Flexible device

Abstract

A flexible device (10) according to the present invention comprises a substrate part (11) and a coating part (12) that covers the substrate part. The substrate part includes a plurality of mounting parts (14), a flexible part (13) that is more flexible than the mounting parts and is connected to the mounting parts, and a coupling member (17) that connects mounting parts adjacent to each other with the flexible part interposed therebetween. An electronic component may be mounted on each mounting part, and electronic components mounted on mounting parts adjacent to each other with the flexible part interposed therebetween may be electrically connected.　Thus, the present invention can provide a flexible device having excellent reliability.

Description

Flexible Devices

[0001] The present invention relates to a flexible device.

[0002] Small and lightweight devices are being used to improve installation flexibility in collecting sensor data. Furthermore, there is a demand for personalized, customized medical and healthcare services that can be analyzed by attaching sensors to the human body (living organism) to acquire continuous biometric data over the long term.

[0003] In order to wear sensors on the human body (living body) on a daily basis, it is necessary to make the sensors smaller and lighter, and to make them feel natural and comfortable to wear. Therefore, flexible and lightweight devices that fit the curved surface of the human body (living body) have been developed (for example, Non-Patent Document 1).

[0004] As an example, the above-mentioned flexible and lightweight device includes a flexible substrate (substrate portion) 41, which is a flexible electronic substrate, and a covering portion (exterior portion, not shown) made of a rubber material such as a flexible silicone resin, as shown in FIG.

[0005] In this substrate section 41, flexible sections (flex sections) 43 composed of single-sided flex (single-layer flex) and mounting sections 44 composed of rigid sections (or multi-layer flex sections) are alternately arranged. This maintains flexibility throughout the substrate. The flex sections 43 are flexible and form internal wiring for connecting electronic elements and chips. Circuit components 45, such as electronic elements and chips, are mounted in the mounting sections 44 (component mounting area). Electrodes 46, etc., formed on the flex sections at both ends contact the living body and acquire signals. Sensors and devices that acquire data without direct contact with the human body (living body) do not need to have electrodes, etc. In addition, to improve adhesion to the human body (living body), a conductive adhesive sheet, etc., may be attached to the electrode section.

[0006] The substrate section 41 is entirely surrounded by a covering section (exterior section) made of a resin molding material such as silicone, except for the electrode section.

[0007] Medical device package insert approval number provided by the Pharmaceuticals and Medical Devices Agency: 302ACBZX00015000 "Electrocardiogram"

[0008] However, the above-mentioned device has a problem with the durability of the flexible substrate, particularly the flexible flex portion (single-sided flex or single-layer flex) 43. Typically, the flex portion (single-sided flex) 43 has only wiring and no electronic components mounted thereon, so it is thinned to a thickness of about 70 μm to give it a flexible structure. As a result, flexibility is improved but durability is reduced. If a device has a rigid, inflexible coating, the load on the internal flex portion (single-sided flex) 43 is small. On the other hand, if a device has a flexible, pliable coating, the flex portion (single-sided flex) 43, which is the internal substrate portion, may be subjected to greater loads, such as bending, pulling, and twisting, than a device with a rigid coating.

[0009] A portion of the peripheral edge of the flexible portion 43 (for example, the dotted line area in FIG. 4) has bending resistance and is therefore durable against simple bending and stretching. However, because it is made of a thin material, it has low durability against shear stress that shifts an object in different directions, such as twisting, and this can cause damage (breakage) or deformation beyond the allowable limit at the peripheral edge.

[0010] Furthermore, the boundary between the flexible portion 43 and the mounting portion 44 is susceptible to tension in the longitudinal direction of the device. The mounting portion (rigid portion or multilayer flexible portion) 44, where the device is mounted, has a multilayer structure with multiple wiring layers, and is further reinforced by thickening the film, so it has high resistance to external loads. On the other hand, at the boundary between the flexible portion 43 and the mounting portion 44, strain is concentrated due to the sudden change in structure (resistance). As a result, the boundary between the flexible portion 43 and the mounting portion 44 is susceptible to tension.

[0011] 5, the flexible part 43 has copper wiring 48 that connects circuit components 45 such as electronic elements and chips between the mounting parts (for example, an analog front end 452, a memory element 455, and a BLE chip 456). As shown in Fig. 6, when a large tensile load (indicated by the white arrow in the figure) is applied in the longitudinal direction of the device, breaks or other defects occur in the copper wiring at the boundary between the flexible part and the mounting part (indicated by the dotted line in the figure), causing the device to fail.

[0012] In order to solve the above-mentioned problems, the flexible device of the present invention comprises a substrate portion and a covering portion that covers the substrate portion, and the substrate portion comprises a plurality of mounting portions, a flexible portion that is more flexible than the mounting portions and connects to the mounting portions, and a connecting member that connects adjacent mounting portions across the flexible portion.

[0013] According to the present invention, a highly reliable flexible device can be provided.

[0014] FIG. 1A is a schematic front cross-sectional view showing the configuration of a flexible device according to a first embodiment of the present invention. FIG. 1B is a schematic top view showing the configuration of a substrate part of the flexible device according to the first embodiment of the present invention. FIG. 2A is a schematic front cross-sectional view showing the configuration of a flexible device according to a first example of the present invention. FIG. 2B is a schematic top view showing the configuration of a substrate part of the flexible device according to the first example of the present invention. FIG. 3A is a schematic front cross-sectional view showing the configuration of a flexible device according to a second example of the present invention. FIG. 3B is a schematic bottom view showing the configuration of a substrate part of the flexible device according to the second example of the present invention. FIG. 4 is a schematic top view for explaining a conventional flexible device. FIG. 5 is a schematic top view for explaining a conventional flexible device. FIG. 6 is a schematic top view for explaining a conventional flexible device.

[0015] First Embodiment A flexible device 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

[0016] 1A, a flexible device 10 according to the present embodiment includes a substrate 11 and a covering 12. The entire substrate 11, excluding the electrode portion, is surrounded by a covering 12 made of a resin molding material such as silicone. Hereinafter, the length in the direction perpendicular to the longitudinal direction (x direction in the figure) of the flexible device 10 will be referred to as the width direction (y direction in the figure), and the direction perpendicular to the x and y directions will be referred to as the thickness direction (z direction in the figure).

[0017] As shown in FIG. 1B, the substrate section 11 includes a flexible section (hereinafter referred to as a “flex section”) 13 and a mounting section 14 .

[0018] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) that is flexible and highly flexible.

[0019] The mounting section 14 is composed of a rigid section or a multi-layer flexible section, and has electronic components 15 mounted thereon. The electronic components 15 are, for example, a battery, various sensors, corresponding sensor front ends, memory, a wireless communication section, and a CPU interconnected with these. In the mounting section 14, components are densely arranged on both sides in order to efficiently utilize the rigid parts. The mounting section 14 also has electrodes 16. The electrodes 16 are exposed and not covered by the covering section 12.

[0020] The mounting sections 14 are joined by the flexible sections 13 and electrically connected by wiring within the board. The flexible flexible sections 13 and the mounting sections 14 on which components are mounted are arranged alternately, so that flexibility and bendability are maintained overall even when rigid mounting sections 14 are arranged.

[0021] Adjacent mounting sections 14 sandwiching the flexible section 13 are connected by a plurality of coupling members 17. Each of the plurality of coupling members 17 is arranged near the periphery of the substrate section 11 in the longitudinal direction of the device 10. In particular, they are arranged near the periphery on both sides of the flexible section parallel to the longitudinal direction of the device 10. The coupling members 17 are fixed near both ends of the end face of the mounting section 14 perpendicular to the longitudinal direction of the device 10. The coupling members 17 may be arranged approximately parallel to the periphery of the substrate section 11. Furthermore, the coupling members 17 may be fixed, for example, with an epoxy resin-based adhesive or with other adhesives or adhesive methods that generate sufficient bonding strength.

[0022] The connecting member 17 is thin, flexible, and bendable. It is desirable that the connecting member 17 be made of a high-elasticity material or a non-stretchable material. For example, the connecting member 17 may be in the shape of a string or a strip. For example, the connecting member 17 may be made of a suitable combination of polyamide synthetic resin such as nylon, polyester, fluorine fiber, glass fiber, aramid fiber, etc. to provide the desired properties.

[0023] As described above, the electrodes 16 formed on the flexible portion 13 at both ends in the longitudinal direction may come into contact with a living body to acquire signals. In sensors and devices that acquire data without direct contact with the human body (living body), electrodes may not be formed. Furthermore, a conductive adhesive sheet or the like may be attached to the electrodes 16 to improve adhesion to the human body (living body).

[0024] In addition to sensors, by incorporating actuators, light-emitting, acoustic, heat-generating and heat-absorbing elements, it is possible to apply various stimuli to the human body (living body), such as vibration, light, sound, and sensations of warmth and cold.

[0025] <Effects> As described above, in conventional flexible devices, the covering portion (exterior) 12 is flexible and bendable, so the substrate portion 11 cannot be maintained or fixed in the same place, and loads are likely to be applied to the peripheral portion of the flexible portion 13, which has low durability, and to the boundary portion between the flexible portion 13 and the mounting portion 14, which are prone to failures such as breakage (fracture) and deformation.

[0026] When the flexible device is twisted, shear stress occurs, causing displacement in a direction that separates two points on the substrate portion 11 .

[0027] Similarly, pulling the flexible device in the longitudinal direction causes the two points on the substrate portion 11 to be pulled apart. On the other hand, simple folding and bending causes the distance between the two points on the substrate portion 11 to simply shrink and then return to its original shape repeatedly, without causing any pulling action. To allow the simple folding and bending required for flexibility and prevent or suppress twisting and pulling that can lead to load on the device, it is sufficient that the distance between the two points on the substrate portion 11 does not exceed a predetermined distance.

[0028] Therefore, in the flexible device 10, as described above, adjacent mounting sections 14 sandwiching the flexible section 13 are connected by a thin, flexible, and bendable joining member 17. As a result, the joining member 17 is flexible and bendable, so it does not hinder displacement that shortens the distance, i.e., simple folding and bending. Furthermore, resistance is generated against displacement that increases the distance between two points on the substrate section 11 due to twisting or pulling, and suppressing displacement reduces the probability of failure.

[0029] In the flexible device 10, adjacent rigid mounting sections sandwiching the flexible section are connected with a thin, flexible, and flexible connecting member. When a force that stretches the connecting member due to twisting or pulling is applied, the connecting member can resist the force and prevent deformation that would break the device, thereby suppressing device failure. Furthermore, by using a high-elasticity material or a non-stretchable material for the connecting member, the connecting member is made strong against deformation. Furthermore, because the connecting member is flexible, simple bending (simple folding) in the longitudinal direction of the device without shear stress such as twisting is permitted, maintaining the flexibility of the flexible device.

[0030] According to this embodiment, with a simple configuration, damage and deformation at the boundary between the flexible portion and the mounting portion caused by twisting or pulling can be suppressed, and the reliability of the device can be improved.

[0031] First Embodiment A flexible device according to a first embodiment of the present invention will be described with reference to FIGS. 2A and 2B.

[0032] 2A , the flexible device 20 includes a substrate 11 and a covering 12. The entire substrate 11, excluding the electrodes 16, is surrounded by the covering 12 made of a silicone resin molding material.

[0033] As shown in FIG. 2B, the substrate section 11 includes a flexible section 13 and a mounting section 14 .

[0034] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) that is flexible and highly flexible.

[0035] The mounting section 14 is a rigid section having a four-layer structure, and electronic components 15 are mounted on it.

[0036] Mounted on the mounting section 14 are a flexible substrate, a secondary battery 151, an analog front end (AFE) 152 for measuring cardiac potentials, an acceleration sensor 153, a temperature sensor 154, a memory element 155 for storing data, a BLE chip 156 that combines wireless and CPU functions, an operation monitoring element 157 that constantly monitors whether the device is operating normally, and a wireless power supply element 158 ​​for charging the battery without a connector.

[0037] To acquire bioelectric potentials, nickel-gold electrodes are formed by electroplating on both ends of device 20 as electrodes 16. After attaching a conductive adhesive sheet onto electrodes 16, the device is attached to the chest of a human body (living body) to form a patch-type electrocardiograph that measures electrocardiograms.

[0038] For example, the device 20 has a length (longitudinal direction) of 110 mm, a width of 30 mm, a thickness of 6 mm, and a weight of 15 g.

[0039] The device 20 measures cardiac potential, acceleration, and temperature near the device using various sensors, and the CPU processes and calculates the data to obtain the required characteristic quantities, after which the required data is wirelessly transmitted by the BLE chip 156. If the BLE connection is unintentionally disconnected, the data at that time is saved in the memory unit of the device, and when the BLE connection is resumed, the data in the memory unit can be wirelessly transmitted (acquired).

[0040] The operation of the device 20 is constantly monitored by the operation monitoring element 157. When a stoppage or abnormality in the device operation is detected, the device is restarted and information about the abnormality is notified wirelessly.

[0041] The mounting section (rigid section) 14 can be mounted on both sides and is densely mounted with various sensors and electronic components 15. The thickness of the flexible section 13 is, for example, 70 μm, and the thickness of the rigid section is, for example, 450 μm.

[0042] The silicone resin of the covering 12 is formed, for example, by molding the upper and lower surfaces independently in a mold based on the joining surfaces, then aligning the joining surfaces and heat-treating them to fuse the silicone resin together. The thickness of the silicone covering the thickest device on each of the upper and lower surfaces (exterior thickness) is, for example, 0.5 mm.

[0043] In the device 20, adjacent mounting sections 14 sandwiching the flexible section 13 are connected by coupling members 17. Each coupling member 17 is disposed near the periphery of the substrate section 11 in the longitudinal direction of the device, and approximately parallel to the periphery of the substrate section 11. Each coupling member 17 is fixed near both ends of the end face of the mounting section 14 that is perpendicular to the longitudinal direction of the device.

[0044] The connecting member 17 is made of a blend of polyamide synthetic resin and polyester synthetic fiber, and is flexible and bendable with low stretchability. The connecting member 17 is, for example, in the form of a string with a width of 0.5 mm and a thickness of 0.5 mm. After the components are mounted, the connecting member 17 is fixed to the end of the mounting portion 14 on the side (electrode surface) of the substrate portion 11 where the electrodes 16 are arranged, using an epoxy resin adhesive. After the connecting member 17 is fixed, the covering portion 12 is joined to seal the substrate portion 11.

[0045] The flexible device 20 is flexible, capable of simple bending and unbending displacement, and can be attached to the curved surface of the human body (living body). Furthermore, the flexible device 20 exhibits strong resistance to twisting and pulling, and is therefore resistant to excessive loads. Thus, the flexible device 20 can improve reliability and lifespan.

[0046] Second Example A flexible device according to a second example of the present invention will be described with reference to FIGS. 3A and 3B.

[0047] <Configuration of Flexible Device> The flexible device 30 according to this embodiment is, as an example, a flexible myoelectric measurement device. As shown in Figures 3A and 3B, the flexible device 30 includes a substrate 11 and a covering 12. The entire substrate 11, except for the electrodes 16, is surrounded by the covering 12 made of a silicone resin molding material.

[0048] The substrate section 11 includes a flexible section 13 and a mounting section 14 .

[0049] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) that is flexible and highly flexible.

[0050] The mounting section 14 is a multi-layer flexible board having a four-layer structure, and electronic components 15 are mounted on it.

[0051] The mounting section 14 is equipped with a flexible substrate, a secondary battery 151, an analog front end (AFE) 252 for measuring myoelectric potential, an acceleration sensor 153, a temperature sensor 154, a memory element 155 for storing data, a BLE chip 156 having both wireless and CPU functions, an operation monitoring element 157 that constantly monitors whether the device is operating normally, and a wireless power supply element 158 ​​for charging the battery without a connector.

[0052] To acquire bioelectric potentials, nickel-gold electrodes are formed by electroplating on both ends of the device 30 as electrodes 16. After attaching a conductive adhesive sheet onto the electrodes 16, the device is attached to the chest of a human body (living body) to form a patch-type electromyograph that measures myoelectric potentials.

[0053] The flexible device 30 has a device configuration that is more flexible and thinner than that of the first embodiment, so that myoelectric potential measurement can be easily performed.

[0054] The substrate section 11 is a flexible substrate, and is a multi-layer flexible substrate in which flex sections 13 and mounting sections 14 of a four-layer multi-layer flex are alternately arranged.

[0055] The mounting section (multilayer flexible section) 14 can be double-sided and is densely mounted with various sensors and electronic components 15. The thickness of the flexible section 13 is, for example, 70 μm, and the thickness of the multilayer flexible section is, for example, 250 μm.

[0056] The silicone resin of the covering portion 12 is formed in the same manner as in Example 1. The covering portion 12 is configured such that the underside is thinner than in Example 1, with the thinnest part being 2.6 mm thick and weighing 12 g.

[0057] In the device 30, adjacent mounting sections 14 sandwiching the flexible section 13 are connected by coupling members 17. Each coupling member 17 is disposed on the surface opposite the electrode surface, near the periphery of the substrate section 11 in the longitudinal direction of the device, and approximately parallel to the periphery of the substrate section 11. Each coupling member 17 is fixed near both ends of the end face of the mounting section 14 that is perpendicular to the longitudinal direction of the device.

[0058] The connecting member 17 is made of aramid fiber, and is flexible and bendable with low stretchability. The connecting member 17 is, for example, a strip-like shape with a width of 2.5 mm and a thickness of 0.5 mm. After the components are mounted, the connecting member 17 is fixed to the end of the mounting portion 14 on the side opposite the electrode surface of the board using an epoxy resin adhesive. After the connecting member 17 is fixed, the covering portion 12 is joined to seal the board portion 11.

[0059] The flexible device 30 is flexible and can be displaced in simple bending and returning directions, allowing it to be attached to the curved surface of the human body (living body). Furthermore, the flexible device 30 exhibits strong resistance to twisting and pulling, and is therefore resistant to excessive loads. Thus, the flexible device 30 can improve reliability and lifespan.

[0060] Although the embodiment of the present invention has been described with reference to an example in which a plurality of flexible parts are provided, this is not limiting and a single flexible part may be provided. Also, although the embodiment has been described with reference to an example in which a plurality of connecting members are provided, this is not limiting and a single connecting member may be provided.

[0061] In the embodiments of the present invention, examples of the structure, dimensions, materials, etc. of each component in the configuration of the flexible device have been shown, but the present invention is not limited to these examples. Anything that can exhibit the functions and effects of the flexible device may be used.

[0062] It should be noted that the present invention is not limited to the above-described embodiments, and it is clear that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present invention.

[0063] A part or all of the above-described embodiment or an example thereof can be described as, but is not limited to, the following supplementary notes.

[0064] (Appendix 1) A flexible device comprising a substrate portion and a covering portion that covers the substrate portion, wherein the substrate portion comprises a plurality of mounting portions, a flexible portion that is more flexible than the mounting portions and connects to the mounting portions, and a connecting member that connects adjacent mounting portions across the flexible portion.

[0065] (Appendix 2) A flexible device as described in Appendix 1, comprising electronic components mounted on the mounting portion, and the electronic components mounted on adjacent mounting portions across the flexible portion are electrically connected.

[0066] (Appendix 3) A flexible device described in Appendix 1 or Appendix 2, wherein the connecting members are each arranged near the periphery of the substrate portion and fixed near both ends of the end surface of the mounting portion that connects to the flexible portion.

[0067] (Supplementary Note 4) A flexible device according to any one of Supplementary Notes 1 to 3, wherein the coupling member is flexible, bendable, and thin.

[0068] (Appendix 5) A flexible device according to any one of appendices 1 to 4, wherein the connecting member is made of a high elastic modulus material.

[0069] (Supplementary Note 6) A flexible device described in Supplementary Note 1 to Supplementary Note 4, wherein the connecting member is made of a non-elastic material.

[0070] (Supplementary Note 7) A flexible device according to any one of Supplementary Notes 1 to 6, wherein the connecting member is string-shaped.

[0071] (Supplementary Note 8) A flexible device according to any one of Supplementary Notes 1 to 6, wherein the connecting member is strip-shaped.

[0072] The present invention can be applied to a wearable device that acquires biometric data.

[0073] REFERENCE SIGNS LIST 10 Flexible device 11 Substrate portion 12 Covering portion 13 Flexible portion 14 Mounting portion 17 Joining member

Claims

1. A flexible device comprising a substrate portion and a covering portion that covers the substrate portion, wherein the substrate portion comprises: a plurality of mounting portions; a flexible portion that is more flexible than the mounting portions and connects to the mounting portions; and a connecting member that connects adjacent mounting portions across the flexible portion.

2. The flexible device according to claim 1, comprising electronic components mounted on the mounting portion, wherein the electronic components mounted on adjacent mounting portions across the flexible portion are electrically connected.

3. A flexible device as described in claim 1 or claim 2, wherein the coupling members are arranged near the periphery of the substrate portion and fixed near both ends of the end face of the mounting portion that connects to the flexible portion.

4. The flexible device according to claim 1 or 2, wherein the coupling member is flexible, bendable, and thin.

5. The flexible device according to claim 1 or claim 2, wherein the coupling member is made of a high modulus material.

6. The flexible device according to claim 1 or claim 2, wherein the connecting member is made of a non-elastic material.

7. The flexible device according to claim 1 or 2, wherein the connecting member is string-like.

8. The flexible device according to claim 1 or 2, wherein the connecting member is strip-shaped.

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