JP2013216028A - Laser bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable laser bonding method for bonding a resin and a metal, configured to prevent thermal decomposition of resin without influence of light absorptivity of metal.SOLUTION: A laser bonding method is used for a pressing material made of metal or ceramics. Resin and metal is pressed from the metal side with the pressing material. The pressing material is laser-irradiated. Heat of the laser beam is thermally transferred via the metal from the pressing material to the resin for join them. High-strength, bubble-less, and highly reliable laser bonding can be achieved between the resin and the metal in a short tact.

Description

  The present invention relates to a technique for bonding a resin and a metal by laser light irradiation.

  Thermoplastic resins are widely used in general industrial applications such as automobiles, electrical equipment, medical / bio equipment, and the like because of their excellent processability and large degree of freedom in shape. And it has become so popular that it can be said that there is no field where thermoplastic resins are not used. At first, it was used as an alternative to natural materials such as wood and paper, but now many special products that can only be made with plastic materials have been developed. Therefore, if the optimal materials and optimal processing methods can be provided for design and development, there is a possibility of creating new products that have never existed before.

In addition, due to the recent trend of CO ₂ emission restrictions and cost reduction, the replacement of metals is gradually being made along with the higher functionality of thermoplastic resins. In addition, thermosetting resins containing carbon fibers are becoming widespread for metal replacement. However, thermoplastic and thermosetting resins generally have lower heat resistance and mechanical strength than metals, have large thermal expansion, are easily deformed and decomposed, are easily dissolved in organic solvents, and are poorly swelled by moisture. Because there are many points, it is impossible to completely replace them.

  In particular, due to the complexity of product structures in recent years, designs that take advantage of the advantages of thermoplasticity and thermosetting resins and metals have been made, and their secondary processing techniques have become important. Among them, due to the widespread use of semiconductor lasers, methods using laser light have been increasingly studied.

  Patent Document 1 describes that acrylic resin bites into an uneven surface by laser irradiation in a state in which tin having an uneven surface roughened with an acrylic resin and sandpaper is adhered, and a strong bond is formed. Has been.

  In Patent Document 2, by irradiating a high-power laser beam in a state where plastic and metal are superposed, micro bubbles are generated in the vicinity of the plastic interface, and strong bonding is achieved by the pressure effect at the time of generation. It has been shown that you can.

  Patent Document 3 shows that, in welding between resins, by applying pressure with an infrared transmitting solid (infrared crystal material) having a thermal conductivity of 15 W / mK or more, surface thermal damage is suppressed and welding is performed. Yes.

  In Patent Document 4, it is possible to firmly bond even if the molded body does not transmit laser light by irradiating laser from the metal side in a state where the molded body made of a thermoplastic resin and the metal are overlapped. It is shown. It is also described that the surface treatment of the metal on the bonding surface side is effective for improving the bonding strength.

JP 2006-15405 A WO2007 / 029440 JP 2009-101560 A JP 2010-76437 A

  The technique disclosed in Patent Document 1 is a particularly effective method when a transparent thermoplastic resin having a transmittance of 70% or more with respect to incident laser light is used. The case is not applicable.

  In the technique disclosed in Patent Document 2, the thermoplastic resin reaches the thermal decomposition temperature due to the heat transfer of the air existing in the gap in the process until the resin and the metal adhere to each other at the time of laser irradiation, and a large amount of bubbles are formed. There was a problem that it would occur. Therefore, long-term reliability is a concern, and in particular, it has been found that it is difficult to ensure airtightness.

  In the technique disclosed in Patent Document 3, when light is irradiated from the thermoplastic resin side, deterioration of the resin on the laser irradiation surface can be suppressed, but when laser light is irradiated from the metal side, heat escapes. As a result, it has been found that the laser power required for bonding increases.

  In the technique disclosed in Patent Document 4, it is shown that laser irradiation is performed from the metal side to join the thermoplastic resin and the metal, but the method for pressurizing the metal is not described.

  As described above, in the technique of joining the resin and the metal using the laser light of Patent Documents 1-4 as a heating source, details on the problem when the laser light is irradiated from the metal side are not described, but the present invention The present inventors have found that there is a significant problem in terms of reliability because thermal decomposition of the resin tends to occur depending on the pressing method and material. In addition, when irradiating laser light from the metal side, it is necessary to carry out irradiation that absorbs light on the laser irradiation surface according to the material of the metal. Was greatly limited.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. In the present invention, a plurality of means for solving the above problems are included. For example, a pressurizing material composed of metal or ceramics is used, and resin and metal are added from the metal side by a pressurizing material. In addition, the pressure material is irradiated with a laser, and heat is transmitted from the pressure material to the resin through the metal to be bonded.

  According to the present invention, it is possible to perform laser bonding between a resin and a metal, which is highly independent of light absorption rate on the metal surface, and has a short tact, high strength, and no bubbles, and high reliability. In addition, it is not necessary to perform special treatment on the metal surface, and the laser power can be reduced, which contributes to cost reduction.

It is a figure which shows one Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a figure which shows the other Example of the laser joining method of resin and metal of this invention. It is a schematic diagram which shows an example when the laser joining method of the metal of this invention and resin is applied to a product.

  Embodiments of the present invention will be described below. The thermoplastic resin used in the present invention is made of an amorphous or crystalline resin. Non-crystalline resins include polystyrene (PS), acrylonitrile styrene (AS), acrylonitrile butadiene styrene copolymer (ABS), polyetherimide (PEI), polycarbonate (PC), polyarylate (PAR), and polymethylmethacrylic. Examples include methyl acid (PMMA), cycloolefin polymer (COP), cycloolefin copolymer (COC), polysulfone (PSF), polyethersulfone (PES), polyvinyl chloride (PVC), and polyvinylidene chloride (PVDC). As crystalline resins, polyethylene (PE), polypropylene (PP), polyoxymethylene (POM), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) ), Polyphenylene sulfide (PPS), nylon 6 (PA6), nylon 66 (PA66), nylon 6T (PA6T), polyetheretherketone (PEEK), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE). . In addition, those alloy materials, inorganic materials such as glass fibers, and thermoplastic resins containing special additives are also targeted. In general, an amorphous resin is excellent in moldability and transparency, whereas a crystalline resin is excellent in heat resistance and chemical resistance. Moreover, not only a thermoplastic resin but also an epoxy-based thermosetting resin may be used. In particular, in the case of the present invention, since the light absorption of the pressurizing material with respect to the laser beam affects the bonding property, the colored state of the thermoplastic resin or the thermosetting resin may be any state.

  Examples of metals to be joined include iron, aluminum, copper, nickel, gold, titanium, alloys (stainless steel, brass, aluminum alloys, phosphor bronze, etc.), die casting, etc., and metal coatings (plating, vapor deposition films, etc.). This also applies to other materials. Further, not only metal but also ceramics can be joined.

  The pressurizing materials used to press the metal materials to be joined include materials such as iron, aluminum, copper, nickel, gold, titanium, alloys (stainless steel, brass, aluminum alloys, phosphor bronze, etc.), die castings, and various ceramics. The surface absorptance must be 70% or more with respect to the incident laser wavelength.

  Lasers having wavelengths in the infrared region, including semiconductor lasers, YAG lasers, and fiber lasers, are effective in terms of cost as the light source used for laser bonding. It may be a wavelength. Further, the intensity distribution of the laser light source can be changed to various intensity distributions depending on attached lenses such as Gaussian, top hat and ring type.

  Laser bonding conditions determine the laser spot size, power, irradiation time, and applied pressure in consideration of the optical absorption rate, thermal conductivity, heat resistance, and rigidity of the pressurized material at the laser irradiation wavelength of the pressurized material. .

  FIG. 1 is a plan view showing an embodiment of the resin and metal laser bonding method of the present invention. In the present embodiment, the upper surface portion of the metal 2 to be joined is pressed with the pressurizing material 10 in a state where the resin 1 and the metal 2 are overlapped, and the pressurizing material 10 has a light absorption rate higher than that of the metal 2 to be joined. A metal or ceramic having a high light absorption rate is used, and the pressure material 10 is irradiated with the laser beam 4 to bond the resin 1 and the metal 2. Normally, when the laser beam 4 is irradiated from the metal 2, for a metal material having a small light absorption rate, such as aluminum or copper for infrared light, the light absorption rate is increased on the laser irradiation surface of the metal material to be joined. Processing has to be performed, and the increase in cost has been an issue. In addition, depending on the product form, such treatment may not be performed or bondability may be deteriorated, and as a result, bonding may not be possible. Further, since laser irradiation is performed from the metal 2 side, in order to avoid deterioration of the laser light source due to reflection of the metal 2, for example, the laser light 4 is irradiated at an angle of 10 to 15 ° with respect to the metal 2 to which the laser light source is bonded. There was a need. However, when tilted by 10 to 15 °, there has also been a problem that the laser junction is less likely to be uniform than when tilted.

  In contrast, as shown in FIG. 1, the present inventors use a metal or ceramic having a high light absorption rate as the pressure material 10 and irradiate the laser beam 4 without tilting the pressure material 10. Thus, it was found that heat conduction was caused in the metal 2 to be joined via the pressurizing material 10 and the resin 1 and the metal 2 could be joined with high strength and uniformity. For example, when aluminum or copper is to be bonded, it has been found that by using SUS304 having a high absorption rate of laser light in the infrared region, it is possible to bond aluminum or copper without any special treatment. In addition, depending on the product, since the laser beam 4 cannot be irradiated at an angle, there is an advantage that the application range is widened. In particular, from the viewpoint of quality, it is desirable that the irradiation angle of the laser beam 4 be 1 ° or less.

  Conventionally, in laser joining of the resin 1 and the metal 2, when laser irradiation is performed from the metal 2 side, a place other than the portion irradiated with the laser 4 is pressurized. In the case of the conventional configuration, since the laser irradiated portion is not pressurized, the metal 2 in the portion irradiated with the laser 4 expands and deforms and is bonded to the resin 1 to be bonded. However, in the process until the contact, the gap became larger, and due to the heat transfer of the air, the resin 1 reached the thermal decomposition temperature and a large amount of bubbles was generated. It has been found that this phenomenon appears particularly when the gap between the resin 1 and the metal 2 is as large as 50 μm or more, or when the thickness of the metal 2 is as thin as 0.5 mm or less. Further, similarly to the usual laser welding of thermoplastic resins, it is possible to hold the metal 2 with a material having a high transmittance such as glass, but in that case, the heat escapes by the glass and the laser irradiation. There was a problem that the glass part that was in close contact with the part was broken. In the present embodiment shown in FIG. 1, since the resin 1 and the metal 2 are brought into close contact with each other by the effects of the pressure by the pressure member 10 and the thermal expansion of the metal 2, the influence of the gap can be reduced, and the bubbles of the resin 1 can be reduced. Can be suppressed. Furthermore, since it can join in the state which does not reach the thermal decomposition temperature of the resin 1, the improvement of interface strength and the strength reduction of the resin 1 itself can also be suppressed, and the strength of the joined body can be improved. There is also an advantage that the required laser power can be reduced. In addition, when the thickness of the pressurizing material 10 is small, warping may occur depending on the heat at the time of laser irradiation. Therefore, it is desirable that the thickness of the pressure material 10 is equal to or greater than the thickness of the metal material 2 to be joined. In particular, the pressure member 10 is preferably 1.0 mm or more, and the pressure applied to the joint is preferably 0.4 MPa or more. In addition, it is desirable that the pressurizing material 10 be made larger than the metal 2 to which not only the thickness but also the rigidity, heat resistance, and melting point are bonded.

  The pressurizing material 10 may not be a flat plate in particular, and when there is a step in the metal material 2 to be joined, it can be dealt with by using the pressurizing material 10 having a shape as shown in FIG.

  In these structures, an adhesive may be added between the metal 2 to be bonded to the resin 1 and laser bonding may be performed. In particular, when an adhesive is present, it is possible to conduct heat in the adhesive portion, so that the influence of the gap can be reduced. However, it is desirable that the adhesive inserted between them has a thermal conductivity of 0.25 W / mK or less.

  FIG. 3 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. This embodiment is characterized in that fine irregularities 11 are formed on the laser irradiation surface of the pressure member 10 to improve the laser absorption rate. The surface of the laser irradiation surface has a larger surface roughness than the opposite surface of the pressure member 10 (the surface facing the metal 2 side) and the surface of the metal 2 on the pressure member side. This technique can reduce the required laser power and enables highly efficient laser bonding. The fine irregularities 11 are more preferably subjected to sandblasting, laser processing, or the like. The fine irregularities 11 are preferably about Rz 4 to 10 μm in terms of roughness. Moreover, when the material of the metal 2 is aluminum, in addition to the sandblasting process, an electrolytic process for forming nanoporous holes may be performed. The process for forming the fine irregularities 11 is an effective means for the metal 2 at the interface of the joint. However, the roughness for improving the bondability depends on the viscosity of the resin 1 at a high temperature, but in general, the roughness of the metal 2 on the bonding surface is greater than the roughness of the surface of the pressure member 10. good. On the other hand, it is desirable to reduce the roughness of the contact surface of the metal 2 to be bonded to the metal pressure member 10 as much as possible.

FIG. 4 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. The present embodiment is characterized in that the light absorption rate is increased, for example, the blackened coating 12 is applied by subjecting the pressure member 10 to electrolytic treatment or the like in advance and appropriately controlling the metal oxide film. The pressurizing material 10 may be coated with a ceramic film 12. The coating 12 by the ceramic film is mainly composed of ceramic powder such as silica, alumina, zirconia, silicon carbide, etc., an inorganic binder, and solvent water. Further, TiO ₂ or the like may be electrodeposited as the coating 12. The coating 12 of the pressurizing material 10 may be provided on a surface to be in close contact with the metal 2, and heat conduction can be efficiently caused to the metal 2 by heat radiation.

  Such a coating 12 is determined depending on the material of the pressure member 10, but greatly affects the material and thickness of the metal 2 and the resin 1 to be joined. What has a larger light absorption rate than the material inside the pressurizing material 10 is good. Further, depending on the material system to be joined, it is also effective to apply a light-absorbing pigment or paint to the laser irradiation surface of the pressure member 10. Although not shown in the figure, the coating 12 for increasing the light absorption rate may be used in combination with the addition of fine irregularities 11 on the laser irradiation surface of the pressure member 10, or the coating 12 itself. Fine irregularities may be formed on the surface.

  FIG. 5 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. In this embodiment, in addition to the pressure member 10, a second pressure member 20 that is not irradiated with laser light is used. In the structure so far, in the laser bonding apparatus, only the pressurizing material 10 is used as the pressurizing mechanism. However, depending on the apparatus and the product configuration, the pressurizing material 10 having a high light absorption rate is used for laser absorption, In some cases, it is better to increase the pressure by giving the pressure member 20 rigidity. Therefore, it is better to set the rigidity of the second pressure member 20> the rigidity of the pressure member 10 and the light absorption rate of the pressure member 10> the light absorption rate of the second pressure member 20. The second pressure member 20 may be bonded to the pressure member 10 in the case of a resin having low heat resistance, but a metal or glass having high heat resistance that is not bonded to the pressure member 10 is used. It is desirable.

  FIG. 6 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. The present embodiment is characterized in that the shape of the contact surface with the metal 2 to which the pressurizing material 10 is bonded is a convex structure 13. With this structure, it is possible to suppress thermal diffusion of the pressure member 10. For this reason, it is a particularly effective means when it is desired to perform fine bonding. In addition, since it is possible to increase the pressure locally, the structure is effective when the length of the joint portion is large due to the structure of the product.

  FIG. 7 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. The present invention is characterized in that the thermal conductivity of the pressure member 10 is larger than the thermal conductivity of the metal 2 to be joined. For example, when the thermal conductivity of the pressure member 10 is increased by 10 times or more compared to the metal 2, heat diffusion occurs in a larger area than in the laser irradiation diameter, and bonding in a large area becomes possible. As shown in FIG. 7, heat is diffused in the surface direction (left and right direction in the drawing) in the pressurizing material 10 having a high thermal conductivity, but in the metal 2, heat is not diffused so much in the surface direction. Usually, when laser bonding is performed, the power density is important. The laser power density is proportional to the laser power and half proportional to the square of the spot radius. For this reason, if the spot radius is small, bonding can be performed with low laser power. In addition, when scanning with a laser, bonding speed is often not uniform when the speed is increased. However, by using this configuration, since the resin is melted or softened more uniformly by heat conduction, high-speed and uniform laser bonding is possible. In that case, a pulse is also an effective means for laser oscillation.

  FIG. 8 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. (A) is sectional drawing, (b) is a figure from a laser irradiation surface. After the thermal conductivity of the pressurizing material 10 is made 10 times or more larger than the thermal conductivity of the metal 2 to be joined, a projection 6 is provided on the joining surface side of the metal material 2 to be joined with the resin 1 to obtain a state. It is characterized by joining. By irradiating the laser with pulses at regular intervals, even if the laser irradiation position 4 is discrete, the bonding at the metal-resin interface is continuous by thermal diffusion, and can be bonded at higher speed and with finer bonding. Is also possible. Further, since the resin 1 is melted or softened, in the case of this structure, the protrusion 6 enters the molten resin 1 and the metal 2 is embedded in the resin. At this time, the resin 1 and the metal 2 can be bonded together including the periphery of the protrusion 6, and the bonding area is increased by the uneven shape of the protrusion 6. Therefore, at the same time, the joint strength can be greatly improved.

  FIG. 9 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. In a state where the metal 2 to be bonded to the resin 1 is pressed by the third pressure member 25, the laser beam 4 is irradiated to the pressure member 10, so that the resin 1 and the metal are caused by heat conduction in a direction different from the laser irradiation direction. 2 is joined. When the pressing direction is limited due to the structure of the product, the resin 1 and the metal 2 can be efficiently bonded by a laser by adopting this structure. However, when this configuration is applied, it is desirable that the thermal conductivity of the metal 2 to be joined is 100 W / mK or more. In the case of this configuration, the second pressure member 20 and the third pressure member 25 shown in the third embodiment may be the same.

  FIG. 10 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. In this embodiment, before laser bonding of the resin 1 and the metal 2, a surface modification treatment is performed on the bonding interface side of the resin 1 to form an oxide layer 7 in which oxygen functional groups are increased or generated, and then bonded. It is characterized by that. As the surface modification treatment, any of dry treatments such as UV ozone treatment, plasma treatment, corona treatment, and short pulse (pulse width is picosecond or less) laser treatment is used in consideration of environmental effects and influence on other parts. And good. By applying such treatment, the main chain and side chain of the resin are cleaved with CC and CH bonds, and oxygen functional groups such as CO, COO, and C = O are generated and increased, surface energy is increased, and bonding properties are increased. Is known to improve significantly. Such surface treatment on the resin is particularly effective for a resin that does not contain an oxygen functional group in the main chain. On the other hand, since the introduction of oxygen functional groups is accompanied by a decrease in the molecular weight of the surface, when the gap between the resin and the metal is large or when joining a resin that does not contain an oxygen functional group in the main chain, compared to the case without treatment There was a problem that it was easy to thermally decompose and a large amount of fine bubbles were generated. However, by adopting the method of the present invention, it is possible to further suppress thermal decomposition and at the same time greatly improve the bonding strength. Therefore, the reliability is also greatly improved. This method is a method in which the merit of introducing or increasing the oxygen functional group by the surface modification treatment to the resin 1 can be further utilized. Therefore, not only two layers of resin 1 and metal 2 but also high quality can be realized in the joining of a laminated structure of three or more layers such as metal-resin-resin and metal-resin-metal. The oxide film 7 containing resin oxygen is preferably at least about 5 nm.

  FIG. 11 is a plan view showing another embodiment of the resin and metal laser bonding method of the present invention. When the laser beam 4 is scanned and bonded, the laser irradiation length is made longer than the length in which the resin 1 and the metal 2 are in close contact with each other. In general, in laser irradiation, since the heat input energy is different between the laser irradiation start point and the end point compared to other scanned portions, there is a problem that the bonding property is not stable. In this configuration, the heat conduction of the pressurizing material 10 is used, and according to the heat conduction effect of the pressurizing material by making the laser irradiation length larger than the length in which the resin 1 and the metal 2 are in close contact with each other, The start point and the end point can also be joined uniformly.

  FIG. 12 is a schematic view showing an example when applied to a sensor 30 on which an electronic component 31 having a resin 1 and metal 2 casing is mounted using the resin and metal laser bonding method of the present invention. The resin 1 and the metal 2 that are the casings are joined and sealed using the pressure member 10 by any method of the embodiment. The applicable target part is effective not only for the housing part of the product on which the electronic component 31 is mounted, but also for all products that can be joined by laser, such as a biochip, an electronic control unit (ECU), a connector, and a power module. .

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. It is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Resin 2 ... Metal 3 ... Molten pool 4 ... Laser 5 ... Thermal conduction area | region 6 ... Metal protrusion 7 to join ... Oxide layer 10 formed in resin ..Pressure material 11... Fine irregularities 12 formed on the pressure material... Coating layer 13 formed on the pressure material and having a high light absorption rate... Projection 20 formed on the pressure material. ... Second pressure member 25 ... Third pressure member 30 ... Sensor 31 ... Electronic component 32 ... Wire 33 ... Joint material

Claims (16)

It is a method of joining the joint surface of resin and metal by laser irradiation,
Used for pressure materials composed of metal or ceramics,
The resin and the metal are pressed from the metal side by the pressurizing material, and the pressurizing material is irradiated with laser, and heat from the laser is conducted from the pressurizing material to the resin through the metal. A laser joining method characterized by joining. In claim 1,
A laser bonding method, wherein a laser irradiation surface of the pressurizing material irradiated with the laser has a higher laser light absorption rate than the metal to be bonded. In claim 2,
A laser bonding method, wherein a laser irradiation surface of the pressurizing material has a higher laser light absorption rate than the pressurizing material base material and the metal to be joined. In claim 3,
The laser irradiation method according to claim 1, wherein the laser irradiation surface of the pressurizing material has a surface roughness larger than that of the metal pressurizing material side surface and the metal side surface of the pressurizing material. In claim 3 or claim 4,
A laser bonding method, wherein a coating for increasing a light absorption rate is formed on a laser irradiation surface of the pressurizing material. In any one of Claims 1 thru | or 5,
The laser joining method according to claim 1, wherein the pressure member has a rigidity higher than that of the metal to be joined. In any one of Claims 1 thru | or 6.
The laser joining method, wherein the pressure material has a thickness greater than a thickness of the metal to be joined. In any one of Claims 1 thru | or 7,
A laser bonding method, wherein the pressure material has higher heat resistance or melting point than the metal to be bonded. In any one of Claims 1 thru | or 8.
The laser bonding method, wherein an angle of laser irradiation is 1 ° or less with respect to a laser irradiation surface of the pressurizing material. In any one of Claims 1 thru | or 9,
The pressurizing material is provided with a protrusion on the metal side of a region to be joined. In any one of Claims 1 thru | or 10.
The joining metal has a protrusion on the resin side of the joining region, and the thermal conductivity of the pressurizing material is larger than the thermal conductivity of the joining metal. Method. In any one of Claims 1 thru | or 11,
The thermal conductivity of the pressurizing material is greater than the thermal conductivity of the metal,
A laser bonding method comprising irradiating the pressurizing material while scanning the pulsed laser.   The pressurizing material according to any one of claims 1 to 12, wherein the pressurizing material includes a first pressurizing material irradiated with the laser and a second pressurizing material having higher rigidity than the first pressurizing material. A laser bonding method comprising: In any one of Claims 1 thru | or 13.
A laser bonding method comprising performing a surface modification treatment for generating and increasing oxygen functional groups on a surface of a resin before laser bonding on the surface to which the resin is bonded. In claim 14,
The laser bonding method, wherein the resin does not contain a polar group in the main chain. In any one of Claims 1 thru | or 15,
A laser joining method comprising forming a joined body of three or more layers comprising a resin and a metal.

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