Manufacturing method of joint, joint, and equipment unit

Abstract

To provide a manufacturing method for jointed body, jointed body, and equipment unit with a superior appearance due to short bonding process time and reduced protrusion of the bonded part.SOLUTION: In the manufacturing method of the bonded body, the electromagnetic wave transmitting base material and the retaining member are dissimilar materials, and the electromagnetic wave transmitting base material, the thermoplastic film, and the retaining member are stacked in this order. The thermoplastic film is then melted by laser irradiation from the side opposite to the side where the thermoplastic film is placed on the electromagnetic wave transmissive base material, and the electromagnetic wave transmitting base material and the retaining member are joined using the thermoplastic film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a bonded body, a bonded body, and a device unit.

Background Art

[0002] In recent years, bonded bodies obtained by bonding different materials have been widely used in various fields such as automotive parts, medical devices, and household appliances. For example, Patent Document 1 discloses a bonded body in which a frame-shaped housing made of a metal plate and a glass plate of a surface panel are bonded with an adhesive.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when bonding different materials by applying a liquid adhesive, it takes time for bonding, and the pot life (usable time) tends to be long. Further, when the members are pressure-bonded via a liquid adhesive, the adhesive easily oozes out from the members, and the appearance is impaired.

[0005] Therefore, an object of the present disclosure is to provide a method for manufacturing a bonded body, a bonded body, and a device unit, which have a short bonding process time, suppress the protrusion of the bonding site, and are excellent in appearance.

Means for Solving the Problems

[0006] The present disclosure includes the following embodiments. <1> The electromagnetic wave transmissive substrate and the holding member are different materials, and the electromagnetic wave transmissive substrate, the thermoplastic film, and the holding member are stacked in this order. A method for manufacturing a bonded body, which comprises irradiating a laser from the side opposite to the side on which the thermoplastic film of the electromagnetic wave transmitting substrate is disposed to melt the thermoplastic film, and bonding the electromagnetic wave transmitting substrate and the holding member with the thermoplastic film. <2> The method for manufacturing a bonded body according to <1>, wherein an absorption member having a laser absorption rate of 90% or more is disposed between the electromagnetic wave transmitting substrate and the thermoplastic film, and the laser is irradiated from the opposite side. <3> The method for manufacturing a bonded body according to <1> or <2>, wherein the laser has at least a part of wavelengths in the range of 900 nm to 1200 nm. <4> The method for manufacturing a bonded body according to any one of <1> to <3>, wherein the transmittance of the laser through the electromagnetic wave transmitting substrate is 30% or more. <5> The electromagnetic wave transmitting substrate and the holding member are made of different materials, and the electromagnetic wave transmitting substrate, a thermoplastic resin layer, and the holding member are provided in this order. The holding member contains a thermoplastic resin as a main component. A bonded body, wherein the difference between the melting point of the thermoplastic resin layer and the melting point of the holding member is within 10 °C. <6> The bonded body according to <5>, wherein an absorption member having a laser absorption rate of 90% or more for at least a part of wavelengths in the range of 900 nm to 1200 nm is disposed between the electromagnetic wave transmitting substrate and the thermoplastic resin layer. <7> The electromagnetic wave transmitting substrate and the holding member are made of different materials, and the electromagnetic wave transmitting substrate, a thermoplastic resin layer, and the holding member are provided in this order. The holding member contains a thermoplastic resin as a main component. The holding member has an extending portion extending along the end face of the electromagnetic wave transmitting substrate. A bonded body, wherein the distance between the extending portion and the end face is within 5 mm. <8> The bonded body according to <7>, wherein an absorption member having a laser absorption rate of 90% or more for at least a part of wavelengths in the range of 900 nm to 1200 nm is disposed between the electromagnetic wave transmitting substrate and the thermoplastic resin layer. <9> The bonded body according to any one of <5> to <8>, and A device unit having a device that transmits and receives electromagnetic waves, disposed inside the holding member.

Effects of the Invention

[0007] According to the present disclosure, it is possible to provide a method for manufacturing a bonded body, a bonded body, and a device unit, which have a short bonding process time, suppress the protrusion of the bonding site, and are excellent in appearance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values and their ranges, which do not limit the present invention. In the numerical range indicated by "~" in the present disclosure, the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical range described step by step in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. In the present disclosure, each component may include a plurality of corresponding substances. When there are a plurality of substances corresponding to each component in the composition, the content of each component means the total content of the plurality of substances present in the composition, unless otherwise specified.

[0010] <Method for Manufacturing a Bonded Body> The method for manufacturing the bonded body of the present disclosure is such that the electromagnetic wave-transmissive substrate and the holding member are made of different materials. The electromagnetic wave-transmissive substrate, the thermoplastic film, and the holding member are stacked in this order, and a laser is irradiated from the side opposite to the side where the thermoplastic film is disposed on the electromagnetic wave-transmissive substrate to melt the thermoplastic film, and the electromagnetic wave-transmissive substrate and the holding member are bonded by the thermoplastic film. In the present disclosure, "different materials" means that they are not the same kind of materials such as resins, glasses, metals, ceramics, etc.

[0011] According to the manufacturing method having the above configuration, the bonding process time is short, the protrusion at the bonding site is suppressed, and a bonded body with excellent appearance can be obtained. The reason is speculated as follows.

[0012] By using the thermoplastic film, compared with applying a liquid adhesive, the handling is not complicated, the protrusion at the bonding site is suppressed, and a bonded body with excellent appearance can be obtained.

[0013] In addition, since the thermoplastic resin hardens and does not bond when it cools, after heating the thermoplastic film, it is brought into contact with the adherend without delay. Therefore, when using a general heating device, the heating device is installed beside the disposed thermoplastic film, and after the heating of the thermoplastic film is completed, the heating device is moved to another position and then the adherend is brought into contact with the thermoplastic film. When using a heating device in this way, it takes time to move the heating device, and depending on the shape of the adherend, the heating device may not be able to be arranged. On the other hand, in the manufacturing method of the present disclosure in which a laser is irradiated to melt the thermoplastic film, the moving time of the heating device can be omitted. Furthermore, in the manufacturing method of the present disclosure, there are few restrictions on the shape of the adherend, and it can be bonded to adherends of various shapes. Regarding the time required to melt the thermoplastic film, the laser irradiation time is shorter than the heating time by a general heating device. Hereinafter, the method for manufacturing the bonded body of the present disclosure will be described step by step.

[0014] 〔Preparation〕 First, stack an electromagnetic wave-transmitting substrate, a thermoplastic film, and a holding member in this order. An absorbing member having a laser absorption rate of 90% or more may be disposed between the electromagnetic wave-transmitting substrate and the thermoplastic film.

[0015] (Electromagnetic wave-transmitting substrate) The electromagnetic wave-transmitting substrate in the bonded body of the present disclosure has electromagnetic wave permeability. Examples of the electromagnetic wave include millimeter wave, infrared ray, microwave, radio wave, etc. The electromagnetic wave-transmitting substrate may transmit any one of these electromagnetic waves.

[0016] The electromagnetic wave-transmitting substrate preferably has a transmittance of 30% or more, more preferably 50% or more, still more preferably 70% or more, and the higher the better, for the laser used.

[0017] The electromagnetic wave-transmitting substrate may be a transparent substrate. The transparent substrate refers to a substrate having a transmittance of 30% or more at at least a part of the wavelengths in the range of 360 nm to 830 nm, which is visible light. In the manufacturing method of the bonded body of the present disclosure, since the protrusion of the bonded portion is suppressed, even if such a transparent substrate is used, the appearance is excellent.

[0018] Examples of the material of the electromagnetic wave-transmitting substrate include resin, glass, colorless mineral, etc. The resin used for the electromagnetic wave-transmitting substrate may be either thermoplastic or thermosetting. When a thermoplastic resin is used, the melting point of the thermoplastic resin is preferably 10°C or higher, more preferably 30°C or higher, still more preferably 50°C or higher, than the melting point of the thermoplastic film. The type of glass is not particularly limited, and glasses of various compositions can be used. In addition to general glass, heat-resistant glass, fireproof glass, refractory glass, chemically strengthened glass used for protecting smartphones, etc. may also be used. Specifically, soda-lime glass, lead glass, borosilicate glass, quartz glass, etc. can be mentioned. From the viewpoints of transparency and strength, the electromagnetic wave-transmitting substrate is preferably glass.

[0019] The thickness of the electromagnetic wave-transmitting substrate can be appropriately set according to the material, application, etc. For example, from the perspective of strength, the thickness of the electromagnetic wave-transmitting substrate may be 5 mm or more. Also, from the perspective of weight reduction, the thickness of the electromagnetic wave-transmitting substrate may be 3 mm or less.

[0020] (Thermoplastic film) The thermoplastic film preferably contains 50% by mass or more of a resin component, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0021] The thermoplastic film is mainly composed of a thermoplastic resin. In the present disclosure, the "main component" in the thermoplastic film means the component with the highest content among the resin components in the thermoplastic film.

[0022] The thermoplastic film preferably contains an amorphous thermoplastic resin as the main component. The main component resin refers to the resin contained in the largest amount among the constituent resins. The amorphous thermoplastic resin refers to a resin that does not have crystals or has only a small amount of crystals and has a heat of fusion of 15 J / g or less. The heat of fusion is calculated from the area of the endothermic peak of DSC (differential scanning calorimeter) and the weight of the thermoplastic resin component. When an inorganic filler or the like is contained in the film, it is calculated from the weight of the thermoplastic resin component excluding the inorganic filler. Specifically, 2 to 10 mg of the sample is weighed, placed in an aluminum pan, and heated from 23°C to 200°C or more at 10°C / min using DSC (for example, DSC8231 manufactured by Rigaku Corporation) to obtain a DSC curve, and then it can be calculated from the area of the endothermic peak at the time of melting obtained from the DSC curve and the above weighing value.

[0023] Also, from the perspectives of airtightness and toughness, the amorphous thermoplastic resin is preferably at least one of a thermoplastic epoxy resin and a phenoxy resin. Among them, from the viewpoints of airtightness and toughness, it is more preferable that the thermoplastic film contains, as a main component, an amorphous thermoplastic resin which is at least one of a thermoplastic epoxy resin and a phenoxy resin. Further, from the viewpoints of airtightness and toughness, it is more preferable that the thermoplastic film contains, as a main component, an amorphous thermoplastic resin which is at least one of a thermoplastic epoxy resin and a phenoxy resin, has an epoxy equivalent of 1,600 or more, and has a heat of fusion of 15 J / g or less.

[0024] Since the thermoplastic epoxy resin and the phenoxy resin have low cohesive force in the resin and may have hydroxyl groups, they have a strong interaction with the electromagnetic wave transmitting substrate and the holding member, and it is expected that different materials can be joined with a higher bonding strength than conventional crystalline hot melt adhesives.

[0025] Among them, from the viewpoint of storage stability, it is preferable that the thermoplastic film has an epoxy equivalent of 1,600 g / eq or more, or is a thermoplastic resin not containing an epoxy group. When the thermoplastic film has an epoxy group, the epoxy equivalent is more preferably 2,000 g / eq or more, further preferably 5,000 g / eq or more, particularly preferably 9,000 g / eq or more, and most preferably not substantially detected above the detection limit. The epoxy equivalent being above the detection limit means that no epoxy group is detected when the epoxy equivalent is measured based on JIS K 7236:2001 described later.

[0026] The epoxy equivalent (the weight of the thermoplastic resin containing 1 mol of epoxy group) is the value of the epoxy equivalent of the thermoplastic resin contained in the thermoplastic film before bonding, and is the value measured by the method defined in JIS-K7236:2001 (unit "g / eq."). Specifically, using a potentiometric titration apparatus, a brominated tetraethylammonium acetate solution was added, and a 0.1 mol / L perchloric acid - acetic acid solution was used. For the solvent-diluted product (resin varnish), the value is calculated as the solid content converted value from the non-volatile content. In the case of a mixture of two or more resins, it can also be calculated from the respective contents and epoxy equivalent.

[0027] The thermoplastic epoxy resin and phenoxy resin preferably have a weight average molecular weight in terms of polystyrene conversion by GPC (gel permeation chromatography) measurement of 10,000 to 500,000, more preferably 18,000 to 300,000, and even more preferably 20,000 to 200,000. The weight average molecular weight is calculated from the elution peak position detected by GPC and is the value of the molecular weight in terms of standard polystyrene conversion. When the weight average molecular weight is within this range, the balance between thermoplasticity and heat resistance is good, a bonded body can be efficiently obtained by melting, and its heat resistance is also high. When the weight average molecular weight is 10,000 or more, the heat resistance is excellent, and when it is 500,000 or less, the viscosity during melting is low and the bondability is high.

[0028] If necessary, the thermoplastic film may contain, as components other than the resin component, fillers, additives, etc.

[0029] Examples of the filler include inorganic fillers and organic fillers (such as resin powders). Examples of the inorganic filler include spherical fused silica, metal powders of metals such as iron, silica sand, talc, calcium carbonate, mica, acid clay, diatomaceous earth, kaolin, quartz, titanium oxide, silica, phenolic resin microballoons, glass balloons, etc.

[0030] When the thermoplastic film contains a filler, the content of the filler in 100% by volume of the total amount of the thermoplastic film is preferably 50% by volume or less, more preferably 30% by volume or less, still more preferably 20% by volume or less, and particularly preferably 10% by volume or less. The volume of the filler can be obtained by dividing the weight of the filler contained in the thermoplastic film by the apparent specific gravity of the filler.

[0031] Examples of the additive include an antifoaming agent, a coupling agent such as a silane coupling agent, a pigment, an adhesion-imparting resin, etc. These may be contained alone or in combination of two or more.

[0032] From the viewpoint of obtaining a joined body that is firmly joined in a short joining process time, the thickness of the thermoplastic film is preferably 3 mm or less, more preferably 1 mm or less, still more preferably 0.5 mm or less, even more preferably 0.3 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.1 mm or less. Also, from the viewpoint of further enhancing the adhesion, the thickness of the thermoplastic film is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, and particularly preferably 40 μm or more.

[0033] The thermoplastic film may be a single layer or a laminate of two or more layers. From the viewpoints of ease of manufacture and improvement of the joining strength, the thermoplastic film is preferably a single layer.

[0034] (Holding member) The holding member is a mating member that holds the electromagnetic wave transmitting substrate with the thermoplastic film. The holding member may be a different material from the electromagnetic wave transmitting substrate. Examples of the material of the holding member include resin, metal, inorganic substance, and composite materials thereof. The material of the holding member may be contained alone or in combination of two or more.

[0035] As the resin used for the holding member, either a thermoplastic resin or a thermosetting resin may be used. When using a thermoplastic resin, the melting point of the thermoplastic resin is preferably 10°C or higher, more preferably 30°C or higher, and even more preferably 50°C or higher than the melting point of the thermoplastic film. From the viewpoint of enhancing the strength of the holding member, the resin may be a cured product of a thermosetting resin such as a glass fiber-reinforced thermosetting resin, an epoxy resin product, a vinyl ester resin, an unsaturated polyester, a high heat-resistant engineering plastic such as a polyimide resin, a polyetherimide, or a polyethersulfone.

[0036] The metal used for the holding member is not particularly limited, and examples include aluminum, iron, copper, magnesium, titanium, and the like. In the present disclosure, the term "iron" is used to mean iron and its alloys. Examples of iron alloys include steel, stainless steel, and the like. Similarly, copper, aluminum, magnesium, and titanium are also used to mean these single substances and their alloys.

[0037] The inorganic substance used for the holding member is not particularly limited, and examples include glass, ceramics, carbon molded bodies, and the like. The glass is not particularly limited, and glasses of various compositions can be used. In addition to general glass, heat-resistant glass, fireproof glass, refractory glass, chemically strengthened glass used for protecting smartphones, and the like may also be used. Specifically, soda-lime glass, lead glass, borosilicate glass, quartz glass, and the like can be mentioned. Examples of the ceramics include fine ceramics used for semiconductors, automobiles, industrial equipment, and the like. Specifically, oxide-based ceramics such as alumina, zirconia, and barium titanate; hydroxide-based ceramics such as hydroxyapatite; carbide-based ceramics such as silicon carbide; nitride-based ceramics such as silicon nitride, and the like can be mentioned.

[0038] The shape of the holding member is not particularly limited. The length, width, and thickness are also not particularly limited. The holding member may have other parts provided in addition to the part that holds the electromagnetic wave transmitting substrate, as long as it does not interfere with the laser irradiation. The bonding surface for bonding the electromagnetic wave transmitting substrate of the holding member is preferably a flat surface. The cross-sectional shape of the part that holds the electromagnetic wave transmitting substrate is not particularly limited.

[0039] The holding member may be pretreated on its surface for the purpose of removing surface contaminants and / or achieving an anchor effect. Examples of the pretreatment include degreasing treatment, UV ozone treatment, blasting treatment, polishing treatment, plasma treatment, corona discharge treatment, laser treatment, etching treatment, frame treatment, etc. As the pretreatment, a pretreatment for cleaning the surface of the holding member or a pretreatment for creating unevenness on the surface is preferable. Specifically, when the holding member is made of aluminum, copper, glass, ceramic, or iron, at least one selected from the group consisting of degreasing treatment, UV ozone treatment, blasting treatment, polishing treatment, plasma treatment, and etching treatment is preferable as the pretreatment. When the holding member is made of FRP, polypropylene, polycarbonate, polymethyl methacrylate, polyetherimide, polyamide, or polybutylene terephthalate, at least one selected from the group consisting of degreasing treatment, UV ozone treatment, blasting treatment, polishing treatment, plasma treatment, and corona discharge treatment is preferable as the pretreatment. The pretreatment may be performed as a single treatment or as two or more treatments. As specific methods of these pretreatments, known methods can be used.

[0040] The degreasing treatment is a method of dissolving and removing dirt such as oil and grease on the surface of the holding member with an organic solvent such as acetone or toluene.

[0041] UV ozone treatment is a method of cleaning or modifying the surface using the energy of short-wavelength ultraviolet rays emitted from a low-pressure mercury lamp and the power of ozone generated thereby. In the case of glass, it is one of the surface cleaning methods for removing organic impurities on the surface. Generally, a cleaning and surface modification apparatus using a low-pressure mercury lamp is called a "UV ozone cleaner", a "UV cleaning apparatus", an "ultraviolet surface modification apparatus", etc.

[0042] Examples of blast treatment include wet blast treatment, shot blast treatment, sand blast treatment, etc. Among them, wet blast treatment is preferable because a denser surface can be obtained compared to dry blast treatment.

[0043] Examples of polishing treatment include buff polishing using a polishing cloth, roll polishing using abrasive paper (sandpaper), electrolytic polishing, etc.

[0044] Plasma treatment is a method of creating a plasma beam with a high-voltage power supply and a rod, applying it to the material surface to excite molecules to a functional state, and examples thereof include an atmospheric pressure plasma treatment method capable of imparting polar groups such as hydroxyl groups to the material surface.

[0045] Examples of corona discharge treatment include a method applied to the surface modification of a polymer film, which is a method of generating polar groups such as hydroxyl groups on the surface starting from radicals generated by cutting the main chain or side chain of the polymer in the polymer surface layer by electrons emitted from an electrode.

[0046] Laser treatment is a technique for rapidly heating and cooling the surface of a holding member by laser irradiation to improve the surface characteristics, and is an effective method for roughening the surface. Known laser treatment techniques can be used.

[0047] Examples of etching treatment include chemical etching treatments such as an alkali method, a phosphoric acid-sulfuric acid method, a fluoride method, a chromic acid-sulfuric acid method, a ferric chloride method, etc., and electrochemical etching treatments such as an electrolytic etching method.

[0048] Frame treatment is a method of making oxygen in the air into plasma by burning a mixed gas of combustion gas and air, and achieving surface hydrophilicity by applying the oxygen plasma to the object to be treated. Known frame treatment techniques can be used.

[0049] (Absorbing member) The absorbing member has a laser absorption rate of 90% or more, preferably 95% or more, and more preferably 99% or more.

[0050] The absorbing member may be composed of a resin containing a black pigment or a black dye, or may be composed of a metal or a ceramic having absorbability to a laser.

[0051] The resin to be contained in the absorbing member is not particularly limited and may be either thermoplastic or thermosetting. When using a thermoplastic resin, from the viewpoint of suppressing the protrusion of the absorbing member, the melting point of the thermoplastic resin is preferably 30°C or higher, more preferably 50°C or higher, and further preferably 100°C or higher than the melting point of the thermoplastic film. Examples of the metal include aluminum, iron, copper, magnesium, titanium, etc. Examples of the ceramics include oxide-based ceramics such as alumina, zirconia, and barium titanate; hydroxide-based ceramics such as hydroxyapatite; carbide-based ceramics such as silicon carbide; nitride-based ceramics such as silicon nitride, etc.

[0052] From the viewpoint of the appearance such as thinning of the joint part, the thinner the thickness of the absorbing member, the better, and it may be 3 mm or less, or may be 1 mm or less.

[0053] (Other members) From the viewpoint of enhancing the adhesiveness between the electromagnetic wave transmitting substrate and the thermoplastic film, an adhesive layer may be provided between the electromagnetic wave transmitting substrate and the thermoplastic film. Also, from the viewpoint of enhancing the adhesiveness between the thermoplastic film and the holding member, an adhesive layer may be provided between the holding member and the thermoplastic film. From the perspective of suppressing the protrusion of the adhesive layer, it is preferable to use an adhesive sheet. The adhesive layer may be composed of a thermoplastic resin. Examples of the thermoplastic resin contained in the insulating adhesive layer include polyamide-imide, polyester-based, olefin-based, etc. From the viewpoints of high heat resistance, high insulation, solvent resistance, etc., polyamide-imide is preferable. The adhesive layer may be composed of a curable resin. Examples of the curable resin contained in the adhesive layer include epoxy, silicone, etc. From the viewpoint of heat resistance, etc., epoxy is preferable. The thickness of the adhesive layer is preferably 3 mm or less, more preferably 1 mm or less, further preferably 0.5 mm or less, still further preferably 0.3 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.1 mm or less. Also, from the viewpoint of further enhancing the adhesion, the thickness of the adhesive layer is preferably 10 μm or more, more preferably 20 μm or more, still further preferably 30 μm or more, and particularly preferably 40 μm or more.

[0054] 〔Laser Irradiation〕 The laminate laminated in the order of the electromagnetic wave-transmitting substrate / thermoplastic film / holding member is irradiated with a laser from the outside of the electromagnetic wave-transmitting substrate (that is, the side opposite to the side where the thermoplastic film is disposed in the electromagnetic wave-transmitting substrate). The laser transmitted through the electromagnetic wave-transmitting substrate melts the thermoplastic film, and the electromagnetic wave-transmitting substrate and the holding member are joined by the thermoplastic film. The above-mentioned "laminate laminated in the order of the electromagnetic wave-transmitting substrate / thermoplastic film / holding member" also includes forms in which other members are disposed. For example, forms in which an absorption member is disposed between the electromagnetic wave-transmitting substrate and the thermoplastic film, forms in which an adhesive layer is disposed between the electromagnetic wave-transmitting substrate and the thermoplastic film, etc. are also included.

[0055] In the manufacturing method of the present disclosure, for example, when the electromagnetic wave transmitting substrate is glass and the holding member is resin, when the electromagnetic wave transmitting substrate is glass and the holding member is metal, when the electromagnetic wave transmitting substrate is resin and the holding member is metal, etc., even when they are different materials, they can be joined and the joining property is excellent.

[0056] The wavelength of the laser is not particularly limited as long as it can melt the thermoplastic film, and it may be 900 nm to 1200 nm. The irradiation time of the laser is sufficient as long as it can melt the thermoplastic film, and it can be appropriately adjusted according to the material, thickness, etc. of the thermoplastic film.

[0057] The melted thermoplastic film solidifies, and the electromagnetic wave transmitting substrate is fixed to the holding member. Examples of the method of solidifying include a method of allowing it to cool at room temperature or a method of allowing it to cool using a cooling device. Note that "room temperature" means a general room temperature within the range of 5 to 30°C. Among them, from the viewpoint of ease of manufacture, the method of allowing it to cool at room temperature is preferable. In the present disclosure, "solidification" means being solid at room temperature, that is, having no fluidity under a pressure-free state at 23°C.

[0058] The state of laser irradiation will be described with reference to FIG. 1. The thermoplastic film 20 and the electromagnetic wave transmitting substrate 10 are arranged in this order at the holding portion 30A of the electromagnetic wave transmitting substrate 10 in the holding member 30. Then, the thermoplastic film 20 is irradiated with a laser 40 through the electromagnetic wave transmitting substrate 10.

[0059] In FIG. 1, the holding member 30 has an extending portion 30B in addition to the holding portion 30A. Since the extending portion 30B extends along the end face 10a of the electromagnetic wave transmitting substrate 10, the extending portion 30B does not exist in the irradiation path of the laser 40, and it does not prevent the thermoplastic film 20 from being irradiated through the electromagnetic wave transmitting substrate 10. Note that the extending portion 30B is not limited to the shape in FIG. 1 as long as it does not prevent the thermoplastic film 20 from being irradiated through the electromagnetic wave transmitting substrate 10.

[0060] When heating and bonding the thermoplastic film 20 with a general heating device, if the distance d between the end face 10a of the electromagnetic wave transmissive substrate 10 and the extending portion 30B is small, the extending portion 30B is likely to be heated together with the thermoplastic film 20, and the extending portion 30B is likely to be damaged. In particular, when the extending portion 30B contains a thermoplastic resin as a main component and the melting point of the thermoplastic resin is close to the melting point of the thermoplastic film (for example, the difference in melting points is within 10 °C), the extending portion 30B is likely to be deformed by the heating of the thermoplastic film.

[0061] Even if the holding member 30 has a shape without the extending portion 30B, when heating the thermoplastic film with a general heating device, the holding member 30 is likely to be damaged. This is due to the general heating device heating the periphery of the thermoplastic film as well.

[0062] In contrast, in the manufacturing method of the present disclosure, since the thermoplastic film is heated by a laser, local heating is possible, and damage to the holding member 30 can be suppressed. Also, even if the distance d between the end face 10a of the electromagnetic wave transmissive substrate 10 and the extending portion 30B is small, for example, 5 mm or less, or 3 mm or less, since the laser has straightness, the extending portion 30B is not heated, and damage to the extending portion 30B can be suppressed. The distance d may be zero, and the end face 10a of the electromagnetic wave transmissive substrate 10 and the extending portion 30B may be in contact.

[0063] Also, when the electromagnetic wave transmissive substrate 10 is glass, since it is difficult for the surface temperature of the glass to rise, it is difficult for the thermoplastic film 20 to fuse to the glass. Therefore, when heating and bonding the thermoplastic film 20 with a general heating device, the glass is heated as a whole to enhance the fusibility between the glass and the thermoplastic film 20. In this case, the equipment is likely to become complicated, such as by arranging the heating device for the glass near the bonding surface of the holding member 30, and the work is also likely to become cumbersome. In particular, when the length L extending from the bonding surface of the extending portion 30B becomes long, the flow line for avoiding the heating device for the glass to another place for laser irradiation is likely to become complicated. However, according to the manufacturing method of the present disclosure, by irradiating a laser from the outside of the electromagnetic wave transmitting substrate, the irradiated portion is heated together with the thermoplastic film and the electromagnetic wave transmitting substrate 10 (including glass), so that it is not necessary to heat the electromagnetic wave transmitting substrate 10 separately.

[0064] FIG. 2 illustrates the state of laser irradiation when the absorption member 50 is used. Since the laser 40 has a rectilinear property, the thermoplastic film 20 is likely to melt at the irradiation point of the laser. However, when the absorption member 50 is disposed between the electromagnetic wave transmitting substrate 10 and the thermoplastic film 20 and then the laser 40 is irradiated, the entire absorption member 50 irradiated with the laser 40 generates heat, and the thermoplastic film 20 is heated on the surface in contact with the absorption member 50. Therefore, due to the arrangement of the absorption member 50, the heating of the thermoplastic film 20 spreads from a point to a surface, and the bonding becomes stronger. Except for using the absorption member 50, it is the same as the case of FIG. 1.

[0065] In addition, when the holding member 30 is made of a material that easily absorbs a laser such as metal or ceramics, the holding member 30 generates heat, and the thermoplastic film 20 is heated on the surface in contact with the holding member 30. Therefore, when the holding member 30 is made of a material that easily absorbs a laser such as metal or ceramics, it is not necessary to provide the absorption member 50, but the absorption member 50 may be provided.

[0066] <Bonded body> The bonded body of the present disclosure is a bonded body manufactured by the manufacturing method of the present disclosure. In the manufacturing method of the present disclosure, compared with the method of heating and bonding a thermoplastic film using a general heating device, there are fewer restrictions on the shape, material, etc. of the holding member.

[0067] Specifically, according to the present disclosure, the electromagnetic wave transmitting substrate and the holding member are dissimilar materials, and the electromagnetic wave transmitting substrate, the thermoplastic resin layer, and the holding member are provided in this order, and the holding member contains a thermoplastic resin as a main component, and a difference between the melting point of the thermoplastic resin layer and the melting point of the holding member is within 10 ° C, and a bonded body can also be obtained. An absorption member having an absorption rate of 90% or more for a laser at at least some wavelengths in the range of 900 nm to 1200 nm may be disposed between the electromagnetic wave transmitting substrate and the thermoplastic film.

[0068] Further, according to the present disclosure, the electromagnetic wave transmitting substrate and the holding member are made of different materials, and the electromagnetic wave transmitting substrate, the thermoplastic resin layer, and the holding member are provided in this order. The holding member contains a thermoplastic resin as a main component, and the holding member has an extending portion extending along an end surface of the electromagnetic wave transmitting substrate, and a bonded body in which a distance between the extending portion and the end surface is within 5 mm can also be obtained. Also in this case, an absorption member having an absorption rate of 90% or more for a laser at at least some wavelengths in the range of 900 nm to 1200 nm may be disposed between the electromagnetic wave transmitting substrate and the thermoplastic film.

[0069] Note that the shape, material, etc. of the holding member are not limited to the above, and are as described in the manufacturing method of the bonded body. The bonded body manufactured by the manufacturing method of the present disclosure has suppressed protrusion at the bonded portion and is excellent in appearance.

[0070] <Device unit> The device unit of the present disclosure includes the bonded body of the present disclosure and a device that transmits and receives electromagnetic waves, which is disposed inside the holding member in the bonded body. The inside of the holding member refers to the inside of the housing formed by the holding member, the space formed by the holding member and other members, and the like. Examples of the electromagnetic wave include those described above. A device that transmits and receives such electromagnetic waves is disposed inside the holding member, and the electromagnetic wave transmitting substrate in the bonded body transmits the electromagnetic wave. As a result, the device disposed inside the holding member can transmit and receive electromagnetic waves through the electromagnetic wave transmitting substrate. Further, since the device unit of the present disclosure uses the bonded body of the present disclosure, the bonded portion is surely bonded, and intrusion of water or the like from the bonded portion is suppressed. Examples of devices that transmit and receive electromagnetic waves may include, but are not limited to, a lidar (light detection and ranging or laser imaging detection and ranging), a GPS (global positioning system) sensor, etc.

Description of Symbols

[0071] 10 Electromagnetic wave transmissive substrate 20 Thermoplastic film 30 Holding member 40 Laser 50 Absorbing member

Claims

1. The electromagnetic wave transmitting substrate and the holding member are made of different materials. The electromagnetic wave transmitting substrate, the thermoplastic film, and the holding member are stacked in this order, and a laser is irradiated from the side opposite to the side where the thermoplastic film of the electromagnetic wave transmitting substrate is disposed to melt the thermoplastic film, and the electromagnetic wave transmitting substrate and the holding member are joined by the thermoplastic film. A method for manufacturing a joined body.

2. An absorption member having a laser absorption rate of 90% or more is disposed between the electromagnetic wave transmitting substrate and the thermoplastic film, and the laser is irradiated from the opposite side. The method for manufacturing a joined body according to claim 1.

3. The method for manufacturing a joined body according to claim 1 or claim 2, wherein the laser has at least a part of wavelengths in the range of 900 nm to 1200 nm.

4. The method for manufacturing a joined body according to claim 1 or claim 2, wherein the transmittance of the laser in the electromagnetic wave transmitting substrate is 30% or more.

5. The electromagnetic wave transmitting substrate and the holding member are made of different materials. The electromagnetic wave transmitting substrate, the thermoplastic resin layer, and the holding member are provided in this order, the holding member contains a thermoplastic resin as a main component, and a difference between the melting point of the thermoplastic resin layer and the melting point of the holding member is within 10°C. A joined body.

6. An absorption member having a laser absorption rate of 90% or more for at least a part of wavelengths in the range of 900 nm to 1200 nm is disposed between the electromagnetic wave transmitting substrate and the thermoplastic resin layer. The joined body according to claim 5.

7. The electromagnetic wave transmitting substrate and the holding member are made of different materials. The electromagnetic wave transmitting substrate, the thermoplastic resin layer, and the holding member are provided in this order, the holding member contains a thermoplastic resin as a main component, the holding member has an extending portion extending along an end face of the electromagnetic wave transmitting substrate, and a distance between the extending portion and the end face is within 5 mm. A joined body.

8. An absorption member having a laser absorption rate of 90% or more for at least a part of wavelengths in the range of 900 nm to 1200 nm is disposed between the electromagnetic wave transmitting substrate and the thermoplastic resin layer. The joined body according to claim 7.

9. The joined body according to claim 5 or claim 7, and a device for transmitting and receiving electromagnetic waves, which is disposed inside the holding member. A device unit.

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