thus, an electrical contact with the electronic device 200 can be established. The electrodes 23a, 23b are enlarged parts of the conductors 27a, 27b, arranged along walls of the microfluidic channel 5.

[0079] In order to improve their functionality, the electrodes 23a, 23b and the connection portions 25a, 25b of the conductors 27a, 27b are plated, or metallized, with at least one metal or with an alloy of metals, the metals preferably being selected from nickel, gold, silver, and palladium. In a preferred embodiment, the electrodes 23a, 23b are plated with a nickel layer of 10 nm to 10 pm, which in turn is covered with a gold layer of 10 nm to 10 pm. In preferred embodiments alternative embodiments, the electrodes 23a, 23b are plated with a layer of nickel covered with a layer of silver, or a layer of nickel covered with a layer of palladium, or a layer of nickel covered with a layer of gold itself covered with a layer of palladium. Thus, the contact resistance can be reduced and / or the corrosion resistance increased.

[0080] The arrangement of connection portions 25a, 25b at one end of the conductors 27a, 27b so as to be accessible via the external surface 17 of the multilayer structure 9 allows simple attachment to the electronic device 200 (see FIG. 1) to measure a resistance and / or conductance between the electrodes, without cluttering the contact surface 1. Thus, the operation and comfort of the device are preserved.

[0081] Figure 2B also shows that the fluid inlet 3 at the center of the parallelepiped of the device 100 corresponds in this embodiment to a cylindrical perforation through the thickness, that is to say through the height, in a z direction, of the base layer 11.

[0082] Thus, a quantity of sweat received by the fluidic inlet 3 is brought into the microfluidic channel 5 and guided by capillary force along the channel 5, then is escaped through the outlet 19. When the sweat passes between the electrodes 23a, 23b, a resistance and / or a conductance between the terminals of the electrodes can be measured. From the resistance R or the conductance G, and from the ratio between the surface area S of the electrodes 23a, 23b and the distance L separating said electrodes 23a, 23b, called the S / L ratio, the electrical conductivity o of the sweat is calculated. From the conductivity o of the liquid, the molar concentration C_NaCl in sodium chloride can be empirically approximated.

[0083] The S / L ratio of the electrodes 23a, 23b arranged in the channel is predetermined and known. In this embodiment, the S / L ratio is between 0.01 m A -1 and 0.1 m A -1, especially between 0.03 m A -1 and 0.05 m A-1 Preferably, the ratio approaches 4 / 100, that is, 0.04 m A -1. In the course of in-depth investigations by the inventors, it has been determined that the relationship between conductivity o and sodium chloride concentration C_NaCI is advantageously linear and deterministic in this range.

[0084] Figures 3A, 3B and 3C represent cross-sections of the device 100 along, respectively, the respective section axes AA, BB and CC as shown in Figure 2A.

[0085] The three sections are centered at the microfluidic channel 5 along, respectively, the axis A of Figure 2A, and the xz plane. Section 3A along the axis AA is centered on the inlet 3 to the microfluidic channel 5. The inlet 3 is a central perforation through the base layer 11. While the perforation of the base layer 11 also passes through the intermediate layer 13, the cover layer 15 is not perforated.

[0086] Figures 3B and 3C also show the two electrodes 23a, 23b arranged on the same surface 29. The surface 29 is opposite the contact surface 1 of the base layer 11 of the multilayer structure 9. The electrodes 23a, 23b are arranged so as to be separated by a distance L. Thus, the electrodes 23a, 23b are arranged in the same plane xz, at the level of the intermediate layer 13. The cover layer 15 covers the intermediate layer 13 and provides an additional wall to the microfluidic channel 5, closing the channel 5. Thus, this embodiment is economical because it is simple to produce by micro-fabrication process.

[0087] In an alternative embodiment, it is possible to arrange the two electrodes 23a, 23b on the cover layer 15, on the same surface of the microfluidic channel wall 5, for example on the surface 31 opposite the external connection surface 17.

[0088] The structure of the device 100 described above allows for manufacturing by micro-manufacturing techniques, in particular by reel-to-reel processes, and thus benefits from significant economies of scale. Thus, the device can be manufactured economically enough to be used in a consumable manner during a physical exercise session.

[0089] Furthermore, the arrangement of connection portions 25a, 25b at one end of the conductors 27a, 27b so as to be accessible via the opposite surface 17 to the contact surface 1 of the multilayer structure 9 allows attachment to the electronic device 200 without cluttering the contact surface. Thus, the simple operation and comfort of the device are preserved.

[0090] In the embodiment according to FIGS. 1 to 3C, the device 100 is provided with a pair of electrical conductors 27a, 27b having respective electrodes 23a, 23b. In alternative embodiments, it is conceivable to arrange several pairs of electrodes in sequence along the same microfluidic channel, for example three pairs. By arranging several pairs of electrodes in a row, a measurement time differential can be established when a quantity of sweat successively passes through the pairs of electrodes. The time differential can, for example, be used to determine, approximate or derive a liquid flow rate and / or a volumetric liquid flow rate.

[0091] Figures 4A and 4B illustrate a device 100' of another embodiment of the invention. Only the characteristics that differ from the device 100 are described, the characteristics being able to be considered equivalent to those described above in relation to the device 100.

[0092] The device 100' also comprises two electrodes 23a' and 23b'. Instead of being arranged on the same wall of the microfluidic channel 5' corresponding to the channel 5 of the device 100, they are arranged on two opposite walls. In particular, they are arranged on the opposite surfaces 29 and 31 of the device 100. Alternatively, it is also possible to arrange the electrodes on two side walls of the channel 5'. Thus, the microquantities of sweat enclosed between the two electrodes 23a', 23'b are less significant than, for example, between the electrodes 23a, 23b. This allows for a more precise measurement.

[0093] An embodiment of a method of manufacturing according to the invention a device configured to capture perspiration from a perspiring body, and to be attached to an electronic device, for example the device 100, is described in the following. The method comprises a first step of manufacturing at least one pair of electrical conductors on a base layer, each conductor comprising at a first end an electrode, and at a second end a connection portion.

[0094] Figure 5 schematically represents the successive steps of a process for carrying out the first step by photolithography.

[0095] In particular, the method begins with a step A of providing a base layer M11. For example, the base layer M11 may be the base layer 11. Preferably, the layer M11 is a layer of a material selected from a polyethylene terephthalate (PET), a glass-epoxy composite film, a polyimide (PI), a polyethylene (PE), a polyethylene naphthalate (PEN), or a paper. The M11 layer is preferably thin, in particular with a thickness of between 20 μm and 200 μm.

[0096] The base layer M11 is in a step B covered with a copper (Cu) layer M12 with a thickness between 1 μm and 100 μm, preferably between 12 μm and 70 μm. Alternatively, it is possible to use a copperclad material in which the copper layer M12 is attached to the base layer M11 by vacuum deposition, by hot joining, or by joining with adhesive. In a step C, a through hole M3 is made in the base layer M11. In this embodiment, the base layer M11 covered with the copper layer M12 is mechanically perforated at a desired location to make the hole M3 forming an inlet to a microfluidic channel. For example, the hole M3 can form the fluidic inlet 3 perforated through the copper-clad base layer 11.

[0097] Then, in a step D, a layer of photosensitive resin M14 is applied to the base layer M11 coated with copper M12 at least on the copper side, alternately on both sides.

[0098] In a step E, the photosensitive resin M14 is selectively polymerized. In this step, called the exposure step, portions of the applied photosensitive resin are exposed to a light beam M16, in particular an ultraviolet beam, delimiting on the copper side of the base layer M11 polymerized areas M14a and non-polymerized areas M14b. The polymerized areas M14a represent the desired paths of electrical conductors formed from the copper layer M12 on the base layer M11. For example, the conductors 27a, 27b are delimited on the layer 11 as illustrated in FIG. 2B. The resin M14 located above the parts of the copper layer M12 not necessary for the formation of electrical conductors is not exposed, i.e. is not exposed to the light beam, and therefore not polymerized M14b.

[0099] In a step F, called the development step, the part of the photosensitive resin layer M14 which is not exposed, and therefore not polymerized and not crosslinked, is dissolved, so that the polymerized zones M14a of the resin M14 remain.

[0100] In a step G, the copper layer M12 is chemically etched. In this step, the polymerized photosensitive resin M14a remaining on the copper M12 selectively protects portions of the copper from etching. Thus, only the non-etched copper protected by the photosensitive resin M12 is etched. A part of the electrical conductor circuit is thus obtained on the base layer. Thus a base-conductor complex M18 is formed, for example the base-conductor complex illustrated in Figure 2B.

[0101] In a step H, a chemical stripping of the base-conductor complex M18, called stripping, is carried out in order to remove from the base layer M11 and the copper M12 forming the conductor circuit the remaining portions of insolated, i.e. polymerized, photosensitive resin. This makes it possible in particular to free the surface of the copper layer M12 and obtain the conductors M27a, M27b. For example, the conductors 27a, 27b are obtained on the base layer 11.

[0102] In a step I, performed after the etching and stripping steps, the electrical conductors M27a, M27b are plated with at least one metal with or an alloy of metals, the metals being for example selected from nickel, gold, silver, and palladium. Preferably, the electrical conductors M27a, M27b are plated with a layer of nickel covered with a layer of gold. Optionally, only certain portions of the conductors, for example the electrodes 23a, 23b and the connection portions 25a, 25b, are plated.

[0103] In another embodiment of the manufacturing method, the first step of the method is not carried out by photolithography, but by an additive printing process. The printing can be carried out by screen printing of conductive inks. Alternatively, the printing can be carried out by inkjet. In this embodiment, the electrical conductors are printed on a provided base layer. Each conductor is printed on the base layer so as to comprise at least one electrode and at least one connection portion.

[0104] For example, the conductors 27a, 27b are printed on the base layer 11. Alternatively, a conductor 27a is printed on the base layer 11 and a conductor 27b is printed on another base layer, for example the cover layer 15. The two layers thus printed can then be joined, for example by an adhesive intermediate layer, such as the intermediate layer 13. By cutting the intermediate layer as described in the following, the device 100' of Figures 4A, 4B can be obtained.

[0105] In another example, conductors 27a, 27b are both etched on base layer 11. Alternatively, one conductor 27a is etched on base layer 11 and a conductor 27b is etched on another base layer, for example the cover layer 15. The two layers thus manufactured can then be assembled, for example by an adhesive intermediate layer, such as the intermediate layer 13. By cutting the intermediate layer as described in the following, the device 100' of Figures 4A, 4B can be obtained.

[0106] In a second step of the method not shown in Figure 5, an additional layer comprising at least one cut region forming a microfluidic channel is provided. The at least one additional layer is cut so as to delimit a microfluidic channel, to form the at least one microfluidic channel of the device.

[0107] Optionally, the at least one additional layer may also be cut so as to delimit an access point to a second end of the electrical conductors. Furthermore, the cut region forming the microfluidic channel comprises an access point to the through hole forming the inlet of step C.

[0108] For example, the intermediate layer 13 may be cut to form the microfluidic channel 5 and to cover the base layer 11 as well as to comprise an access point to the fluidic inlet 3. In particular, the microfluidic channel delimited in an additional layer, for example in the intermediate layer 13, extends from a perforation location, for example the inlet 3, to a circumferential end of said additional layer, for example the outlet 19.

[0109] In a third step of the manufacturing process, the base-conductor complex comprising the base layer obtained at the end of step I is assembled by colamination with the additional layer such that the electrodes are arranged in the cut region. For example, the intermediate layer 13 is laminated onto the base-conductor complex of FIG. 2B comprising the base layer 11 and the conductors 27a, 27b.

[0110] In a fourth step of the manufacturing method, the microfluidic channel is closed with another additional layer by colamination. For example, the cover layer 15 closes the microfluidic channel cut and delimited in the intermediate layer 13 and assembled with the base-conductor complex comprising the base layer 11 and the electrical conductors 27a, 27b. In one example, the cover layer 15 is perforated and then selectively laminated onto the intermediate layer 13 so as to delimit an access opening to the connection portions 25a, 25b. Cutting and colamination can be advantageously carried out in line on a converting machine.

[0111] In an alternative embodiment, one of the additional layers may also correspond to a product resulting from one of the processes described above, for example to the product resulting from step H or I. For example, the cover layer 15 may be a base-conductor complex comprising an electrical conductor 27a'. In this embodiment, the additional layer and the first base-conductor complex comprising the base layer 11 and a conductor 27b' may be joined using another additional adhesive layer, for example the intermediate layer 13, cut to the pattern of the desired microfluidic channel. This embodiment may for example be implemented to obtain the configuration represented by FIGS. 4A and 4B. In another example, the cover layer 15 may be a base-conductor complex comprising electrical conductors 27a” and 27b”.In this embodiment, not shown, the cover layer 15 and the base layer 11 can be joined using another additional adhesive layer, for example the intermediate layer 13, cut to the pattern of the desired microfluidic channel. In this embodiment, the connection portions 25a”, 25b” can be located on the external connection surface 17 and the electrodes 23a”, 23b” on the opposite face of the layer 15. Metallized holes or vias are then used to electrically connect the connection portions 25a”, 25b” and the electrodes 23a”, 23b”.

[0112] The additional layers may be layers of materials that are the same or different from each other and from the material of the base layer. In particular, in a preferred embodiment, an additional layer may be a layer of an adhesive material to hold the base layer together with another additional layer superimposed thereon. For example, the material of the intermediate layer 13 is different from the material of the base 11 and cover 15 layers.

[0113] The method described makes it possible to obtain economically and quickly a device having the characteristics and advantages of the device 100. In particular, this method can be implemented on a large scale, for example in a reel-to-reel process, and it is possible to obtain sufficient cost efficiency to propose a device for capturing consumable and replaceable perspiration.

[0114] Digital references 1 contact surface of the device 3 inlet to the microfluidic channel 5 microfluidic channel 7 groove in the contact surface 9 multi-layer structure 11 base layer 13 intermediate layer 15 layer cover 17 external connection surface 19 microfluidic channel outlet 21 corner of the device 22a, 22b surfaces adjacent to the contact surface 23a, 23b electrodes at the first ends of the conductors 25a, 25b connection portions at the second ends of the conductors 27a, 27b electrical conductors 29 surface of the base layer opposite the contact surface 31 surface of the cover layer opposite the external connection surface 100,100 devices to capture perspiration 200 electronic device 300a, 300b parts of a watch strap 1000 device for measuring perspiration M3 through hole according to manufacturing process M11 base layer according to the manufacturing process M12 copper layer according to the manufacturing process M14 photosensitive resin layer according to the manufacturing process M14a resin polymerization zone according to the manufacturing process M14b unpolymerized area of ​​the resin according to the manufacturing process M16 light beam according to the manufacturing process M18 base-conductor complex according to the manufacturing process M27a, M27b electrical conductors according to the manufacturing process

Claims

CLAIMS Device (100, 100') configured to capture perspiration from a perspiring body and to be attached to an electronic device (200), comprising: a multilayer structure (9) having a contact surface (1) configured to be placed in contact with the body, the multilayer structure (9) comprising an internal microfluidic channel (5) extending through the multilayer structure (9) and fluidically connecting at least one fluidic inlet (3) to at least one fluidic outlet (19), the inlet (3) being located at said contact surface (1), and the outlet (19) being located at another surface (22a, 22b) different from said contact surface (1), and at least one pair of electrical conductors (27a, 27b), each conductor (27a, 27b) comprising: at a first end an electrode (23a, 23b) having a surface area (S) extending along a wall of the microfluidic channel (5),and at a second end a connection portion (25a, 25b), the connection portion (25a, 25b) being accessible by an adjacent surface (22a, 22b) or an opposite surface (17) to the contact surface (1) and being configured to be electrically coupled to the electronic device (200). Device according to claim 1, wherein the microfluidic channel (5) extends in a straight line from the fluid inlet (3) to the fluid outlet (19) of the multilayer structure (9). Device according to claim 1 or 2, wherein the contact surface (1) comprises at least one groove (7) for conducting transpiration towards the fluid inlet (3). Device according to one of claims 1 to 3, in which the respective electrodes (23a, 23b) of the pair of conductors (27a, 27b) extend along the same wall of the microfluidic channel (5)., Device according to one of claims 1 to 3, wherein the respective electrodes (23a, 23b) of the pair of conductors (27a, 27b) extend along opposite walls of the microfluidic channel (5). Device according to one of claims 1 to 5, wherein the structure (9) has the shape of a parallelepiped, in particular a flat rectangular parallelepiped. Device according to one of claims 1 to 6, wherein the ratio (L / S) between the distance (L) separating the electrodes (23a, 23b) and the surface area (S) of the electrodes (23a, 23b) is between 0.01 and 0.1 m A -1, especially between 0.03 and 0.05 m A-1. Device according to one of claims 1 to 7, wherein the multilayer structure (9) comprises a base layer (11), an intermediate layer (13) and a cover layer (15), the base layer (11) comprising the contact surface (1) configured to be placed in contact with the body, and the intermediate layer (13) being arranged between the base layer (11) and the cover layer (15). Device according to claim 8, wherein the microfluidic channel (5) is provided in the intermediate layer (13). Device according to one of claims 1 to 9, characterized in that the multilayer structure (9) comprises only three layers. Device according to one of claims 1 to 10, characterized by the absence of electronic components.A perspiration measuring apparatus (1000), comprising a device (100, 100') according to one of claims 1 to 11 and an electronic device (200), the device (100, 100') being attached to the electronic device (200), the connection portions (25a, 25b) of at least one pair of conductors (27a, 27b) of the device (100, 100') being electrically coupled to the electronic device (200), and the electronic device (200) being configured to measure an electrical conductance and / or an electrical resistance between the electrodes of the device (23a, 23b). Method for manufacturing a device (100, 100') according to one of claims 1 to 11, comprising the steps of: (a.) Providing a base layer (11) and fabricating at least one pair of electrical conductors (27a, 27b) on the base layer (11), each conductor (27a, 27b) comprising at a first end an electrode (23a, 23b), and at a second end a connection portion (25a, 25b) (b.) Providing an additional layer (13,15) comprising at least one cut-out region forming a microfluidic channel, and (c.) Assembling, in particular by colamination, the base layer (11) and said at least one additional layer (13, 15) such that the electrodes (23a, 23b) are arranged in the cut-out region. Method according to claim 13, comprising an additional step of: (d.) Closing the microfluidic channel (5) with another additional layer (15), in particular by colamination. Method according to claim 13 or 14, comprising an additional step of: (e.) Making a through hole (M3) in the base layer forming an inlet (3) to the microfluidic channel (5) Method according to claim 14, the cut region forming a microfluidic channel (5) comprises an access point to the through hole (M3) forming an inlet (3). Method according to one of claims 13 to 15, wherein step (a.) comprises the steps of: i) Providing a base layer (M11) ii) Covering the base layer (M11) with a copper layer (M12) iii) Applying a photosensitive resin layer (M14) at least on the copper layer (M12) iv) Selectively exposing the photosensitive resin (M14) to a light beam (M16), in particular an ultraviolet beam, so as to delimit a path of the conductors (M27a, M27b) v) Dissolving the unexposed photosensitive resin (M14b), and vi) Chemically etching the copper layer (M12) so as to obtain a base-conductor complex (M18). Method according to one of claims 13 to 15, in which step (a.) comprises the steps of: i) Providing a base layer (11), and ii) Printing the conductors (27a, 27b) on the base layer (11). Method according to one of claims 13 to 16, comprising the additional step of: x) Plating the conductors (27a, 27b), in particular the electrodes (23a, 23b), with at least one metal, in particular a metal selected from nickel, gold, silver, and palladium, or with a metal alloy, in particular a metal alloy comprising at least one metal selected from nickel, gold, silver, and palladium.The method of claim 19, wherein the plating of step x) is plating with a layer of nickel covered with a layer of gold.

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