Stretchable device

Abstract

Provided is a stretchable device including a stretchable base material. The stretchable base material is provided with a main surface region extending along a direction different from the thickness direction of the stretchable base material, and an oil / fat barrier layer containing an oil / fat material is located in the main surface region.

Description

stretchable devices

[0001] The present disclosure relates to stretchable devices.

[0002] Stretchable devices including a stretchable substrate have been known for some time. These stretchable devices can be used in, for example, living organisms or devices that require stretchability.

[0003] Japanese Patent Application Laid-Open No. 2023-29398

[0004] Generally, stretchable devices include a stretchable substrate made of resin. When a stretchable device including such a stretchable substrate is used in a living body or an apparatus, foreign matter such as sebum, proteins derived from the living body, or machine oil applied to the apparatus may adhere to the stretchable substrate. The present inventors have newly discovered that when such foreign matter adheres locally to the stretchable substrate, the stretchable substrate is prone to breakage at the adhesion site.

[0005] The present disclosure has been made in view of the above-mentioned problems. That is, a main object of the present disclosure is to provide a stretchable device in which breakage of a stretchable substrate is suitably suppressed.

[0006] The inventors of the present application attempted to solve the above problems by approaching them in a new direction rather than by simply extending the conventional technology, and as a result, they came up with the invention of a stretchable device that achieves the above-mentioned main object.

[0007] A stretchable device according to the present disclosure includes a stretchable substrate, the stretchable substrate having a main surface region extending along a direction different from a thickness direction of the stretchable substrate, and an oil-and-fat barrier layer containing an oil-and-fat material is positioned on the main surface region.

[0008] According to the stretchable device according to an embodiment of the present disclosure, breakage of the stretchable substrate is suitably suppressed.

[0009] FIG. 1 is a perspective see-through view schematically showing the appearance of a stretchable device according to a first embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing an A-A cross section of the stretchable device shown in FIG. 1. FIG. 3 is a perspective see-through view schematically showing the appearance of a stretchable device including a stretchable wiring according to a first embodiment of the present disclosure. FIG. 4 is a schematic cross-sectional view showing a B-B cross section of the stretchable device shown in FIG. 3. FIG. 5 is a schematic cross-sectional view showing a modified version of the stretchable device according to the first embodiment of the present disclosure. FIG. 6 is a schematic cross-sectional view showing a modified version of the stretchable device according to the first embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view showing a modified version of the stretchable device according to the first embodiment of the present disclosure. FIG. 8 is a perspective see-through view schematically showing a modified version of the stretchable device according to the first embodiment of the present disclosure. FIG. 9 is a schematic cross-sectional view showing a C-C cross section of the stretchable device shown in FIG. 8. FIG. 10 is a schematic cross-sectional view showing a modified version of the stretchable device according to the first embodiment of the present disclosure. FIG. 11 is a schematic cross-sectional view showing a modified version of the stretchable device according to the first embodiment of the present disclosure. Fig. 12 is a schematic cross-sectional view showing a stretchable device according to a second embodiment of the present disclosure. Fig. 13 is a schematic cross-sectional view showing a stretchable device according to a third embodiment of the present disclosure. Fig. 14A is a schematic cross-sectional view showing a modified version of the stretchable device according to the third embodiment of the present disclosure. Fig. 14B is a schematic cross-sectional view showing a modified version of the stretchable device according to the third embodiment of the present disclosure.

[0010] The following describes specific embodiments of the present disclosure. The applicant provides the following description and examples to enable those skilled in the art to fully understand the present disclosure, and it should be noted that these are not intended to limit the subject matter described in the claims. In other words, the present disclosure is not particularly limited to the preferred embodiments described below, and can be implemented with appropriate modifications within the scope of its purpose. For convenience, the present disclosure may be divided into embodiments and examples to facilitate explanation or understanding of the key points. However, partial substitution and / or combination of the configurations shown in different embodiments is possible. In describing such embodiments, redundant explanations of substantially identical features may be omitted, and only differences may be described. In particular, similar effects resulting from similar configurations may not be mentioned in each embodiment.

[0011] In this specification, the terms "thickness direction of the stretchable device," "thickness direction of the stretchable substrate layer," "stacking direction of the stretchable substrate," and "stacking direction" may be used interchangeably. This direction corresponds to direction Y in the drawings.

[0012] As used herein, the term "cross-sectional view" or "cross-sectional shape" refers to the shape of the stretchable device as viewed from a direction substantially perpendicular to the thickness direction (in other words, the shape of the stretchable device cut along a plane parallel to the thickness direction). When the stretchable device has a layered structure including multiple stretchable substrate layers, the term "cross-sectional view" or "cross-sectional shape" refers to the shape of the stretchable device as viewed from a direction substantially perpendicular to the stacking direction of the stretchable substrates (in other words, the shape of the stretchable device cut along a plane parallel to the stacking direction). Furthermore, the term "planar view" used herein refers to a sketch of the object as viewed from above or below along the thickness direction (or stacking direction) of the stretchable device.

[0013] Furthermore, in this specification, "above" an element includes not only the case of contacting the top surface of the element, but also the case of not contacting the top surface of the element. In other words, "above" an element does not only mean above the element, i.e., a position above the element via another object or a position above with a gap, but also a position directly above the element. Furthermore, "above" does not necessarily mean above in the vertical direction. "Above" merely indicates the relative positional relationship of an element.

[0014] The various numerical ranges referred to herein are intended to include the lower and upper numerical limits themselves unless otherwise specified, and the term "about" means that there may be a variation or difference of a few percent, e.g., ±10%.

[0015] As used herein, "vertical" and "substantially vertical" do not necessarily mean completely "vertical," but include aspects that are slightly deviated from the completely vertical (for example, a range of ±10°, e.g., ±5°, from the completely vertical).

[0016] Furthermore, in this specification, "substantially parallel" does not necessarily mean completely "parallel," but includes a state where the parallelism is slightly deviated from the parallelism (for example, within a range of ±10° from completely parallelism, e.g., within a range of ±5°).

[0017] [Basic configuration of stretchable device] The structure of a stretchable device will be described with reference to Figures 1 and 2. Figure 1 is a perspective view illustrating an example of a stretchable device according to an embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along line A-A of the stretchable device in Figure 1. Note that cross-sectional views in this specification are cross-sections parallel to the thickness direction Y of the stretchable device 1.

[0018] The main components included in the stretchable device of the present disclosure will be described below with reference to FIGS. 1 and 2.

[0019] (Stretchable Substrate 10) The stretchable device 1 includes at least the stretchable substrate 10. The stretchable substrate 10 (hereinafter also simply referred to as "substrate") may be a sheet-like or film-like stretchable substrate, and may be made of, for example, a resin material having stretchability. Here, in this specification, "stretchability" simply means the property of being able to expand and contract, and may also be referred to as "stretchability" or "stretchable." More specifically, "stretchability" means the property of being able to expand from a non-stretched state, which is the normal state in which no tensile stress is applied, by applying tensile stress, and being able to contract when released from the stretched state. Examples of resin materials used as the stretchable substrate 10 include thermoplastic polyurethane.

[0020] The stretchable substrate 10 has a main surface. In this specification, the "main surface" of the stretchable substrate refers to a surface extending in a direction different from the thickness direction Y of the stretchable substrate, for example, a surface extending in directions X and Z that are approximately perpendicular to the thickness direction Y of the stretchable substrate. The sheet-like or film-like stretchable substrate 10 may extend along the stretch direction of the stretchable device 1. In such a structure, the "main surface" of the stretchable substrate 10 can also be interpreted as a surface extending along the stretch direction of the stretchable substrate 10. In an embodiment including a stretchable wiring, which will be described later, it can also be interpreted as a surface extending along the extension direction of the stretchable wiring (see FIG. 3). Note that, although the drawings show a stretchable device extending in a specific direction for clarity, the shape of the stretchable device is not particularly limited. The planar view shape of the stretchable device is also not particularly limited, and can be various shapes, such as a quadrangle (e.g., square, rectangle, etc.), a polygon such as a triangle, a circle, an ellipse, a semicircle, a crescent, or an irregular shape.

[0021] The thickness of the stretchable substrate 10 is not particularly limited, but when emphasis is placed on the stretchability of the device, it is preferably 1 mm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. When emphasis is placed on the mechanical strength of the device, the thickness of the stretchable substrate 10 is preferably 1 μm or more. When a laminate is formed from multiple stretchable substrates, each of the multiple stacked stretchable substrates may have the same thickness or may have different thicknesses.

[0022] (Stretchable Wiring 20) The stretchable device 1 may further include a stretchable wiring 20 arranged on the stretchable substrate 10 (see FIG. 3). The stretchable wiring 20 (hereinafter also simply referred to as "wiring") contains conductive particles and a resin. Examples of the stretchable wiring 20 include a mixture of metal powder such as Ag (silver), Cu (copper), or Ni (nickel) as conductive particles and an elastomer resin such as a silicone resin. The average particle size of the conductive particles is not particularly limited, but is preferably 0.01 μm or more and 10 μm or less. The conductive particles may be spherical in shape.

[0023] Furthermore, for the sake of clarity, FIG. 3 only depicts the stretchable wiring 20 extending in a specific direction, but the stretchable wiring 20 may extend in any direction on the main surface of and / or inside the stretchable substrate 10. Preferably, the stretchable wiring 20 may extend along the extension direction of the main surface of the stretchable substrate 10. Furthermore, when viewed from the thickness direction Y of the stretchable substrate 10, the stretchable wiring 20 does not necessarily have to be arranged in a straight line, and may be arranged, for example, in a curved line. Furthermore, when viewed from the thickness direction Y, the stretchable wiring 20 does not necessarily have to extend in one direction. The number of stretchable wirings 20 is not particularly limited, and one or more wirings may be arranged.

[0024] [First embodiment] Based on the details of the main components of the stretchable device 1 described above, the following will describe characteristic parts of the stretchable device 1 according to the first embodiment of the present disclosure. As shown in Fig. 1 and Fig. 2 , the stretchable device 1 of the present disclosure includes an oil-and-fat barrier layer 30 in the main surface region 12A of the stretchable substrate. The stretchable device 1 includes the oil-and-fat barrier layer 30 positioned in the main surface region 12A of the stretchable substrate. The oil-and-fat barrier layer 30 may be provided so as to cover the stretchable substrate 10 in the main surface region 12A. In other words, the main surface side of the stretchable substrate 10 may be covered with the oil-and-fat barrier layer 30.

[0025] In this specification, the terms "main surface region," "side surface region," and "surface region" refer to a region on the surface of the stretchable substrate, on the main surface, on the side surface, or on a surface including the main surface and the side surface, and a region inside the stretchable substrate within 3 μm depth from the surface along the thickness direction Y. In other words, the "main surface region 12A" refers to a region on the main surface of the stretchable substrate 10 and a region inside the stretchable substrate within 3 μm depth from the main surface along the thickness direction Y. The oil-barrier layer 30 may be positioned in a region on the main surface of the stretchable substrate 10 and / or in a surface region including the main surface of the stretchable substrate 10.

[0026] In this specification, the "oil-barrier layer 30" is, simply put, a layer located in the surface region of the stretchable substrate and containing primarily an oil-and-fat material. The oil-and-fat barrier layer 30 refers to a layer in which an oil-and-fat material is located in the surface region of the stretchable substrate 10. More specifically, the oil-and-fat barrier layer 30 contains, in the surface region of the stretchable substrate 10, at least one of an oil-and-fat material impregnated inside the stretchable substrate 10 and an oil-and-fat material located on the surface of the stretchable substrate 10. The oil-and-fat barrier layer 30 can also be simply referred to as an "oil-and-fat layer" or an "oil-and-fat-containing layer." Such an oil-and-fat barrier layer 30 is located in a surface region that includes at least the main surface region 12A of the stretchable substrate, and is different from sebum that is locally attached by, for example, touching the stretchable device 1.

[0027] The stretchable device 1 can be attached to various objects, including living organisms such as the human body or equipment. During use of the stretchable device 1, including the attachment of the stretchable device 1, various foreign substances, including sebum from fingers, protein, and / or machine oil applied to equipment, may locally adhere to the stretchable device 1. The present inventors have newly discovered that such locally adhered foreign substances may cause damage to the stretchable device 1.

[0028] As described above, the stretchable substrate 10 included in the stretchable device 1 is made of a resin material. When the stretchable substrate 10 is stretched, the molecules that make up the stretchable substrate 10 are pulled along the stretching direction, increasing the distance between the molecules that make up the stretchable substrate 10 compared to the normal state (i.e., the non-stretched state). In other words, the molecular structure of the stretchable substrate 10 becomes looser in the stretched state of the stretchable substrate 10. In this state, if foreign matter adheres to the surface of the stretchable substrate 10, the foreign matter can enter between the loose molecular structure.

[0029] Foreign matter that has entered the molecular structure can inhibit the movement of molecules that make up the stretchable substrate 10 or cause the molecular structure to break. If molecular movement is inhibited, the stretchability of the stretchable substrate 10 can be locally reduced, and uniform stretchability throughout the stretchable substrate 10 can be lost. If the stretchability of the stretchable substrate 10 is uneven, stress tends to concentrate in areas of low stretchability, potentially causing the stretchable substrate 10 to break at those areas. Furthermore, if the molecular structure of the stretchable substrate 10 is partially broken, the mechanical strength of the stretchable substrate 10 can be locally reduced, potentially causing the stretchable substrate 10 to break. Thus, if foreign matter adheres locally to the surface of the stretchable substrate 10, the adhered foreign matter can enter the molecular structure that makes up the stretchable substrate 10, making the stretchable substrate 10 more likely to break at the location where the foreign matter is attached.

[0030] In response to these problems, the inventors of the present application have newly discovered that breakage of the stretchable substrate 10 due to adhesion of foreign matter can be suppressed by providing the stretchable device 1 with an oil barrier layer 30 on the main surface region 12A of the stretchable substrate. As described above, breakage of the stretchable substrate 10 due to adhesion of foreign matter can be caused by a local decrease in the stretchability and / or mechanical strength of the stretchable substrate 10 at the location where the foreign matter is attached.

[0031] In the stretchable device 1 of the present disclosure, the stretchable substrate 10 is provided with the oil-and-grease barrier layer 30 in advance, so that even if foreign matter adheres to the stretchable substrate during use, the intrusion of the foreign matter into the interior of the stretchable substrate 10 can be suppressed. Specifically, because the oil-and-grease material constituting the oil-and-grease barrier layer 30 is pre-disposed in the main surface region 12A of the stretchable substrate 10, even if external foreign matter adheres to the main surface, the foreign matter cannot easily penetrate into the molecular structure of the stretchable substrate 10. This suppresses local changes in the molecular structure of the stretchable substrate 10, allowing the stretchable substrate 10 to maintain more uniform stretchability and mechanical strength as a whole. In other words, the stretchable device 1 of the present disclosure can suppress local changes in the stretchability and / or mechanical strength of the stretchable substrate 10 due to the adhesion of foreign matter, thereby favorably suppressing breakage of the stretchable substrate 10.

[0032] As described above, in the stretchable device 1 of the present disclosure, the oil barrier layer 30 serves to protect the stretchable substrate 10 from foreign matter, and may also be referred to as a "protective layer," a "protective film," or a "coating layer."

[0033] In a preferred embodiment, the oil-barrier layer 30 may extend over the main surface region 12A of the stretchable substrate. More specifically, the oil-barrier layer 30 may extend continuously along the main surface region 12A of the stretchable substrate. With this structure, the main surface of the stretchable substrate 10 is suitably protected by the oil-barrier layer 30 extending over the main surface region 12A. This makes it possible to suitably prevent foreign matter from reaching the main surface of the stretchable substrate 10 and / or from penetrating into the molecular structure of the stretchable substrate 10. This makes it possible to provide a stretchable device that can prevent damage to the stretchable substrate due to adhesion of foreign matter.

[0034] The oil-and-fat barrier layer 30 may be provided continuously as described above, or alternatively, may be provided discontinuously. That is, the oil-and-fat barrier layer 30 may extend continuously over the surface region of the stretchable substrate 10, or a plurality of discontinuous oil-and-fat barrier layers 30 may be provided on the surface of the stretchable substrate 10.

[0035] The principal surface region 12A may have a region where the oil-and-fat barrier layer 30 is not located. In other words, the oil-and-fat barrier layer 30 may not be provided in some regions of the principal surface region 12A. When viewed from the thickness direction Y of the stretchable substrate, the oil-and-fat barrier layer 30 may be located in a range that occupies 50% or more, 70% or more, or 90% or more of the area of ​​the principal surface region 12A where the oil-and-fat barrier layer 30 is located. The presence of the oil-and-fat barrier layer 30 in the above-mentioned range makes it possible to suitably suppress breakage of the stretchable substrate 10. The area of ​​the principal surface region 12A when viewed from the thickness direction of the stretchable substrate can also be said to be the area of ​​the principal surface.

[0036] The oil-and-grease barrier layer 30 is provided at least on the principal surface region 12A of the stretchable substrate 10. In a sheet-like stretchable substrate 10, the principal surface may be the surface with the largest area among the multiple surfaces constituting the stretchable substrate 10. The principal surface, which is a large surface, is more susceptible to foreign matter adhesion than the other surfaces. Therefore, providing the oil-and-grease barrier layer 30 on the principal surface region 12A can effectively prevent breakage of the stretchable substrate 10 due to foreign matter adhesion. As shown in FIGS. 1 and 2 , the stretchable substrate 10 may have two principal surface regions 12A facing each other. In this structure, the oil-and-grease barrier layer 30 is positioned in at least one of the two principal surface regions 12A facing each other. That is, the oil-and-grease barrier layer 30 may be positioned in either one of the two principal surface regions 12A, or alternatively, it may be positioned in both of the two principal surface regions 12A.

[0037] 1 and 2 , the oil-and-grease barrier layer 30 may be provided in the main surface region 12A of a stretchable substrate that does not include stretchable wiring. In the stretchable device 1 of the present disclosure, the oil-and-grease barrier layer 30 is applicable regardless of the presence or absence of stretchable wiring, and can suitably suppress breakage of the stretchable substrate 10. In such a structure, the oil-and-grease barrier layer 30 may be provided so as to cover at least the central portion of the main surface region 12A when viewed from the thickness direction Y of the stretchable substrate.

[0038] Alternatively, as shown in FIG. 3 , the oil-and-fat barrier layer 30 may be provided on a stretchable substrate 10 including a stretchable wiring 20. The stretchable substrate 10 may include a stretchable wiring 20 disposed therein, and may include an oil-and-fat barrier layer 30 in at least the main surface region 12A. Preferably, the oil-and-fat barrier layer 30 may be provided in a region overlapping with the stretchable wiring 20 when viewed from the thickness direction Y of the stretchable substrate. That is, when viewed from the thickness direction Y of the stretchable substrate, the stretchable wiring 20 and the oil-and-fat barrier layer 30 may be arranged so as to overlap with each other. In the stretchable device 1 of the present disclosure, by arranging the oil-and-fat barrier layer 30 in at least a region overlapping with the stretchable wiring 20 when viewed from the thickness direction Y, the stretchable substrate 10 located in the region overlapping with the stretchable wiring 20 can be suitably protected from adhesion of foreign matter. Generally, when using the stretchable device 1, an electrical signal is transmitted via the stretchable wiring 20 disposed in the stretchable substrate 10. If the stretchable substrate 10 breaks in the region overlapping with the stretchable wiring 20, the break may damage the stretchable wiring 20, potentially causing abnormalities in the transmission of electrical signals. In the stretchable device 1 of the present disclosure, the oil and grease barrier layer 30 is disposed in at least the region overlapping with the stretchable wiring 20 when viewed from the thickness direction Y, and by protecting the stretchable substrate 10 that covers the stretchable wiring 20, damage to the stretchable wiring 20 can be suitably suppressed.

[0039] Preferably, the oil-and-fat barrier layer 30 may be provided over the entire main surface of the stretchable substrate 10. In other words, the entire main surface of the stretchable substrate 10 may be covered with the oil-and-fat barrier layer 30. This allows the entire main surface of the stretchable substrate 10 to be suitably protected against adhesion of foreign matter, making it possible to more suitably prevent the stretchable substrate 10 from breaking.

[0040] The oil-and-grease barrier layer 30 can be present in at least one of a surface layer region inside the stretchable substrate 10 and a region on the outer surface of the stretchable substrate 10. That is, the oil-and-grease barrier layer 30 may include at least one layer present inside the stretchable substrate 10 and a layer present outside the stretchable substrate 10. The oil-and-grease barrier layer 30 containing an oil-and-grease material impregnated inside the stretchable substrate 10 and located inside the stretchable substrate 10 will be referred to below as the "first oil-and-grease layer" (see FIGS. 1 to 4). The first oil-and-grease layer may also be referred to as the "inner oil-and-grease layer" or "impregnated oil-and-grease layer." The oil-and-grease barrier layer 30 containing an oil-and-grease material located on the surface of the stretchable substrate 10 will also be referred to below as the "second oil-and-grease layer" (see FIG. 5). The second oil-and-grease layer may also be referred to as the "outer oil-and-grease layer" or "applied oil-and-grease layer." That is, the stretchable device 1 of the present disclosure may include an oil-and-fat barrier layer that includes at least one of a first oil-and-fat layer and a second oil-and-fat layer.

[0041] As shown in FIG. 4 , the provision of the first oil / fat layer 30 containing an impregnated oil / fat material allows the oil / fat material to be disposed within the molecular structure located at the surface layer of the stretchable substrate 10. The pre-disposition of the oil / fat material within the molecular structure can prevent localized foreign matter from penetrating into the molecular structure. While not intended to be limited to a particular theory, this is presumably because the oil / fat material constituting the oil / fat barrier layer 30 at the surface layer of the stretchable substrate 10 is interposed within the molecular structure of the stretchable substrate 10, blocking the path of penetration of foreign matter. Therefore, it is believed that local changes in the stretchability and / or mechanical strength of the stretchable substrate 10 are prevented, and as a result, breakage of the stretchable substrate 10 can be effectively prevented.

[0042] 5, the second oil layer 30 containing an oil material disposed on the surface of the stretchable substrate 10 can prevent foreign matter adhering to the stretchable device 1 from reaching the stretchable substrate 10. In other words, the second oil layer can prevent foreign matter from penetrating the surface of the stretchable substrate. This can prevent foreign matter from locally penetrating the molecular structure of the stretchable substrate, thereby making it possible to suitably prevent breakage of the stretchable substrate due to local adhesion of foreign matter.

[0043] Preferably, the oil-and-fat barrier layer 30 includes at least a first oil-and-fat layer. By including at least the first oil-and-fat layer in the oil-and-fat barrier layer, it is possible to suitably prevent the intrusion of foreign matter into the interior of the stretchable substrate 10. For example, the oil-and-fat barrier layer 30 may include only the first oil-and-fat layer 30a (see FIG. 4 ), or alternatively, may include both the first oil-and-fat layer 30a and the second oil-and-fat layer 30b (see FIG. 6 ). When viewed in the thickness direction of the oil-and-fat barrier layer 30, the first oil-and-fat layer 30a and the second oil-and-fat layer 30b may at least partially overlap each other. When viewed in the thickness direction of the oil-and-fat barrier layer 30, the region where the first oil-and-fat layer 30a and the second oil-and-fat layer 30b overlap corresponds to a configuration in which an oil-and-fat material is further applied to the surface of the stretchable substrate 10, the surface of which is impregnated with an oil-and-fat material. As a result, the first oil layer 30a prevents foreign matter from entering the inside of the stretchable substrate 10, and the second oil layer 30b prevents foreign matter from reaching the surface of the stretchable substrate 10. This makes it possible to more effectively prevent local stress concentration in the stretchable substrate 10 due to the adhesion of foreign matter.

[0044] Furthermore, in the oil-and-fat barrier layer 30 including both the first oil-and-fat layer 30a and the second oil-and-fat layer 30b, the first oil-and-fat layer 30a and / or the second oil-and-fat layer 30b may be positioned discontinuously. For example, the first oil-and-fat layer 30a may extend continuously, while the second oil-and-fat layer 30b may be discontinuous. Alternatively, the first oil-and-fat layer 30a may be positioned discontinuously, while the second oil-and-fat layer 30b may extend continuously. Alternatively, both the first oil-and-fat layer 30a and the second oil-and-fat layer 30b may extend continuously. In yet another embodiment, both the first oil-and-fat layer 30a and the second oil-and-fat layer 30b may be positioned discontinuously. When viewed in the thickness direction of the oil-and-fat barrier layer 30, the discontinuous first oil-and-fat layer 30a and the second oil-and-fat layer 30b may at least partially overlap. This may form, macroscopically, a continuously extending oil-and-fat barrier layer 30. For example, the surface region of the stretchable substrate may be covered with at least one of the first oil-and-fat layer 30a and the second oil-and-fat layer 30b.

[0045] In a cross-sectional view, the thickness T1 of the first oil layer may be, for example, 1 μm or more, 1.5 μm or more, or 3 μm or more (see FIG. 4 ). The "thickness of the first oil layer" can be interpreted as the depth of the first oil layer from the surface of the stretchable substrate 10 toward the interior of the stretchable substrate 10. Having the thickness T1 of the first oil layer within the above-described range can effectively prevent localized penetration of foreign matter into the interior of the stretchable substrate 10. For example, the thickness of sebum adhering to human skin is generally about 0.5 μm. Therefore, if the lower limit of the thickness T1 of the first oil layer is as described above, even if the skin comes into contact with the stretchable device 1, the stretchable substrate 10 can be effectively protected from sebum that may locally adhere to the stretchable device 1 due to such contact. Furthermore, when the overall stretchability of the stretchable substrate 10 is emphasized, the thickness T1 of the first oil layer may be 100 μm or less, 70 μm or less, or 40 μm or less.

[0046] Furthermore, in a cross-sectional view, the thickness T2 of the second oil layer may be, for example, 1 μm or more, 1.5 μm or more, or 3 μm or more (see FIG. 5 ). When the thickness T2 of the second oil layer is within the above-mentioned range, it is possible to suitably prevent foreign matter from reaching the surface of the stretchable substrate 10. Furthermore, when prioritizing the overall stretchability of the stretchable substrate 10, the thickness T2 of the second oil layer may be 100 μm or less, 70 μm or less, or 40 μm or less.

[0047] As shown in FIG. 7 , the stretchable substrate 10 has a side surface connecting two opposing main surfaces. The oil-and-fat barrier layer 30 may be disposed from the main surface to the side surface of the stretchable substrate 10. That is, the oil-and-fat barrier layer 30 may extend from the main surface region 12A to the side surface region 12B of the stretchable substrate 10. Specifically, the oil-and-fat barrier layer 30 may be disposed so as to cover the entire main surface region 12A and at least a portion of the side surface region 12B. In such a structure, when the stretchable substrate 10 has a rectangular sheet shape in cross section, the oil-and-fat barrier layer 30 may be disposed so as to cover the ridges and / or corners of the stretchable substrate 10. This allows the oil-and-fat barrier layer 30 to protect not only the main surfaces of the stretchable substrate 10 but also the ridges and / or corners where stress is likely to concentrate. Therefore, the above-described structure can more effectively prevent damage to the stretchable substrate 10. Furthermore, since the oil-and-fat barrier layer 30 is formed over multiple surfaces of the stretchable substrate 10, the oil-and-fat barrier layer 30 can be more suitably retained on the stretchable substrate 10 compared to a configuration in which the oil-and-fat barrier layer 30 is formed on only a single surface.

[0048] In a preferred embodiment, the oil-and-grease barrier layer 30 is disposed so as to cover the entire outer surface of the stretchable substrate 10 (see FIGS. 8 to 11 ). That is, the oil-and-grease barrier layer 30 may be provided so as to surround the stretchable substrate 10. In other words, the stretchable substrate 10 may be covered with the oil-and-grease barrier layer 30 located in a surface region including the main surface region 12A and the side surface region 12B of the stretchable substrate 10. This configuration can also be interpreted as a configuration in which the oil-and-grease barrier layer 30 extends along the outer contour of the stretchable substrate 10. For example, the oil-and-grease barrier layer 30 may be formed continuously over the entire surface of the stretchable substrate 10. In this configuration, all corners 14 and ridges 16 of the stretchable substrate 10 can be covered with the oil-and-grease barrier layer 30 (see FIG. 8 ). This protects the entire stretchable substrate 10 with the oil-and-grease barrier layer 30, making it possible to more effectively prevent damage to the stretchable substrate 10 due to the adhesion of foreign matter.

[0049] The oil-and-fat material contained in the oil-and-fat barrier layer 30 provided over the entire stretchable substrate 10 may be applied to the surface of the stretchable substrate 10 in the main surface region 12A and the side surface region 12B of the stretchable substrate (see FIG. 9 ), or may be impregnated into the interior of the stretchable substrate 10 (see FIG. 10 ). Alternatively, the oil-and-fat barrier layer 30 may include both the first oil-and-fat layer 30a and the second oil-and-fat layer 30b. That is, the oil-and-fat barrier layer 30 may include at least one of the first oil-and-fat layer 30a and the second oil-and-fat layer 30b. Furthermore, the oil-and-fat barrier layer 30 provided in the main surface region 12A and the side surface region 12B does not necessarily have a uniform structure. For example, the oil-and-fat barrier layer 30 may have different thicknesses in the main surface region 12A and the side surface region 12B. Furthermore, for example, the main surface region 12A may have both the first oil layer 30a and the second oil layer 30b, while the side region 12B may have only the first oil layer 30a, so that the oil barrier layers 30 have different structures in the main surface region 12A and the side region 12B.

[0050] The oil and fat material contained in the oil and fat barrier layer 30 can be any oil and fat material used in the fields of food, feed, cosmetics, pharmaceuticals, industry, etc. For example, the oil and fat material contained in the oil and fat barrier layer 30 can be at least one selected from the group consisting of vegetable oils, animal fats, mineral oils, and synthetic oils. The oil and fat material can be liquid or solid.

[0051] The vegetable oils and fats are not particularly limited, but examples thereof include soybean oil, corn oil, cottonseed oil, rapeseed oil, sesame oil, perilla oil, rice bran oil, sunflower oil, peanut oil, olive oil, palm oil, palm kernel oil, rice germ oil, wheat germ oil, brown rice germ oil, Job's tears oil, garlic oil, macadamia nut oil, avocado oil, evening primrose oil, flower oil, camellia oil, coconut oil, castor oil, linseed oil, cacao oil, Japan wax, jojoba oil, and grapeseed oil, either alone or in mixtures, or processed oils and fats obtained by subjecting these to hardening, fractionation, interesterification, etc.

[0052] Examples of animal fats and oils include, but are not limited to, fish oil, chicken oil, beef tallow, lard, milk fat, horse oil, snake oil, egg oil, egg yolk oil, turtle oil, mink oil, and processed products of these fats and oils (margarine, shortening, butter, etc.).

[0053] Examples of mineral oils include, but are not limited to, rust preventative oil, cutting oil, engine oil, gear oil, and grease.

[0054] Examples of synthetic oils include, but are not limited to, non-polar oils such as hydrocarbon oils, silicone oils, ester oils, etc. Specific examples include hydrocarbon oils such as petrolatum, solid paraffin, and liquid paraffin; silicone oils such as cyclopentasiloxane; and ester oils such as cetyl ethylhexanoate, ethylhexyl palmitate, isopropyl myristate, isopropyl palmitate, caprylic / capric triglyceride, and triethylhexanoin.

[0055] For example, when the stretchable device 1 is applied to the human body, the oil and fat material contained in the oil and fat barrier layer 30 is preferably an oil and fat material with excellent biocompatibility. Furthermore, for example, when the stretchable device 1 is used in industrial equipment, the oil and fat barrier layer 30 preferably contains the same type of oil and fat material as the oil and fat material used as machine oil. Thereby, even if machine oil adheres locally during use of the stretchable device 1, the machine oil has components equivalent to those contained in the oil and fat barrier layer 30, and therefore local changes in the stretchability and mechanical strength of the stretchable substrate 10 can be suitably suppressed.

[0056] (Method for Producing a Stretchable Device) An exemplary method for producing a stretchable device according to an embodiment of the present disclosure will now be described.

[0057] First, a stretchable substrate is prepared. After preparing a stretchable substrate layer, stretchable wiring may be formed on the main surface of the stretchable substrate layer.

[0058] The stretchable wiring may be formed by printing a conductive paste (e.g., a conductive paste containing a mixture of silver and resin) onto the stretchable substrate using screen printing, inkjet printing, etc. This allows a desired circuit pattern to be obtained.

[0059] After forming a circuit pattern of the stretchable wiring 20 on the stretchable substrate 10, the conductive paste for the stretchable wiring is dried and cured, thereby forming the stretchable wiring 20 on the stretchable substrate 10. Note that printing may be performed not only on one main surface of the stretchable substrate 10, but also on both surfaces including the opposite main surface. Furthermore, it is also possible to mount components such as electronic components on the stretchable wiring 20, as necessary.

[0060] Next, another stretchable substrate 10 may be stacked in the thickness direction Y so as to cover the stretchable wiring 20 arranged on the stretchable substrate 10. Thereafter, the stacked stretchable substrates 10 may be bonded to each other by, for example, pressing the substrates 10 under predetermined temperature conditions. This makes it possible to obtain a stretchable substrate 10 having the stretchable wiring 20 therein.

[0061] Thereafter, an oil-and-fat material is applied to the outer surface of the stretchable substrate 10 to form the oil-and-fat barrier layer 30. For example, an oil-and-fat material capable of impregnating the stretchable substrate 10 may be applied to the outer surface of the stretchable substrate 10 and left for a predetermined time (e.g., 1 second or more), thereby impregnating the surface layer of the stretchable substrate 10 with the oil-and-fat material. There are no particular limitations on the method for applying the oil and fat, and known application methods can be used. For example, the application method may be a roll coater method, a spray method, a dipping method, or the like.

[0062] In one embodiment, the entire applied oil-and-fat material may be impregnated into the surface layer of the stretchable substrate 10. Alternatively, the oil-and-fat material may be retained on the surface of the stretchable substrate 10 without being impregnated into the stretchable substrate 10. That is, only the first oil-and-fat layer may be formed so that the stretchable substrate 10 contains only the impregnated oil-and-fat material (see FIG. 9), or only the second oil-and-fat layer may be formed so that the oil-and-fat material is retained on the surface without being impregnated (see FIG. 10). For example, the second oil-and-fat layer may be formed by applying an oil-and-fat material that does not impregnate the stretchable substrate 10 to the surface of the stretchable substrate 10. Alternatively, the applied oil-and-fat material may not be entirely impregnated, and some of the oil-and-fat material may remain on the stretchable substrate 10. Alternatively, both the first oil-and-fat layer and the second oil-and-fat layer may be formed (see FIG. 11).

[0063] Second Embodiment Next, a description will be given of a stretchable device 1B according to a second embodiment. The stretchable device 1B differs from the stretchable device 1 according to the first embodiment in that the stretchable wiring 20 is arranged on the surface of the stretchable substrate 10, rather than inside the stretchable substrate 10, and an oil barrier layer 30 is provided so as to cover the stretchable wiring 20.

[0064] FIG. 12 is a cross-sectional view of a stretchable device 1B according to the second embodiment. As shown in the figure, the stretchable device 1B may include a stretchable wiring 20 disposed on the outer surface of a stretchable substrate 10. In such a structure, an oil barrier layer 30 may be provided so as to cover the stretchable wiring 20 positioned on the stretchable substrate 10. The stretchable wiring 20 may include an oil barrier layer 30 on an outer surface 20A that is not in contact with the stretchable substrate 10. The oil barrier layer 30 may integrally surround the stretchable substrate 10 and the stretchable wiring 20 positioned on the stretchable substrate 10. As with the stretchable substrate 10, if the stretchability and mechanical strength of the stretchable wiring 20 change locally due to the adhesion and intrusion of foreign matter, breakage due to stress concentration may occur. According to the above-described configuration, by providing the oil barrier layer 30 that covers the stretchable wiring 20, it is possible to suitably protect the stretchable wiring 20 positioned outside the stretchable substrate 10, rather than inside the stretchable substrate 10, from the adhesion of foreign matter.

[0065] For example, the surface layer of the stretchable wiring 20 disposed on the outer surface of the stretchable substrate may also be impregnated with the oil and fat material that constitutes the oil and fat barrier layer 30. This allows the oil and fat barrier layer 30 to be suitably held on the stretchable wiring, and also makes it possible to suitably protect the stretchable wiring 20 from foreign matter.

[0066] Third Embodiment Next, a stretchable device 1C according to a third embodiment will be described. The stretchable device 1C differs from the stretchable device 1 according to the first embodiment in that it includes a laminate 50 in which a plurality of stretchable substrates 10 are laminated.

[0067] 13, 14A, and 14B are schematic cross-sectional views of a stretchable device 1C according to the third embodiment. The stretchable substrates 10 may be stacked on top of each other in the thickness direction Y. More specifically, a multi-layer structure may be formed in which a plurality of stretchable substrates 10 are stacked with their main surfaces facing each other. In other words, a plurality of stretchable substrates 10 may be stacked in the thickness direction Y of the stretchable substrates to form a laminate 50. The number of stacked stretchable substrates 10 is not particularly limited.

[0068] In such a structure, the oil-and-fat barrier layer 30 may be positioned in the main surface region 50A of the stretchable substrate that constitutes the outer surface of the laminate 50. More specifically, the oil-and-fat barrier layer 30 may be positioned in the upper main surface region of the stretchable substrate 10 that is positioned in the uppermost layer of the laminate 50 and / or in the lower main surface region of the stretchable substrate that is positioned in the lowermost layer of the laminate 50. In other words, the oil-and-fat barrier layer 30 can be understood as being positioned in the main surface region 50A of the outer surface of the laminate 50. With such a structure, the main surface region 50A of the laminate 50 is protected by the oil-and-fat barrier layer 30, and therefore damage to the stretchable substrate 10 due to the adhesion of foreign matter can be suitably suppressed.

[0069] The oil-and-fat barrier layer 30 may be disposed in a side region of the stretchable substrate 10 that constitutes the outer surface of the laminate 50 (see FIGS. 14A and 14B ). The oil-and-fat barrier layer 30 may extend from the main surface region 50A of the stretchable substrate 10 located in the uppermost and / or lowermost position to a side region 50B that is continuous with the main surface region 50A. Preferably, the entire laminate 50 may be covered with the oil-and-fat barrier layer 30 that is continuously provided over the outer surface of the laminate 50. Such an oil-and-fat barrier layer 30 can also be considered to constitute the outermost layer of the stretchable device by continuously covering the outer surface of the laminate 50. According to the above-described structure, it is possible to suitably reduce the effects of adhesion of foreign matter over the entire stretchable device 1C that includes the laminate 50.

[0070] The oil-and-fat barrier layer 30 may include at least one of a first oil-and-fat layer (see FIG. 14A ) containing an oil-and-fat material impregnated into the interior of the surface of the stretchable substrate 10 that constitutes the outer surface of the laminate 50, and a second oil-and-fat layer (see FIG. 14B ) containing an oil-and-fat material present on the outer surface of the laminate 50. Preferably, the oil-and-fat barrier layer 30 covering the laminate 50 may include at least the first oil-and-fat layer. For example, the oil-and-fat material contained in the first oil-and-fat layer may penetrate into gaps between adjacent stretchable substrates 10 on the outer surface side of the laminate 50. This makes it possible to suitably prevent localized deterioration in the stretchability and / or mechanical strength of the stretchable substrate 10 due to the intrusion of foreign matter through gaps between the stacked stretchable substrates 10.

[0071] Although the embodiments of the present disclosure have been described above, they are merely typical examples. Those skilled in the art will readily understand that the present disclosure is not limited thereto, and that various modifications are possible within the scope of the present disclosure.

[0072] For example, the stretchable device may include a portion in the main surface region of the stretchable substrate 10 (or in the main surface region of the laminate, in the case where the stretchable device has a laminate structure) that does not have the oil-and-grease barrier layer 30. For example, the oil-and-grease barrier layer 30 may not be provided in a portion of the stretchable substrate 10 where the stretchability is locally reduced, such as a portion that overlaps with a member having lower stretchability than the stretchable substrate 10, such as an electronic component, when viewed from the thickness direction Y of the stretchable substrate. That is, the oil-and-grease barrier layer 30 may be positioned in the main surface region excluding a portion that overlaps with a member, such as an electronic component, provided on the stretchable substrate 10, when viewed from the thickness direction Y of the stretchable substrate. With this configuration, damage to the stretchable substrate 10 due to adhesion of foreign matter can be suitably suppressed in the stretchable substrate 10 around the electronic component.

[0073] The oil-and-grease barrier layer 30 can also function to slightly reduce the stretchability of the stretchable substrate 10. Therefore, for a stretchable device whose stretchability has been locally reduced due to the mounting of components, for example, by providing the oil-and-grease barrier layer 30 in an area excluding the low-stretchability area, the stretchability of the stretchable substrate 10 in the area where the oil-and-grease barrier layer 30 is provided can be slightly reduced. This reduces the difference in stretchability of the stretchable substrate 10 between the component-mounted area and the non-mounted area, thereby mitigating the local decrease in stretchability of the stretchable substrate 10 in the component-mounted area. In other words, by selecting the arrangement of the oil-and-grease barrier layer according to the difference in stretchability of the stretchable device, the overall stretchability of the stretchable device can be adjusted. This allows the stretchable device to have more uniform stretchability overall, and can suitably suppress the occurrence of breakage of the stretchable substrate 10 due to a local decrease in stretchability.

[0074] It should be noted that one embodiment of the present disclosure as described above includes the following preferred aspects. <1> A stretchable device comprising a stretchable substrate, wherein the stretchable substrate has a main surface region extending along a direction different from a thickness direction of the stretchable substrate, and an oil-and-fat barrier layer containing an oil-and-fat material is positioned on the main surface region. <2> The stretchable device according to <1>, wherein the oil-and-fat barrier layer extends along the main surface region. <3> The stretchable device according to <1> or <2>, wherein the oil-and-fat barrier layer comprises a first oil-and-fat barrier layer located on an inner side of the stretchable substrate, and the first oil-and-fat barrier layer contains an oil-and-fat material impregnated into the inside of the stretchable substrate. <4> The stretchable device according to <3>, wherein the thickness of the first oil-and-fat barrier layer is 1 μm or more and 100 μm or less in a cross-sectional view. <5> The stretchable device according to any one of <1> to <4>, wherein the oil-and-fat barrier layer comprises a second oil-and-fat barrier layer located on an outer surface of the stretchable substrate, and the second oil-and-fat barrier layer contains an oil or fat material located on the outer surface of the stretchable substrate. <6> The stretchable device according to <5>, wherein a thickness of the second oil-and-fat barrier layer is 1 μm or more and 100 μm or less in a cross-sectional view. <7> The stretchable device according to any one of <1> to <6>, further comprising stretchable wiring arranged on the stretchable substrate, and wherein the oil-and-fat barrier layer is located in at least the main surface region overlapping with the stretchable wiring when viewed in a thickness direction of the stretchable substrate. <8> The stretchable device according to any one of <1> to <7>, wherein the oil-and-fat barrier layer is located over the entire surface of the main surface region. <9> The stretchable device according to any one of <1> to <8>, wherein the stretchable substrate comprises two main surface regions facing each other and a side region located between the two main surface regions, and the oil-and-fat barrier layer extends from the main surface regions to the side regions. <10> The stretchable device according to any one of <1> to <9>, wherein the oil-and-fat barrier layer is continuous over the entire outer surface region of the stretchable substrate. <11> The stretchable device according to any one of <1> to <10>, wherein the stretchable substrate is surrounded by the oil-and-fat barrier layer.<12> The stretchable device according to any one of <1> to <11>, further comprising a stretchable wiring arranged on an outer surface of the stretchable substrate in the main surface region, wherein the oil-and-fat barrier layer integrally covers the main surface region and the stretchable wiring. <13> The stretchable device according to any one of <1> to <12>, comprising a laminate including a plurality of the stretchable substrates stacked on each other, wherein the oil-and-fat barrier layer is positioned in the main surface region of the stretchable substrate that constitutes the outer surface of the laminate, among the plurality of stretchable substrates. <14> The stretchable device according to <13>, wherein, among the plurality of stretchable substrates, the stretchable substrate that has a surface that constitutes the outer surface of the laminate comprises the oil-and-fat barrier layer that is continuous over the entire surface that constitutes the outer surface. <15> The stretchable device according to <13> or <14>, wherein the laminate is surrounded by the oil-and-fat barrier layer. <16> The stretchable device according to any one of <1> to <15>, wherein the oil / fat barrier layer contains at least one oil / fat material selected from the group consisting of vegetable oils, animal oils, mineral oils, and synthetic oils.

[0075] The above effects are merely exemplary, and the present disclosure is not limited to the above, and additional effects may also be achieved.

[0076] DESCRIPTION OF SYMBOLS 1: Stretchable device 10: Stretchable substrate 12A: Main surface region of stretchable substrate 12B: Side surface region of stretchable substrate 14: Corner portion 16: Ridge line portion 20: Stretchable wiring 30: Oil barrier layer 50: Laminate 50A: Main surface region of laminate 50B: Side surface region of laminate

Claims

1. A stretchable device comprising a stretchable substrate, the stretchable substrate having a major surface region extending along a direction different from a thickness direction of the stretchable substrate, and an oil-and-fat barrier layer comprising an oil-and-fat material being positioned on the major surface region.

2. The stretchable device of claim 1, wherein the grease barrier layer extends along the major surface region.

3. The stretchable device according to claim 1 or 2, wherein the oil-and-fat barrier layer comprises a first oil-and-fat barrier layer located on the inner side of the stretchable substrate, and the first oil-and-fat barrier layer comprises an oil material impregnated into the inside of the stretchable substrate.

4. The stretchable device according to claim 3, wherein the first oil barrier layer has a thickness of 1 μm or more and 100 μm or less in a cross-sectional view.

5. The stretchable device of any one of claims 1 to 4, wherein the grease barrier layer comprises a second grease barrier layer located on an outer surface of the stretchable substrate, the second grease barrier layer comprising an oleaginous material located on the outer surface of the stretchable substrate.

6. The stretchable device according to claim 5, wherein the second oil barrier layer has a thickness of 1 μm or more and 100 μm or less in a cross-sectional view.

7. The stretchable device according to any one of claims 1 to 6, further comprising a stretchable wiring disposed on the stretchable substrate, wherein the oil barrier layer is positioned at least in the main surface region overlapping with the stretchable wiring when viewed in the thickness direction of the stretchable substrate.

8. The stretchable device according to any one of claims 1 to 7, wherein the oil barrier layer is positioned over the entire surface of the main surface region.

9. The stretchable device according to any one of claims 1 to 8, wherein the stretchable substrate comprises two principal surface regions opposing each other and a side surface region located between the two principal surface regions, and the oil-and-fat barrier layer extends from the principal surface regions to the side surface regions.

10. The stretchable device of any one of claims 1 to 9, wherein the oil barrier layer is continuous across the entire outer surface area of ​​the stretchable substrate.

11. The stretchable device of any one of claims 1 to 10, wherein the stretchable substrate is surrounded by the oil barrier layer.

12. The stretchable device according to any one of claims 1 to 11, further comprising a stretchable wiring disposed on an outer surface of the stretchable substrate in the main surface region, and the oil barrier layer integrally covers the main surface region and the stretchable wiring.

13. The stretchable device according to any one of claims 1 to 12, comprising a laminate including a plurality of the stretchable substrates stacked on top of one another, wherein the oil barrier layer is positioned in the main surface region of the stretchable substrate that constitutes the outer surface of the laminate, among the plurality of the stretchable substrates.

14. The stretchable device according to claim 13, wherein the stretchable substrate having a surface constituting the outer surface of the laminate among the plurality of stretchable substrates has the oil barrier layer continuous over the entire surface constituting the outer surface.

15. The stretchable device of claim 13 or 14, wherein the laminate is surrounded by the oil barrier layer.

16. The stretchable device of any one of claims 1 to 15, wherein the oil barrier layer comprises at least one oil material selected from the group consisting of vegetable oils, animal oils, mineral oils, and synthetic oils.

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