Electronic devices that can be attached and detached from flat surfaces without adhesion

Abstract

To provide an electronic device that can be freely attached and detached to the smooth surfaces of various containers or housings made of plastic, glass, metals such as stainless steel, etc., and that, when attached, can detect environmental or physical information such as temperature, humidity, air pressure, vibration, or the brightness on the surface of an object or in its surroundings, and collect information as needed.SOLUTION: The present invention provides an electronic device that forms wiring on the back surface of a plastic film having a non-adhesive, detachable surface that can be attached to a smooth object, and having an electronic circuit with electronic components mounted on the wiring, and the non-adhesive, detachable surface is attached to the surface of an object such as a container or housing made of plastic, glass, metal, etc., to read environmental information or physical information, and obtain information by wireless communication. The electronic device attached to the surface of the object can be easily removed, and the function of attachment and detachment is not lost even when the device is repeatedly attached and removed.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an electronic device characterized in that wiring is formed on a plastic film having a surface that is non-adhesive and detachable from a smooth object, and the electronic device has an electronic circuit made of electronic components mounted on the wiring. [Background technology]

[0002] In recent years, the production value of the electronics and information industry has followed a growth trajectory similar to the growth rate of global GDP, with particularly remarkable growth in semiconductors, communication devices such as 5G, and solution services that are the result of advanced data utilization. Even under the new lifestyles forced upon us by the spread of COVID-19 in 2019, the electronics and information industry has grown year on year, proving that electronics plays a large role in solving problems during major social changes (Non-Patent Document 1).

[0003] 5G and other communication devices include smartphones, tablets, wearable devices, and personal computers, and are capable of collecting real-time information from anywhere in the world, as well as enabling autonomous driving of automobiles and remote control of robots. The performance of communication devices is supported by transistor miniaturization technology, and while the most advanced technology as of 2022 is the 3nm process, technological development for further miniaturization is ongoing.

[0004] On the other hand, in order to install sensors in various places around the world, as they are called "trillion sensors," to avoid disasters, prevent equipment failures, and protect human health, not only miniaturization of transistors is required, but also electronic devices such as sensors that can be easily and inexpensively attached to the surfaces of various objects and living bodies. It is expected that such electronic devices will contribute to the realization of a fifth-generation society (Society 5.0) in which sensor information is collected, accumulated through the Internet of Things (hereinafter referred to as IoT), which communicates information via wired or wireless connections, data analysis is performed, and added value is fed back.

[0005] When electronic devices such as the aforementioned sensors are manufactured using technologically mature printed circuit boards (hereafter referred to as PCBs), the board is a hard glass epoxy board, which lacks flexibility and the ability to be attached and removed, and the PCB cannot be attached to objects or living organisms as is. Because PCBs are not removable, there is no idea of ​​attaching them to objects to collect sensor information, and they are installed near the object or embedded inside it. Although it is possible to apply an adhesive or bonding layer to the PCB for attachment and detachment, when considering attaching them to objects with various surfaces, the resulting bulkiness would change the design of the object, and it would be unable to fit the surfaces of curved objects.

[0006] In addition to PCBs, electronic devices are being manufactured using flexible printed circuit boards (hereafter referred to as FPCs) made of brown polyimide. However, polyimide is also not detachable, so it cannot be directly attached to objects or living organisms as is. For this reason, an adhesive or bonding layer may be applied to the FPC for attachment and detachment, but polyimide is a highly rigid polymer material and cannot be flexibly adapted to the surface of a curved object. Furthermore, polyimide has a low light transmittance for visible light, which can cause a visual discomfort to humans.

[0007] Until now, electronic devices such as sensors have been manufactured using PCBs and FPCs, but their applications are limited due to their inability to be attached to the surfaces of objects or living bodies, their bulkiness, and their visual discomfort. In recent years, expectations are growing that printed electronics will contribute to solving these issues. Printed electronics is a technology in which wiring is drawn by coating or printing using metal particle ink, metal paste, conductive polymers, etc. on thin, bendable and stretchable paper or plastic substrates, and then heated and baked to form circuits. In addition, flexible hybrid electronics, which utilize the flexibility of paper and plastic while supplementing electronic functions by mounting resistors, capacitors, coils, diodes, semiconductor integrated circuit chips, and wireless communication modules on the circuits using solder, has attracted attention.

[0008] For example, there is an electronic device that is characterized by applying a molecular ink consisting of a metal such as silver or copper, a polymer binder, and an organic solvent to a flexible substrate by a method such as screen printing, inkjet printing, flexographic printing, gravure printing, offset printing, airbrushing, or aerosol printing, and then sintering it (Patent Document 1). It has been shown that this electronic device can be mounted with electronic components such as inductors, capacitors, and electronic filters.

[0009] In addition, a device has been disclosed as an electronic device that can be used in clothing-type wearable devices aimed at monitoring the health status of living organisms, in which flexible wiring is formed on a flexible substrate, the terminals of a semiconductor circuit chip are mounted on the wiring, and the semiconductor circuit chip and the flexible substrate are elastically fixed and supported in a spaced-apart state (Patent Document 2). This is an example of the flexible hybrid electronics mentioned above, and polyurethane or polyester is used for the flexible substrate.

[0010] In Patent Document 1, polyimide Kapton (trademark) or polyethylene terephthalate (hereinafter referred to as PET) is used for the substrate, but these substrates have a Young's modulus of 2 GPa or more and are hard, so their usage is essentially the same as that of electronic devices made with the above-mentioned FPC. In addition, Patent Document 2 shows that polyurethane can be used for flexible substrates, but general-purpose polyurethane cannot be used for applications that require elasticity to the extent that it can fit the skin shape of a living body. To address the need for electronic devices with high flexibility and elasticity, a wiring board using polyurethane as a substrate, which can be synthesized by reacting a long-chain polyol with a polyisocyanate and has a storage modulus of 20 to 200 MPa at 25°C, and a stretchable electronic device using the same board and equipped with a sensor for measuring physical quantities and a wireless communication device have been developed (Patent Document 3). When the wiring board and the stretchable electronic device using the same board are worn by a subject, they are soft, non-sticky, and comfortable to the touch.

[0011] However, the flexible substrate of the electronic device of Patent Document 1 is made of PET (e.g., Melinex™), polyolefin (e.g., Teslin™), polydimethylsiloxane, polystyrene, polycarbonate, polyimide (e.g., Kapton™), cellulose-based fabric, paper, etc., and is not only a hard substrate, but also does not have the ability to be attached and removed. In order to attach it to the surface of an object or a living body, a pressure-sensitive adhesive or glue must be applied to the substrate, which is not a preferred method considering the complexity of the application process and the tendency of the pressure-sensitive adhesive or glue component to remain on the object or living body when peeled off. Furthermore, it is known that metal ink or metal paste does not adhere well to the substrate, and it is necessary to promote the adhesion of the metal ink or metal paste by surface treatment, which lengthens the process of producing the electronic device and increases the manufacturing cost.

[0012] Furthermore, the electronic device in Patent Document 2 uses polyurethane or polyester for the flexible substrate, but has a semiconductor circuit chip spaced apart from the substrate and a distortion buffer structure configured to elastically fix and support the end of the semiconductor circuit chip, resulting in a thick electronic device that does not take full advantage of the thin film characteristics of the polyurethane or polyester substrate.

[0013] In response to the problems of the substrates of Patent Documents 1 and 2, such as the lack of flexibility to fit the surface of a living body, the substrate being unable to be stretched, and the problem of the fixation of metal ink or metal paste, Patent Document 3 discloses a wiring substrate formed on the surface of a film made of polyurethane having a storage modulus of 20 to 200 MPa at 25°C and a temperature of 155°C or higher at which the storage modulus becomes 1 MPa by dynamic viscoelasticity measurement, and a stretchable electronic device using the same, which realizes a significant improvement in flexibility. In addition, since the resistivity of this wiring substrate can be measured even when it is stretched, there is no problem with the fixation of circuits made of metal ink or metal paste to the substrate. However, although it has elasticity to fit the surfaces of various objects including curved surfaces due to its flexibility and stretchability, it has a low attachment and detachment function of being attached to and peeled off from the substrate, and thus has not yet been used as an electronic device such as a sensor that can be easily and inexpensively attached to the surfaces of the above-mentioned objects or living bodies. Furthermore, considering the practical life required for the electronic device, it is necessary to protect the wiring from damage caused by impact, moisture absorption, water absorption, and gas, but such a protection technology has not been established. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] WO2018 / 076110 [Patent Document 2] Patent No. 6781983 [Patent Document 3] WO2020 / 090634 [Non-patent literature]

[0015] [Non-Patent Document 1] Japan Electronics and Information Technology Industries Association, "World Production Outlook for the Electronics and Information Industry," December 2021 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention provides an electronic device comprising an electronic circuit in which wiring is formed on the back surface of a plastic film having a surface that can be attached and detached to a smooth object without adhesion, and electronic components are mounted on the wiring. The objective of the present invention is to provide a thin, flexible electronic device that can be attached and detached to smooth objects such as various containers and housings made of plastic, glass, stainless steel, and other metals without adhesion, and that can transmit physical information such as ID information stored in the electronic device, measured temperature, humidity, brightness, gas concentration, air pressure, impact, and stress, and can collect information on the state of the object and the environment in which it is placed. [Means for solving the problem]

[0017] The present invention is presented below. (1) An electronic device comprising a plastic film having a non-adhesive surface that can be attached and detached to a smooth object, a wiring formed on the back surface of the plastic film, and an electronic circuit having electronic components mounted on the wiring, (2) The electronic device according to (1), wherein the plastic film has a non-adhesive, detachable surface having a concave-convex structure with a width of 50 nm to 500 μm, a spacing of 50 nm to 500 μm, and a height of 50 nm to 500 μm; (3) The electronic device according to (1), wherein the plastic film is a plastic film having a non-adhesive and detachable surface containing a urethane bond; (4) The electronic device according to (3), wherein the hardness A (Asker) of the non-adhesive and detachable surface containing the urethane bond is 80A to 85A; (5) The electronic device according to (1), wherein the electronic circuit is covered with a protective film, (6) The electronic device according to any one of (1) to (5), characterized in that the plastic film having the non-adhesive and detachable surface is bonded to an electronic circuit formed on a plastic film, (7) The electronic device according to any one of (1) to (6), wherein the detachable surface is attached to an object. Effect of the Invention

[0018] According to the present invention, a plastic film electronic device can be attached and detached without adhesion to flat and smooth objects such as various containers and housings made of plastic, glass, metals such as stainless steel, etc., without applying any adhesive or bonding agent to the back side. This can be repeatedly attached and peeled off from such objects, and can collect ID information, physical information, and environmental information at any location, or can manage information by transmitting data itself. [Brief description of the drawings]

[0019] [Figure 1] This shows an example of a concave-convex structure in which a non-adhesive, removable surface is formed by curing a photocurable resin composition containing urethane acrylate on a plastic film support for an electronic device, and has an adhesive strength of 1 N / 25 mm (180° peel strength against silicone). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described.

[0021] The present invention is an electronic device having an electronic circuit in which wiring is formed on the back surface of a plastic film having a non-adhesive and detachable surface, and electronic components are mounted on the wiring. The non-adhesive and detachable surface is not a plastic film having a back surface coated with a pressure sensitive adhesive or adhesive, and does not firmly stick to a human or animal living body or object, but has a pressure sensitive adhesive strength of, for example, 5 N / cm 2By pressing with a stress of 5N / cm or more for about 1 second, the film can be attached to the surface of a smooth object having unevenness with a height of less than 1 μm, a width of 10 μm or more, and an interval between unevenness of 10 μm or more, such as various containers and housings made of polyolefins such as polyethylene and polypropylene, polyesters such as PET, polyvinyl chloride, etc., and the like, and can maintain its attached state for more than 1 hour without peeling off even after the pressing stress is removed. Furthermore, when an attempt is made to peel off the attached plastic film, a stress of 5N / cm or more is applied. 2 More than 25N / cm 2 This plastic film has a surface that can be easily peeled off with a force of 5 N / cm. This peeling stress can be measured with a tack tester. This plastic film can be peeled off easily even in temperature environments ranging from -20 to 40°C indoors and outdoors with a force of 5 N / cm. 2 More than 25N / cm 2 It adheres to the required degree of stress and can be easily peeled off by hand when no longer needed. In addition, the resin layer forming the non-adhesive and detachable surface is firmly fixed to the plastic film, and does not peel off due to the stress when peeling it off from the object to which it is attached, and has the characteristic that no adhesive residue of the resin layer remains or is transferred to the surface of the object or to the hand of the person.

[0022] The plastic film having a non-adhesive and detachable surface may be a plastic film consisting of only one resin layer having a non-adhesive and detachable surface, or a plastic film consisting of a structure in which a non-adhesive and detachable resin layer and a resin layer of a support of a non-detachable plastic film are laminated. In the laminated structure of two or more layers, each resin layer may be laminated with the same area, or may be laminated with different areas. Furthermore, a plastic film having a non-adhesive and detachable surface may be formed by a resin layer having an uneven structure as shown in FIG. 1. The thickness of the plastic film is not particularly limited, but in order to use it as an electronic device attached to the surface of an object and to easily peel it off by hand when it is no longer needed, it is preferably 1000 μm or less, more preferably 500 μm or less.

[0023] In the present invention, the non-adhesive and detachable surface can be attached to the surface of objects such as various containers and housings made of smooth plastic, glass, stainless steel, etc. The resin layer having a non-adhesive and detachable surface is not particularly limited, and a resin composition mainly made of natural rubber, a resin composition mainly made of acrylic polymer, a resin composition mainly made of methacrylic polymer, a resin composition mainly made of silicone rubber, a resin composition mainly made of polyurethane, etc. can be used. In particular, it is preferable to use a resin composition mainly made of an acrylic polymer having a urethane bond, a resin composition mainly made of a methacrylic polymer having a urethane bond, a resin composition mainly made of a thermoplastic polyurethane having a urethane bond, or a silicone resin composition having a siloxane bond.

[0024] The acrylic polymer having a urethane bond is obtained by radical polymerization of a composition containing a urethane acrylate, which is an oligomer having a urethane bond and an acrylic group. From the viewpoint of controlling the viscosity before polymerization and the adhesion and hardness after polymerization, this composition may contain a radical polymerizable monomer having an acrylic group that does not contain a urethane bond, and / or a radical polymerizable monomer having a methacrylic group, and / or an organic solvent or a polymer additive that is not involved in polymerization. The urethane acrylate may be an aliphatic urethane acrylate containing an aliphatic hydrocarbon in the main chain and / or an aromatic urethane acrylate containing an aromatic hydrocarbon in the main chain, and the number of functional groups of the acrylic group is not particularly limited, and a bifunctional, trifunctional, tetrafunctional, pentafunctional, hexafunctional or higher urethane acrylate may be used.

[0025] The methacrylic polymer having a urethane bond is obtained by radical polymerization of a composition containing a urethane methacrylate, which is an oligomer having a urethane bond and a methacrylic group. This composition may also contain a radical polymerizable monomer having an acrylic group that does not contain a urethane bond, and / or a radical polymerizable monomer having a methacrylic group, and / or an organic solvent or a polymer additive that is not involved in polymerization. The urethane methacrylate may be an aliphatic urethane methacrylate containing an aliphatic hydrocarbon in the main chain and / or an aromatic urethane methacrylate containing an aromatic hydrocarbon in the main chain, and the number of functional groups of the methacrylic group is not particularly limited, and a bifunctional, trifunctional, tetrafunctional, pentafunctional, hexafunctional or higher functional urethane methacrylate may be used. The acrylate methacrylate resin obtained by polymerizing a composition in which the urethane acrylate and urethane methacrylate are mixed may be used as a resin layer having a non-adhesive and removable surface.

[0026] The radical polymerization method of the acrylic polymer having a urethane bond or the methacrylic polymer having a urethane bond can be a method by heating, a method by light irradiation, a method by heating after light irradiation, etc. In the case of radical polymerization by heating, for example, heating at 80°C or higher is preferable, and it is carried out by using a thermal radical polymerization initiator such as an azo compound such as 2,2'-azobisbutyronitrile, or a peroxide such as benzoyl peroxide. In addition, the radical polymerization by light irradiation is not particularly limited as long as it can provide energy to generate radicals by light irradiation, and benzoin derivatives, 2,2-dimethoxy-2-phenylacetophenone, α-hydroxyacetophenone, α-aminoacetophenone, acylphosphine oxide derivatives, etc. can be used as the radical initiator. As the irradiation light source, a light beam with a wavelength of 400 nm or less, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp and a metal halide lamp, i-rays, G-rays, KrF excimer laser light, and ArF excimer laser light can be used.

[0027] The irradiation intensity is not particularly limited, but for example, the light irradiation intensity in the light wavelength region effective for activating the photopolymerization initiator described below (which varies depending on the photopolymerization initiator, but light of 300 to 420 nm is usually used) is 0.1 to 100 mW / cm 2 It is preferable that the irradiation intensity on the composition is 0.1 mW / cm 2 If it is less than 100mW / cm, the reaction time will be too long and 2 If the radiation amount exceeds this range, the heat radiated from the lamp and the heat generated during polymerization of the composition may cause a decrease in the cohesive strength of the resulting cured product, yellowing, or deterioration of the plastic film support.

[0028] The light irradiation time is not particularly limited, but the integrated light amount expressed as the product of the light irradiation intensity in the light wavelength region and the light irradiation time is usually 3 to 1000 mJ / cm 2 More preferably, it can be set to 5 to 500 mJ / cm. 2 and particularly preferably 10 to 300 mJ / cm2 The total amount of light incident on the composition is 3 mJ / cm 2 If the photopolymerization initiator is less than 1000 mJ / cm, the generation of active species from the photopolymerization initiator is insufficient, and the properties of the obtained cured product may be deteriorated. 2 If the temperature exceeds this range, it is disadvantageous for improving productivity. In some cases, it may be preferable to use heating in combination to promote the polymerization reaction. In addition, the temperature when the curable resin is cured by irradiating light is usually preferably 0 to 150°C, more preferably 0 to 60°C.

[0029] Furthermore, thermoplastic polyurethane can be used for the non-adhesive and removable surface. Thermoplastic polyurethane is synthesized by reacting polyol with polyisocyanate, and the polyol is preferably a polyester polyol whose main chain is made of polyester, a polycarbonate polyol whose main chain is made of polycarbonate, a polyether polyol whose main chain is made of polyether, or a mixture of a plurality of such polyols. The polyisocyanate is also not particularly limited, but preferably contains 1,4-bis(isocyanatomethyl)cyclohexane, which includes stereoisomers of cis-1,4-bis(isocyanatomethyl)cyclohexane and trans-1,4-bis(isocyanatomethyl)cyclohexane, and preferably contains 70% by mass or more, more preferably 95% by mass or more of trans-1,4-bis(isocyanatomethyl)cyclohexane. In order for the surface of this thermoplastic polyurethane to be non-adhesive and removable, the hardness A (Asker) is preferably 85A or less, more preferably 80A to 85A. It has become clear from the present invention that polyurethanes of 86A or higher do not provide the non-adhesive and removable functions.

[0030] The ability to attach and detach from an object is believed to be manifested by the resin layer forming a detachable surface deforming under stress like rubber, and weak interactions with the object surface such as hydrogen bonds and van der Waals forces. That is, it is believed that the resin layer is manifested when the temperature at which the resin layer is attached and detached exceeds its glass transition temperature, the storage modulus is in the rubber-like plateau region, for example, in the temperature range of 0.1 MPa to 50 MPa, and / or the hardness A (Asker) is in the above range. The storage modulus is measured by solid viscoelasticity measurement of the resin layer, which is a measurement in which a resin layer molded into a uniform film shape is pulled. On the other hand, the hardness A (Asker) is measured by applying a stress to the resin layer in a vertical direction and measuring the degree to which the resin layer sinks in the vertical direction. In the present invention, the resin layer is attached and detached by applying a stress that presses the resin layer in a vertical direction and a stress that peels it in a vertical direction, and therefore, it was found that the hardness A (Asker) has a stronger influence on the attachability and detachability than the storage modulus as a physical property of the resin layer. According to Patent Document 3, when a polyurethane film with a hardness of 80A is heated at 130°C for 30 minutes to form wiring, the film is significantly deformed and wiring is not possible. However, in the present invention, an electronic circuit is formed in advance on one side of a plastic film that does not have a detachable surface but can be used to form wiring, and a polyurethane film with a hardness of 80A to 85A is attached to the back side of the plastic film on which the electronic circuit is formed, for example, at 20 to 30°C, with an adhesive or the like, to form an electronic device that can be attached and detached to an object without adhesion. As a result, it has been invented that a polyurethane film with a hardness of 80A can be used as a non-adhesive and detachable surface.

[0031] The present invention is an electronic device that can be attached to a smooth object surface without any unevenness, although the non-adhesive and detachable surface may be used in a smooth state without any unevenness, and has a function of being attached to a smooth object surface by forming a concave-convex structure on the non-adhesive and detachable surface. The width, interval, and height of the convexities of the concave-convex structure of the detachable surface when viewed from the cross-sectional direction are preferably 10 nm to 1 mm, 10 nm to 1 mm, and 10 nm to 1 mm, more preferably 50 nm to 500 μm, 50 nm to 500 μm, and 50 nm to 500 μm. The aspect ratio of the width of the convexities to the depth of the concaves is usually 0.1 to 500, and preferably 0.5 to 20. The shape and method of forming the concave-convex structure that can be attached and detached without any adhesion between the electronic device and the smooth object surface are not particularly limited, but there is a method of forming a resin layer that becomes a concave-convex structure having softness that deforms under stress from a paste or ink of a thermosetting resin composition or a photocurable resin composition. The paste or ink can be applied to a resin layer of a plastic film support that does not have a concave-convex structure by a method such as inkjet printing, dispenser, screen printing, gravure printing, gravure offset printing, soft blanket gravure offset printing, flexographic printing, letterpress reverse printing, or the like, and then heat-cured and / or photo-cured to form a concave-convex structure. Further, a thermal nanoimprinting method can be used in which a paste made of a thermosetting resin composition is applied to the resin layer surface of a plastic film support, a heated mold having the uneven structure on its surface is pressed against the paste to harden the paste, and the paste is cooled and then released to transfer the uneven structure; a photo-nanoimprinting method can be used in which a paste made of a photocurable resin composition is applied to the resin layer surface of a plastic film support, a mold having the uneven structure on its surface is pressed to mold the paste, the paste is hardened by irradiation with visible ultraviolet light, and the mold is released to transfer the uneven structure; and a molding method can be used in which a film or sheet of a thermoplastic resin composition such as thermoplastic polyurethane is placed on the resin layer surface of a plastic film support, and a mold having the uneven structure on its surface that has been heated to a temperature equal to or higher than the glass transition temperature of the thermoplastic resin composition is pressed against the paste.The thermosetting resin composition and the photocurable resin composition preferably use a composition containing a urethane acrylate, which is an oligomer having a urethane bond and an acrylic group, and / or a composition containing a urethane methacrylate, which is an oligomer having a urethane bond and a methacrylic group.

[0032] The shape of these concave-convex structures is not particularly limited, but examples thereof include rectangular parallelepiped, cylindrical, prism, triangular pyramid, polyhedron, hemisphere, etc. The cross-sectional shapes of the convex and concave portions include quadrangle, triangle, semicircle, semiellipse, etc. Furthermore, the arrangement thereof may be either equally spaced or non-equidistant, continuous or non-continuous, and is not particularly limited.

[0033] The resin layer of the plastic film support is not particularly limited, and may be, for example, low-density polyethylene, high-density polyethylene, polypropylene, nylon 6, nylon 66, polyethylene terephthalate (hereinafter referred to as PET), polyethylene naphthalate (hereinafter referred to as PEN), polyurethane, polyvinyl chloride, polyacetal, polymethyl methacrylate, polycarbonate, polystyrene, polyvinyl fluoride, polyvinylidene fluoride, polyimide, polybutadiene, butyl rubber, polydimethylsiloxane, polyacrylonitrile, polyether ether ketone, polyphenylene sulfide, polyarylate, acrylic resin, epoxy resin, etc. However, from the viewpoint of firmly fixing the resin layer of the plastic film support and the resin layer having a non-adhesive and detachable surface and preventing transfer to a human hand or an object, it is preferable to select from nylon 6, nylon 66, PET, PEN, polyurethane, polymethyl methacrylate, polycarbonate, polyimide, and acrylic resin.

[0034] The present invention is an electronic device having an electronic circuit consisting of wiring and electronic components on the back surface of the plastic film having the non-adhesive and detachable surface. The non-adhesive and detachable surface having a concave-convex structure has concaves and convexes with a width of 50 nm to 500 μm, a spacing of 50 nm to 500 μm, and a height of 50 nm to 500 μm. If wiring is formed on the concaves and convexes, there is a risk of an increase in wiring resistance or disconnection, which impairs the detachable function of the present invention.

[0035] When forming an electronic circuit consisting of wiring and mounted electronic components on the back surface of a plastic film having a non-adhesive and detachable surface that can be attached to a smooth object, the electronic circuit may be formed directly on the back surface of the plastic film having the detachable surface, or a laminate structure may be formed by bonding a plastic film having a detachable surface to a non-detachable plastic film on which an electronic circuit has been formed.

[0036] This laminated structure will be described. First, an electronic circuit consisting of wiring and electronic components mounted on the wiring is formed on one side of a plastic film that is not detachable. After that, a plastic film having a non-adhesive and detachable surface is laminated on the side on which the electronic circuit is not formed by bonding the non-adhesive and detachable surface to the outside using a method of bonding the plastic film with the non-adhesive and detachable surface via an adhesive or a pressure sensitive adhesive, a method of bonding the plastic film with the non-adhesive and detachable surface by dry lamination, or a hot melt method in which the plastic film is softened or melted by heating and pressure bonded if it is thermoplastic. In Patent Document 3, wiring was attempted to be formed on a polyurethane film with a hardness A (Asker) of 80A, but it was deformed by heating at 130°C, and wiring could not be formed. However, by these lamination methods, a non-adhesive and detachable surface can be exposed to the outside using a polyurethane film with a hardness A (Asker) of 80A to 85A. Furthermore, as long as the non-adhesive, removable surface is exposed to the outside, the non-detachable plastic film and the plastic film having a non-adhesive, removable surface may each be a laminate structure of one layer, or each may be a laminate structure of two or more layers.

[0037] The method of forming wiring on a plastic film is not particularly limited, but may include a method of laminating a wiring pattern punched out of a metal foil with a punching blade or a die blade onto a plastic film, a method of printing or applying a wiring pattern with a conductive ink or conductive paste and forming conductive wiring by heating and baking at 100° C. or higher, or a method of forming a wiring pattern by vapor deposition or sputtering of a metal or metal oxide, connecting with jumper wires or forming cut wiring to form circuit wiring. Any of these methods may be selected, or they may be combined to form wiring.

[0038] Here, as the conductive ink and conductive paste used to prepare wiring by printing or coating, metal particle ink and metal paste are preferably used, and for example, metals such as gold, silver, copper, aluminum, nickel, palladium, indium, tin, platinum, and alloys of these metals, pyrolytic metal compounds such as silver oxide, organic silver, and organic gold that are pyrolyzed at relatively low temperatures to produce conductive metals, and metal oxide particles such as zinc oxide and indium tin oxide can be used. Among these, silver and copper are preferable in terms of versatility and price. Furthermore, by adding a polymer compound to such metals, metal particle ink and metal pastes that have improved adhesion to plastic films and durability against bending and stretching may be used. In addition, it is preferable that the metal particle ink and metal paste contain an organic solvent so that they can be printed or coated. The organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, butanol, ethers such as tetrahydrofuran, diethyl ether, dibutyl ether, dimethoxyethane, dioxane, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, aliphatic hydrocarbons such as pentane, hexane, heptane, alicyclic hydrocarbons such as cyclopentane, cyclohexane, dimethylcyclohexane, decalin, esters such as methyl acetate, ethyl acetate, etc. These may be used alone or in combination of two or more.

[0039] Examples of printing and coating methods for metal particle ink and metal paste include spin coating, spray coating, blade coating, dip coating, cast coating, roll coating, bar coating, die coating, inkjet printing, dispenser, screen printing, gravure printing, gravure offset printing, soft blanket gravure offset printing, flexographic printing, letterpress reverse printing, and the like, and these may be used in combination. The metal particle ink and / or metal paste after printing or coating is baked at a temperature of 100°C or higher. The baking method may be a heating method using a hot air oven, a purge oven under an inert gas atmosphere, a hot plate, or the like, or a method of heating for a short time using light baking.

[0040] Also, an insulating film may be formed on the wiring to ensure electrical insulation. The insulating film is also not particularly limited, but may be formed, for example, by a method of curing a paste or / and ink-like composition by heating or light irradiation, or by evaporating and removing a solvent from a polymer solution. As a method of curing by heating or light irradiation, it is preferable to use a paste or ink consisting of a thermosetting or / and photosetting acrylic monomer composition, methacrylic monomer composition, epoxy resin composition, polyester resin, and a curing agent such as a radical polymerization initiator or a cationic polymerization initiator. As a method of evaporating and removing a solvent from a polymer solution, it is preferable to use, for example, a fluororesin solution, and evaporate and remove an organic solvent to form an insulating film. As with the formation of wiring, the application or / and printing of the paste, ink, or polymer solution may be performed by spin coating, spray coating, blade coating, dip coating, cast coating, roll coating, bar coating, die coating, inkjet printing, dispenser, screen printing, gravure printing, gravure offset printing, soft blanket gravure offset printing, flexographic printing, letterpress reverse printing, etc., and these may be used in combination. Alternatively, an electronic device may have a multilayer wiring structure of two or more layers, in which holes are formed in a part of an insulating film, wiring is filled in the holes, and new wiring is formed on the insulating film.

[0041] In the present invention, electronic components are mounted using solder or conductive adhesive so as to be electrically connected to the wiring, and this is called an electronic circuit. The electronic components are passive elements such as resistors, capacitors, coils, and inductors, transistors, operational amplifiers (amplifiers), regulators, wireless radio wave transmitting and receiving elements such as NFC (Near Field Communication), UHF, Bluetooth Low Energy, and ZigBee, analog-digital converters, flip-flop circuits, DC-DC converters, microcontrollers, Schottky diodes, light-emitting diodes, and other elements made of semiconductors. Also, thermistor elements that exhibit a specific resistance value depending on temperature, photoresistor elements that exhibit a specific resistance value depending on illuminance, and sensor elements made of semiconductors. The semiconductors are often integrated circuits (hereinafter referred to as ICs) such as silicon, but semiconductor materials made of organic compounds may also be used.

[0042] It is preferable to use a surface mount type electronic component so that the electronic device does not become bulky. In the case of passive elements, there are elements with a long side of 2.0 mm and a short side of 1.2 mm, elements with a long side of 1.6 mm and a short side of 0.8 mm, elements with a long side of 1.0 mm and a short side of 0.5 mm, elements with a long side of 0.6 mm and a short side of 0.3 mm, etc., and it is preferable to use elements with a size as small as possible. This electronic component is mounted by electrically connecting it to the wiring. The mounting method is not particularly limited, but solder paste or conductive adhesive is applied to the wiring by screen printing, transferring using a metal mask, or using a dispenser, etc., and the electronic component is placed on the applied part and heated at 170°C or less for 10 minutes or less, so that the resistance value of the mounting part is 0.1Ω or less.

[0043] In this embodiment, in order to make the electronic device less bulky, it is preferable that the electronic circuit and the plastic film are not spaced apart, and it is preferable that the electronic circuit and the plastic film are in contact with each other.

[0044] In the present invention, it is preferable to fix and reinforce the mounting portion of the electronic component by solder or conductive adhesive with a curable resin composition. The solder or conductive adhesive at the mounting portion is often hard and brittle, and the reinforcement is intended to prevent the connection between the wiring and the electronic component from being broken due to the stress when attaching it to an object or peeling it off, causing the electronic device to not work. The curable resin composition is not particularly limited, but a moisture-curable resin composition, a photocurable resin composition, a thermosetting resin composition that is heated at a temperature above room temperature, and a two-stage curing resin composition that is thermosetting after photocuring are used. The curable resin composition includes a urethane resin system made from the reaction of a composition of an isocyanate monomer and a polyol, an acrylic resin system and a methacrylic resin system made from the radical polymerization of a composition of an acrylic monomer or a methacrylic monomer, an epoxy resin system made from the cationic polymerization or anionic polymerization of an epoxy monomer, and an epoxy resin system made from the cationic polymerization of an epoxy monomer and an oxetane monomer, and is composed of a liquid or paste-like composition containing an initiator or a curing agent that promotes such a reaction or polymerization, other polymer additives that are not involved in the reaction or polymerization, and an inorganic filler. The curable resin composition can be cured, for example, by contacting it with moisture in the air, by irradiating it with ultraviolet light having a wavelength of 400 nm or less from a metal halide lamp, high pressure mercury lamp, or LED lamp for 30 seconds or less, or by heating it at 40° C. or higher in a hot air oven or on a hot plate for 2 hours or less. In the case of a two-stage curing type resin composition that is photocured and then thermally cured, a method is used in which irradiation with ultraviolet light having a wavelength of 400 nm or less is performed, followed by heating in a hot air oven or on a hot plate.

[0045] In the present invention, it is preferable to provide an electronic device that can be operated for a long period of time, at least one month, by covering and protecting an electronic circuit with a protective film. By covering with a protective film, the electronic device is protected from external impacts and stresses, and water vapor, water, and other atmospheric gases are prevented from entering. As a result, it is possible to operate the electronic device for preferably one month or more, more preferably three months or more, and particularly preferably six months or more. For example, when the electronic device functions as a humidity or gas component sensor, holes are made in the protective film at the sensing location so that water vapor and gas components can be taken in. Conventional printed electronics and flexible hybrid electronics do not provide protection with practicality in mind, and can only be operated for a short period of time depending on the environmental conditions, which solves the problem that electronic devices could not be provided to users. The method of forming the protective film is not particularly limited, and includes a method of laminating a plastic in the form of a film to adhere it to a plastic film on which an electronic circuit is formed, a method of adhering or bonding the plastic film with a pressure sensitive adhesive or adhesive, a method of applying a varnish of a polymer dissolved in an organic solvent and drying it to make the remaining polymer into a protective film, a method of heating and curing ink or paste of a curable resin composition such as a urethane resin system made from the reaction of a composition of an isocyanate monomer and a polyol, an acrylic resin system and a methacrylic resin system made from the radical polymerization of a composition of an acrylic monomer or a methacrylic monomer, a cationic polymerization or anionic polymerization of an epoxy monomer, or an epoxy resin system made from the cationic polymerization of an epoxy monomer and an oxetane monomer, etc. In addition to protective films using organic polymer materials, there are also methods of attaching an electronic circuit to a glass or metal substrate or housing to cover it, and a method of applying a SiO 2 A method for forming inorganic films such as TiC, TiN, and Al by physical vapor deposition. 2 O 3 Alternatively, a method of forming an inorganic film such as a fluororesin film by chemical vapor deposition may be used. Note that the non-adhesive and detachable surface of the plastic film may be exposed to the outside so as not to hinder attachment to an object.

[0046] When a plastic is used for the protective film of the present invention, the material is not particularly limited, and examples thereof include low density polyethylene, high density polyethylene, polypropylene, polyvinyl chloride, ethylene-vinyl alcohol copolymer, acrylonitrile copolymer, nylon, PET, PEN, polyurethane, polyacetal, polycarbonate, polystyrene, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyimide, polybutadiene, butyl rubber, polydimethylsiloxane, fluororesin, and the like.

[0047] The thickness of the protective film is preferably 5 to 1000 μm, more preferably 10 to 100 μm, and particularly preferably 20 to 80 μm. If the protective film has a thickness exceeding 1000 μm, the rigidity of the electronic device increases and the flexibility decreases, making it difficult to attach to an object or peel off from the object.

[0048] The protective film is formed on at least the surface on which the electronic circuit is formed, but may be formed on both sides of the plastic film on which the electronic circuit is formed. The surface of the protective film exposed to the outside may be a non-adhesive and detachable surface, or may be a non-detachable surface. However, when covering with a non-detachable protective film, a laminate structure can be formed by bonding a plastic film having a non-adhesive and detachable surface and a protective film with an adhesive or pressure-sensitive adhesive, by bonding them together by dry lamination, or by a hot-melt method in which the plastic film having a non-adhesive and detachable surface is softened or melted by heating and pressure-bonded if it is thermoplastic. EXAMPLES

[0049] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0050] [Example 1] A smooth 80μm thick polyurethane film (product name FORTIMO) with a hardness of 85A (Asker) and a non-adhesive, removable surface. TM (Mitsui Chemicals, Inc.) on the back side of the silver paste (product name Dotite TM A solder paste (XA-9521, Fujikura Kasei Co., Ltd.) was screen-printed on the wiring and baked in a hot air oven at 100°C for 60 minutes to form wiring. Solder was transferred to the mounting locations of the wiring where electronic components were to be mounted using a metal mask, and electronic components such as the NFC IC NT3H1101 (NXP Semiconductors), the microcontroller LPC824M201JHI33E (NXP Semiconductors), the op-amp LT6004 (ANALOG DEVICES), thermistor NTCG163JX103DTDS (TDK), resistors, capacitors, and light-emitting diodes were placed, and the wiring was baked at 160°C for 1 minute to mount the electronic components on the wiring. Furthermore, a curable resin composition (trade name WORLD ROCK X-CBP01, manufactured by Kyoritsu Chemical Industries Co., Ltd.) that is UV cured and then heat cured is applied around the mounting area, and the composition is irradiated with 2500 mJ / cm 2 from a metal halide lamp in a nitrogen glove box. 2 The soldered portion was reinforced with a hardening resin by irradiating the device with light and heating it at 100°C for 10 minutes. In this way, an NFC-type temperature sensor device was created that showed a resistance value according to temperature, and it was confirmed that the temperature of the environment in which the device was placed was displayed on a smartphone. The adhesive-free, detachable polyurethane surface on the back side of the electronic circuit of this temperature sensor device was attached by hand to the curved surface of a smooth stainless steel container, and when it was stored indoors at a temperature of 23°C and a humidity of 50%, it operated for three weeks. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no adhesive substance remained on the container. The device was attached to the surface of the container and peeled off 10 times, but the attachment and detachment did not decrease.

[0051] [Example 2] The same polyurethane film as in Example 1 was applied to the back side of the film with silver paste (product name: Dotite). TMXA-9521, manufactured by Fujikura Kasei Co., Ltd.) was screen-printed and baked in a hot air oven at 100°C for 60 minutes to form wiring. TM XB-3212, Fujikura Kasei Co., Ltd.) was screen-printed to cover a part of the wiring, and baked in a hot air oven at 130 ° C for 30 minutes to form an insulating film. Furthermore, the same silver paste as above was screen-printed on the insulating film so as to connect to the wiring through the pores of the insulating film, and baked in a hot air oven at 100 ° C for 60 minutes to form a wiring. Solder was transferred to the mounting location of the electronic components of this wiring using a metal mask, and electronic components such as an IC, a microcontroller, an operational amplifier, a thermistor, a resistor, a capacitor, and a light-emitting diode that communicate with NFC as in Example 1 were placed, and baked at 160 ° C for 1 minute to mount the electronic components on the wiring, and the surroundings of this mounting location were reinforced with the same curable resin as in Example 1. In this way, an NFC communication type temperature sensor device that shows a resistance value according to temperature was formed, and it was confirmed that the temperature of the environment in which the device was placed was displayed on a smartphone. The adhesive-free, detachable polyurethane surface on the back side of the electronic circuit of this temperature sensor device was attached by hand to the curved surface of a smooth stainless steel container, and when stored indoors at a temperature of 23°C and humidity of 50%, it operated for three weeks. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no adhesive substance remained on the container. The device's detachability did not decrease even after it was attached and peeled off ten times on the surface of the container.

[0052] [Example 3] A protective film was formed by laminating a 60 μm thick polypropylene film on the surface of the temperature sensor device of Example 1 on which the electronic circuit was formed. The non-adhesive and detachable surface of this temperature sensor device, which is the opposite of the protective film, was attached by hand to the curved surface of a smooth stainless steel container, and when it was stored indoors at a temperature of 23° C. and a humidity of 50%, it operated for 10 months. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no sticky substance remained on the container. The attachability and detachability did not decrease even when it was attached and peeled off 10 times on the surface of the container.

[0053] [Example 4] A glass substrate with a thickness of 1 mm was attached with an adhesive to the surface of the temperature sensor device of Example 1 on which the electronic circuit was formed. The non-adhesive and detachable surface of this temperature sensor device, which is the opposite of the protective film, was attached by hand to a smooth window glass, and when it was stored indoors at a temperature of 23°C and a humidity of 50%, it operated for 10 months. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the window glass, and no sticky substance remained on the container. The attachability and detachability did not decrease even when it was attached and peeled off 10 times to the surface of the container.

[0054] [Comparative Example 1] A smooth 80μm thick polyurethane film (product name FORTIMO) with a hardness of 90A (Asker) and no adhesive or removable surface. TM An NFC-type temperature sensor device was produced in the same manner as in Example 1, except that a polyurethane surface (manufactured by Mitsui Chemicals, Inc.) was used. The temperature of the environment in which the device was placed was displayed on a smartphone, but it was not possible to attach the device by hand to the smooth curved surface of a stainless steel container using this polyurethane surface.

[0055] [Example 5] A PET film with a smooth surface and a thickness of 70 μm (product name: Lumirror) TM A resin layer of a plastic film support (Toray Industries, Inc.) was used, and a paste of a photocurable resin composition containing a urethane acrylate and a radical polymerizable monomer having an acrylic group was applied to one side of the support using a blade coater, and a mold with cylindrical protrusions of 30 μm in diameter and 20 μm in height formed at intervals of 40 μm was pressed against the photocurable composition. 2The photocurable resin composition was cured by irradiating the photocurable resin composition with a metal halide lamp, and the mold was released to produce a plastic film having a non-adhesive and detachable surface on one side of which cylindrical protrusions having a diameter of 30 μm (i.e., a width of 30 μm) and a height of 20 μm were formed at intervals of 40 μm. An electronic circuit was formed on the PET side opposite the non-adhesive and detachable surface of this plastic film in the same manner as in Example 1 to produce an NFC communication type temperature sensor device, and it was confirmed that the temperature of the environment in which the device was placed was displayed on a smartphone. The non-adhesive and detachable surface opposite the electronic circuit of this temperature sensor device was attached by hand to the curved surface of a smooth stainless steel container, and when it was stored indoors at a temperature of 23°C and a humidity of 50%, it operated for 3 weeks. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no adhesive substance remained on the container. The device was attached to the surface of the container 10 times and peeled off, but the attachability did not decrease.

[0056] [Comparative Example 2] When a temperature sensor device was produced in the same manner as in Example 5 using a PET plastic film that had a non-adhesive, removable surface, it was not possible to attach it by hand to the smooth curved surface of a stainless steel container.

[0057] [Example 6] The PET film of Example 5 was applied to a smooth 75 μm-thick PEN (Teonex TM A temperature sensor device was produced in the same manner as in Example 5, except that a film of 10000g / cm2 (manufactured by Toyobo Co., Ltd.) was used as the resin layer of the support of the plastic film. The non-adhesive and detachable surface of the temperature sensor device, opposite to the electronic circuit, was attached by hand to the curved surface of a smooth stainless steel container, and when stored indoors at a temperature of 23°C and a humidity of 50%, it operated for 3 weeks. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no sticky substance remained on the container. The device's detachability did not decrease even when it was attached to and peeled off the surface of the container 10 times.

[0058] [Comparative Example 3] When a temperature sensor device was produced in the same manner as in Example 6 using the PEN film that had no adhesive or removable surface, it was not possible to attach it by hand to the smooth curved surface of a stainless steel container.

[0059] [Example 7] The PET plastic film of Example 5 was then coated with a smooth 75 μm-thick polyimide film (trade name: Kapton TM A temperature sensor device was produced in the same manner as in Example 5, except that a film of 10000g / cm2 (manufactured by DuPont-Toray Co., Ltd.) was used as the resin layer of the support of the plastic film. The non-adhesive and detachable surface of the temperature sensor device, opposite to the electronic circuit, was attached by hand to the curved surface of a smooth stainless steel container, and when stored indoors at a temperature of 23°C and a humidity of 50%, it operated for 3 weeks. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no sticky substance remained on the container. The device's detachability did not decrease even when it was attached to and peeled off the surface of the container 10 times.

[0060] [Example 8] A smooth surface 75μm thick PEN (Teonex) TM A plastic film (manufactured by Toyobo Co., Ltd.) was used as the resin layer of the plastic film support, and on one side of the film was a polyurethane plastic film (trade name Fortimo) with a hardness of 80A (Asker) and a thickness of 50 μm. TMA mold with a diameter of 30 μm and a height of 20 μm, heated to 80° C., was pressed against the polyurethane film. These films were cooled to room temperature to produce a plastic film on one side of the PEN film, on which a non-adhesive and detachable polyurethane surface was formed with cylindrical protrusions of 30 μm in diameter (i.e., 30 μm in width) and 20 μm in height at 10 μm intervals. An electronic circuit was formed on the PEN surface opposite to the non-adhesive and detachable surface of this plastic film in the same manner as in Example 5 to produce an NFC communication type temperature sensor device, and it was confirmed that the temperature of the environment in which the device was placed was displayed on a smartphone. The non-adhesive and detachable surface of this temperature sensor device opposite to the electronic circuit was attached by hand to the curved surface of a smooth PET container, and the device was stored indoors at a temperature of 23° C. and a humidity of 50%, and it operated for 3 weeks. Furthermore, the temperature sensor device could be peeled off by hand from the surface of the PET container without leaving any sticky substance on the container. The device's removability did not decrease even after it was attached and peeled off ten times.

[0061] [Example 9] Wiring and an insulating film were formed in the same manner as in Example 2. Solder was transferred to the mounting portion of the wiring where the electronic components were to be mounted using a metal mask, and electronic components such as an NFC IC NT3H1101 (manufactured by NXP Semiconductors), a microcontroller LPC824M201JHI33E (manufactured by NXP Semiconductors), a temperature and humidity sensor IC SHT40-AD1B (manufactured by Sensirion), an air pressure sensor IC BMP390 (manufactured by Bosch Sensortec), resistors, capacitors, and light-emitting diodes were placed, and the electronic components were mounted on the wiring by baking at 160°C for 1 minute, and the periphery of the mounting portion was reinforced with the same curable resin as in Example 1. A protective film was formed by laminating a 60 μm thick polypropylene film on the top of the electronic circuit consisting of the wiring and electronic components, and the electronic components were covered and protected. In order to measure humidity and air pressure, holes were made in the protective film on the top of the electronic components of the SHT40-AD1B and the BMP390. In this way, an NFC-type sensor device was created that simultaneously measured temperature, humidity, and air pressure, and it was confirmed that the temperature, humidity, and air pressure of the environment in which the sensor device was placed were displayed by wireless communication with a smartphone. This sensor device was attached by hand to the surface of a window glass so that the non-adhesive, removable surface, opposite to the electronic circuit, was in contact with the surface, and it was kept in an indoor environment with varying temperatures of -10 to 30°C and humidity of 30 to 80%, including summer and winter, and it continued to function for 10 months. Furthermore, this electronic device could be peeled off by hand from the surface of the window glass, and no sticky substances were left behind in the container. The device's removability did not decrease even when it was attached and peeled off the surface of the window glass 10 times.

[0062] [Example 10] The same procedure was followed as in Example 3, except that the protective film of the polypropylene film in Example 3 was replaced with a 60 μm thick polyethylene T5010A (manufactured by Mitsui Chemicals Tohcello Co., Ltd.). The non-adhesive and detachable surface of this temperature sensor device, which is the opposite of the protective film, was attached by hand to the curved surface of a smooth stainless steel container, and when stored indoors at a temperature of 23°C and a humidity of 50%, it operated for 10 months. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no sticky substance remained on the container. The device did not lose its detachability even when attached and peeled off 10 times to the surface of the container.

[0063] [Example 11] The same procedure was followed as in Example 3, except that the protective film of the polypropylene film in Example 3 was replaced with a 60 μm thick polyvinyl chloride masking tape N-380R (manufactured by Nitto Denko Corporation). The non-adhesive and detachable surface of this temperature sensor device, which is the opposite of the protective film, was attached by hand to the curved surface of a smooth stainless steel container, and when it was stored indoors at a temperature of 23° C. and a humidity of 50%, it operated for 10 months. Furthermore, this temperature sensor device could be peeled off by hand from the surface of the stainless steel container, and no sticky substance remained on the container. The device did not lose its detachability even when it was attached and peeled off 10 times to the surface of the container. [Industrial Applicability]

[0064] The electronic device of the present invention is characterized by forming wiring on the back surface of a plastic film having a non-adhesive and detachable surface, and having an electronic circuit consisting of electronic components mounted on the wiring. It is a device that can be easily attached to the surface of a plastic container, a plastic housing, glass, or a metal object like a sticker, and peeled off. Information such as temperature, humidity, air pressure, vibration, and brightness of the object to which it is attached and its surroundings can be collected and used appropriately. The information can be transmitted and collected by wireless communication, and analysis data can be fed back to life and industry, which can be useful for safety, security, and health in life, as well as for the utilization of information in industry. By covering the electronic circuit of this electronic device with a protective film, it is waterproofed and protected from external stimuli and humidity and rainwater exposed during outdoor use, and the electronic device can be operated for more than one month. This electronic device can be used for welfare and medical applications, wearable device applications, RFID applications, smartphones, tablet terminals, computers, displays, etc., as sensors or control parts for medical applications, nursing beds, crime prevention, childcare, self-driving automobiles, pet robots, drones, etc., and as electronic parts for organic electroluminescence (EL) displays, liquid crystal displays, lighting, automobiles, robots, electronic glasses, music players, etc.

Claims

1. An electronic device comprising: wiring formed on the rear surface of a plastic film having a non-adhesive surface that can be attached and detached to a smooth object; and an electronic circuit having electronic components mounted on the wiring.

2. The electronic device according to claim 1, characterized in that the plastic film has a non-adhesive, detachable surface having a concave-convex structure with a width of 50 nm to 500 μm, a spacing of 50 nm to 500 μm, and a height of 50 nm to 500 μm.

3. 2. The electronic device according to claim 1, wherein the plastic film is a plastic film having a non-adhesive and removable surface containing urethane bonds.

4. 4. The electronic device according to claim 3, wherein the non-adhesive and removable surface containing urethane bonds has a hardness A (Asker) of 80A to 85A.

5. 2. The electronic device of claim 1, wherein said electronic circuitry is covered with a protective film.

6. 6. The electronic device according to claim 1, wherein the plastic film having a non-adhesive and detachable surface is attached to an electronic circuit formed on a plastic film.

7. The electronic device of any one of claims 1 to 6, wherein the detachable surface is attached to an object.

Images