Flexible device

Abstract

This flexible device (10) comprises a substrate section (11) and a cover section (12) covering the substrate section. The substrate section comprises a flexible section (13) and a mounting section (14) connected with the flexible section. The flexible section is more pliable than the mounting section. The flexible section comprises a groove section (17) and a protective structure (18) disposed around the groove section.　As a result, the present invention makes it possible to provide a flexible device with 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 (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. Electronic 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 43 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. Furthermore, 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-layer flex) 43. Typically, the flex portion 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 portion, the load on the internal substrate portion 41 is small. On the other hand, if a device has a flexible, pliable coating portion, the flex portion 43, which is the internal substrate portion 41, may be subjected to greater loads, such as bending, pulling, and twisting, than a device with a rigid coating portion.

[0009] A portion of the peripheral edge of the flexible portion 43 (for example, the dotted line area in FIG. 6) 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] Therefore, as shown in Fig. 7, a dummy copper wiring pattern 47 is formed in the flexible portion (single-sided flexible) 43 of the device near the peripheral portion where breakage is likely to occur. The arrangement of metal (copper wiring) improves the hardness of the area near the copper wiring compared to a polyimide layer alone without copper wiring, thereby improving durability against bending, twisting, etc. Furthermore, as shown in Fig. 8, in addition to the metal (copper wiring), a hard resin 48 such as epoxy may be arranged along the peripheral portion of the flexible portion.

[0011] However, in a configuration with a long flexible section, it is impossible to predict where breakage or deformation will occur, so the periphery must be uniformly reinforced (strengthened). This increases the effort, cost, and man-hours required, and the hardening of the periphery of the flexible section reduces its flexibility, making it less likely to bend. This reduced flexibility of the device becomes a problem.

[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, the substrate portion comprises a flexible portion and a mounting portion that connects to the flexible portion, the flexible portion is more flexible than the mounting portion, and the flexible portion comprises a groove portion and a protective structure that is arranged around the groove 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. 2 is a schematic top view showing an example of the configuration of the substrate part of the flexible device according to the first embodiment of the present invention. FIG. 3 is a schematic top view showing an example of the configuration of the substrate part of the flexible device according to the first embodiment of the present invention. FIG. 4A is a schematic front cross-sectional view showing the configuration of a flexible device according to a first example of the present invention. FIG. 4B is a schematic top view showing the configuration of the substrate part of the flexible device according to the first example of the present invention. FIG. 5A is a schematic front cross-sectional view showing the configuration of a flexible device according to a second example of the present invention. FIG. 5B is a schematic bottom view showing the configuration of the substrate part of the flexible device according to the second example of the present invention. FIG. 6 is a schematic top view for explaining a conventional flexible device. FIG. 7 is a schematic top view for explaining a conventional flexible device. FIG. 8 is a schematic top view for explaining a conventional flexible device.

[0015] First Embodiment A flexible device according to a first embodiment of the present invention will be described with reference to FIGS. 1A to 3. FIG.

[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 electrodes, 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 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.

[0019] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) and is more flexible and has higher flexibility than the mounting portion 14 .

[0020] The mounting sections 14 are joined by 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 overall flexibility and bendability are maintained even when rigid mounting sections 14 are arranged.

[0021] The flexible part 13 has a plurality of grooves 17 in part of its periphery. The plurality of grooves 17 are arranged in pairs on both peripheries parallel to the longitudinal direction of the flexible part 13. Of the grooves 17 arranged in pairs on both peripheries, one groove 17 is arranged at a position opposite the other groove 17. In other words, the grooves 17 arranged in pairs are arranged on the same line perpendicular to the longitudinal direction.

[0022] The tip of the groove 17 is formed of a curved surface. The curved shape is semicircular when viewed from above. The curved shape of the tip of the groove 17 is not limited to a semicircular shape when viewed from above, but may be a semi-elliptical shape or another curved shape.

[0023] The flexible part 13 further includes a protective structure 18 around the groove 17. A dummy wiring pattern is used as the protective structure 18. This hardens the area around the groove 17, improving durability.

[0024] As described above, the electrodes 16 formed on the flexible portions 13 at both ends 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).

[0025] 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.

[0026] <Effects> As described above, the flexible device 10 has a flexible and bendable covering portion (exterior) 12, which means that the substrate portion 11 cannot be maintained or fixed in the same place, and stress is 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 is likely to cause failures such as breakage (fracture) or deformation.

[0027] One load that can cause a failure is a twist (torsion) to the flexible part 13. Because the flexible part 13 is thin and flexible, it is durable against the load of simple bending or folding. On the other hand, because the flexible part 13 is thin, twisting that generates shear stress can cause breakage or significant deformation that causes irreversible changes.

[0028] In order to avoid the above-mentioned breakage and deformation, if the peripheral edge of the flexible portion 13 is hardened uniformly, the labor, cost, and process will increase, and flexibility will decrease.

[0029] On the other hand, the flexible part 13 of the flexible device 10 has a groove 17 in part of the periphery and a protective structure 18 around the groove 17. This makes it possible to limit the area of ​​the flexible part 13 where load increases, strengthen the area around the limited area, and improve durability. Details are explained below.

[0030] The shear stress generated when the flexible part 13 is twisted is a stress generated in opposite directions at arbitrary points on both ends. At this time, the recessed portions of the periphery of the flexible part 13 have low resistance to stress and are easily deformed. In non-recessed portions of the periphery, the sides parallel to the periphery support each other, suppressing deformation. On the other hand, in recessed portions of the periphery, the sides do not support each other, resulting in a difference in supporting force, which reduces the balance and causes deformation.

[0031] Therefore, by forming the grooves 17, it is possible to selectively deform the portions of the grooves 17. In this way, stress is concentrated in the portions of the grooves 17, so the areas where the load increases can be limited to the grooves 17. As a result, stress in other areas is reduced, and the load on areas where no grooves are formed is also reduced.

[0032] On the other hand, if the tip of the groove 17 is configured as a curved surface and has no protrusions, there are fewer areas that can become the starting point of fracture, so large fractures do not occur. By reinforcing the area around the groove 17 with a dummy wiring pattern, hard resin, or the like, it is possible to reduce deformation around the groove 17. Furthermore, in the event of fracture (breakage), the protective structure (reinforcement structure) 18 is disposed around the groove 17, so the effects of the fracture (breakage) do not progress further inward than the protective structure 18.

[0033] This allows areas in the flexible part 13 of the flexible device 10 that are likely to break to be identified in advance. Therefore, areas where measures against breakage, deformation, etc. should be taken can be easily limited and managed. Furthermore, the cause of breakage, etc. can be identified, the progression of damage can be prevented, and reliability can be improved. Furthermore, since there are fewer hard areas, the flexibility of the flexible device 10 can be maintained.

[0034] The protective structure may be made of a cured resin 19 such as epoxy resin, as shown in Fig. 2. Alternatively, a dummy wiring pattern 18 and a cured resin 19 such as epoxy resin may be used in combination, as shown in Fig. 3.

[0035] According to this embodiment, in a flexible device, the load on the flexible portion due to shear stress such as twisting can be reduced, and reliability can be improved.

[0036] First Example A flexible device according to a first example of the present invention will be described with reference to FIGS. 4A and 4B.

[0037] 4A and 4B , the flexible device 20 includes a substrate 11 and a covering 12. The entire substrate 11, excluding the electrode portions, is surrounded by the covering 12 made of a silicone resin molding material.

[0038] The substrate section 11 includes a flexible section 13 and a mounting section 14 .

[0039] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) that is flexible and highly flexible.

[0040] The mounting section 14 is a rigid section having a four-layer structure, and electronic components 15 are mounted on it.

[0041] 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.

[0042] To acquire bioelectric potentials, nickel-gold electrodes are formed by electroplating on both ends of device 20 as electrodes 16. After a conductive adhesive sheet is attached to electrode 16, the device is attached to the chest of a human body (living body) to form a patch-type electrocardiograph that measures electrocardiograms.

[0043] 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.

[0044] 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).

[0045] The operation of the device 20 is constantly monitored by the operation monitoring element 157. When a stoppage or abnormality in the operation of the device 20 is detected, the device 20 is restarted and information about the abnormality is notified wirelessly.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In the substrate portion 11, two grooves 17 are formed on each of the peripheral edges on both sides of the central 20 nm long flexible portion 13. In addition, one groove 17 is formed on each of the peripheral edges on both sides of the 20 nm long flexible portion 13 connected to the central flexible portion 13 via the mounting portion 14. Around each groove 17, a dummy wiring pattern is arranged as a protective structure 18.

[0050] The curved shape of the tip of the groove 17 may be, for example, semicircular when viewed from above. The radius r of the semicircle is, for example, 1 mm, and may be 0.5 mm to 1 mm. The curved shape of the tip of the groove 17 is not limited to a semicircular shape when viewed from above, but may be a semi-elliptical shape or another curved shape. The length of the groove 17 is, for example, 2 mm, but is not limited to this.

[0051] 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 is resistant to twisting and can withstand excessive loads. Thus, the flexible device 20 can improve reliability and lifespan.

[0052] Second Example A flexible device according to a second example of the present invention will be described with reference to FIGS. 5A and 5B.

[0053] 5A and 5B, the flexible device 30 includes a substrate 11 and a covering 12. The entire substrate 11, excluding the electrode portions, is surrounded by the covering 12 made of a silicone resin molding material.

[0054] The substrate section 11 includes a flexible section 13 and a mounting section 14 .

[0055] The flexible portion 13 is made up of a single-sided flexible board (single-layer flexible board) that is flexible and highly flexible.

[0056] The mounting section 14 is a multi-layer flexible board having a four-layer structure, and electronic components 15 are mounted on it.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The mounting section (multilayer flexible 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 mounting section (multilayer flexible section) 14 is, for example, 250 μm.

[0062] The silicone resin of the covering 12 is formed in the same manner as in the first embodiment. The covering 12 is configured so that the bottom surface is thinner than in the first embodiment, with the thinnest part being 2.6 mm thick and weighing 12 g. The thickness of the silicone covering the thickest device on each of the top and bottom surfaces (exterior thickness) is, for example, 0.5 mm.

[0063] In the flexible part 13, a groove 17 is formed in the same manner as in the first embodiment. The curved shape of the tip of the groove 17 may be, for example, semicircular when viewed from above. The radius r of the semicircle is, for example, 1 mm, and may be 0.5 mm to 1 mm. The curved shape of the tip of the groove 17 is not limited to a semicircular shape when viewed from above, but may be a semi-elliptical shape or another curved shape. The length of the groove 17 is, for example, 2 mm, but is not limited to this.

[0064] A dummy wiring pattern is arranged around each groove 17 as a protective structure 18. Since the load on the multilayer flexible substrate, which is more flexible than in the first embodiment, is greater, a strong protective structure can be formed by arranging an epoxy-based cured resin 19 in the vicinity of the dummy wiring pattern 18 (for example, on the inner side of the flexible portion 13).

[0065] 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 is durable against twisting and can withstand excessive loads. Thus, the flexible device 30 can improve reliability and lifespan.

[0066] In the embodiment and examples of the present invention, examples have been shown in which the tip of the groove is formed by a curved surface, but this is not limiting. The tip of the groove does not have to be formed by a curved surface, and may have a ridge line. The tip of the groove may have a polygonal shape when viewed from above.

[0067] Although the embodiment and examples of the present invention have been described with reference to examples including multiple flexible portions and multiple mounting portions, the present invention is not limited to this. A single flexible portion or multiple mounting portions may also be provided.

[0068] In the embodiment and examples of the present invention, an example has been shown in which a plurality of grooves are arranged in pairs on the periphery of both sides of the flexible part, with the grooves facing each other, but this is not limiting. The grooves do not have to be arranged in pairs, and they do not have to be arranged in opposing positions. Furthermore, the number of grooves is not limited to a plurality of grooves, and a single groove may also be used.

[0069] In the embodiments and examples of the present invention, examples of the structure, dimensions, materials, etc. of each component in the configuration and manufacturing method of the flexible device are shown, but the present invention is not limited to these examples. Anything that can exhibit the functions and effects of the flexible device can be used.

[0070] 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.

[0071] 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.

[0072] (Appendix 1) A flexible device comprising a substrate portion and a covering portion that covers the substrate portion, the substrate portion comprising a flexible portion and a mounting portion that connects to the flexible portion, the flexible portion being more flexible than the mounting portion, and the flexible portion comprising a groove portion and a protective structure that is arranged around the groove portion.

[0073] 2. The flexible device of claim 1, wherein the groove is disposed on a peripheral edge parallel to the longitudinal direction of the flexible device.

[0074] (Appendix 3) A flexible device as described in Appendix 1, comprising a plurality of the groove portions, each of the plurality of groove portions being arranged in pairs on both peripheral edges parallel to the longitudinal direction of the flexible device, and each of the groove portions arranged in pairs being arranged on the same line perpendicular to the longitudinal direction.

[0075] (Supplementary Note 4) A flexible device according to any one of Supplementary Notes 1 to 3, wherein the tip of the groove is configured with a curved surface.

[0076] (Appendix 5) The flexible device according to any one of appendices 1 to 4, wherein the protective structure is composed of metal wiring.

[0077] (Appendix 6) A flexible device according to any one of appendices 1 to 4, wherein the protective structure is made of a cured resin.

[0078] (Appendix 7) A flexible device as described in appendix 1 to appendix 6, comprising electronic components mounted on the mounting portion, and the electronic components mounted on adjacent mounting portions across the flexible portion are electrically connected.

[0079] The present invention can be applied to a wearable device that acquires biometric data.

[0080] REFERENCE SIGNS LIST 10 Flexible device 11 Substrate portion 12 Covering portion 13 Flexible portion 14 Mounting portion 17 Groove portion 18 Protective structure

Claims

1. A flexible device comprising: a substrate portion; and a covering portion that covers the substrate portion; the substrate portion comprising: a flexible portion; and a mounting portion that connects to the flexible portion; the flexible portion being more flexible than the mounting portion; and the flexible portion comprising: a groove portion; and a protective structure that is disposed around the groove portion.

2. The flexible device according to claim 1, wherein the groove is disposed on the periphery of the flexible device parallel to the longitudinal direction.

3. A flexible device as described in claim 1, comprising a plurality of said groove portions, each of said plurality of groove portions being arranged in pairs on the peripheral edges on both sides parallel to the longitudinal direction of said flexible device, and each of said groove portions arranged in pairs being arranged on the same line perpendicular to said longitudinal direction.

4. A flexible device according to claim 1 or claim 2, wherein the tip of the groove is formed with a curved surface.

5. The flexible device according to claim 1 or 2, wherein the protective structure is made of metal wiring.

6. The flexible device according to claim 1 or 2, wherein the protective structure is made of a cured resin.

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